Hydraulic fracturing test apparatus based on conventional testing machine for rock mechanics, rock specimen and hydraulic fracturing testing method

Abstract

The invention provides a hydraulic fracturing test apparatus based on a conventional testing machine for rock mechanics. The hydraulic fracturing test apparatus comprises a lower pressing head and an upper pressing head. The lower pressing head is arranged on a triaxial base plate, and an axial compression bar acts on the upper pressing head. Both the upper pressing head and the lower pressing head are designed with pressure water channels. The hydraulic fracturing test apparatus is characterized by further comprising a leak-proof sleeve and a permeable plate; the leak-proof sleeve sleeves the rock specimen to prevent pressure water from mixing with confining oil in a triaxial chamber, and the upper end and the lower end of the leak-proof sleeve are respectively fixed to the upper pressing head and the lower pressing head; the permeable plate is distributed with pressure water permeable holes and is arranged between the rock specimen at the pressure water outlet end and the upper pressing head; one of the upper pressing head and the lower pressing head is a pressing head combination combined by an acting pressing head acting on the rock specimen and an adapting pressing head, and the acting pressing head is connected with the adapting pressing head through a tongue-and-groove insertion structure. The invention further provides the rock specimen for the apparatus and the hydraulic fracturing testing method utilizing the hydraulic fracturing test apparatus based on the conventional testing machine for rock mechanics to achieve hydraulic fracturing tests on the conventional test machine for rock mechanics.

Description

technical field [0001] The invention belongs to the field of hydraulic fracturing indoor experiments, and in particular relates to a device, a rock sample and a method for realizing hydraulic fracturing experiments on a conventional rock mechanics testing machine. Background technique [0002] As a high-quality and efficient clean energy, natural gas occupies a very important position in my country's energy structure. However, in the short term, my country's conventional natural gas extraction capacity cannot match the rapidly growing demand, and it is urgent to increase the exploration and development of unconventional natural gas. Most unconventional natural gas reservoirs have the characteristics of "low porosity and low permeability", so one of the core technologies for unconventional natural gas exploitation is fracturing and permeability enhancement of reservoirs, and hydraulic fracturing technology is the current reservoir fracturing transformation the most mature tec...

AI Technical Summary

Problems solved by technology

However, the rock core taken out of the well is a cylindrical sample, which needs to go through a series of cumbersome processes such as cutting and grinding in the process of processing it into a hexahedral sample, which will cause unnecessary damage to the rock, and the size of the sample will also be reduced after processing

Moreover, the true triaxial experimental system has high requirements on the parallelism and perpendicularity of each surface of the specimen. No matter whether the rock specimen is processed by using core or outcrop, it will face problems such as processing difficulties and high processing costs.

The true triaxial experimental system itself is very expensive, and has high requirements for the anti-leakage sleeve that wraps the sample, which increases the experimental cost

In addition, the true three-axis experimental system is difficult to control and has low experimental accuracy when performing experiments.

These all limit the research depth of hydraulic fracturing technology to a certain extent.

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