Method and system for analyzing fluid potential of fractured-vuggy reservoir

Abstract

The invention discloses a method for analyzing the fluid potential of a fractured-vuggy reservoir, which comprises the following steps of: carving a target fractured-vuggy unit, determining a geometrical shape model of the target fractured-vuggy unit, and obtaining a geological model of the target fractured-vuggy unit on the basis of the geometrical shape model in combination with drilling and logging data for the fractured-vuggy unit; based on the geologic model, according to the current carving result and historical yield data of the target fracture-cavity unit, a numerical simulation technology is used for fitting the development and production history of the target fracture-cavity unit, and an initial distribution model, including an oil reservoir pressure field, an oil saturation field and a fluid velocity field, of the target fracture-cavity unit is established; according to the initial distribution model, fluid potential energy at all positions in the model is counted, and a fluid potential energy distribution model of the target fracture-cavity unit is obtained. The invention provides a fluid potential analysis model and characterization for fracture-vug type oil reservoir development, and provides a theoretical basis for a regulation and control technology for balanced exploitation of fracture-vug type oil reservoirs.

Description

technical field [0001] The invention relates to the technical field of energy development of unconventional oil and gas reservoirs, in particular to a method and system for calculating the fluid potential of fracture-cavity reservoirs. Background technique [0002] Compared with clastic rock reservoirs, the fracture-cavity storage media are diverse, the spatial distribution of reservoirs is discrete, and the flow patterns and development methods have significant temporal and spatial differences. Fluid potential is the total mechanical energy of the fluid in the reservoir, and it is a classic theoretical method to study the migration of underground oil, gas, water and other fluids from the perspective of energy conservation. The research on the mass fluid potential in oil and gas accumulation mainly focuses on: petroleum geology of oil and gas migration and accumulation. With the continuous deepening of oilfield development theory and understanding, fluid potential has been ...

AI Technical Summary

Problems solved by technology

[0004] Specifically, there are the following problems in the development of existing carbonate-salt fracture-cavity reservoirs: because the fluid flow in the fracture-cavity medium of the main body of fracture-cavity reservoirs does not conform to the Darcy flow law, the development of this type of oilfield cannot learn from clastic rocks. Mature development theory and technology

With the deepening of development, the oilfield has gradually exposed the following specific problems in the development: ①Due to the strong heterogeneity of Ordovician fractured-vuggy reservoirs and the complexity of oil-water relationship, water breakthrough in oil wells is sudden and early warning are difficult, and the production decline caused by violent water flooding accounts for a large proportion; ② As the main body of storage and seepage in the Ordovician fracture-cavity reservoir in Tahe River—karst caves and fractures are dominated by pipe flow, and various oil-water flow patterns cause The development law of oil wells is poor, and the theoretical method of clastic rock reservoir engineering based on Darcy's law is not suitable for dynamic analysis and index prediction of fracture-vuggy carbonate reservoir development; ③ mine production shows that due to formation The production decline caused by insufficient energy is 5-7 percentage points, and the energy supplement methods and technical policies in the middle and later stages of fracture-cavity reservoir development need to be further improved; ④ due to the complex geological characteristics and development methods of fracture-cavity carbonate reservoirs The understanding of water flooding mechanism is not clear, the effect of water injection is single, water channeling is easy to occur, and wells with water injection failure are gradually increasing

Due to the limitation of the accuracy of describing the static characteristics of fractured-vuggy reservoirs and the accurate characterization of the complex flow patterns of fractured-vuggy media, the comprehensive control technical policies and parameter optimization strategies adopted by Tahe Oilfield, such as controlling water and stabilizing oil production, delaying decline, etc. Systematic theoretical support, the effect of mine implementation is often much lower than the expected effect of theoretical research

[0006] Therefore, there is a lack of a method in the prior art that can be applied to the analysis of the fluid potential distribution characteristics of fractured-vuggy reservoirs

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