Method and system for predicting seepage and suction quality of reservoir fracture

Abstract

The invention provides a method and system for predicting seepage and suction quality of a reservoir fracture. The method comprises the following steps: determining the seepage suction height of eachfracture at the current seepage and suction moment according to the capillary force of each fracture and the gravity at the previous seepage and suction moment; when the seepage and suction height ofeach fracture is less than or equal to the height of a rock core, obtaining the seepage and suction quality of the fracture at the current seepage and suction moment according to the length of the fracture, the seepage and suction height of the fracture at the current seepage and suction moment, the number of the fractures in the length of the fracture and the density of wet phase fluid; otherwise, obtaining the seepage and suction quality of the fracture at the current seepage and suction moment according to the fracture length, the rock core height, the fracture number of the fracture length, the density of the wet phase fluid and the average tortuosity of the fracture; and predicting the seepage and suction quality of the rock core at the current seepage and suction moment according tothe seepage and suction quality of each fracture at the current seepage and suction moment so as to establish or adjust an oil and gas resource development scheme of a reservoir. The method and the system can effectively guide the development process of oil and gas resources.

Description

technical field [0001] The invention relates to the technical field of oil reservoir exploration and development, in particular to a method and system for predicting imbibition quality of reservoir fractures. Background technique [0002] The development of unconventional oil and gas resources such as tight gas and shale gas is of great significance to ensuring national energy security. Different from conventional oil and gas reservoirs, tight oil and gas reservoirs have the characteristics of low porosity and low permeability, complex pore throat structure, strong capillary force, and obvious spontaneous imbibition phenomenon. Large-scale hydraulic fracturing is a commonly used technical means to improve the productivity of tight reservoirs. A large amount of fracturing fluid is injected into the reservoir to create artificial fractures. However, in field applications, more than 50% of fracturing fluid stays in underground reservoirs, and spontaneous imbibition is one of t...

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Problems solved by technology

[0003] At present, there are weighing method, volumetric method, CT scanning, nuclear magnetic resonance and neutron radiography for the research on fracture spontaneous imbibition mechanism, but these methods have the following problems: (1) The porosity of tight sandstone is generally less than 10%, which is It means that the mass change of the core during the imbibition process is very small, that is, the accuracy of the measurement tool is very high, and the conventional measurement tool is difficult to achieve satisfactory accuracy. Therefore, although the weighing method and the volume method can study the core imbibition quality over time dynamic changes, but often with large errors

(2) Although methods such as CT scanning and nuclear magnetic resonance have high precision, they are expensive and cannot study the dynamic change of imbibition mass over time; although neutron radiography can study the dynamic change in the process of imbibition, its It has very high requirements for experimental equipment, and the cost of the experiment is extremely high. It is difficult to popularize and apply, which is not conducive to the development of oil and gas resources.

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