低渗透裂缝性油藏渗吸数值模拟研究

Numerical Simulation of Low-permeability Fractured Reservoirs on Imbibition

低渗透裂缝性油藏作为一种特殊的油藏,裂缝很发育,基质非常致密,普遍存在孔隙度小、孔隙压力低和储层渗透率低等特点。因此其采收率相对较低,开采成本较高,经济效益亦较低。低渗透裂缝性油藏的生产机理主要表现为裂缝系统中的水靠毛细管力作用渗入岩块排油。因此,亲水的致密岩块、水的毛细管自吸作用是主要的采油机理。应用数值模拟方法,建立双重介质模型。结果表明,裂缝发育程度、黏度比、基质毛管力大小、初始含水饱和度为影响渗吸的关键因素。明确了主要地质因素、开发因素对渗吸的控制作用和作用机理,为渗吸开发低渗透裂缝性油藏具有一定指导意义。

Low permeability fractured reservoir is a special reservoir feature with complex fracture distribution and dense matrix. Low permeability fractured reservoir always have small porosity, low pore pressure and permea- bility. Therefore, low permeability fractured reservoir has low recovery efficiency. Besides, the developing complex process and higher costs make low economic benefit. Low permeability fractured reservoir production mechanisms in the fracture system mainly by the capillary force of water into the matrix. Therefore, the hydrophilic blocks of dense, self-priming effect of capillary water is the main mechanism of oil. Numerical simulation, the establishment of a dual media model analysis show that the capillary suction from the oil production rate and the final volume flow channel structure, the capillary force, viscosity of crude oil and other factors. Clear the main geological factors, development factors on the control of the role and mechanism of imbibition, and gui^ling significance for develop- ment of low-permeability fractured reservoirs in imbibition.