鄂尔多斯盆地长7超低渗油藏渗流规律研究

Study on seepage law of Chang 7 ultra-low permeability reservoir in Ordos Basin

陈明强 任龙 李明 岳艳芳

西安石油大学石油工程学院，陕西 西安 710065 中国石油大学（华东）石油工程学院，山东 青岛 266580 中国石油塔里木油田公司勘探开发研究院，新疆 库尔勒 841000

School of Petroleum Engineering, Xi′an Shiyou University, Xi′an 710065, China College of Petroleum Engineering, China University of Petroleum, Qingdao 266580, China Research Institute of Exploration and Development, Tarim Oilfield Company, PetroChina, Korla 841000, China

超低渗油藏由于岩性致密，导致渗流阻力大、压力传导能力差，直接影响到油井的产能。文中在岩心流动实验的基础上，利用统计分析方法，对长7超低渗油藏的启动压力梯度、储层的应力敏感性和油水两相渗流规律进行了分析讨论，得出流体在该油藏中流动时普遍具有启动压力梯度，储层的应力敏感性较为明显，原始含油饱和度较低且可动油体积较小。结合低渗油田开发理论，对油井的产水规律及无因次采油/采液指数变化规律进行了深入分析，提出在注水开发过程中，长7超低渗油藏应尽早注水以保持合理的地层压力，应预先采取措施以防止油井过早水淹。研究方法及结果对合理开发超低渗油藏具有一定的指导意义。

Ultra-low permeability reservoirs have high flow resistance and poor pressure conductivity because of the great compacted lithology. It affects the productivity of oil well directly. Based on the core flow experiment, the authors took advantage of statistical analysis methods to analyze the start-up pressure gradient, stress sensitivity and seepage law of oil-water two-phase flow of Chang 7 ultra-low permeability reservoir. The results show that the fluid flow in the reservoir generally has start-up pressure gradient, the reservoir has more obvious stress sensitivity, low original oil saturation and small volume movable oil. Combining with the development theory of low permeability oilfield, the water producing law and changing law of dimensionless oil and liquid production indexes in oil well were deeply analyzed. It was put forward that Chang 7 reservoir should be injected water as early as possible to maintain a reasonable formation pressure in the process of waterflooding development. At the same time, the effective measures should be taken beforehand to protect watering out from happening too early. The research approach and results have certain guiding significances on the reasonable development of ultra-low permeability reservoir.

10.6056/dkyqt201302014