Method for evaluating etching forms of surface of rock plate in acid etching physical simulation test

Abstract

The invention discloses a method for evaluating the etching forms of the surface of a rock plate in an acid etching physical simulation test. The method sequentially comprises the following steps of: A, using a three-dimensional laser scanner to scan the rough surface of the rock plate subjected to acid etching to obtain three-dimensional data on the surface of the rock plate; B, calculating the transverse twisting ratio and the longitudinal twisting ratio of the surface of the rock plate; C, using the two parameters (the transverse twisting ratio and the longitudinal twisting ratio) to classify the etching forms of the surface of the rock plate; D, describing and evaluating various etching forms of the surface of the rock plate on the basis of the classification results; and E, sequentially sequencing various etching forms from the poorest one to the best one. The method has the advantages that a rock sample of an oil and gas reservoir is used for performing the acid etching physical simulation test; and rock samples with different etching forms are obtained through changing different test parameters (acid liquid viscosity, acid liquid concentration and acid injection discharge capacity). The principle is reliable; the operation is simple and convenient; and the guidance can be provided for acid fracturing construction parameter optimization.

Description

technical field [0001] The invention relates to the petroleum field, in particular to an evaluation method of rock slab surface etching morphology in acid etching physical simulation experiments in the field of acid fracturing. Background technique [0002] Acid fracturing (acid fracturing for short) is the main measure for oil and gas stimulation, which is mainly to inject acid liquid (or pre-fluid) into the reservoir under the condition of higher than the fracture pressure of oil and gas reservoirs or the closure pressure of natural fractures. New artificial fractures are formed in the reservoir or natural fractures are opened, and the injected acid solution causes non-uniform etching on the surface of the fractures. After the acid flowback, due to the rough surface of the fracture, the convex part of the surface keeps the fracture open to a certain extent under the closing pressure, thereby forming a fracture that provides a flow space for the fluid and has a certain flow...

AI Technical Summary

Problems solved by technology

In contrast, the domestic research work is still in its infancy, and the existing research results are still unsatisfactory, mainly because the etching of the crack surface by the acid solution is extremely random, and the etching form is complex and changeable. hard to describe

The current research is mainly based on the acid etching physical simulation experiment to describe and evaluate the etching morphology of the rock slab surface, and the results are simply divided into uniform etching and groove-like etching. However, in actual situations, there are still many etching forms that cannot accurately determine which type of etching they belong to, so the etched surface of rock slabs The description and evaluation of morphology is not comprehensive enough and not refined enough

Images