SU1548436A1 - Method of assessing inhibiting properties of drilling muds - Google Patents

Abstract

The invention relates to mining and can be recommended in the practice of drilling as a method for controlling the quality of drilling fluids (BR). The purpose of the invention is to improve the accuracy, reliability and expressness. The moistened rock is poured into the mold and a test specimen is obtained from it by pressing. An indenter (I) is installed on the sample surface, the end of which is made in the form of a pointed tip. Measurements are made directly in the mold. Immerse And in the sample and affect the surface of the sample studied BR. The external load is chosen so as to ensure the invariance of the immersion rate AND in the moistened sample. The depth of penetration And into the sample is measured over a certain period of time. Measurements are carried out on several samples. Determine the average value of H _{in the} depth of penetration And in the sample of rock, which is affected by distilled water, and the average value H _{p of the} depth of introduction And in the sample of rock, which is affected by the studied BR. The inhibiting properties of the solution are evaluated by the indicator Q, the inhibiting ability of the BR, which is determined from the expression Q = H _c - H _p / H _c .

Description

which is made in the form of a pointed (at an angle of 60 °) tip.

Measuring directly in the mold ensures the elimination of undesirable mechanical effects on the rock sample and contributes to the preservation of internal stresses in the sample, close to the reservoir. This leads to an increase in the accuracy and reliability of measurements and to a reduction in the time spent on work on the preparation of a rock sample for measurement.

The use of an indenter, the end of which is made in the form of a pointed tip, provides that the tip of the indenter is constantly supported by a high-strength, not yet exposed to moisture, part of the sample, both at the beginning and at the end of the experiment (measurements), since it suppresses the compression of the weakened (moistened ) the rocks beneath and almost neutralize its inhibitory effect. Thus, the rate of immersion of the indenter in the sample is determined by the rate of impregnation with water or filtrate of the drilling fluid and the corresponding loss of strength of a particular layer of the sample.

The magnitude of the load on the indenter, which has a pointed end geometry, affects its rate of penetration into the rock specimen only up to a certain value that is critical for the rock, which is under the action of water or drilling mud. Under these conditions, the moistening rates of the sample and the indentation of the indenter, i.e. speed invariance is achieved, which leads to an increase in the accuracy and reliability of measurements.

In turn, the maximum of this speed provides an increase in the rapidity of measurements by reducing the time for conducting measurements. Having immersed the indenter in the sample, set the scale of the indicator for the depth of indentation of the indenter to zero.

The sample is exposed to the surface of the sample with distilled water or the drilling mud under test, pouring the surface of the sample and simultaneously include a stopwatch. After a certain period of time has elapsed (4 minutes), fixing the indication is 0.

torus (with an accuracy of 0.01 mm), measure the depth of the indenter in the sample. Measurements are performed on several samples. The mean value hj of the depth of penetration of the indenter into the sample of rock affected by distilled water and the average value h p of the depth of penetration of the indenter into the sample of rock affected by the test mud are determined.

The inhibitory properties of the solution are evaluated in terms of the inhibitory

5 capacity of the solution, which is determined from the expression

q -JlE.0

P8

The high sensitivity of the proposed method for evaluating the inhibitory properties of drilling fluids makes it possible to reveal the best composition of the fluid even with a slight change of 5 (0.1-0.2%) of the concentration of the inhibitory agent.

Claims (1)

The proposed method, which provides an increase in accuracy, reliability and expressiness, can be recommended in the practice of drilling operations as one of the methods for monitoring the quality of drilling fluids in order to optimize their composition during drilling in the occurrence of unstable rocks. Invention Formula A method for evaluating the inhibitory properties of drilling fluids, which consists in moistening the rock and pressing it into a test specimen, the surface of which is exposed to the drilling fluid and, through an indenter, externally applied external stress to the sample for a certain period of time and evaluate mud properties, characterized in that, in order to increase accuracy, reliability and expressiness, an indenter is used, the end of which is made in the form of a pointed tip However, the external load is chosen to ensure the invariance of the rate of immersion of the indenter into the moistened sample, while measurements are made directly 5 in the mold, and the inhibiting properties of the solution are evaluated in terms of the inhibitory capacity of the solution, which is determined from the expression 0 five 0 five 0 5 15484366 q p Pk.jhp respectively depth In the indentation of the indenter into the sample for the same time, q is an indicator of the inhibitory effect of time in the distillation capacity of drilling ripted water and in drilling thief; solution.