【作者】 张平；

【导师】 赵金洲； 刘延平；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2009， 博士

【摘要】 水力压裂技术经过60多年的发展,已从单井压裂发展应用到油藏整体压裂,从低渗透储层压裂发展应用到高渗透储层压裂,从直井压裂发展应用到水平井压裂,从油水井压裂发展应用到煤层气井压裂。但在低渗透底水油藏压裂方面,由于层间应力差异小或根本没有隔层形成层间应力差异,有效阻挡裂缝在垂向上的延伸扩展,必将导致水力压裂形成的裂缝在垂向上延伸进入底部水层,从而造成底水油藏压裂后,底水沿着裂缝上窜流入井筒,引起油井暴性水淹,致使水力压裂施工无效,不能达到提高油井产量的目的。低渗透底水油藏压裂作为一个“禁区”,一致未能得到很好解决,相关报道很少。本文采取了理论研究、数值模拟、室内实验和现场试验相结合的方法。根据断裂力学理论,建立了裂缝垂向延伸数学模型,定量分析了岩石垂向非均一性对裂缝垂向延伸扩展规律和敏感性分析;应用相似理论建立了水力压裂物理模拟的相似准则,进行了水力压裂裂缝大尺寸真三轴模拟实验;建立了利用测井资料预测岩石力学参数数学模型,研制了利用常规测井资料预测岩石力学参数软件;对底水油藏控制裂缝下延技术进行了系统研究,研制了利用热固性树脂、固化剂和填充料组成的新型下沉式转向剂;研制了底水油藏压裂施工用携带转向剂的携带液和无残渣压裂液;制定现场施工工艺,设计施工参数,进行了现场应用,取得了显著效果。本文研究取得了以下成果:(1)理论分析了岩石垂向非均一性对裂缝垂向延伸的影响,分析认为:地层岩石层间地应力差是影响裂缝垂向延伸及延伸范围的主要因素,地层岩石的断裂韧性能够明显阻碍压裂裂缝的垂向延伸,缝中流体重力梯度使裂缝产生下延倾向,地层岩石地应力梯度使裂缝产生上扩倾向;(2)依据相似准则,进行了水力裂缝物理模拟实验,通过实验认为:层间地应力差和层间界面自身的性质是影响裂缝垂向扩展的关键因素,层间物性参数对比差异对裂缝穿过层间界面进入隔层影响不大;(3)完成了岩石力学参数预测软件的研制,该软件可以利用常规测井资料预测地层岩石力学参数;(4)研究筛选出了底水油藏压裂改造工作液,包括携带液和无残渣压裂液,无残渣压裂液具有配制简单,自动破胶,无固相无残渣等特点;(5)研制了具有自主知识产权的新型下沉式转向剂,该转向剂既可以有效控制裂缝下延,又可以阻止底水沿着裂缝上窜:(6)系统研究了控制裂缝下延技术,提出了多级充填建立人工隔层控缝高压裂工艺,通过现场应用表明,该工艺具有一定的新颖性,在建立人工隔层控缝高压裂工艺方面进行了创新。更多还原

【Abstract】 After about 60 years of development, hydraulic fracturing technology has been improved from single well fracturing to integral fracturing, fracturing of low permeability reservoir to high-permeability reservoir fracturing, vertical well fracturing to horizontal well fracturing and fracturing in oil-water wells to coalbed methane well fracturing. With regard to the low permeability bottom water reservoir fracturing, the fracture could not be controlled effectively in vertical direction since the interlaminar stress contrast is not big enough or there is no barrier which could generate interlaminar stress contrast, so the hydraulic fracturing will fail because the induced fracture would extend into bottom aquifer in the vertical derection and cause the oil well sudden water flooding once the bottom water flow into the wellbore along the fracture. The problem of low permeability bottom water reservoir fracturing hasn’t been solved well and the related reports is very few.This paper take the integration of measures including theoretical investigation, numerical simulation, laboratory test and field test. According to the fracture mechanics, this paper establish the fracture vertical extending mathematical model and similarity criteria of physical simulation of hydraulic fracturing on the basis of similarity theory, analyse the effect of vertical heterogenize on the vertical extending of the fracture quantitatively, carry out experiments hydraulic fractring by a large-size triaxial simulator, set up the mathematical model of rock mechanics parameter on the basis of well-log information, develop the software of forecasting rock mechanics parameter on the basis of conventional well-log information, study the technology of controlling the fracture downward extending on bottom water reservoir, develop new sinking diverting agent made of thermoset resin, solidifying agint, stuff, carrier fluid for carrying the diverting agent and non-residue fracture fluid and design site operation technology and construction parameter. We achieved remarkable results after field practice.The results are showed below(1) Analyse the effect of vertical heterogenize on the vertical extending of the fracture quantitatively theoretically: Interlaminar stress contrast of the rock plays an vital role in the vertical extending of fracture and expanded range, fracture toughness of rock could control the vertical extending of induced fracture, the fluid gravity gradien will make the fracture extend downward and the stress gradient of rock will have the adverse effect on it.(2)Carry out the physical simulation of hydraulic fracturing on the basis of similarity criteria. In accordance with the experiment, interlaminar stress contrast and the properties of bed interface play an important role in the vertical extending of fracture and the interlaminar physical parameters difference will not affect the extending of the fracture into the barrier through the bed interface.(3)Develop the software of forecasting rock mechanics parameter which could forecast rock mechanics parameters on the basis of conventional well-log information.(4)Develop carrier fluid and non-residue fracture fluid which is easy to prepare, it has the properties of automatically breaking, free solid and non-residue. (5)Develop the new sinking diverting agent which has Independent intellectual property rights, the agent could control the downward extending of the fracture effectively and stop the bottom water flow upward into the wellbore.(6)Study the technology of controlling the downward extending of fractre and present the technology of using artificial barrier to control high in hydraulic fracturing through multi-level filling. Field practice shows that the technology is innovative.更多还原