Method and device for predicting permeability on basis of pore structures of carbonate rock

Abstract

The invention provides a method and a device for predicting permeability on the basis of pore structures of carbonate rock. According to the method, firstly, the pore structures are classified on thebasis of similarity level of mercury injection curves, then each type of pore structure reservoir is analyzed with a mathematical statistics method, key pore throat size Rs for controlling permeability is identified, and the relation between the key pore throat size Rs and the permeability of each type of pore structure is established, so that the permeability of a highly anisotropic reservoir canbe predicted. According to the provided scheme, microscale and macroscale combination is realized by comprehensively using a core, property testing, mercury injection and well logging, the theoretical basis is firm, the operability is high, and practice proves that the method and the device have good application effect and high applicability to porous-type carbonate rock reservoirs, can effectively predict the permeability of the carbonate rock and have great significance in identification of barriers and interlayers of highly anisotropic carbonate rock as well as design and regulation of oiland gas field development programs.

Description

technical field [0001] The invention belongs to the technical field of oil field development, and in particular relates to a method and a device for predicting permeability based on carbonate rock pore structure. Background technique [0002] The permeability of reservoir rock refers to the property that rock allows fluid to pass under the action of pressure difference. It is a key parameter reflecting the seepage capacity of reservoir rock. Accurate prediction of permeability is very important for the design and adjustment of oil and gas field development plans. The prediction of reservoir permeability mainly has the following methods: [0003] (1) Prediction of permeability based on the relationship between porosity and permeability [0004] Herron found that the logarithm of permeability has a linear correlation with porosity through the study of single-porosity sandstone reservoirs: [0005] [0006] In the formula, K is the permeability, mD; is porosity, %; a and...

AI Technical Summary

Problems solved by technology

[0025] It has been agreed that the pore structure controls the permeability of reservoir rocks, especially carbonate reservoirs, which are controlled by sedimentation and diagenesis, have very complex pore structures and strong heterogeneity, resulting in the porosity-permeability The permeability relationship is not clear, and most of the permeability prediction methods based on clastic rocks are not applicable to carbonate rocks. Theoretical and practical research results show that the permeability of porous carbonate rock reservoirs is obviously controlled by the pore structure of the reservoir rocks. Especially the control of pore-throat size. However, many scholars have different views based on samples from different research areas, and there is no unified opinion on which pore-throat size is controlled. Therefore, it is not clear which pore-throat size controls the permeability.

Moreover, using a certain pore throat size to characterize the reservoir pore structure is generally only suitable for unimodal samples with similar capillary pressure curves. For strongly heterogeneous carbonate rocks, the capillary pressure curves are complex and diverse, and a single pore throat size Not applicable to characterize the overall pore structure characteristics

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