Method for fast confirming compact rock core damage

A core and dense technology, applied in the field of quickly determining the damage of dense cores, can solve the problems of time-consuming, large errors, and high requirements for experimental equipment, and achieve the effects of difficult measurement, rapid damage, and easy evaporation

Active Publication Date: 2009-07-22
SOUTHWEST PETROLEUM UNIV
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for quickly determining the damage of tight rock cores. The method evaluates the damage degree of fluids to tight rock cores by the pressure decay rate when the fluid passes through the rock cores under a certain initial pressure, which can effectively solve the problem of the existing evaluation methods in evaluating When the working fluid damages the tight core, it has the disadvantages of high requirements for experimental equipment, time-consuming and large errors.

Method used

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  • Method for fast confirming compact rock core damage
  • Method for fast confirming compact rock core damage
  • Method for fast confirming compact rock core damage

Examples

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Effect test

Embodiment 1

[0042] Two tight sandstone cores with similar lithology and physical properties in western Sichuan outcrop were selected to evaluate the damage degree of distilled water to the cores by the invented method. The experimental results show that the permeability is 0.115×10 -3 μm 2 Under the confining pressure of 3MPa, the pressure half-life of the 3% KCl solution and the initial pressure of distilled water 0.8MPa are 285min and 375min respectively, and the damage rate calculated by the inventive method is 24%; the other piece has a permeability of 0.1×10 -3 μm 2 Under the confining pressure of 3MPa, the pressure half-life of the 3% KCl solution and the initial pressure of distilled water at 0.8MPa are 375min and 525min respectively, and the damage rate calculated by the inventive method is 28.57%. Distilled water has weak damage to the two cores with similar lithology and physical properties.

Embodiment 2

[0044] Two tight sandstone cores with similar lithology and physical properties in outcrops in western Sichuan were selected to evaluate the damage degree of alkali solution to the cores by the method of the invention. The experimental results show that the permeability is 0.094×10 -3 μm 2 Under the confining pressure of 3MPa, the pressure half-life of 3% KCl solution and 3% KCl solution with a pH value of 13 (that is, adding lye to 3% KCl solution) at an initial pressure of 0.8MPa is 375min and 405min respectively, The damage rate calculated by the inventive method is 7.41%; the other block has a permeability rate of 0.075×10 -3 μm 2 Under the confining pressure of 3MPa, the pressure half-life of 3% KCl solution and 3% KCl solution with a pH value of 13 at an initial pressure of 0.8MPa are 405min and 435min respectively, and the damage rate calculated by the inventive method is 6.90%. The lye with a pH value of 13 has weak damage to the two cores with similar lithology and...

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Abstract

The invention relates to a method for fast determination of damage compact core to determine the damage rate and evaluate the damage degree of the fluids to the compact core according to the half-life change of pressure through the pressure attenuation experiment when the fluid passes through the core under a certain initial pressure. The invention overcomes the shortcomings, such as high requirement of laboratory equipment, high time consumption, big error and the like, in the evaluation of working fluid that damages the compact core through the current evaluation methods, and is capable of fast evaluating the sensitive damage from the compact reservoir fluid and damage degree from the working fluid to provide foundation for the damage mechanism diagnosis of oil-gas bed and the preference of working fluid.

Description

Technical field: [0001] The invention relates to a damage evaluation method for oil and natural gas reservoirs. The method can quickly determine the sensitivity damage of tight reservoir fluid and the damage degree of working fluid without measuring the flow rate of the core, reducing the error of the flow measurement of the tight core, and can be Diagnosis of oil and gas layer damage mechanism and providing basis for optimization of working fluid belong to the experimental method of oil and gas layer protection in the process of oil and gas exploration and development. Background technique: [0002] With the sharp decline in the production of conventional oil and gas resources and the increasing demand for oil and gas, low-permeability oil reservoirs and tight gas reservoirs (including tight sandstone gas reservoirs, tight carbonate rock gas reservoirs and shale gas reservoirs) urgently need to be developed on a large scale. However, tight gas reservoirs are characterized b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/00
Inventor 游利军康毅力杜新龙李相臣
Owner SOUTHWEST PETROLEUM UNIV
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