Rock-like material for simulating reservoir rock heterogeneity and test piece preparation method

Abstract

The invention relates to a rock-like material for simulating reservoir rock heterogeneity and a test piece preparation method, and belongs to the field of rock-like material preparation. The method comprises the following steps: measuring reservoir rock heterogeneity, particle size distribution condition and mechanical parameters; analyzing the influence of the particle size ratio degree on the reservoir rock heterogeneity and the mechanical parameter sensitivity of the rock-like material, and establishing a grading model and a mathematical relationship curve of the rock-like material with different heterogeneity degrees under different particle size ratio conditions by taking the particle size of the quartz sand particles as an index; referring to a fracturing test, and selecting quartz sand particles with corresponding particle sizes to perform aggregate proportioning by using a heterogeneous degree of rock and a rock-like specimen aggregate particle size grading schematic table; preparing a rock-like test piece by taking the quartz sand particles as aggregate, and carrying out maintaining and demolding operation to obtain the rock-like material. The heterogeneous rock-like material provided by the invention can well reflect the control effect of the particle size on the rock heterogeneity, and can accurately describe heterogeneity characteristics of a complex lithologic stratum.

Description

technical field [0001] The invention belongs to the field of preparation of rock-like materials, and in particular relates to a rock-like material for simulating reservoir rock heterogeneity and a method for preparing a test piece. Background technique [0002] The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. [0003] Through the observation of the fracture system formed by the tectonic activities of tight reservoir rocks and many phenomena such as topography, landform, and geological structure, as well as the research on the correlation between neotectonic activities and oil and gas accumulation, it is shown that the heterogeneity of reservoir rocks is the cause of rock formation. One of the main reasons for t...

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Problems solved by technology

[0007] (1) Since the general reservoir rocks have undergone long-term geological tectonic action and the conditions are complex, the crystal particle size inside the original rock cannot be artificially controlled and sampling is difficult

On the other hand, defects such as primary fractures and joints in the reservoir rock will have an impact on the hydraulic fracturing test results of the reservoir rock.

[0008] (2) When studying the influence of reservoir rock joints, natural fractures and other factors on hydraulic fracturing tests, due to the complex structure of natural rock mass and various structural surface shapes, it is necessary to collect natural rock mass specimens containing joints, natural cracks, etc. Very difficult and susceptible to damage to structural surfaces due to artificial disturbance

However, the specimens processed by manpower into structures including joints or prefabricated cracks are not only complicated in workmanship, but also difficult to meet the accuracy requirements of the test.

[0009] (3) The hydraulic fracturing test based on the original rock is difficult to monitor the mechanical response of the rock during the fracturing process, which limits the analysis and research on the crack propagation mechanism, and the test results based on real rock samples are difficult to repeat, which limits the Study on the damage pattern of the specimen under the influence of different factors

[0010] (4) Reservoir rocks are highly heterogeneous, which has a great impact on hydraulic fracturing and other experimental research, and is not a homogeneous form as considered by traditional rock-like materials research

The rock-like specimens prepared so far have not considered the influence of reservoir rock heterogeneity, and there is a lack of clear standards to characterize the degree of heterogeneity of rock-like materials

[0011] To sum up, the existing rock-like materials cannot truly reflect the differences in the heterogeneity of reservoir rocks in actual hydraulic fracturing engineering. How to accurately and conveniently prepare rock-like specimens that can reflect the actual rock heterogeneity has become an important and urgent issue. Research topics that need to be solved urgently

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