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A method for selecting wells and layers for repeated fracturing of gas wells

A technology for repeated fracturing and gas wells, which is applied in wellbore/well components, earthwork drilling, data processing applications, etc. It can solve problems such as unreliable experience, numerous calculation parameters, and inaccurate calculations, and achieve strong portability, Effects with high accuracy and simple calculation

Active Publication Date: 2020-08-07
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] (1) The field experience method lacks theoretical and data support, and there is a problem of unreliable experience, and the accuracy rate is low;
[0006] (2) Fuzzy identification method, artificial neural network method is used to calculate by establishing geological and engineering factor models or equations related to repeated fracturing. On the one hand, the calculation process is complicated and difficult to implement. Factors and subfactors are difficult to distinguish and easily reversed

Method used

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  • A method for selecting wells and layers for repeated fracturing of gas wells
  • A method for selecting wells and layers for repeated fracturing of gas wells
  • A method for selecting wells and layers for repeated fracturing of gas wells

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Effect test

Embodiment 1

[0036] This embodiment provides a method for selecting wells and layers for repeated fracturing of gas wells, comprising the following steps:

[0037] Step 1) Calculate the poroelastic stress-steering coefficient Π according to the rock mechanics parameters Poisson's ratio, in-situ stress, gas zone formation pressure, and bottomhole flow pressure poro , Π poro Gas wells <2 are the primary target gas wells for refracturing;

[0038] Step 2) Calculate the gas leakage volume V according to the gas reservoir pressure coefficient, bottom hole flow pressure, single well daily gas production, and production time of the primary target gas well selected for refracturing d ;

[0039] Step 3) Calculate the instantaneous recovery rate IRR according to the cumulative gas production and gas leakage volume of the primary target gas well selected for refracturing, when V d >3.3, select the gas well with IRRd 0.21 as secondary target gas wells for refracturing;

[0040] Step 4) Calculate t...

Embodiment 2

[0046] On the basis of Embodiment 1, this embodiment provides a method for selecting wells and layers for repeated fracturing of gas wells. The process is as follows:

[0047] Step 1) Calculate the poroelastic stress steering coefficient Π according to the rock mechanics parameters Poisson's ratio, in-situ stress, formation pressure of the gas zone, and bottomhole flow pressure poro ,Calculated as follows:

[0048]

[0049] Where: σ hmax —Maximum in-situ horizontal stress, MPa; σ hmin —Minimum in-situ horizontal stress, MPa; σ * —stress difference caused by pore pressure gradient, mm; γ—Poisson’s ratio; —gas reservoir pressure, MPa; P wf —Bottomhole pressure, MPa.

[0050] select Π poro The gas wells with <2 are the primary target gas wells for refracturing.

[0051] Step 2) Calculate the gas leakage volume V according to the gas reservoir pressure coefficient, bottom hole flow pressure, single well daily gas production, and production time of the primary target gas...

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Abstract

The invention provides a gas well re-fracturing well selection and layer selection method. The gas well re-fracturing well selection and layer selection method comprises the following steps: (1) calculating a porous elastic stress steering coefficient Piporo; (2) taking a well selected according to step (1) as an alternative target well for repeated fracturing, calculating the deflation volume Vdof the target well; (3) calculating the instantaneous recovery percent IRR; (4) calculating the yield decreasing coefficient Di by taking the well selected according to step (3) as an alternative target well for repeated fracturing; (5) calculating a gas reservoir attenuation coefficient RDep by taking the well selected according to step (4) as an alternative target well for repeated fracturing; (6) calculating each single-layer reserve abundance omegai of the target well, and selecting a layer with the air layer reserve abundance greater than 0.2 as an alternative air layer for repeated fracturing. According to the gas well re-fracturing well selection and layer selection method, a judgment algorithm is determined by application of mathematical statistics and the dynamic analysis of the gas reservoir engineering, and the calculation is simple. In the method, factors affecting the repeated fracturing are considered comprehensively, the repeated fracturing well and layer are optimized,the implementation accuracy is high, the method has high transplantability, and the application is wide.

Description

technical field [0001] The invention belongs to the technical field of gas field fracturing, and in particular relates to a method for selecting wells and layers for repeated fracturing of gas wells. Background technique [0002] Tight gas reservoirs are one of the important positions to increase reserves and increase production in Changqing Oilfield. It is very difficult for the gas field to maintain stable production without drilling new wells. Therefore, it is urgent to repeat the reconstruction of some low-production wells to restore their fracture conductivity To re-improve the productivity of single well; for some gas wells with considerable production in the short term but with greater potential after transformation, reasonable transformation can obtain higher single well productivity and improve the recovery rate of the well group. [0003] There have been successful attempts at refracturing of gas wells at home and abroad. The commonality is to analyze the causes of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/26G06Q50/02
CPCE21B43/26G06Q50/02
Inventor 白建文牟春国李达马得华贾建鹏胡子见衣德强梁凌云邝聃魏克颖孙振何平张家志滕飞启崔云群张家富薛亚斐吴明松朱李安
Owner PETROCHINA CO LTD
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