【摘要】 为了提高特低渗透油藏新井的压裂效果,提出了采用定向射孔技术进行转向压裂从而形成"X"形水力裂缝的新方法。基于有限元三维应力分析,研究了定向射孔下水力裂缝的起裂机理。根据断裂力学理论,建立了基于复合应力强度因子的裂缝延伸和转向判据模型,推导确定了缝内压力分布、复合应力强度因子及裂缝扩展方向角的计算公式,编制了定向射孔转向压裂裂缝延伸形态的模拟软件,分析了射孔方位角、最大水平主应力和最小水平主应力差值对转向裂缝形态的影响程度,采用定向射孔和限流法压裂的施工方式,形成了在单个油层中压开"X"形裂缝的改造方法。现场试验了6口井,通过裂缝监测,证明该技术是可行的。更多还原

【Abstract】 Low permeability reservoir is poor in physical properties and characterized by low permeability and low natural productivity. In response to these problems, experiments, theoretical discussion and the numerical stimulation method were utilized to study the reform manner in deflection fracturing of oriented perforation so as to generate the "X"-fracture in the single layer and enhance the individual well producing rate. This paper established the fracture extension model based on the strength divisor of the combined stress and the oriented judgmental criterion, derived the calculating formulas of the pressure distribution and the strength divisor of the combined stress and the direction angle of the fracture, compiled the simulation software of the fracture extension, and modality of the deflection fracturing of the oriented perforation, analyzed the influencing degree of the perforation angle, the max and the min horizontal stress to the fissure morphology, and provided the theory foundation for the detail designing of the "X"-fracture. Six wells have been tested in field and the technique has been proven feasible through fracture monitoring technique.更多还原