清水不加砂压裂增产机理及导流能力测试

Study on yield increase mechanism and flow conductivity test method for water-fracturing without proppant

清水压裂技术在低渗透油气田增产增注中应用广泛,但并非所有低渗透地层都适合清水压裂,因而需要深入研究清水压裂增产机理及导流能力测试。利用有限元模拟方法,从岩石材料的非均质性、岩石力学性质、地应力偏差、裂缝起裂方向与最大水平地应力夹角等方面揭示了清水压裂裂缝转向和滑移机理、滑移量的影响因素和影响规律、裂缝闭合残余孔隙空间形成机理,并建立了清水压裂自支撑裂缝壁面组合制备方法和导流能力的室内评价方法,为深入认识清水压裂增产机理及适用储层条件提供了手段。

At present,water-fracturing is a key stimulated technique in widespread use for low permeability oil-gas filed to gain extremely economic benefit,on the other hand,the process is not suitable for all low permeability reservoirs.Studies on yield increase mechanism and flow conductivity test method for water-fracturing should be deeply conducted.The mechanisms of fracture diverting and slip for water fracturing,influencing factors and influence law of slippage and the forming mechanism of residual space after crack closed are addressed with the finite element method from different aspects： heterogeneity of rock materials,rock mechanics property,deviation of in-situ stress,the angle between the direction of fracture starting and the maximal horizontal principle stress.The preparation method of self-supporting fracture wall surface combination and test method of flow conductivity for water-fracturing are established,which provide the reference means for deep understanding the production increasing mechanism and suitable reservoir conditions of water-fracturing.