CN-122017007-A - Old oil pipe evaluation and regeneration method

CN122017007ACN 122017007 ACN122017007 ACN 122017007ACN-122017007-A

Abstract

A method for evaluating and regenerating an old oil pipe comprises the following steps of 1, cleaning an oil pipe to be repaired, taking the oil pipe to be repaired, which is unqualified in a drift diameter test, as the scrapped oil pipe, 2, performing appearance detection and preliminary judgment on the qualified oil pipe in the step 1, 3, performing thread repair and coupling replacement on a primary oil pipe and a secondary oil pipe, 4, performing pressure test on the primary oil pipe and the secondary oil pipe, 5, setting a coating and a protection device on the primary oil pipe and the secondary oil pipe, and 6, putting the primary oil pipe and the secondary oil pipe into use again to finish oil pipe regeneration. The invention can solve the problem of high waste judging rate of the old oil pipe repair abnormality, obviously reduces the development cost of the oil field and has potential popularization value.

Inventors

LV QINGGANG
TONG LIANG
DENG LI
ZHANG YONG
WEI SHANQUAN
HU JILIN

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司西北油田分公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (10)

1. The old oil pipe evaluation and regeneration method is characterized by comprising the following steps of: step 1, cleaning an oil pipe to be repaired and taking the oil pipe to be repaired, which is unqualified in a drift diameter test, as a scrapped oil pipe; step 2, performing appearance detection and preliminary judgment on the qualified oil pipe in the step 1, and specifically comprising the following steps: Step 2.1, carrying out preliminary visual inspection on the qualified oil pipe in the step 1, and taking the oil pipe to be repaired with pipe bending or pipe deformation as a scrapped oil pipe; step 2.2, measuring corrosion defects which cause wall thickness loss in the qualified oil pipe in the step 2.1, and primarily classifying and judging the corrosion defects into a primary oil pipe to be determined and a secondary oil pipe to be determined according to the depth of a corrosion pit and the degree of linear axial abrasion defects; and 2.3, performing flaw detection and judgment on the undetermined primary oil pipe and the undetermined secondary oil pipe by adopting an ultrasonic flaw detector, wherein the method specifically comprises the following steps of: step 2.3.1, detecting the undetermined primary oil pipe; Performing flaw detection on the to-be-determined first-stage oil pipe judged in the step 2.2, judging whether the to-be-determined first-stage oil pipe meets flaw detection requirements of an L2 acceptance level specified by an API SPEC 5CT 10.15 table C.43, if so, judging the to-be-determined first-stage oil pipe, executing the step 3, otherwise, judging the to-be-determined second-stage oil pipe, and executing the step 2.3.2; Step 2.3.2, detecting the undetermined secondary oil pipe, which specifically comprises the following steps: 2.3.2.1, detecting the undetermined secondary oil pipe judged in the step 2.2 and the step 2.3.1, using a new oil pipe with the same diameter, wall thickness and material as the secondary oil pipe as a sampling pipe, processing artificial defects on the sampling pipe, testing the artificial defects on the sampling pipe by adopting an ultrasonic flaw detector to obtain reference sensitivity, and improving the reference sensitivity by 5-7db as scanning sensitivity; Step 2.3.2.2, based on the scanning sensitivity, detecting the undetermined secondary oil pipe by adopting an ultrasonic flaw detector, judging whether the undetermined secondary oil pipe meets the condition that the corrosion pit depth is less than 30% of the standard wall thickness, if yes, judging the undetermined secondary oil pipe as the secondary oil pipe, and executing step 3, otherwise, judging the undetermined secondary oil pipe as the scrapped oil pipe; step 3, performing thread repair and coupling replacement on the primary oil pipe and the secondary oil pipe; step 4, testing the pressure of the primary oil pipe and the secondary oil pipe; step 5, coating and protecting devices are arranged on the primary oil pipe and the secondary oil pipe; and step 6, putting the primary oil pipe and the secondary oil pipe into use again, and thus finishing oil pipe regeneration.
2. The method according to claim 1, wherein the preliminary classification in the step 2.2 is specifically that the primary oil pipe is judged to be pending if the corrosion pit depth is not more than 12.5% of the standard wall thickness and no linear axial wear defect exists in the inner wall of the pipe body, the secondary oil pipe is judged to be pending if the corrosion pit depth is more than 12.5% of the standard wall thickness but the corrosion pit depth is less than 30% of the standard wall thickness and the linear axial wear defect in the inner wall of the pipe body is less than 12.5% of the standard wall thickness, and the rest is judged to be scrapped.
3. The method of claim 1, wherein in step 2.3.2.1, the coupon is processed thereon The vertical through holes of the test tube are used as artificial defects, an ultrasonic flaw detector is used for testing the artificial defects on the test tube, and the sensitivity value displayed by the ultrasonic flaw detector is used as reference sensitivity when the intensity of reflected waves of the artificial defects is equal to 80+/-0.5% of the peak value of the reflected waves.
4. The method according to claim 1, wherein the step 3 is specifically: step 3.1, checking and judging threads; Checking the corrosion conditions of the factory end screw thread and the field end screw thread of the primary oil pipe and the secondary oil pipe and the corrosion conditions of the inner surface and the outer surface within 300mm from the pipe end, judging whether the male end screw thread has the defects of corrosion, sticking buckle and broken screw thread continuity and corrosion pits, cutting the head of the male end screw thread, re-turning the head if the male end screw thread has the defects, and otherwise, executing the step 3.2; step 3.2, checking and judging the coupling; judging whether the first-level oil pipe and the second-level oil pipe have the defects of rusting, sticking buckle and breaking the continuity of the threads of the coupling or whether the outer surface of the coupling has the defects of corrosion and end surface damage exceeding the specified depth, if so, judging that the coupling needs to be replaced, otherwise, executing the step 3.3; And 3.3, repairing and buckling the primary oil pipe and the secondary oil pipe, and replacing the coupling according to the judging result of the step 3.2.
5. The method according to claim 4, wherein the step 4 is specifically that hydrostatic test is performed on the primary oil pipe and the secondary oil pipe by using a hydrostatic test production line and a supporting facility, the test pressure is the hydrostatic test pressure specified by API SPEC 5CT, the full pressure test state is maintained for no less than 10 seconds, whether the oil pipe passes the hydrostatic test is judged, if so, the step 5 is executed, and otherwise, the oil pipe is judged to be scrapped.
6. The method according to claim 5, wherein step 5 further comprises checking the appearance of the threads before the primary and secondary oil pipes are coated and protected, judging whether the pressure test causes damage to the threads, if so, repairing the threads, and returning to step 4, otherwise, continuing to perform step 5.
7. The method according to any one of claims 1 to 6, wherein the step 5 further comprises identifying the primary oil pipe and the secondary oil pipe on which the coating and the protection device are arranged, wherein the identification content comprises a name or trademark of a processing plant, a steel grade, a wall thickness, an outer diameter, a buckle type, hydrostatic test pressure, whether to replace a coupling or not, and an oil pipe grade.
8. The method of claim 1, wherein in step 2.3, the coverage rate of the ultrasonic flaw detector on the workpiece is greater than or equal to 120% when the ultrasonic flaw detector works, and the signal to noise ratio of the ultrasonic flaw detector is greater than 8dB.
9. The method of claim 1, wherein in step 2.1, the items of preliminary visual inspection include the presence or absence of cracks, fissures, pits, corrosion damage to the inner and outer surfaces, damage to the inner and outer surface wire ropes, damage to the outer surface slips and tongs, wear to the inner surface sucker rod, pipe bending, collar appearance and threads, pin thread damage.
10. The method according to claim 1, wherein in the step 6, the primary oil pipe is used according to a new oil pipe using method, the secondary oil pipe is used for a pumping well and an electric pump well, and the strength of the secondary oil pipe is checked according to 80% of the connection strength of a new oil pipe body.

Description

Old oil pipe evaluation and regeneration method Technical Field The invention relates to the field of old oil pipe treatment in the petroleum industry, in particular to an old oil pipe evaluation and regeneration method. Background Tubing is a metallic workpiece that is heavily used in the petroleum industry and the new tubing delivery specifications are typically API Spec5CT, which requires surface finishing of the tubing, does not allow pits to be present in the surface of the tubing to a depth exceeding 12.5% t, or does not allow the remaining wall thickness of the tubing to be less than the minimum required (87.5% t) wall thickness of the tubing. After the oil pipe meeting the technical requirements of API Spec5CT is in a well operation for a period of time, rust pits are formed on the surface of the oil pipe due to corrosion, rust and the like. In order to reduce the purchasing cost of the oil pipe and improve the economic benefit, the old oil pipe needs to be recovered and repaired in the oil field development. In order to ensure the use safety of the repaired old oil pipe in the well, the API SPEC 5CT standard is adopted to detect and judge the old oil pipe at present, but the API SPEC 5CT standard is adopted as the judging standard of the repaired old oil pipe, although the use safety is ensured, the waste judging rate is too high, the recycling economy of the old oil pipe is reduced, and in fact, a plurality of waste judging oil pipes still can meet the use requirement according to different use environment requirements, so the evaluation standard on the new oil pipe is not suitable for recycling the repaired old oil pipe. The usability judgment standard and the repairing method for the old oil pipe are not widely accepted and applied standard or specification promulgated at home and abroad so far. The main reasons are that (1) the judging standard of the old oil pipe is complicated in related factors, not only relates to the production standard of the product, but also relates to the influence of various defects (corrosion, cracks, thread damage, deformation and the like) on the performance of the oil pipe, and is closely related to different service conditions of an oil field; the method comprises the steps of (1) carrying out oil pipe analysis on the oil pipe, wherein the oil pipe is subjected to oil pipe analysis, and (2) the requirements of different oil fields, different blocks and different well conditions on the safety and the economical efficiency of the oil pipe are different, and (3) the method for judging the old oil pipe by using enough data accumulation and preparation can better ensure the organic unity of the economical efficiency and the safety of the old oil pipe judgment. Disclosure of Invention The invention provides an evaluation and regeneration method for an old oil pipe, which aims to solve the problem that the prior art has no unified and applicable method for repairing and judging the availability of the old oil pipe. The old oil pipe evaluation and regeneration method is characterized by comprising the following steps of: step 1, cleaning an oil pipe to be repaired and taking the oil pipe to be repaired, which is unqualified in a drift diameter test, as a scrapped oil pipe; step 2, performing appearance detection and preliminary judgment on the qualified oil pipe in the step 1, and specifically comprising the following steps: Step 2.1, carrying out preliminary visual inspection on the qualified oil pipe in the step 1, and taking the oil pipe to be repaired with pipe bending or pipe deformation as a scrapped oil pipe; step 2.2, measuring corrosion defects which cause wall thickness loss in the qualified oil pipe in the step 2.1, and primarily classifying and judging the corrosion defects into a primary oil pipe to be determined and a secondary oil pipe to be determined according to the depth of a corrosion pit and the degree of linear axial abrasion defects; and 2.3, performing flaw detection and judgment on the undetermined primary oil pipe and the undetermined secondary oil pipe by adopting an ultrasonic flaw detector, wherein the method specifically comprises the following steps of: step 2.3.1, detecting the undetermined primary oil pipe; Performing flaw detection on the to-be-determined first-stage oil pipe judged in the step 2.2, judging whether the to-be-determined first-stage oil pipe meets flaw detection requirements of an L2 acceptance level specified by an API SPEC 5CT 10.15 table C.43, if so, judging the to-be-determined first-stage oil pipe, executing the step 3, otherwise, judging the to-be-determined second-stage oil pipe, and executing the step 2.3.2; Step 2.3.2, detecting the undetermined secondary oil pipe, which specifically comprises the following steps: 2.3.2.1, detecting the undetermined secondary oil pipe judged in the step 2.2 and the step 2.3.1, taking a new oil pipe with the same diameter, wall thickness and material as the original size of the sec