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A productivity evaluation method for determining unsteady flow pressure correction in low permeability gas wells

An evaluation method and a technique for stabilizing flow, applied in earth-moving drilling, wellbore/well components, measurement, etc., can solve the problems of complex testing process, poor field application promotion, unstable flow pressure, etc. The effect of promoting application prospects and strong applicability

Active Publication Date: 2022-03-29
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because isochronous well test or corrected isochronous well test has complex testing process, multiple processes, and long test time, and requires isochronous well test and corrected isochronous well test, the extended test flow pressure and production are stable, and the shut-in pressure recovery is stable; However, it is sometimes difficult to achieve in actual operation, and the conventional back pressure test is directly used for productivity test on site
Due to stress sensitivity, starting pressure gradient and high-velocity non-Darcy effects often appear in low-permeability gas wells, the flow pressure of each working system of the back pressure test is unstable, and there is no extended test stability point for correction, making the productivity evaluation of low-permeability gas wells The result is quite different from the actual
In order to solve this problem, the existing technical method starts from the seepage differential equation and converts the back pressure well test into the modified isochronous well test for productivity evaluation; however, this method requires the interpreter to have a deep theoretical foundation, and the field application is poor in generalization, and the productivity Evaluation takes a long time

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  • A productivity evaluation method for determining unsteady flow pressure correction in low permeability gas wells
  • A productivity evaluation method for determining unsteady flow pressure correction in low permeability gas wells

Examples

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Embodiment 1

[0024] As a preferred embodiment of the present invention, with reference to the attached figure 1 and 2 , this example discloses:

[0025] The productivity evaluation method for determining unsteady flow pressure correction of low-permeability gas wells includes the following steps:

[0026] S1. Well test interpretation steps: use commercial well test software to interpret the pressure recovery test section at the end of the back pressure test well shut-in, and obtain relevant parameters of the wellbore and formation of the gas well;

[0027] S2. Process conversion step: through the well test design module of the commercial well test software, keep the back pressure well test work system unchanged, and perform the amended isochronous well test conversion. For the first N-1 back pressure work systems, each work system Afterwards, a shut-in pressure recovery test at the same time as the back pressure well test work system is added, and for the Nth back pressure work system, a...

Embodiment 2

[0031] As another preferred embodiment of the present invention, with reference to the attached figure 1 and 2 , this example discloses:

[0032] The productivity evaluation method for determining unsteady flow pressure correction of low-permeability gas wells includes the following steps:

[0033] S1. Well test interpretation: Input gas well reservoir thickness, porosity, water saturation, gas relative density, formation pressure temperature, back pressure test working system and bottom hole pressure data into commercial well test software such as Saphir; comprehensive static and dynamic Accurately select the well test model from the data to interpret the final shut-in pressure recovery test section, and obtain relevant parameters such as the wellbore and formation of the gas well;

[0034] S2. Process conversion: transfer to the well test design module of commercial well testing software, keep the working system of back pressure well testing unchanged and perform isochrono...

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Abstract

The invention discloses a productivity evaluation method for determining unsteady flow pressure correction of a low-permeability gas well, and relates to the technical field of natural gas exploitation. The key to the technical solution of the present invention is to directly use the parameters that can reflect the real information of the wellbore and the formation of the low-permeability gas well to construct a prediction model, to modify the design of the corrected isochronous well test process repeatedly, and to simulate the actual production capacity test process on site to achieve the best evaluation effect. This method does not require complex formula derivation, and can realize process conversion and production capacity evaluation in the same software platform. The evaluation speed is fast, the operation is simple, and it is easy to promote.

Description

technical field [0001] The invention relates to the technical field of natural gas exploitation, in particular to a productivity evaluation method for determining unsteady flow pressure correction of low-permeability gas wells. Background technique [0002] Low-permeability gas well reservoirs have poor reservoir properties, low porosity and low permeability characteristics. During the testing and production process, the opening flow pressure drops rapidly and the shut-in pressure recovers slowly. Therefore, the productivity test of low-permeability gas wells generally uses isochronous well testing or correction Time to test the well. Because isochronous well test or corrected isochronous well test has complex testing process, multiple processes, and long test time, and requires isochronous well test and corrected isochronous well test, the extended test flow pressure and production are stable, and the shut-in pressure recovery is stable; However, it is sometimes difficult ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B47/00E21B49/00
CPCE21B47/00E21B49/00
Inventor 张文彪刘荣和李洪玺陈杰
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD