Testing device for anisotropism of shale in true-triaxial condition and testing method of testing device

Abstract

The invention discloses a testing device for the anisotropism of shale in a true-triaxial condition and a testing method of the testing device, and aims at solving the problems that the conventional testing method for the anisotropism of shale needs at least 3 times of coring, and the anisotropism of the shale at true crustal stress state cannot be really reflected. The testing device comprises a pressurization mechanism, an acoustoelectric testing mechanism and a data processing mechanism, wherein the pressurization mechanism can apply different pressures to X, Y and Z directions, so that the stress state of the shale in a formation condition can be more really simulated. The acoustoelectric testing mechanism can measure the sound wave and the specific resistance of the shale when the mechansim forms 0 degrees, 45 degrees and 90 degrees with shale bedding. The acoustic and electrical anisotropisms of the shale can be obtained through measured sound wave and specific resistance information. The testing device has the advantages that rock samples are easy to obtain, the success ratio is high, the measurement result is real and reliable, and a reference base can be provided for the accurate evaluation of the thickness of a container rock, the accurate evaluation of water saturation and the design of a fracturing operation scheme.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploration, in particular to a device for testing shale anisotropy under true triaxial conditions and a testing method thereof. Background technique [0002] Shale is a kind of clay rock. After compaction, dehydration, and recrystallization, the clay material has a small mineral composition, the particle size is less than 1 / 256mm, and it has a sheet-like or thin-sheet shape. It is brittle and permeable. Sex is bad. Complex geological structure, deep burial, complex in-situ stress and different maturity are the reasons for the strong anisotropy of shale. Accurately evaluating the anisotropy of shale is essential for understanding the thickness of shale gas reservoirs and estimating water saturation, establishing appropriate closure pressures during fracturing operations, forming criss-cross fracture networks, and determining appropriate safe density windows to ensure Wellbore stability is of g...

AI Technical Summary

Problems solved by technology

However, there are certain deficiencies in the traditional method. First of all, for the first method, at least three samples need to be prepared for the experiment, and the shale is highly brittle, and the clay mineral content is high and easy to hydrate and expand. Water must be used in the coring process, which is easy to cause The shale fractures along the bedding plane, and it is difficult to obtain rock samples that are 45° from the shale bedding, making it difficult to carry out experiments

Shale has strong heterogeneity, and the three samples will have certain differences in mineral composition and rock mechanical properties, resulting in the obtained shale anisotropy that cannot truly reflect the properties of the rock

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