Downhole flexible composite pipe service life prediction method

A flexible composite pipe and life prediction technology, applied in the direction of applying stable tension/pressure to test the strength of materials, can solve the problem of high temperature sensitivity of non-metallic materials

Inactive Publication Date: 2016-05-04
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, non-metallic materials are highly sensitive to temperature, and it is necessary to carry out research on service life evaluation methods under high-temperature and high-pressure produced wa

Method used

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  • Downhole flexible composite pipe service life prediction method

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Effect test

Embodiment 1

[0018] Such as figure 1 As shown, the present invention provides a method for predicting the service life of a downhole flexible composite pipe, comprising the following steps:

[0019] Step 1, select different test blocks, determine the follow-up test wells, and determine the sampling time of each follow-up test well;

[0020] Step 2: According to the determined sampling time, carry out serial inspection operation for each tracking test well. After the serial inspection operation is completed, perform wellbore sampling for each tracking test well, and take out the wellbore samples as sample tubes;

[0021] Step 3, the sample tube taken in step 2 is divided into two parts, one part is subjected to hydrostatic pressure and burst pressure tests, and the other part is subjected to tensile tests;

[0022] Step 4, according to the hydrostatic pressure, burst pressure test and tensile test carried out in step 3, respectively draw the burst pressure-time curve and the tensile streng...

Embodiment 2

[0030] In the process of carrying out wellbore sampling to each tracking test well in the described step 2, the wellbore sampling shall be carried out at the wellhead, the middle part and the bottom of the well respectively; in the described step 4, the breaking pressure-time curve and the tensile strength-time Curve, the blasting pressure-time curve and the tensile strength-time curve of wellhead, the middle part and the bottom of the well should be drawn respectively at the wellhead, the middle part and the bottom of the well, and then, carry out numerical fitting according to the trend respectively; The minimum expected service life value is the minimum value among the expected service life values ​​at the wellhead, middle and bottom of the well.

Embodiment 3

[0032] In the second step, the wellbore is sampled from the wellhead, the middle part and the bottom of the wellbore, and at least 6 sample pipes of different lengths are taken from each part according to different lengths.

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Abstract

The invention discloses a downhole flexible composite pipe service life prediction method, which can effectively evaluate service lives of downhole flexible composite pipes to provide a theoretical basis for the string inspection cycle of the downhole flexible composite pipe water injection process. The main steps are as follows: different test blocks are chosen, and test wells to be tracked regularly are determined; according to different service times, samples are collected at different positions of wellbores, and after sampling, strings are tripped into the original wells; indoor tensile resistance, bursting and hydrostatic pressure are tested on the extracted sample pipes; numerical fitting is conducted on the same test item of the same well at different service times to draw a fitted curve; according to water injection string performance requirements, service lives corresponding to corresponding values, i.e. the service lives of the downhole flexible composite pipe water injection strings, are determined on the fitted curves.

Description

technical field [0001] The invention belongs to the technical field of downhole water injection of non-metallic pipes, and in particular relates to a method for predicting service life of downhole flexible composite pipes. Background technique [0002] The produced water of Changqing Oilfield contains oxygen, scale-forming ions such as Ca2+, Mg2+, Ba2+, SO42-, HCO3-, sulfate-reducing bacteria and saprophytic bacteria, and has strong corrosion performance. According to the corrosivity of produced water, Changqing Oilfield divides the oilfield area into Class I, II and III corrosion areas. At present, domestic produced water reinjection wells generally adopt the coating anti-corrosion process, which is simple to construct and meets the anti-corrosion requirements of produced water re-injection well water injection pipe strings in Class II and III corrosion areas of Changqing Oilfield. For Class I corrosion zone, the service life of this process string is only 3 to 5 years. Fo...

Claims

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Application Information

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IPC IPC(8): G01N3/12G01N3/08
CPCG01N3/12G01N3/08
Inventor 申晓莉姚斌巨亚锋王守虎张随望王薇王俊涛王晓娥胡改星何汝贤
Owner PETROCHINA CO LTD
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