Plugging effect evaluation method for low-aperture low-permeability formation

An evaluation method and technology of holes and slits, applied in earthwork drilling, wellbore/well parts, etc., can solve the problems of inaccurate evaluation results, poor repeatability, complicated operation, etc., and achieve low cost, short time consumption and good repeatability Effect

Active Publication Date: 2018-09-11
SOUTHWEST PETROLEUM UNIV
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  • Claims
  • Application Information

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Problems solved by technology

[0009] However, the above evaluation methods have problems such as poor repeatability, inaccurate evaluation results, complicated operation, long time-consuming and high cost. There is an urgent need for a convenient, accurate, simple, and low-cost evaluation method for shale drilling fluid plugging performance. Development of Water-based Drilling Fluid Technology for Rock Gas

Method used

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  • Plugging effect evaluation method for low-aperture low-permeability formation
  • Plugging effect evaluation method for low-aperture low-permeability formation
  • Plugging effect evaluation method for low-aperture low-permeability formation

Examples

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Effect test

Embodiment 1

[0154] This example is used to illustrate the plugging effect evaluation method for low porosity, fracture and low permeability formations of the present invention.

[0155] (1) Preparation of "simulated core" of low porosity, fracture and low permeability formation

[0156] Measure a certain volume of 10% prehydrated bentonite slurry (10% bentonite + 5% Na 2 CO 3 ) into an enamel cup, add 1.5% SXY while stirring with a D96 electric mixer, and after stirring for 40 minutes, pour it into a high-temperature aging tank, seal and hydrate at 60°C for 24 hours, take it out and cool it to room temperature, and pour it into an enamel cup while stirring While adding 0.5% FV-2, continue to stir until there is no "fish eye" (about 40min), then add 70g of barite (API barite: nanobarite = 7:3), and stir for 40min , put it into the aging tank, and roll it under the condition of 105°C / 16h to prepare the standard slurry for plugging evaluation.

[0157] Cool the standard slurry to room tem...

Embodiment 2

[0174] This example is used to illustrate the plugging effect evaluation method for low porosity, fracture and low permeability formations of the present invention.

[0175] Evaluate according to the same method as in Example 1, the difference is that the formulation of the drilling fluid containing the plugging agent is: zwitterionic polymer system b: zwitterionic polymer system a+plugging agent YFD-1 ( blocking agent).

[0176] Permeability reduction rate K of drilling fluid containing plugging agent r and K 0 and K 1 As shown in Table 1.

Embodiment 3

[0178] This example is used to illustrate the plugging effect evaluation method for low porosity, fracture and low permeability formations of the present invention.

[0179] Evaluate according to the same method as in Example 1, except that the formula of the drilling fluid containing the plugging agent is: amphoteric potassium-based polyalcohol system a: 4% soil slurry+0.2%FV-2+0.3 %FA 367 +1.6%JT 888 +33%KCOOH+0.1%XY 27 +0.05%CaO+5.0%CaCO 3 +2.0% RH-220.

[0180] Permeability reduction rate K of drilling fluid containing plugging agent r and K 0 and K 1As shown in Table 1.

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Abstract

The invention belongs to the field of evaluation of plugging effects, relates to a test evaluation method, and particularly discloses a plugging effect evaluation method for a low-aperture low-permeability formation. The method comprises the following steps that (1) 'simulation corestone' of the low-aperture low-permeability formation is prepared; (2) the prepared 'simulation corestone' serves asa filtering medium of a high-temperature and high-pressure filtration instrument, and the average permeability of a drilling fluid the drilling fluid not containing a blocking agent and drilling fluidcontaining the blocking agent is measured; and (3) the reduction rate of the average permeability of the drilling fluid containing the blocking agent is calculated. The method has the advantages of simple operation, good repeatability, low cost, short time consumption, accurate evaluation results and the like, in addition, the established plugging effect evaluation method for the low-aperture low-permeability formation is conductive to quickening the technological progress of the water-based drilling fluid such as shale gas.

Description

technical field [0001] The invention belongs to the field of evaluating plugging effect, relates to a test evaluation method, in particular to a method for evaluating plugging effect of low porosity, fracture and low permeability strata. Background technique [0002] The use of oil-based drilling fluids to drill shale gas wells has defects such as high cost, serious environmental pollution, danger, and difficulty in recovery. All these shortcomings of oil-based drilling fluids have led people to start researching water-based drilling fluids, but water-based drilling fluids are harmful to shale There is no direct and effective way to evaluate the plugging effect, which restricts the development of water-based drilling fluid technology. [0003] Over the years, scholars at home and abroad have studied the evaluation methods of drilling fluid plugging performance, and established more than ten methods. [0004] The most commonly used methods to evaluate the plugging performanc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B49/00
CPCE21B49/005
Inventor 王平全唐涛白杨陈杰宋丹王建龙邓嘉丁杨萍
Owner SOUTHWEST PETROLEUM UNIV
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