Waterflood simulation recovery ratio test method considering energy flow in low-permeability reservoir

Abstract

The invention relates to a waterflood simulation recovery ratio test method considering energy flow in a low-permeability reservoir. The method is completed by means of a core displacement device. Thedevice is composed of a confining pressure pump, a core holder, a back pressure pump, a simulated oil intermediate container, a formation water intermediate container and the like. The method comprises the following steps that (1), simulated oil is prepared, and the volume factor B0 of the simulated oil is tested; (2), a plurality of blocks cores containing crack plungers are selected, and the diameter Di, the length Li, the mass Mi1 and the permeability Ki of the cores are tested; (3), the core bound water saturation is established; (4), the cores are saturated with the simulated oil; (5), the recovery ratio R0 of the failure development simulated oil is calculated; (6), the simulated oil intermediate container is opened, far-well zone energy flow is simulated, and a first round of waterflood simulation oil recovery cumulative recovery ratio R1 is obtained; and (7), the sixth step is repeated, and the i-th round of waterflood simulation oil recovery cumulative recovery ratio Ri is obtained. The method is reliable in principle, simple and applicable, can accurately evaluate the waterflood simulation recovery ratio under a real reservoir condition and has a wide market applicationprospect.

Description

technical field [0001] The invention relates to a water injection huff and puff recovery factor test method in the field of oil and gas exploration and development in consideration of energy flow in the far well area of ​​low-permeability tight oil reservoirs. Background technique [0002] Low-permeability tight oil reservoirs have gradually become the main production targets in the field of oil and gas exploration and development in my country. Such reservoirs have small porosity, poor permeability, and low degree of depletion recovery. Water injection huff and puff development after volume fracturing is one of the widely used production methods for this type of reservoirs. After volume fracturing, the reservoir fracture network develops. The oil-water contact area in the fracture-pore reservoir improves the water-oil replacement efficiency and improves the huff and puff effect. [0003] At present, many scholars at home and abroad have carried out a lot of research on the...

AI Technical Summary

Problems solved by technology

[0003] At present, many scholars at home and abroad have carried out a lot of research on the mechanism and application of water injection. Most of the existing experimental test methods close the inlet and outlet valves when the well is stuffy, and open the outlet valve during production (Wang Yibang, Yang Shenglai, Wu Runtong, etc. Imbibition in tight oil reservoirs Influencing factors and mechanism of oil production [J]. Daqing Petroleum Geology and Development, 2018, 37(06): 158-163), but this method does not consider that in the real formation, the underground crude oil in the far well area will flow to the near well area. flow, energy replenishment

At the same time, for the establishment of irreducible water in low-permeability cores, most of the experimental methods are to flood with simulated oil after vacuuming and saturating water (Gao Tao, Zhao Xisen, Dang Hailong, et al. Mechanism and application of water injection huff and puff in tight reservoirs of Yanchang Oilfield[J]. Special Oil and Gas Reservoirs, 2018, 25(04):134-137) or a general method to quantify saturated irreducible water (Du Jianfen, Wang Zhouhua, Guo Ping, et al. Determination and establishment of irreducible water in fracture-pore (cavity) reservoir core method [P].CN102608011A, 2012-07-25), but for low-permeability tight oil reservoirs, with this kind of experimental method, the distribution of irreducible water in the core is uneven, which has a great impact on the accuracy of the experiment

Images