Method for evaluating shale stratum borehole wall stabilizing capacity of drilling fluid based on acoustoelectric response

Abstract

The invention discloses a method for evaluating the shale stratum borehole wall stabilizing capacity of drilling fluid based on acoustoelectric response. The method comprises the steps: carrying out well drilling, coring and drying on a shale stratum to be drilled; calculating the density, the longitudinal wave velocity and the resistivity of a test sample; putting the sample into an aging tank ora high-temperature and high-pressure water loss instrument, adding a drilling fluid to be evaluated, enabling the drilling fluid to completely immerse a plunger core sample, applying pressure, and enabling the aging tank or the high-temperature and high-pressure water loss instrument to be at a soaking temperature; after soaking is finished, carrying out cooling, releasing the pressure, and taking out the soaked sample; measuring the length, the diameter and the mass of the sample soaked in the drilling fluid, calculating the density, testing the longitudinal wave velocity and the resistivityof the sample, and calculating the acoustoelectric disturbance comprehensive index; and judging the shale stratum borehole wall stabilizing capacity of the drilling fluid according to the acoustoelectric disturbance comprehensive index. The method provided by the invention provides an efficient and reliable experimental method for drilling fluid performance design, performance optimization and drilling fluid formula system optimization of the shale stratum.

Description

technical field [0001] The invention relates to an indoor evaluation method of drilling fluid, in particular to a method for evaluating the ability of drilling fluid to stabilize the borehole wall of a shale formation based on the acoustic-electric response. Background technique [0002] The collapse and instability of shale formations that are common in the drilling process greatly increases the downhole complex risk, prolongs the drilling cycle and increases the drilling cost. Major problems that have not been effectively resolved. [0003] The wellbore stability of shale formations is not only controlled by geomechanical characteristics such as formation rock mechanical strength and in-situ stress, but also depends on the stability properties such as inhibition and plugging of drilling fluid. Therefore, it is necessary to optimize and optimize the drilling fluid before drilling, so as to maintain the stability of the wellbore in the shale formation to the greatest extent...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for evaluating the ability of drilling fluid to stabilize the borehole wall of shale formations based on acoustic and electric responses, which solves the problem that the existing drilling fluid performance evaluation method has poor adaptability to the wellbore stability performance evaluation of shale formations and cannot be objective , Truly reflect the ability of the drilling fluid to stabilize the borehole wall, and the evaluation results are not accurate and reliable enough

Images