Research And Application Of Low Damage Fracturing Technology For Thin Layer In Western Qaidam Basin

All of the formation of the numerous reconnoiter exploitation the Western Qaidam Basin district of Qinghai Oilfield belong to the Complex Lithology reservoir. The clay content of thickness reservoir is high (20-35%) and the lithology is complex with weak cement and strong water sensitivity, which belongs to typical high clay content and complex lithological reservoir. The reservoir is put into production by fracturing. The characteristics of rock mechanics show that the formation stress field is complex, additional stress is high and plastic feature is obvious. At the same time, the reservoir thickness is large, the fracture initiation is difficult, the volume of fracture is limited and the sand absorption capacity is not enough. Fracturing treatment which is suitable for reservoir was studied on the basic of fracturing fluid optimization design and flow conductivity of proppant, also the fracturing designed parameters through numerical simulation. For that, the fracturing liquid system that emulsion pad fluid + conventional water-base fracturing liquid with two composite anti-swelling agent is selected through reservoir evaluation and experiment analysis. A effective fracturing treatment technology that fracture initiation with variable displacement and artificial barrier is operated to control the fracture height.A set of technologies and material systems suitable for the reservoir have been formed which ensures the success of fracturing and obtains a good effect.