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ESASTSUN OILFIELD EQUIPMENT MANUFACTURING (CAMBODIA) CO., LTD attended the Offshore Technology Conference 2003 (OTC) in Houston USA from May1-4 2023 successfully. Our products mainly include API 5CT coupling, pup joint, tubing and casing, nipples, crossover and slotted liner. Our products strictly comply with the API 5CT standard and obtained the API 5CT certificate in 2016. On this basis, our products are exported to more than ten countries, including the United States, Canada, Argentina, India, Oman, and the like, with an annual sales volume of 5 million US dollars.

ESASTSUN OILFIELD EQUIPMENT MANUFACTURING (CAMBODIA) CO., LTD will attend the Offshore Technology Conference 2003 (OTC) in Houston USA from May1-4. Sincerely welcome everyone's arrival and attendant. EASTSUN Group was established in 2003 and is one of the earliest enterprises engaged in OCTG production and trade in China. There are Wuxi Dongsen Trading Co., Ltd., Jiangsu Taishun Energy Technology Development Co., Ltd., and Isason Oilfield Equipment Manufacturing (Cambodia) Co., Ltd. Our products mainly include API 5CT tubing and casing couplings, nipples, cross drill pipes, and slotted liners. Our products strictly comply with the API 5CT standard and obtained the API 5CT certificate in 2012. At the same time, our company has also passed the audit of the ISO9000 quality management system. It has also established a factory in Cambodia to explore and promote a larger global market. On this basis, our products are exported to more than ten countries, including the United States, Canada, Argentina, India, Oman, and the like, with an annual sales volume of 20 million US dollars.

The technical service of oil casing overhaul is one of the most important links in the technical service of oil and gas field engineering inspection. How much do you know about this technology? Learn from Xiaobian together! What is oil casing maintenance technology Oil and casing maintenance technical services mainly follow API and special thread standards, and carry out the whole process maintenance services of new and old oil and casing and sucker rod, such as cleaning, non-destructive testing, thread repair processing, thread blasting, pipe end reducing, hydrostatic test, spray painting, label spraying, etc. Repair the old, recycle the old, help customers to maximize the cost of production. Industry standard for inspection and repair of petroleum casing API Specification 5CT(10th edition) API Specification 5B (16) API Specification Q1(Phase 9) API Specification Q2(Phase 2) Q/SY TZ 0267-2015 API Tubing repair Q/SY TZ 0439-2015 Technical requirements for oil field gathering and transportation pipeline maintenance Q/SY TZ 0474-2016 "13Cr Special Threaded Joint Tubing Repair Technical Regulations" Standard test methods and definitions for mechanical properties of steel products Ultrasonic test methods for metallic tubes Test method for magnetic flux leakage of ferromagnetic steel tube products ASTM E709-21 Standard Guide for Testing Magnetic Particles SY/T 5991-2016 Thread protectors for casing, tubing and conveying steel pipes Petroleum and natural gas industry -- Steel tubes for casing of oil and gas Wells Oil casing maintenance Tips API ordinary thread and special (sealed) thread difference: ·API thread is sealed with triangular thread surface, without forming sealing surface and shoulder surface, low production and maintenance cost, fast coupling loading and unloading speed, and average sealing performance. It is often used in oil well production operations and well conditions without air tightness requirements. · Special (sealed) threads have their own shoulder surface and sealing surface. Threads are used only for storing thread grease and connections. The sealing surface on the pipe external thread and the coupling internal thread joint is squeezed and slightly deformed to seal. Good sealing performance, reliable connection, but high production and maintenance costs. It is often used in the production of gas Wells, oil and gas mixtures and Wells requiring gas tightness.

ESASTSUN OILFIELD EQUIPMENT MANUFACTURING (CAMBODIA) CO., LTD got the API-5CT certificate in 2016, we are the first factory to get the API-5CT certificate in Cambodia. We have always carried out the enterprise spirit of people-oriented, honesty and pride, realistic innovation, unity and dedication, mutual benefit and win-win. While creating material value, the company promotes the basic principles and common values of human society and pursues continuous improvement for a long time. Adhere to the guiding ideology of "REPUTATION FIRST, USER FIRST", serve customers, abide by the contract, and whole heartedly provide high-quality products and services for customers!

The casing head is an important connector between casing and wellhead equipment. The casing head is an important connector between casing and wellhead equipment. Its lower end is connected with surface casing through thread, and its upper end is connected with wellhead equipment or BOP through flange or clamp. Characteristics of casing head Casing connection can be either threaded connection or slip connection. Hanging casing is fast and convenient; The casing hanger adopts a rigid and rubber composite sealing structure, and metal sealing can also be used to enhance the sealing performance of the product; The anti wear sleeve and pressure test extraction tool are designed to facilitate the removal of the anti wear sleeve and the pressure test of the casing head; The upper flange is designed with pressure test and secondary grease injection device; The casing head side valve configuration is designed according to user requirements; Role of casing head The casing head is installed at the upper end of the surface casing string, and is used to suspend the casing of each layer outside the surface casing and the wellhead equipment components in the annular space of the sealing casing. Its main functions are as follows 1. Suspend part or all weight of each layer of casing except surface casing through hanger; 2. Connect BOP and other wellhead devices; 3. Forming a pressure seal between the inner and outer casing strings; 4. Provide outlet for releasing pressure that may accumulate between two casing strings; 5. In case of emergency, fluid can be pumped into the well from the side hole of casing head, such as killing fluid or fire extinguishing agent; 6. Special operations: a. If the cementing quality is poor, multiple side holes can be re injected with cement; b. During acid fracturing, pressure balance fluid can be injected from the side holes. Classification of casing head 1. According to the number of layers of suspended casing According to the number of hanging casing layers, it can be divided into single-stage casing head, two-stage casing head and three-stage casing head; Single stage casing head is generally used in production wells in low pressure shallow formation; The two-stage casing head is applicable to most areas with clear formation pressure, and is widely used; The third stage casing head is generally used in high-pressure deep wells or exploration wells 2. According to the structure type of casing hanger According to the structure type of casing hanger, it can be divided into slip type casing head, mandrel type (threaded) casing head and integral type (welded) casing head; 3. According to the connection mode between bodies It can be divided into flange type casing head, clamp type casing head and independent thread type (casing head with thread connection at the upper end of suspended casing string and the lower end of tubing head body) according to the connection mode between the bodies; 4. According to the structure type of the body According to the structural type of the body, it can be divided into single casing head (one hanger is installed in one body) and combined casing head (multiple hangers are installed in one body); Structure and sealing of casing head 1. Structure of casing head The casing head is composed of four-way, casing hanger, jacking assembly, flange type parallel gate valve, connector, pressure display mechanism, etc; 2. Working principle of rubber seal The casing head seal is composed of the casing head body, BT rubber seal ring, casing hanger, dovetail rubber seal ring, top thread V-shaped seal ring, and sealing gasket ring. The casing hanger is mounted on the casing head body step. Because of the hanging weight of the casing, the contact between metal and metal produces a rigid passive seal. The seal between the casing hanger and the casing is a thread seal. The casing head spool has a BT seal matching the outer diameter of the casing hanger (or the outer diameter of the casing) and corresponding grease injection and pressure test holes. When using, high-pressure sealing grease must be injected from the grease injection valve to make the BT seal work. If the seal leaks, the sealing grease shall be injected into the grease injection valve and pressure test valve respectively to make the seal continue to take effect. The grease injection pressure shall not exceed the rated working pressure of the flange; If the casing is sealed, the rated allowable collapse pressure of the casing shall not be exceeded. The pressure test hole is used for external seal test of casing hanger. The flange is provided with a jack screw for locking the anti-wear sleeve (protecting the sealing surface). The casing hanger can be locked after the casing hanger is seated. If there is leakage at the jackscrew, tighten the pressure cap to make the seal effective. The flanges at both sides of the spool of the casing head are connected to the flat valve (or blind flange) at one end and the flat valve, threaded flange, connector, stop valve and pressure gauge at the other end. The annular pressure between the two casing layers can be observed through the pressure gauge. 3. Metal and rubber seal of casing head The metal and rubber seals of the casing head are composed of the casing head body, BT rubber seal ring, upper metal seal component, lower metal seal component, casing hanger, dovetail rubber seal ring, top thread V-shaped seal ring, and sealing gasket ring. The casing hanger is mounted on the casing head body step. Because of the hanging weight of the casing, the contact between metal and metal will produce a rigid passive seal. The casing hanger and casing are sealed by thread (see the figure above); Before installing the upper flange, measure the position and size of the upper metal sealing ring in the upper flange hole, and then determine the thickness of the adjusting ring, so that a certain amount of interference will emerge from the adjusting ring in the upper flange hole. When the upper flange is connected with the casing head cross, the adjusting ring is compressed through the casing head cross to deform the upper metal sealing ring, thus achieving the function of sealing casing hanger. The sealing principle of the lower metal sealing component of the casing hanger is to ensure the geometric dimensions of each part through the design of the metal sealing ring, the casing head cross and the casing hanger. The 45 ° cone on the jackscrew rotates to make the lower metal sealing component press ring down, so that the U-shaped ring of the metal sealing ring component is deformed, thus achieving the role of the casing hanger. Casing head hanger 1. Mandrel hanger The mandrel type (i.e. threaded type) hanger is equivalent to a casing coupling. It is convenient to cut the casing (both W and WE types are required), and the casing can be suspended without even opening the BOP to solve the problem of wellhead suspension seal. However, the casing depth shall be calculated to avoid bottoming. It is generally used in relatively stable production wells. Generally, the mandrel (threaded) hanger is used with the threaded casing head, and the corresponding slip hanger can also be replaced. The sealing principle of the mandrel hanger with metal and rubber seals on the casing head is the same as that of the mandrel hanger with metal and rubber seals on the tubing head. 2. Slip hanger a. Structure of slip hanger: Slip hanger is mainly composed of slip tooth (quartered), slip seat (quartered), rubber seal (quartered), support seat (quartered), etc. b. Operating principle of slip hanger: Hold the sleeve by the slip hanger of the two halves and put it into the casing head hole as a whole to make the slip teeth firmly stick to the casing. Under the effect of the casing self weight and the taper of the slip teeth, the more wedged the slip teeth are, the more tight the slip teeth become to the casing. The rubber seals deform under the action of their own weight, forming a seal on the casing and casing head body. c. Reverse slip hanger The inverted slip hanger seat is fixed at the lower part of the casing head body with bolts. After the casing is installed into the BT sealing ring, the slip is put down, so that the slip tooth firmly sticks to the casing. Under the effect of the self weight and taper of the casing, the more wedged the slip tooth is, the tighter the slip tooth is, so that the more tightly the slip tooth sticks to the casing. Slip hanger 1. WE slip hanger: Generally speaking, WE slip hanger is used for surface layer, which is characterized by large size and low sealing annulus pressure (compared with W type). Another situation is that the casing can not be lifted and lowered when it is cemented (this is a prerequisite for the W-type hanger), and WE can be installed and sealed passively (the casing is not moved, the hanger is movable, and the seal is activated manually rather than by the hanging weight) for remedy. If the hanging weight, sealing and other factors are not strictly considered, the WE type and W type with the same size and the same manufacturer can generally be interchanged. 2. W-type casing hanger Compared with the WE type, it relies on the suspended weight of the drill string to activate the seal. Its characteristics are: the largest suspended tonnage, better sealing, more stable, and generally used for the suspension of technical casing. 3. WD hanger It is only used for surface casing head, and the lower part is connected with surface casing.

1. Ferrule 01 Handling of ferrule There are two reasons for casing seizure: One is adhesive card; The second is shaft wall collapse or sand bridge jamming. After the casing gets stuck, full pressure can be applied but no more lifting is allowed. The annular clearance between casing and well wall is small, so it is impossible to perform casing milling and backoff. 1. Sticking card When the drilling fluid can be circulated, the method of injecting the releasing fluid is the same as that of treating sticking. 2. Collapse or sand jam (1) Sand bridge has been formed in the well, but some drilling fluid has returned. Therefore, small displacement and low pump pressure circulation shall be insisted to improve the viscosity and shear of drilling fluid, and the well shall be cemented after normal circulation is restored. (2) The casing has been run to the bottom of the well, and leakage occurs in case of collapse or sand sticking. Analyze the leakage layer, cement the well rapidly, and squeeze the cement slurry into the leakage layer. (3) If the casing is not run to the bottom of the well but is not far from the target layer, the well can be cemented first, then the cement plug and casing shoe can be drilled through, the well can be circulated to the bottom, and the oil and gas reservoir can be sealed by hanging the tail pipe. 02 Measures to prevent casing pipe from sticking The measures to prevent casing pipe from sticking mainly include the following: (1) Before running the casing, circulate and adjust the performance of the drilling fluid to ensure that there is no leakage or blowout. If necessary, mix crude oil or plastic balls, and run the casing only when the downhole is safe. (2) Before running the casing, the wellhead shall be calibrated to make the crown block, rotary table and wellhead in a vertical line, so as to ensure that it is not easy to make wrong connections. (3) When running the casing, the drilling fluid must be filled regularly and fully according to the technical requirements to prevent crushing the pressure valve or casing body. The automatic grouting equipment can be installed on the lower accessories of the casing, but it is necessary to judge whether the automatic grouting equipment is working according to the hanging weight of the casing and the amount of drilling fluid discharged from the well at any time. (4) When manual grouting is used, the casing string shall be moved continuously, and the upper and lower moving range shall not be less than 2m. In case of any indication of downhole obstruction, grouting shall be stopped, the casing shall be moved for a long distance immediately, and grouting shall be carried out after the downhole condition is normal. (5) If the wellhead casing is wrongly buckled for many times and the downhole casing is stationary for a long time, the downhole casing shall be moved first and then another casing shall be replaced. (6) In case of lost circulation, well collapse and other phenomena during casing running, the casing shall be pulled out and run in for treatment. The casing shall not be run until the downhole conditions are normal. If the casing has been run to the design depth, whether to cement or pull out the casing shall be determined according to the depth of the leakage layer. (7) For deep wells, the casing can be circulated in sections to break the structural force of the drilling fluid. Each time the pump is started, the pump should be started from small to large and gradually to the normal flow rate to prevent pressure excitation and leaking formation. (8) The casing lowering speed shall be controlled, especially when passing through the known leakage layer. Each single casing shall be controlled within 1.5~2min. After running the casing, the drilling fluid must be filled first, and then the pump can be started for circulation to prevent air from mixing. 2. No circulation after casing running 01 Back pressure valve blocked 1. Treatment measures Immediately perforate near the choke ring, resume circulation, and then cement the well. Cementing bump can be measured by displacement to retain cement plug, which will solidify after fracturing. 2. Preventive measures (1) Prevent gloves, brushes and other small objects from falling into the well. (2) When running the casing, special personnel shall check the casing one by one, and there shall be no objects in the casing. 02 No circulation due to well collapse or sand blockage 1. Treatment measures After running the casing, it is found that the well is collapsed or sand blocked. After the pump is started, the pump pressure rises. The drilling fluid only enters but does not return. It is impossible to pull out the casing. Different remedial measures can only be taken according to the downhole situation. (1) If the leakage layer is in the upper soft formation, the pump pressure is not too high, and there is a large absorption capacity, the cement can be directly injected. If the leakage layer is in the medium hard formation, there is also a certain amount of absorption, but the pump pressure is high, the cement slurry can also be squeezed, but the thickening time and initial setting time of the cement slurry should be appropriately extended. (2) If the leakage layer is the production layer, squeezing cement will seriously damage the production layer. If the absorption capacity of the formation is very small and the conditions for cement squeezing are not met, the wellhead must be fixed. Perforate at an appropriate position above the production layer below the collapsed layer section, run the small drill pipe or tubing packer into the casing, set the packer below the perforation position, and then inject cement slurry to seal the production layer after circulation is smooth. 2. Preventive measures (1) Before running casing, the drilling fluid must be adjusted and treated during the well trip circulation. The drilling fluid must be thoroughly circulated to remove sand accumulation and consolidate the well wall. The return speed must meet the requirements for the return speed during cementing. If there are any problems in the well, it is not necessary to run casing for cementing. (2) It is necessary to master the collapse law of the formation. The collapse of some formations has obvious periodicity, so casing cementing should be carried out in the stable period of the formation. (3) Before tripping out, pay special attention to filling drilling fluid, which shall be continuously filled. (4) The time from tripping out to the start of casing running shall be as short as possible. It is not allowed to run casing directly without swabbing after electric logging and sidewall coring. (5) In some wells, there are many centralizers and mud scrapers connected to the casing string, and a lot of filter cakes are accumulated during casing running. If these filter cakes are located in the well section with small diameter, forming a blockage, the circulation is blocked. Therefore, the number of centralizers should be reasonably designed, and mud scrapers should be used with caution. (6) When running the casing, the drilling fluid in the pipe must be filled regularly according to the technical requirements to prevent well collapse caused by crushing the pressure valve. 03 No circulation due to lost circulation 1. Treatment measures In this case, the following measures should be taken instead of hastily cementing: (1) If it is known that the pressure of the oil and gas reservoir is not high, the leakage layer is above the oil and gas reservoir, and reliable well control equipment is available, which can be used for cementing. After cement injection and pressure bump, close the BOP and pump drilling fluid from the annulus to maintain the annulus pressure. (2) If the location of the leakage layer is not known, and the pressure of the oil and gas reservoir is high, there is a danger of downhole blowout, or the leakage layer is an oil and gas reservoir, it should be plugged before cementing. The plugging slurry can be replaced into the annulus and squeezed in sections. After the downhole circulation is restored, the well will be shut in and squeezed in a part of the plugging slurry. After a period of inactivity, a part of the plugging slurry will be squeezed in. When the pressure bearing capacity of the formation meets the requirements of cementing, the drilling fluid will be recycled before cementing. 2. Preventive measures (1) During pigging circulation, the flow rate required by the design return speed during cementing shall be used for circulation. If the circulation is abnormal, the drilling fluid has poor performance, and the casing has to be run. (2) The casing running speed shall be strictly controlled to avoid excessive exciting pressure and formation leakage. (3) During casing running, keep the annular drilling fluid flowing. After running to the designed deep well, first use small displacement to jack up. After the structural strength of downhole drilling fluid is completely destroyed, gradually return to normal displacement circulation. The maximum circulating flow rate shall not be greater than the circulating flow rate during well trip. (4) Use fewer centralizers and mud scrapers. Because the filter cake has a certain effect on stabilizing the well wall and preventing leakage. (5) There is no leakage during pigging circulation. If leakage occurs after running casing, the leakage layer is usually the formation that has been lost during drilling. To be prudent, the formation that has been lost can be plugged once before running casing. 3. Collapsed casing or back pressure valve During casing running, the main reason for casing or back pressure valve collapse is insufficient drilling fluid filling. 01 Treatment measures (1) During various operations before and after cementing, the safety of casing must be considered. No matter what causes casing collapse, it is difficult to remedy it. (2) If only the back pressure valve is destroyed, the well can be cemented by manually measuring the replacement amount of drilling fluid. 02 Preventive measures (1) Fill drilling fluid regularly according to design requirements. (2) For cementing in the formation with salt rock creep, the collapse strength of casing shall be designed according to the creep stress of the creep layer. (3) Cement must be filled evenly around the casing in the creep layer, and channeling is not allowed. (4) The fishing depth during well testing shall be strictly limited to the allowable range of casing collapse strength and shall not be exceeded. (5) When it is necessary to run the packer to squeeze cement, the packer shall be at least 35m away from the perforated well section. 4. Casing fracture 01 Treatment measures (1) If the upper casing slips from the coupling and the coupling thread is still intact, a new casing butt joint can be run in. (2) If the surface casing or technical casing is broken from the lower part, the tapered guide shoe can be lowered to centralize and be fixed with cement. (3) If the lower broken casing is very short, or only one casing shoe can not be straightened with the tapered guide shoe, the lower grinding shoe shall be milled. (4) If the surface casing or technical casing is disconnected from the middle and the fracture is misaligned, the bit shall be lowered to a smaller level for drilling. If the bit cannot be lowered, the milling cone shall be lowered to trim the lower fracture until the upper and lower passage is unimpeded, and then a layer of casing shall be lowered to separate the fracture. If the milling cone cannot be run in, sidetrack. 02 Preventive measures (1) Sulfur proof casing and wellhead devices shall be used for sour oil and gas wells. The production layer containing hydrogen sulfide must be stabilized, the drilling fluid shall be fully recycled and treated, and the casing can be run only after the hydrogen sulfide mixed in the drilling fluid is removed. (2) When connecting the casing, it is not allowed to make a mistake. After making a mistake, it must be re installed, and it is not allowed to use electric welding after making a mistake. (3) In case of a snap, the casing can be fully pressed, but not lifted more. The lifting tension shall not exceed 80% of the tensile strength of the weakest casing in the casing string or the anti slip strength of the thread. (4) The surface layer or the lower part of the technical casing shall be connected with 3~6 pieces of anti loose thread grease, and the threads must be cleaned without oil stain. (5) The surface layer or technical casing shoe shall be located in the stratum that is not easy to collapse. (6) The surface casing cement shall be returned to the ground. The cement return depth of the technical casing depends on the situation, and it is better to return to the ground or within the upper casing. (7) It is better to use double rubber plugs for cementing, or leave more cement plugs in the pipe. For large-diameter casing, the internal pipe can be used for cementing, and the sealing quality of the casing tail shall be ensured. (8) When drilling with rotary table in a well that has been cased, the rotary table speed shall be limited. Before the drill collar is out of the casing, the speed shall not exceed 60r/min, and after the drill collar is out of the casing, the speed shall not exceed 150r/min. For wells with a long construction period, protective measures shall be taken for technical casing, such as adding rubber hoops or anti-wear joints on drill pipes. (9) The waiting time of cement shall be appropriately extended, and the cement plug shall be drilled when the cement stone has sufficient strength. When drilling the cement plug, the drilling tool shall not be equipped with a stabilizer, and the pressurization shall be uniform. (10) When unloading the cement head and the landing joint, the casing at the bottom of the well must be fixed, and the casing shall not be reversed. 5. Casing leakage 01 Remedies Find out the leakage position and plug the sleeve leakage with superfine cement. The superfine cement is finely ground cement with an average particle size of 6 μ m. The maximum particle size is 15 μ m. It is 1/5-1/7 of the standard cement particle size. The superfine cement used for squeeze injection is composed of 20%~30% finely ground cement and 70%~80% hydraulic slag. 02 Preventive measures (1) Hydraulic pressure test and flaw detection inspection shall be carried out for all casing running in the well one by one. (2) Sealing grease or adhesive for thread grease. (3) Tighten according to the specified torque. (4) Gas tight casing shall be used for gas well. (5) The casing cement slurry of each layer of the gas well shall be returned to the ground. (6) During shut in pressure test or well control operation, the shut in pressure shall not exceed 80% of the internal pressure resistance strength of the weakest casing. (7) If rotary drilling is used in technical casing, anti-wear measures shall be taken for casing.

1. Casing During or after the drilling of oil and gas well, one or several steel pipes are lowered according to the design requirements to prevent the collapse of the well wall, separate the fluid of each layer, and form the oil and gas production channel. These steel pipes are called casings. Note: φ101.6mm casing is a 4 "uncoupled casing Step 2: Tubing Tubing is a special tubing for oil Wells. Tubing is divided into two ends of the thickened tubing and flat tubing according to the thickening situation. Deep well completion uses thickened tubing at both ends, which is generally 6-10m in length. 3. Sucker rod 1) Sucker rod technical specifications The main body of the sucker rod is a solid rod with a round section, and the two ends are provided with a thickened forging head, and the forging head is provided with a wrench connecting the thread and a square section. The rod nominal diameters are 16mm(5/8 in), 19mm(3/4 in), 22mm(7/8 in), and 25mm(1 in). In addition to the most common 8m rod length, there are also five rod lengths of 1.0m, 1.5m, 2.5m, 3.0m and 4.4m, specially processed in combination. 2) Rod material There are two kinds of domestic sucker rod, one is carbon steel sucker rod, the other is alloy steel sucker rod. Carbon steel sucker rod is generally made of 40 # high quality carbon steel, alloy steel sucker rod is generally made of 20 # chromium molybdenum steel or 15 # nickel molybdenum steel. 3) Rod grade Grade C, D and K (1) Grade C tensile strength is low (620-794MPa), suitable for medium and light load, shallow and deep Wells with slight seawater corrosion; (2) Grade D has high tensile strength (794-965MPa), which is suitable for medium-heavy duty and medium-deep Wells with slight salt water corrosion; (3) Grade K has the lowest tensile strength (588-794MPa), suitable for light and medium loads with hydrogen sulfide and carbon dioxide corrosive media 4. Drill pipe Drill pipe is the basic unit of drill string, which mainly transmits the torque and load of rotary table, and establishes the circulation channel of workflow body. It is the basic supporting special pipe to complete workover operation. The joints of the drill pipe itself are commonly called drill pipe joints, which are used in pairs, that is, both ends of the drill pipe are equipped with male and female joints, whose function is to connect and protect the drill pipe for filling. Figure 2-2 shows the feature parameters. The oil drill pipe joint is composed of a fixture joint part, a welded joint part, a joint thread and a sealing shoulder. Divided into internal thread joint and external thread joint, used in pairs. Drill pipe is the basic component of the drill string and is made of seamless steel pipe (wall thickness is usually 9~11mm). Its main role is to transfer torque and drilling fluid, by gradually lengthening the drill pipe to deepen the hole. Therefore, drill pipe plays a very important role in oil drilling. Drill pipe structure and specifications The drill pipe consists of seamless steel pipe with a wall thickness of 9-11mm, consisting of a drill pipe body and a drill pipe joint. There are two ways to connect the drill pipe body joint: one is fine thread connection, that is, there is a fine male thread at both ends of the pipe body, and the female thread at one end of the joint is connected. This drill pipe is called fine thread drill pipe; The other is to butt the pipe body and the joint together by friction welding, called butt welding drill pipe. Fine thread drill pipe has been basically eliminated, domestic production or imported drill pipe are butt welded drill pipe (no fine thread drill pipe).

1. Technical introduction In order to meet the requirements of fine cutting, rapid layering, full hole production after fracturing and large rate fracturing in horizontal well reservoir reconstruction, the CT bottom seal drag fracturing technology was developed. Through the optimization and improvement of core tools such as packer and sand-blasting perforator, erosion analysis and field verification, the construction performance index of full displacement of 14m3/min under quartz sand condition is broken through, and the fixed-point refined transformation of the reservoir is realized, overcoming the imbalance and deficiency of single cluster transformation of horizontal well drilling bridge plug + cable cluster perforating process. In particular, the idea of single stage and double cluster fracturing was innovatively proposed, and the new asymmetric hydraulic spray gun support with independent intellectual property rights was adopted to form double main fractures and complex fracture network structure in the process of fracturing reconstruction, which increased the contact area between fractures and reservoir matrix, and achieved good reconstruction effect. 2. Technical characteristics It has the characteristics of precise positioning and fine transformation. Do not kill well, reduce the damage to oil and gas reservoir; Fast tripping speed enables rapid layer-changing and multiple layers can be fractured in one trip. After operation, the wellbore is smooth and clean, allowing rapid production and eliminating complex processes such as drilling and plugging. 3. Technical indicators The maximum deviation of construction well is 90°, the temperature resistance is 120℃, and the pressure resistance is 70MPa. The drag capacity of a single set of tools is 15 segments; Maximum construction displacement 15m3/min; The maximum construction capacity is 6 sections per day. 4. Scope of application Horizontal well fracturing for unconventional reservoirs such as shale oil, tight oil and volcanic rock; Fine layered fracturing in new vertical Wells; Fracture fracturing is used in new vertical Wells, fracture fracturing is used in new high-inclination Wells, and reverse fracturing is used in old Wells. It can also be used for leak detection in new and old Wells. Coiled tubing hydraulic jet capping annulus fracturing technology 1. Technical introduction Coiled tubing carries downhole tools into the well. The bottom packer was first sealed, then the coiled tubing channel was used for hydraulic jet perforation, followed by a large-scale fracturing operation through the annulus. Setting, perforating, fracturing, opening, lifting, and multizone fracturing are completed in stages. 2. Technical characteristics There is no limit to the number of stages/formations; Coiled tubing sandblasting and annulus fracturing can realize large-scale transformation. The packer can be set and unpacked multiple times, and can be used in conjunction with coiled tubing to enable continuous multistage reconstruction without killing the well. 3. String combination 1 -- Coiled tubing connection/release; 2 - Centralizer; 3 - Hydraulic injection tools; 4 - Balance valve/reverse circulation connector; 5 - Packers and anchors; 6 - Mechanical casing joint locator; 7 - guide cone 4. Scope of application It is suitable for horizontal well with multi-thin reservoir, coal-bed methane branch well and well with small casing size that cannot be conventional fracturing.

1. Overview Oil well tubing is the basic material of petroleum industry, the special tubing is indispensable for petroleum exploration and development, and the bulk strategic material of petroleum industry. Its quality and performance are related to the comprehensive economic benefits and security interests of the petroleum industry. Classification of well pipe by use; Casing, tubing, drill pipe, etc.; According to the production process can be divided into seamless oil well pipe and welded oil well pipe. Casing is mainly used to support the well wall during drilling and after completion to ensure the normal operation of the whole well during drilling and after completion. Tubing mainly carries oil and gas from the bottom of the well to the surface; Oil drill pipe is mainly used to connect the drill collar to the drill bit and transfer drilling power The use of oil well pipe has been completely domestic, its performance can meet the requirements of the oilfield. The scope includes oil exploration and development drilling, oil production, overhaul operations and other major production systems and corresponding equipment manufacturing enterprises. The basic standard used in pipe production is the API standard (API is short for American Petroleum Institute). API well tubing production standards are API SPEC 5CT Casing Specification and API SPEC 5DP Drill Pipe Specification. API SPEC 5CRA Specification for Seamless Corrosion Resistant Alloy Steel Tubes for casing, tubing, and Joint materials is also being adopted to meet the demand for corrosion resistant alloy well tubes in domestic oilfield development. However, from the perspective of the development of well tubing products, in addition to API well tubing products, there are a small number of non-API tubing. Non - API pipeline is a special pipeline to meet the needs of oilfield exploration and development. They are used in small quantities. Most of them are high-end products for well tubing. Their performance and main technical indicators are characterized by four points: special geometry sizes, materials, types of steel, and special thread types not covered by API standards. These four aspects are the most significant differences from API well tubes. With the technological progress of petroleum industry, the technical level of exploration and development is getting higher and higher. With the popularization and application of modern advanced drilling technologies such as complex horizontal well development and deep-sea oil and gas development, higher technical requirements are put forward for the performance of oil pipelines. Such as high-end special thread, anticorrosive materials, special strength requirements. API tubing is difficult to meet the special technical requirements of oilfield development. Especially in the old oil fields with complex geological conditions and long development history, the phenomenon of premature failure of oil well pipeline is more common, and the loss of economic benefits is serious. API well pipe can not meet the requirements of use. Non-api well tubing, such as high crush resistance, high corrosion resistance, and high performance gas seal threads, will be in increasing demand. For different oil field corrosion environment, such as hydrogen sulfide, carbon dioxide, high salinity and other media, should be based on different temperature, pressure, PH environment, ion concentration, corrosive media content and composition, optimize the selection of materials, determine scientific and reasonable corrosion resistant materials. In order to adapt to the geological characteristics of high temperature, high pressure and high corrosion in oil fields, it is necessary to further enrich and improve the types of corrosion resistant alloy made in China, and gradually catch up with the variety advantages of advanced production enterprises in the world. According to the different oilfield production environment, special thread will be more widely used. At present, foreign pipe manufacturers have developed more than 100 special thread types, considering both high-end special thread required for high-end service performance and economic thread required for low oil and gas development costs to meet the special requirements of different fields. In addition, China's oil and gas resources have huge potential, according to the latest dynamic evaluation results of the country's oil and gas resources released by the Ministry of Land and Resources. China's oil and gas production is expected to double from current levels to nearly 700 million tons of oil and gas equivalent by 2030. The ability of oil and gas resource succession in the western region has been significantly enhanced, and a new pattern of west succeeding east will be formed. At present, China's petroleum geological resources reach 103.7 billion tons, an increase of 36% over the 2007 assessment; Natural gas geological resources amounted to 62 trillion cubic meters, an increase of 77 percent over the 2007 assessment. According to preliminary statistics, the national oil production reached 210 million tons in 2013, up 1.8% year on year; Natural gas output was 120.9 billion cubic meters, including 117.7 billion cubic meters of conventional natural gas, up 9.5 percent year on year. Coal bed gas and shale gas production reached 3 billion cubic meters and 200 million cubic meters, respectively. The country has 320 million tons of oil and gas equivalent, up 4.6 percent year on year. The evaluation results show that around 2025, natural gas and oil will form a "" binary pattern, the proportion of unconventional oil and gas will gradually increase. Unconventional oil and gas such as shale gas, coal-bed methane and tight oil are expected to account for one-third of total production by 2030. In the remaining oil and gas resources, low-grade resources such as deep water, deep water and low permeability will account for about 2/3. The difficulty and cost of exploitation will gradually increase, which puts forward higher requirements for the demand of oil well pipe and the content of scientific and technological reform. 2. Current production situation of oil well pipe in China At present, the global annual consumption of oil well pipe is about 14.5 million tons, of which 11.5 million tons of seamless pipe and 3 million tons of welded pipe. China has become the world's leading producer and consumer of oil and tubing. In 2012, the actual oil casing production was about 5.33 million tons, the domestic consumption was 3.2 million tons, the exports were 2.21 million tons, and the imports were 80,000 tons. Domestic oil casing production and consumption in 2013 are expected to be roughly the same as in 2012. (Incomplete statistics of drill pipe) In the past 10 years, a number of modern pipe rolling units and pipe processing production lines have been put into production by the backbone enterprises of domestic steel pipe production, making China basically self-sufficient in oil well pipe from the last century when most people depended on imports. In 2012, the oil casing market share reached 97.63%. It effectively guarantees the safety and stability of oil well pipe supply in China and greatly reduces the oil field procurement cost. At the same time, a considerable amount of products are exported to meet the needs of the international market. China's oil well pipe industry has developed together with China's petroleum industry and has rapidly entered the international market, making China the world's largest oil well pipe producer.

Oil pipelines are used to transport crude oil and natural gas from oil and gas reservoirs to the surface after drilling to withstand the pressure generated in the production process. The outer diameter of the pipe is generally 60.3 mm ~ 114.3 mm. End processing forms are: no thread coupling thickening, external thread coupling thickening, flat end face, no thread coupling thickening, external thread coupling thickening. Tubing inspection range Fuel oil pipe, automobile oil pipe, excavator oil pipe, oil pipe, high pressure oil pipe, hydraulic oil pipe, brake oil pipe, air compressor oil pipe, rubber oil pipe, brake oil pipe, etc. Tubing inspection item Resonance test, sealing test, permeability test, sealing test, pressure test, hydraulic test, pulling force test, ring stiffness test, bursting pressure test, pulse test, etc. Tubing inspection standard (Part) 1. GB/T 34204-2017 Coiled tubing 2. Oil and gas industry. Machining, measurement and inspection of casing, tubing and pipe threads (GB/T 9253.2-2017) 3.GB/T 17745-2011 Petroleum and natural gas industries -- casing and tubing maintenance and use 4. GB/T 18052-2000 "Casing, tubing and pipe thread measurement and inspection method" 5. Technical Guidelines for Environmental Risk Assessment and Control of Petroleum Pipelines GB/T 38076-2019 6. GB/T 39096-2020 Petroleum and natural gas industry -- Aluminium alloy tubing for oil and natural gas Wells 7. GB/T 40543-2021 Oil and Gas industry -- Material selection for casing, tubing and downhole tools in high CO2 environments 8. GB/T 19830-2017 Petroleum and natural gas industry -- Steel tubes for casing or tubing of oil and gas Wells 9. GB/T 21267-2017 Petroleum and Natural Gas Industry. Test code for casing and tubing threaded connections 10. GB/T 23512-2015 Oil and Natural Gas Industry. Evaluation and testing of threaded compounds for casing, tubing, pipeline and drill string assemblies 11. GB/T 23802-2015 Specification for delivery of seamless tubes of corrosion-resistant alloy for casing, tubing and coupling billets for the petroleum and natural gas industry 12. GB/T 20657-2011 Oil and Gas Industry. Performance formulas and calculations for casing, tubing, drill pipe and line pipe for casing or tubing 13. GB/T 34350-2017 "Inspection Methods for Internal and external Corrosion of Oil Pipelines"

Tubing coupling is a kind of oil field drilling tool, mainly used for tubing connection. It mainly solves the problem of fatigue fracture caused by stress concentration of existing coupling. The structure of the tubing coupling is: the tubing end is connected with the inner wall of the coupling by means of conical thread, and the coupling body end is connected with the tubing by means of flat thread with the same pitch and thread. The utility model has the characteristics of relieving the stress concentration at the root of the external thread of the tubing with a single cone thread, and is not easy to produce fatigue fracture, and the connection effect is good. Effectively prevent the occurrence of oil well broken pipe string accident. The joint is divided into tubing joint and casing joint. Commonly used steel types are J55, K55, N80, L80, P110 and so on.

Precautions before running drill pipe into the well: Before the drill pipe is used in the well, the internal thread joint shall be placed on the movable drill pipe stand 0.3m above the ground according to the specifications, and sufficient support shall be provided in the direction of the drill floor to prevent corrosion of the drill pipe caused by water, tide and soil. The drill pipe frame should be kept parallel and at the same level to prevent the drill pipe from bending and deformation; The drill pipe at both ends of the pipe frame should be clamped with plugs to prevent the drill pipe from rolling and falling. Before the drill pipe goes on the drill floor, the joint thread and shoulder sealing surface of the drill pipe should be thoroughly cleaned and checked. After confirming that the joint is in good condition, it can be used in the well. Wear a protective wire (steel protective wire is recommended) to prevent collision and damage between the thread and shoulder surface during the hoisting process. When the drill pipe is hoisted along the slide rail on the drill floor, the winch should maintain uniform speed as far as possible. When the drill pipe leaves the slide, a soft rope should be used for manual blocking to prevent collision. Clean and check the joint thread and shoulder sealing surface before working with single wellhead joint. After confirming that there is no problem, apply special thread oil for oil drilling tools containing 60% fine metal lead powder or 40-60% fine metal zinc powder on the joint thread and shoulder sealing surface (the joint thread in the hole and shoulder sealing surface should also be fully and evenly coated with special thread oil). Prevent sand and other foreign matters from mixing with thread oil, affecting the performance of thread protection oil or scratching thread and shoulder sealing surface. Precautions for using drill pipe: When the new drill pipe is used for the first time, it is recommended to unscrew the joint at the wellhead twice, with the unscrewing torque slightly below the specified value. After confirming that the joint thread and sealing surface are in good condition, apply a uniform amount of thread oil, tighten the joint thread according to the specified torque, and then use it in the well. The operation of the opening and closing button is beneficial to strengthen the surface hardness of the thread, enhance the anti-bonding performance of the thread, and extend the service life of the drill pipe. When docking the drill pipe at the wellhead, it should be pierced manually to prevent the male connector from impacting the female connector end face or thread and causing damage; Chain tongs are then used to manually identify the threads. After introducing at least two threads, use hydraulic power pliers to tighten the drill pipe joint thread according to the specified torque (different types of steel, specifications, water hole size need different tightening torque, must be treated differently). Before each trip, the drill string is replaced and the shackle is removed so that each pair of joints can be removed once in each of the three trips to check the thread condition of each joint in a timely manner to reduce problems such as sticking, tripping, and leakage. At the same time, the position of the upper and lower drilling tools should be changed regularly to change the stress state of the drilling tools, so that the stress of all parts of the whole drilling tools tends to be consistent, so as to improve the service life of the drilling tools and reduce the occurrence of early failure accidents. When drilling, a reasonable speed and weight on bit should be selected according to the formation, well diameter and BHA configuration to ensure that the drill tool is in an ideal working condition and achieve satisfactory drilling efficiency. When the rotational speed of drill pipe reaches the critical speed, the longitudinal, transverse and torsional vibration frequencies generated by the rotation of drill pipe coincide with the natural frequency of drill pipe itself, which will cause resonance, make the whole drill string in a serious instability state, and make it bear additional fatigue stress, so as to accelerate the fatigue failure of drill pipe. The greater the weight of the bit, the greater the resistance to the bottom hole bit, easy to cause stuck. When increased drilling weight exceeds the critical drilling weight of the drill tool, the drill tool will bend, causing inclination and fatigue fracture of the BHA thread. When the drill pipe is operating in a corrosive environment, deoxidizer and corrosion inhibitor can be added to the drilling fluid; Increase the PH value of drilling fluid to more than 10; Use sulfur-resistant drill pipe; Use drill pipe with internal coating; On the premise of meeting the strength requirements, try to use low steel grade drill pipe and other relevant measures to reduce the impact of corrosion factors on the drill. When removing the drill pipe thread at the wellhead, the low speed gear should be used first, and the hook spring should maintain a certain tension to ensure that there is no pressure between the thread surface of the two joints. After the joint thread is completely disconnected, the hook is lifted to prevent the thread from being pulled up and also to prevent the upper drill pipe from bumping and colliding with the wellhead female joint under the action of spring force. Maintenance management of drill pipe after use: After the drilling operation is completed, the drilling tools shall be neatly placed on the drill pipe rack according to different specifications, wall thickness, water hole size, steel type and grading. Clean, rinse and dry the inside and outside surface, joint thread and shoulder sealing surface with clean water. Check the drill pipe surface for cracks and nicks, thread integrity, eccentric wear of joints, flat shoulder surface without scratches, bending and squeezing bite of pipe body, corrosion, pitting and other defects on the inside and outside of the drill pipe. If conditions permit, the drill pipe body should be carried out ultrasonic inspection from time to time, and magnetic particle inspection should be carried out on the thread, so as to reduce the probability of joint thread breakage and drill pipe body leakage. For no problem drilling tools, the thread and shoulder sealing surface should be coated with anti-rust oil, wear protective wire, and take various protective measures. Faulty drill pipe should be painted on site and stored separately to prevent misuse. Timely maintenance and replacement of drill pipe problems to avoid affecting later construction. The drill pipe that is not used in the open air for a long time should be covered with waterproof tarpaulin, and the corrosion of the inside and outside surface of the drill pipe should be checked regularly to do a good job of moisture-proof and anticorrosive work.

1. Introduction of special buckle Special thread is a pipe thread with special structure different from API thread. Although API threaded casing has been widely used in oil well production, its disadvantages are obvious in the special environment of some oil fields. Although API round threaded string has good sealing performance, the tension of the threaded part is only 60% to 80% of the strength of the string, so it cannot be used in deep well production. Although the API eccentric trapezoidal thread string has much higher tensile performance than the API circular thread string, its sealing performance is not good enough to be used in high-pressure gas Wells. In addition, thread grease only works in temperatures below 95 ° C, so it cannot be used in high-temperature Wells. Compared with API round thread connection and eccentric trapezoidal thread connection, special buckle connection has made breakthrough progress in the following aspects :⑴ Good sealing performance. Through the design of elastic and metal sealing structure, the gas sealing resistance of the joint reaches the ultimate internal yield pressure of the tube body. ⑵ High connection strength. The connection strength of the oil sleeve connected by the special buckle reaches or exceeds the strength of the pipe body, which fundamentally solves the problem of slipping; (3) Through the selection of materials and the improvement of surface treatment technology, the problem of thread bonding is basically solved; (4) Through structural optimization, the stress distribution of the joint is more reasonable and more conducive to stress corrosion resistance; ⑸ The reasonable shoulder strap structure design makes the feeding operation more convenient. At present, more than 100 special buttons with patented technology have been developed in the world.

1. Classification of pipelines Pipeline pipe is the abbreviation of the steel pipe used in the oil and gas industry to transport oil, refined oil, natural gas, water and other pipelines. Oil and gas transmission pipelines are mainly divided into three types: trunk pipeline, branch pipeline and urban pipe network pipeline. Using 406 ~ 1219 mm channel, the wall thickness is 10 ~ 25 mm, and x ~ X80 steel. Branch pipeline and urban pipe network pipeline general specification for the | 114 ~ 700 mm, thickness is 6 ~ 20 mm, the grade of steel is X42 ~ X80. Pipes Pipes include welded steel pipes and seamless steel pipes, and welded steel pipes are used more than seamless steel pipes. 2. Pipeline standard The implementation standard of pipeline is API 5L "Specification for Pipe Steel Pipe", However, China issued two national standards for pipeline piping in 1997 :GB/T9711.1-1997 Oil and Gas Industry - Steel tubes for Power transmission - Part I: Class A and GB/T9711.2-1997 Oil and Gas Industry - Steel tubes for power transmission - Part 2: Class B steel tubes. These two standards are equivalent to the standards set by API 5L, and many domestic users require supply in accordance with these two national standards. 3. About PSL1 and PSL2 PSL stands for Product Specification Grade. The product specification grade of pipeline is divided into PSL1 and PSL2, and the quality grade is also divided into PSL1 and PSL2. PSL1 is higher than PSL2, and the two specification grades not only have different inspection requirements, but also different chemical composition and mechanical properties requirements. Therefore, when ordering under API 5L, in addition to the usual indicators such as specification and steel grade, the product specification class, i.e. PSL1 or PSL2, must be stated in the contract terms. PSL2 is more strict than PSL1 in chemical composition, tensile property, impact energy, nondestructive testing and other indicators. 4. Grade and chemical composition of pipeline steel The steel types of pipe are divided into A25, A, B, X42, X46, X52, X60, X65, X70 and X80 from low to high. 5. Water pressure and non-destructive requirements of pipelines Water pressure test shall be carried out one by one on pipelines, and the standard does not stipulate that the use of non-destructive water pressure is allowed, which is also a big difference between API standard and Chinese standard. PSL1 does not require nondestructive testing, while PSL2 requires nondestructive testing one by one.

The kelly, drill pipe, weighted drill pipe and drill collar in the drill tool constitute the drill string. The drill string is the core drilling tool that drives the drill bit from the surface to the bottom of the hole, as well as the passage from the surface to the bottom of the hole. It has three main functions: (1) transfer torque, drive the bit drilling; (2) Rely on the weight of the bit to exert pressure on it to break the rock at the bottom of the well; (3) Well flushing fluid transportation, that is, drilling mud through the high pressure mud pump on the ground into the drill string hole, into the bottom hole to wash cuttings and cool the drill bit, and through the outer surface of the drill string and the ring space between the wall to bring the cuttings back to the ground, so as to achieve the purpose of drilling. During the drilling process, the drill string has to withstand various complex alternating loads, such as tension, pressure, torsion, bending and other stresses, and the inner surface also has to withstand the erosion and corrosion of high-pressure mud. ⑴ Kelly: There are two types of kelly: Kelly and hexagonal. In China, square drill pipe is usually used for each group of oil drill pipe. Specifications :63.5mm (2-1/2in), 88.9mm (3-1/2in), 107.95mm (4-1/4in), 133.35mm (5-1/4in), 152.4mm (6in), etc. Generally, the length is 12 to 14.5m. (2) Drill pipe: Drill pipe is the main tool of drilling and is connected with the lower end of kelly pipe. As the drill goes deeper, the drill pipe lengthens the drill string one by one. Drill pipe specifications are 60.3mm (2-3/8in), 73.03mm (2-7/8in), 88.9mm (3-1/2in), 114.3mm (4-1/2in), 127mm (5in), 139.7mm (5-1/2in), etc. (3) Weighted drill pipe: Weighted drill pipe is a transition tool connecting drill pipe and drill collar, which can improve the stress condition of drill pipe and increase the pressure borne by drill bit. The main specifications for weighted drill pipe are 88.9mm (3-1/2in) and 127mm (5in). (4) Drill collar: The drill collar is connected to the lower part of the drill string. It is an extra-thick tube wall with high rigidity that applies pressure to the drill bit to break the rock. It can be used as a guide in drilling vertical Wells. Commonly used drill collars are 158.75mm (6-1/4in), 177.85mm (7in), 203.2mm (8in), 228.6mm (9in), etc.

Casing is the steel pipe that supports the wall of an oil and gas well. Depending on the drilling depth and geological conditions, each well with multiple casing should be used. The cement used to cement the casing after it has been run should be used. Unlike tubing and drill pipe, it cannot be reused. It's a disposable consumable. As a result, casing consumption accounts for more than 70% of all well tubing. Casing can be divided into conduit casing, surface casing, technical casing and reservoir casing according to service conditions. Guide sleeve: mainly used for Marine and desert drilling, separation of seawater and sand, to ensure the smooth drilling. The main specifications of this casing are: Φ762 mm (30in) x 25.4mm, ∮762 mm (30in) x 19.06mm. (2) Surface casing: mainly used for bedrock drilling in soft strata. In order to seal this part of the formation without collapse, surface casing is needed to seal it. Main specifications of surface casing :508mm (20in), 406.4mm (16in), 339.73mm (13-3/8in), 273.05mm (10-3/4in), 244.48mm (9-5/9in), etc. The depth of pipeline laying depends on the depth of soft strata, generally 80~1500m. Its withstand external pressure and internal pressure are not big, generally using K55 steel grade or N80 steel grade. ③ technical casing Technical casing is used in the drilling process in complex formations. When complex parts such as collapse layer, oil layer, gas layer, water layer, leakage layer and salt gypsum layer are encountered, technical casing is needed to seal, otherwise drilling operation cannot be carried out. Some Wells are deep and complex, with Wells several kilometers deep. This deep well requires multiple technical casing, which requires high mechanical and sealing performance. The grade of steel used is also very high. In addition to K55, N80 and P110 steel are used more. Some deep Wells also use non-API steel grades Q125 or higher, such as V150. The main specifications of technical casing are 339.73mm (13-3/8in), 273.05mm (10-3/4in), 244.48mm (9-5/8in), 219.08mm (8-5/8in), 193.68mm (7-5/8in) and 177.8mm (7in), etc. (4) Reservoir casing When drilling to the target zone (oil and gas bearing zone), the oil casing should be used to seal the oil and gas reservoir and the upper exposed formation, and the oil reservoir is in the oil casing pipe. Reservoir casing has the deepest running depth among all kinds of casing and requires the highest mechanical and sealing performance. The steel used is K55, N80, P110, Q125, V150 and so on. The main casing sizes are 177.8mm (7in.), 168.28mm (6-5/8in.), 139.7mm (5-1/2in.), 127mm (5in.), and 114.3mm (4-1/2in.).

1. Tubing classification Tubing is divided into flat tubing (NU), thickened tubing (EU) and integral connector tubing. Flat pipe refers to the pipe end is directly threaded, and is provided with a fitting without thickening. Thickened pipe means that two pipe ends are externally thickened, then threaded, and equipped with a coupling. Integral joint tubing refers to one end through the internal thickened external thread, the other end through the external thickened internal thread, direct connection, no coupling. 2. The role of tubing ① Oil and gas extraction: after oil and gas well drilling and cementing, oil and gas are extracted to the surface by placing tubing in the oil casing. ② Water injection: when the downhole pressure is not enough, water injection into the well through the tubing. Steam injection: In the process of hot recovery of heavy oil, heat insulation pipe should be used to input steam into the well. (4) Acid fracturing. 3. Steel grade of tubing Pipeline steel types include H40, J55, N80, L80, C90, T95, P110, etc. N80 is divided into N80-1 and N80Q. The similarity between them is in tensile properties. The difference between them is the delivery state and the impact properties. N80-1 is delivered under normalizing condition, or when the final rolling temperature is higher than the critical temperature Ar3 and the reduced tension is air cooling, hot rolling can be used instead of normalizing. Non-impact energy and non-destructive testing requirements; The N80Q must be treated with tempering (tempering) heat, impact energy in accordance with API 5CT, and nondestructive testing. L80 is divided into L80-1, L80-9Cr and L80-13Cr. Their mechanical properties and transport conditions are the same. The differences are in use, difficulty of production and price. L80-1 is a common type of tubing, while L80-9Cr and L80-13Cr are highly corrosion-resistant tubing, which are difficult and expensive to produce and are usually used in Wells with severe corrosion. C90 and T95 are divided into type 1 and type 2, namely C90-1, C90-2, T95-1 and T95-2. 4. Delivery status of commonly used steel products, grades and oil pipelines Steel delivery condition J55 tubing 37Mn5 Flat tubing: hot rolling instead of normalizing Thickened tubing: After thickening, the full length is normalized N80-1 tubing 36Mn2V Flat tubing: hot rolling instead of normalizing Thickened tubing: After thickening, the full length is normalized N80-Q Tubing 30Mn5 full length quenching and tempering L80-1 tubing 30Mn5 full length conditioning P110 Tubing 25CrMnMo full length quenching and tempering J55 coupling 37Mn5 Hot rolled on-line normalizing N80 coupling 28MnTiB full length conditioning L80-1 coupling 28MnTiB full length conditioning P110 coupled 25CrMnMo full conditioning

1. Explanation of terms related to oil pipelines API: American Petroleum Institute, American Petroleum Institute. OCTG: English is short for Oil Country tube Goods, Chinese is special oil pipe meaning, including product casing, drill pipe, drill collar, coupling, short joint, etc. Tubing: Tubing used for oil production, gas production, water injection and acid pressure in oil Wells. Casing: Pipe lowered from the surface into a borehole to serve as a lining to prevent the wall from collapsing. Drill pipe: Pipe used to drill holes. Pipeline: A pipeline used to transport oil and natural gas. Couplings: Used to connect two cylinders with threaded pipes and internal threads. Joint material: Pipe used to make joint. API thread: Pipe thread specified in API 5B standard, including tubing round thread, casing short round thread, casing long round thread, casing eccentric trapezoid thread, pipe thread, etc. Special thread: Non-API thread type with special sealing properties, connection properties, etc. Failure: Deformation, fracture, surface damage and loss of original function under specific service conditions. The main forms of casing failure include collapse, slip, fracture, leakage, corrosion, adhesion, wear and so on. 2. Petroleum related standards API 5CT: Casing Specification (latest version is Version 8) API 5D: Drill pipe Specification (latest edition: 5th edition) API 5L: Specification for pipe steel tube (latest version 44) API 5B: Specification for machining, measuring, and inspecting casing, tubing, and pipe threads GB/T 9711.1-1997: Oil and Gas industry. Steel pipe for transmission. Technical delivery conditions. Part 1: Class A steel pipe GB/T9711.2-1999: Oil and gas industry. Steel pipe for transmission. Technical delivery conditions. Part 2: Class B steel pipe GB/T9711.3-2005: Oil and Gas industry. Steel pipe for transmission. Technical delivery conditions. Part 3: Class C steel pipe

1. Oil pipe joints are classified according to shape Tubing joints are classified into five types by shape: (a) External thickened non-thickened joint -- both ends of the same specification, one end is connected to the external thickened oil pipe, the other end is connected to the non-thickened oil pipe or special thread oil pipe (b) External thickening and reducing joints -- different specifications at both ends. One end of the tubing joint is connected to a large extra thickened tubing and the other end is connected to a small tubing (c) Outer thickening to outer thickening -- the same specifications at both ends. One end of the tubing connector is connected with an external small tubing, and the other end is connected with an external thickened tubing of the same specification; (d) Nipple of the same diameter -- the two ends of the nipple are of the same specification, one end of the nipple is connected to the non-thickened tubing or specially threaded tubing, the other end is connected to the non-thickened tubing or specially threaded tubing, (e) Non-thickening and reducing joints - different specifications at both ends. One end of the tubing joint is connected to a large non-thickened tubing and the other end is connected to a small tubing 2 Tubing joints are classified by function Tubing fittings are classified into three types according to their functions (a) The two ends of the double male short joint are of external thread, with any type of external thickening, non-thickening short joint, external thickening, non-thickening short joint, external thickening, non-thickening short joint, equal diameter short joint, non-thickening short joint. (b) Conversion connector, one end of which is external thread and the other end of which is internal thread. Screw the coupling on the outer thickening to the non-thickening section, the outer thickening reducer section, the outer thickening to the outer thickening section, the same diameter section and the non-thickening reducer section (c) The length of the adjusting joint is uncertain, which shall be designed according to the needs of the project. One end is the external thread and the other end is the internal thread. The coupling is screwed on externally thickened to non-thickened sub, externally thickened to externally thickened sub, same-diameter sub and non-thickened sub.