裂缝性油藏水驱过程中基质的动用程度及基质贡献率

摘要

裂缝性(双重介质)油藏渗流过程复杂、注水开发过程中含水上升快、开发难度大,针对注水能否有效采出基质中原油问题,研究基质动用机理、程度及规律.采用ECLIPSE油藏数模模拟软件,分析裂缝系统和基质系统的采出程度、基质产油量在总产油量中的比例,分析窜流系数、基质渗透率、裂缝渗透率、注水速度等因素对水驱基质贡献率的影响.研究表明:裂缝越发育,基质渗透率越高,基岩的渗吸排油作用越明显,越有利于提高水驱油效果;注水速度越低,越能发挥基质的渗吸排油作用,水驱效果越好.该研究获得了基质贡献率和动用程度的数值范围及变化规律,建议对裂缝性油藏采取低速注水开发策略.%Seepage process of the fractured dual-porosity media reservoirs is complicated and water cut rises rapidly which are all made it is difficult to develop this kind of reservoirs with water flooding.Aiming at answering the questions, such as whether oil in the matrix can be produced effectively by water flooding, the mechanism, producing degree and laws of matrix development are studied.By using ECLIPSE reservoir simulation software, recovery degree of the fracture and matrix systems and the ration of the production oil in the matrix to the total oil production were analyzed.The influences of the interporosity flow factor, matrix permeability, fractured permeability and water injection rate on the contribution rate of the water flooding in matrix were investigated.Results show that the more developed the fractures, the higher the matrix permeability, and effect ofoil seepage and displacement were easily noticeable which affords benefit for enhancing oil displacement effect.The water drive effects could be greatly improved when fracture developed is better and water injection rate are lower.Variation laws and numerical ranges of the matrix contribution rate and producing degree were obtained.It is recommended that strategy of lower water injection rate for the fractured reservoir should be taken.