Method for improving water flooding by flow channel adjustment in fracture-vug type carbonate reservoirs

Abstract

The invention discloses a method for improving water flooding by flow channel adjustment in fracture-vug type carbonate reservoirs. The method comprises the following steps that 1, a fracture-vug bodyto be adjusted is determined; 2, a matched channel flow adjusting agent is selected according to injection-production characteristics of different types of fractured-vug bodies; 3, field injection testing with the selected degradable flow adjusting agent is carried out for stratum matching test; 4, the tested matched flow adjusting agent is injected into the water flooding flow channel, and the flow adjusting agent moves along the channel with injected water, the flow adjusting agent accumulates and blocks in a fracture channel or settles and accumulates in the fracture so as to realize jointcontraction or joint clamping of a dominant water injection channel; and 5, unit water injecting is recovered, the injected water is mainly driven along a secondary channel or a secondary direction channel to improve the development effect of the unit water flooding. The method can effectively adjust the dominant channel of water flooding and utilize the residual oil in the secondary channel andis suitable for the fractured-vug carbonate reservoirs. In addition, the field test results are good, and the method for improving water flooding by flow channel adjustment in the fracture-vug type carbonate reservoirs is especially suitable for improving water flooding development effect after water injection in the fractured-vug carbonate reservoirs.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploitation, in particular to a method for adjusting flow passages of fracture-cavity carbonate rock reservoirs and improving water flooding. Background technique [0002] Tahe fractured-vuggy reservoirs belong to ultra-deep (>5000m), high temperature (120-140℃), high salinity (20×10 4 mg / l) multi-stage superimposed accumulation of karst fracture-cavity reservoirs, the reservoir heterogeneity is extremely strong, the interwell reservoirs are connected by large-scale fractures and caves, and the fluid flow is mainly pipe flow. Non seepage. At present, water injection development has become the most important development method for stable production and enhanced recovery of fractured-cavity carbonate reservoirs. However, with the continuous advancement of unit water injection, the injected water can easily enter along the main dominant fracture channels between wells. As a result, oil well...

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Problems solved by technology

[0004] 1) The idea of ​​conventional profile control is only suitable for seepage-dominated reservoir types, and poorly adaptable to fracture-cavity reservoirs dominated by pipe flow

[0005] 2) The temperature and salt tolerance of conventional organic systems cannot meet the high temperature and high salt requirements of fracture-cavity reservoirs, and conventional water-based profile control systems have high density and are easy to leak in caves;

[0006] 3) Conventional profile control agents are only suitable for micron-scale pores and fractures, not for millimeter-scale fractures and meter-scale fractures and caves

[0007] Therefore, the improved water flooding technology for fractured-cavity carbonate reservoirs is still immature, and a new type of improved water flooding technology is urgently needed to improve the development effect of this type of reservoir unit in the water cut stage after water injection

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