低渗透砂岩油藏注采井网调整对策研究

Adjustment Strategy of Injection-Production Patterns for Low Permeability Sandstone Reservoirs

曲瑛新

Qu Yingxin

中国石油大庆油田有限责任公司第九采油厂, 黑龙江大庆 163853; 浙江大学地球科学系, 浙江杭州 310027

No.9 Oil Production Plant, Daqing Oilfield Ltd., PetroChina, Daqing, Heilongjiang, 163853, China; Department of Earth Sciences, Zhejiang University, Hangzhou, Zhejiang, 310027, China

低渗透油藏注水开发后,注采井网难以满足后续开发需求。应用油藏工程和数值模拟预测等方法,对低渗透油藏合理油水井数比、注采井网调整方式、调整时机以及调整后新、老井合理注水调整方法进行系统研究,形成了低渗透油田井网调整技术。考虑低渗透储集层的渗流特性、启动压力梯度导致油水井地层压力的差异,推导了适应低渗透油藏的油水井数比计算公式。根据储层裂缝发育状况以及剩余油分布特征,选择水驱面积波及系数较高的井网进行调整。敖南油田合理的调整方式是将裂缝不发育井区反九点法井网调整为五点法井网,裂缝发育井区转线性注水。对不同调整时机下的开发效果预测表明,调整越早,效果越好。井网调整后要适当控制老井注水,加强新井注水,使地层压力分布更加合理。研究结果表明,利用上述调整对策对低渗透油藏实施注采井网调整是可行的,可以为低渗透油田井网调整提供新的技术支持。

When low-permeability reservoirs turn to waterflooding,injection-production well pattern,it is difficult to meet the actual needs of the subsequent development.By using reservoir engineering and numerical simulation,the ratio of producer to water injector,injection-production well pattern adjustment,adjustment timing and proper water injection regime of new and old wells are studied systematically.Considering the seepage flow in low permeability reservoirs,formation pressure difference between the producer and water injector,the formula of producer to water injector ratio for low-permeability reservoirs was derived.According to the distribution of fracture and remaining oil,the pattern with high sweeping coverage factor should be selected for adjustment.The adjustment in Aonan Oilfield involves the conversion of inverted nine spot well pattern to five spot well pattern in areas with undeveloped fractures,and linear water injection in blocks with developed fractures.Prediction of development effect at different adjustment timing shows the sooner the adjustment,the better the effect.After the pattern adjustment,injection in old wells should be restricted while injection in new wells should be strengthened to make the reservoir pressure distribution more reasonable.The results show that the well pattern modification method is feasible for low-permeability reservoirs and will provide technical support for well pattern modification of low permeability reservoirs.

https://doi.org/10.3969/j.issn.1001-0890.2012.06.018