CN-117307131-B - Comprehensive diagnosis method for corrosion perforation of oil pipe

CN117307131BCN 117307131 BCN117307131 BCN 117307131BCN-117307131-B

Abstract

The invention relates to the technical field of oil and gas well production, in particular to an oil pipe corrosion perforation comprehensive diagnosis method which comprises the following steps of monitoring pressure difference to judge that perforation or fracture of an oil pipe possibly occurs, verifying gas lift, determining that perforation or fracture occurs in the oil pipe through injecting a gas source from an oil sleeve annulus through a pump, detecting a hoop-saving signal of a pipe column through a gamma magnetic positioning instrument in a shaft, judging whether the oil pipe is broken or perforated, measuring the inner diameter of the oil pipe, obtaining the number and distribution positions of holes through an electromagnetic flaw detector, and establishing a salvage treatment scheme. The advantages of all detection schemes are integrated, the rapid and accurate acquisition of the diagnosis result is realized, decision basis is provided for oil pipe treatment, the defects of low judgment efficiency and inaccurate judgment result caused by experience errors are avoided in the diagnosis process compared with the judgment of single experience, the resource waste caused by directly adopting an instrument for flaw detection is also avoided, and the method has a wide application prospect.

Inventors

LI ZHILI
YAN XIAOYONG
NI JIE
LI JIAYU
QIU LEI
ZHANG WUZHUANG
LONG YONGPING
WANG TENG
XIE JING

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南油气分公司

Dates

Publication Date: 20260512
Application Date: 20220623

Claims (1)

1. The comprehensive diagnosis method for the corrosion perforation of the oil pipe is characterized by comprising the following steps of: Monitoring differential pressure, namely monitoring the differential pressure value of the oil pressure and the sleeve pressure in real time, judging that perforation or fracture of the oil pipe possibly occurs if the differential pressure value is instantaneously reduced, and performing a second step; Step two, gas lift verification, namely injecting a gas source from the annular space of the oil sleeve through a pump, monitoring the pumping pressure value of the pump, the gas pressure value in the oil pipe and the annular liquid level position in real time, calculating a theoretical pumping pressure value according to the annular liquid level position when the oil pipe is pressurized, and if the pumping pressure value of the pump when the oil pipe is pressurized is lower than the theoretical pumping pressure value, determining that the oil pipe is perforated or broken, and carrying out step three; step three, magnetic positioning verification, namely detecting a joint hoop signal of a pipe column by putting a gamma magnetic positioning instrument into a shaft, judging whether an oil pipe is broken or perforated according to the change condition of the joint hoop signal, and carrying out step five if the oil pipe is broken; measuring the inner diameter of the oil pipe, determining the wall thickness loss of the oil pipe through an electromagnetic flaw detector, and obtaining the number and distribution positions of the holes; Step five, making a salvage treatment scheme; Step two, nitrogen is injected into the annular space of the oil sleeve through the gas lift truck; In the second step, the difference between the pump pressure value of the pump and the theoretical pump pressure value when the oil pipe is pressurized is inversely related to the distance between the perforation or fracture position and the wellhead; step two, synchronously monitoring the interval time from the pumping to the oil pipe pressurizing, wherein the interval time is positively correlated with the distance between the perforation or fracture position and the wellhead; Judging that the oil pipe breaks if the joint hoop signal weakens and the interval distance of the joint hoop signal is consistent with the length of the single sleeve, and judging that the oil pipe is perforated if the joint hoop signal is regular and consistent; Step one, respectively acquiring monitoring curves of oil pressure, casing pressure and oil casing pressure difference, in step two, respectively acquiring monitoring curves of pump pressure value of a pump, air pressure value in an oil pipe and annular liquid level position, synchronously timing, and prompting a judging result by a computer according to the fluctuation state of the monitoring curves; In the fifth step, if the oil pipe is broken, the salvage treatment scheme comprises a fish top shape acquisition step and a salvage step, and if the oil pipe is perforated, the salvage treatment scheme comprises a hole plugging step and an oil pipe lifting step.

Description

Comprehensive diagnosis method for corrosion perforation of oil pipe Technical Field The invention relates to the technical field of oil and gas well production, in particular to a comprehensive diagnosis method for corrosion perforation of an oil pipe of a shale gas well. Background In the production stage of the shale gas well by adopting the oil pipe, the bacteria bred in the pressure return liquid can continuously corrode the oil pipe, and the fracturing sand can also continuously erode the oil pipe, so that part of the oil pipe of the shale gas well is corroded and perforated, even the oil pipe is broken, and if the corroded and perforated hole is not found and treated in time, serious harm is caused to the production of the gas well, and the normal production of the gas well is influenced. At present, the corrosion perforation of the shale gas well oil pipe is generally obtained through experience judgment or data calculation after long-time monitoring of the wellhead pressure change condition, but specific conditions such as corrosion degree, perforation number, perforation distribution and the like cannot be intuitively judged and obtained, so that the corrosion perforation condition of the shale gas well oil pipe cannot be rapidly and accurately diagnosed, timely implementation of treatment measures is affected, and normal production of a gas well is affected. Therefore, a technical scheme is needed at present to solve the technical problems that the specific condition of the corrosion perforation of the existing shale gas oil pipe cannot be timely diagnosed and known, and the normal production of a gas well is affected. Disclosure of Invention The invention aims to provide a comprehensive diagnosis method for corrosion perforation of an oil pipe, aiming at the technical problem that the specific condition of corrosion perforation of the existing shale gas oil pipe cannot be timely diagnosed and known and normal production of a gas well is affected. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The comprehensive diagnosis method for corrosion perforation of oil pipe comprises monitoring differential pressure, real-time monitoring oil pressure and sleeve pressure difference, judging perforation or fracture of oil pipe if the difference is instantaneously reduced, and performing step two; step three, magnetic positioning verification, namely detecting a hoop-saving signal of a pipe column by a gamma magnetic positioning instrument in a shaft, judging whether the oil pipe is broken or perforated according to the change condition of the hoop-saving signal, and carrying out step five, if the oil pipe is broken, carrying out step four, namely measuring the inner diameter of the oil pipe, determining the wall thickness loss of the oil pipe by an electromagnetic flaw detector, and obtaining the number and distribution position of the holes, and step five, namely making a salvaging treatment scheme. According to the comprehensive diagnosis method for the oil pipe corrosion perforation, after preliminary judgment is carried out through pressure difference monitoring, the results of all detection schemes are integrated by combining the detection processes of gas lift verification, magnetic positioning verification and electromagnetic flaw detection, so that the rapid and accurate acquisition of diagnosis results is realized, a more scientific and reasonable decision basis is provided for oil pipe treatment, compared with the judgment of single experience, the diagnosis process avoids the defects of low judgment efficiency and inaccurate judgment results caused by experience errors, also avoids the resource waste caused by directly adopting an instrument flaw detection, and has a wide application prospect. In the second step, nitrogen is injected into the oil sleeve annulus through the gas lift truck. In the second step, the difference between the pump pressure value of the pump when the oil pipe is pressurized and the theoretical pump pressure value and the distance between the perforation or fracture position and the wellhead are inversely related. In the second step, the interval time from the start of the pump to the start of the pressure of the oil pipe is synchronously monitored, and the interval time is positively correlated with the distance between the perforation or fracture position and the wellhead. In the third step, if the joint hoop signal is weakened and the interval distance of the joint hoop signal is consistent with the length of the single sleeve, the oil pipe is judged to be broken, and if the joint hoop signal is regular and consistent, the oil pipe is judged to be perforated. In the first step, the monitoring curves of oil pressure, casing pressure and oil casing pressure difference are respectively obtained, in the second step, the monitoring curves of pump pressure value of the pump, air pressure value in the oil pipe and annular li