龙虎泡低渗透油田井网适应性研究

Well patten adaptability study of low permeability Longhupao oilfields

在油田实际开发中实施了反九点法和五点法两种井网开发,解剖对比了两个区块的开发特点。在采出程度相同的情况下,五点法井网油井含水高,两个区块的单井产液量接近。反九点法井网开发中后期采取加密结合注采系统调整方式,能够提高差油层的动用程度和好油层的注水波及体积进而提高采收率。同时,应用水驱特曲线和Weibull模型等油藏工程分析方法对其最终采收率和水驱波及体积系数进行了评价,认为龙虎泡油田应采用反九点法注采井网开发。

Reasonable well pattern is always an important subject in water flooding sandstone oil fields, because it is related to ultimate recovery factor. The paper has identified the effective flooding well space in low permeability reservoir, and discussed the well space required to satisfy water flooding control degree with reservoir sand body scale, and reached the conclusion from reservoir relative permeability curve and core test that during the whole oil field development process, the reservoir water injectivity is high and liquid producing capacity is low. In real oil field development, inverted 9 - spot pattern and inverted 5 - spot pattern are used. The paper has analyzed the development characteristics of the two blocks. When the recovery degree is the same, inverted 5 - spot pattern has higherwater content and the single well fluids production of the two blocks are similar. At the later stage of inverted 9 - spot pattern development , to adopt combination of infill and injection/production system adjustment can improve the development degree in poor oil layers and the water injection swept volume in good oil layers, thus the recovery rate is improved. To evaluate the ultimate recovery factor and water flooding swept volume coefficient with water flooding property curve and Weibull model the well pattern adaptability of low permeability oil fields can be more effectively discussed. Reasonable well pattern theory study and field practice have shown that inverted 9 -spot pattern should be adopted in Longhupao oilfield, and at the later stage of development, the combination of infill and injection/production system adjustment should be adopted, thus the formation pressure will be kept between initial formation pressure and saturation pressure and the water flooding ultimate recovery factor will be the highest.