【作者】 胥永杰；

【导师】 陈平； 张恒晨；

【作者基本信息】 西南石油学院 ， 油气井工程， 2005， 博士

【摘要】 四川所有探区均存在不同程度的井漏问题,特别是川东北地区,地质构造复杂,且80%以上构造属高陡构造。实际钻探中,由于构造陡、地层破碎、断层多、裂缝和孔洞发育、产层多、同一裸眼井段压力系数相差悬殊,多套压力系统共存,井漏十分频繁,井眼复杂在所难免,严重地制约了该地区的钻井速度。为了实现安全快速钻进,井漏是必须逾越的难关。 针对钻井过程中的井漏难题,基于岩石力学室内实验和现场试验数据,用固体力学和流体力学的理论及有限元分析方法,系统地研究高陡复杂地层井漏机理,这对推动四川盆地的油气勘探开发具有十分重要的意义。本文重点开展了以下7个方面的研究工作:①岩石力学实验和岩石力学参数的测井解释方法研究;②高陡复杂构造地层地应力的测井提取方法研究;③高陡复杂构造漏层位置确定及漏失通道性质的测井研究;④高陡复杂构造井漏的地质力学分析;⑤高陡复杂构造漏失通道性质及裂缝形态与井漏的相关性研究;⑥高陡复杂构造井漏规律研究;⑦高陡复杂构造封堵的力学机理研究。论文工作量大、内容丰富、难度大,通过研究取得了以下的创新成果: (1)结合高陡复杂构造的实际地质特征,建立了一套基于测井资料确定漏层位置和漏失通道性质、较为准确计算地应力和破裂压力的方法技术,为钻井液安全密度窗口的设计提供了科学依据。 (2)用非线性岩石力学的理论和方法分析高陡复杂破碎地层的地质力学问题。应用断裂力学和损伤力学的理论,从压剪和拉剪两种应力状态出发,建立复杂应力状态下高陡复杂破碎地层含节理岩体损伤演化模型,研究了高陡复杂破碎地层井漏的力学机制,给出了适合高陡复杂破碎地层的岩石力学分析方法。 (3)基于非牛顿流体在裂缝地层中的流动规律,将漏失过程分成三个流动范围,即裂缝内的流动、滤饼层的流动、地层滤失带内的流动,建立了高陡复杂构造井漏分析模型;研究了地层因素(孔隙度、渗透率)、漏失通道的空间特征、施工参数(钻井液密度、流变性、泥饼等)等对井漏的影响规律,并对影响井漏的主要因素进行了敏感性分析;运用非牛顿流体力学有限元法研究了流体漏失的流场性质(流动速度和压力降)和漏失特征。 (4)基于漏失压力剖面特征,应用流体力学原理与颗粒随机运移模型分析了裂缝性地层的封堵机理,结合裂缝的分布形态,研究钻井液和堵漏液在裂缝中的漏失压力传播规律及封堵强度特征,为裂缝性地层有效封堵提供理论依据。更多还原

【Abstract】 The well leak problem in different degree occurs in all prospect area of SiChuan, especially, in the east of Sichuan. Its geologic structure is complex, and 80% structures belong to aloft-steep structure, In practical drilling process, structure is steep, formation is fragmented, fault is more, fracture and porosity are developing, pay formation is more, open hole well pressure coefficient discrepancy are great, many suite pressure system coexist, well leak is fairly frequency, complex borehole is unavoidable, and drilling and exploratory development speed are severely restricted, In order to put into effect safely rapidly drilling, well leak must overstep difficulty.Aiming at the well leak problem in drilling process, based on rock mechanics laboratory experiment and field experiment data, using finite element approach of solid mechanics and fluid mechanics, the well leak mechanization of complex aloft-steep structure is systematically studied. It is fully significant sense to promote exploratory development of oil gas in the Sichuan Basin. This dissertation was emphatically researched below 7 respects work.(1)The method to interpret rock mechanics parameter using well logging and the rock mechanics experiment are studied.(2)The method to calculate formation stress of aloft-steep structure is studied using well logging data.(3)The leak formation of complex aloft-steep structure is identified, and the property of leak channel is studied using logging data.(4)The geomechanics of complex aloft-steep structure well leak is analyzed.(5)The correlativity of complex aloft-steep structure to property of leak channel, fracture morphology and well leak are studied. (6)The rule of well leak in complex aloft-steep structure is studied.(7)The blockage mechanics mechanism of aloft- and steep structure is studied. The working capacity of the dissertation is greatly, the content is rich, and the difficulty is greatly. The innovation efforts are acquired by means of research, as following:(1)Considering the actual geology feature of complex structure of aloft- steep, a series of approaches are established to calculate formation stress magnitude and orientation accurately, and determine leak formation and channel property.(2)The geomechanics problem is analyzed to complex aloft-steep structure using the theory and method of the non-linear rock mechanics. Applying the theory of fracturing mechanics and the injury mechanics and stemming from two kinds of stress conditions such as compression and stretching shear, the injured evolution model is established at the complex crumble formation under the complex stress condition, and the mechanics mechanism of well leak is researched in complex aloft-steep fractured formation. The principle and method of rock mechanics analysis fitting complex aloft-steep fractured formation are presented.(3)Based on the rule to non-Newton fluid in fracture formation, the well leak model isestablished. Leaking process are divided into three flowing ranges, that is to say, flowing in fracture, flowing in filter cake , and flowing in formation. The analytic model is established to complex aloft- steep well leak. The influences of well leak rule are studied on the formation elements(porosity, permeability), the space of feature leak channels, construction parameter(drilling fluid density, rheological property, mud cake etc.), the mostly factors infecting well leak sensibility are analyzed, utilizing the finite element method of non-Newton fluid mechanics to research the character of flow field of fluid leak(flowing speed, pressure drop) and leak feature.Based on the feature of leak pressure profile, the blockage mechanism of fractured formation is analyzed applying fluid mechanics rule and random migration model. Uniting the distribution form in natural fracture, the propagation regular of leak pressure and strength character of blockage material are studied drilling fluid and stop water loss in fracture, the theory reference is provided for effective blockage technology and measure to fractured formation.更多还原