Device for simulating crack initiation and evaluating fissured flow under true triaxial stress

Abstract

The invention discloses a device for simulating crack initiation and evaluating fissured flow under true triaxial stress and belongs to the field of fracture acidizing. The device disclosed by the invention comprises a rock core clamping system, a true triaxial stress loading system, an acid liquor and fracturing fluid injection system, a filtration capacity measuring system and a fracturing data acquisition and processing system, wherein the rock core clamping system is used for clamping a cubic rock core sample which has the side length of 100-300mm and a simulation wellbore is embedded inside the rock core sample; the true triaxial stress loading system is used for applying stresses on the rock core sample in an X axis direction, a Y axis direction and a Z axis direction, so as to simulate a true triaxial stress state of the rock core sample; the acid liquor and fracturing fluid injection system is used for injecting acid liquor and fracturing liquid into the simulation wellbore of the rock core sample, so that crack initiation is carried out on the rock core sample and a fracture extends to simulate the fracture acidizing process of the rock core sample; the filtration capacity measuring system is used for injecting saline water into the rock sample subjected to crack initiation, thus data representing filtration capacity of the fracture of the rock core sample are measured; and the fracturing data acquisition and processing system is used for acquiring data representing a simulated crack initiation process in the rock core sample and data representing the filtration capacity of the fracture in the rock core sample, processing the data and outputting a processing result.

Description

technical field [0001] The invention relates to the field of fracturing and acidizing, in particular to a device for simulating crack initiation and evaluating fracture seepage under true triaxial stress. Background technique [0002] During oil and gas well stimulation operations, fracturing and acidizing processes are usually used to form high-permeability fractures in oil and gas reservoirs to increase seepage capacity. It can be seen that clarifying the fracture propagation mechanism of fracturing and acidizing is of great significance for improving productivity. In addition to mechanical parameters and natural fracture system, horizontal stress difference, liquid performance, construction fluid volume, construction displacement, etc. are all key factors affecting fractures after fracturing. Therefore, the fracture simulation device is the most important and effective means to study fractures. Ordinary fracture simulators cannot truly simulate formation conditions, and ...

AI Technical Summary

Problems solved by technology

[0005] The devices provided by the prior art are suitable for small core specimens, which cannot avoid the influence of boundary seepage conditions; the pressure range is small, and it is impossible to simulate the cracking process of acid fluid or fracturing fluid under high stress difference conditions, and it is impossible to perform fracturing Determination of post-seepage rate

In addition, the energy of the acoustic emission monitoring system used is low, making it difficult to accurately locate and describe complex or small cracks

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