腰英台油田特低渗透油藏压裂技术研究及应用

Research and application of fracturing technology in extra-low permeability oil reservoirs in Yaoyingtai Oilfield

腰英台油田不仅具有低孔、低渗透、层多而薄、微裂缝发育以及应力敏感性强的特点,还表现出明显的双重介质储层特征。由于天然裂缝开启导致的压裂液过量滤失和压裂早期砂堵,制约了该区油藏的有效开发。结合腰英台油田勘探开发过程中的压裂改造实践,利用储层裂缝开启机理和压力降分析成果,通过分层地应力剖面研究及全三维压裂模拟、配套射孔优化、限流压裂、暂堵、双转向控缝和前置段塞等工艺的施实,较好地解决了该类储层压裂易早期砂堵的矛盾。现场应用60井次,有效率达80%,累积增产原油5×104t。

Yaoyingtai Oilfield is a low porosity,low permeability reservoir,with thin layers,developed microfractures,strong stress sensibility,which exhibits the characteristics of dual-porosity media.Excessive fracturing fluid loss and early sand block resulted from opening of natural fractures restricts the development of the oilfield.Combined with the fracturing practices in Yaoyingtai Oilfield exploration and development,the issues of easily early sand block in the fracturing of this type of reservoirs is solved based on the mechanism of natural fracture opening in the formations and pressure drop analysis results.The technologies adopted consist of full three dimensional fracturing simulation,allied perforating optimization,limited-entry fracturing,temporary blocking,' dual-steering limiting fractures and prepad slug,etc..Fracturing treatment has been implemented in more than 60 wells with a successful rate of 85%,30% of fracturing cost decrement and 5×104t of cumulative oil increment.