【作者】 叶登胜；

【导师】 赵金洲；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2009， 博士

【摘要】 中国非常规油气资源的勘探领域极为广阔,资源前景远超过现在常规油气资源。对于这类难动用储层的安全高效开发对保持我国石油工业稳定发展和国家石油安全都具有十分重要的意义。压裂作为这类储层常用的投产/增产措施,受到日益广泛的关注。然而,由于这类井压裂仍处于初级阶段,其在技术上存在不少局限:如由于储层岩石致密坚硬,杨氏模量、抗张强度和地层闭合压力超高或高污染,要想进行深穿透的大型加砂压裂,通常井口施工压力很高,以至于超过设计要求的压裂井井口、井下工具等承压能力而不得不终止施工,造成大量的人力物力资源的浪费。本文针对目前异常破裂压力储层降低破裂压力的主要问题展开较为系统和深入的研究,取得了以下主要成果:1)形成了利用测井资料,结合室内岩芯测试结果,获取静动岩石力学参数的相关性特征,从而获得纵向上大量静态力学参数的方法。2)在获取了岩石力学参数的此基础上,利用弯曲薄板作为力学模型,结合区块实际地质特征对背斜构造进行曲率分析,通过曲率与应力的关系,利用背斜构造不同部位的主曲率求得相应的构造应力值,从而建立起背斜储层的分层应力模型;对已有压裂资料的区块分层,形成了综合利用测试、室内实验、压裂资料反演获得该区块构造应力系数,建立起分层地应力的力学模型的方法。3)综合考虑储层地质、油藏、岩石力学特性和储层伤害等因素,分析造成高破裂压力的主要原因,综合利用岩石力学、弹性力学等知识,建立了裸眼完井、射孔完井条件下以及储层受到伤害后的储层破裂压力定量预测模型,为降低施工风险和优化施工工艺提供了依据。4)完成了物性、岩性影响岩石力学参数的因素分析,找出了各影响因素和岩石力学参数之间的关系,为从机理上解释酸化预处理降低破裂压力提供了理论基础;从微观元素的角度阐述了单矿物与酸反应的机理;并在此基础上,有效评价了各种矿物的酸敏感性,定量确定了岩石中各矿物的一级反应动力学方程。5)完成了不同温度下的酸液类型、酸液浓度、注酸量等一系列砂岩损伤实验,结合岩石力学三轴应力实验,系统揭示了在不同条件下注酸而引起的岩石力学性质变化。6)将损伤力学与砂岩酸化相结合,在宏观、微观两个方面认识酸岩反应引起岩石力学参数变化基础上,建立了砂岩损伤力学模型,并对其进行验证,在此基础上定量计算酸化后的破裂压力,有效指导现场施工。更多还原

【Abstract】 The exploration area of China’s unconventional hydrocarbon resources is so amplitude that the prospect of resourse gose far beyond current conventional petroleum resource. Developing this kind of tough reservoir in a safety and high efficient way is significant for both China’s steady development of petroleum industry and petroleum security . There is a increasingly comprehensive attention on fracture which is applied to the reservoir. However, because fracture in this type of well is still at the primary stage,it still has some localization in technically, such as compact reservoir rock, Young’s modulus,tensile strength,high layer shut-in pressure and severe pollution. In order to conduct a deep penetrating large-scaled sandfrac, the well intake pressure is so high even exceed the design requirement that we have to terminate construction, as a result,there will be a big waste of human and material resource. This article that focuses on the systematic and in-depth research in the current primal problem about abnormal burst pressure reservoir depress burst pressure has procured following main fruits:1) It forms the method which could obtain massive vertical static state mechanics parameters.2) In a foundation of acquisition of rock mechanics parameters,apply bent lamella that as mechanical model along with characteristic of actual geologic characteristics to analysis curvature for anticlinal strcture, get homologous tectonic stress value throug relation between the curvature and stress and different principal curvature in anticlinal structure,consequently set up laminational stress model for anticline reservoir. The block lamination for existed fracturing date has formed method of setting up mechanical model of lamination terrestrial stress by abtaining the block tectonic stress coefficients which are got by complex utilization test, laboratory test and fracturing date playback.3) Analysesing the main reason which lead to high burst pressure by considering the characteristic of reservoir geology,reservoir,and rock mechanics and reservoir damage,etc.Establishing burst pressure quantitative prediction model which provide gist for depressing construction risk and optimizing construction craft under the condition of open hole completion ,gun-perforated completion and damaged reservoir.4) Provding theoretical basis for interpreting acidification pretreatment which could depress busrt pressure by finding the relation between the influencing factors and rock machanics parameters and analysing the factors that have effect on rock mechanics parameters. Expounding the mechanism of reaction of mixed monomineral and acid from the angle of microcosmic element, evaluating quantitatively acid sensilility of different kinds of mineral effectively, and determing the first-order reaction dynamical equation of each mineral.5) Revealing rock mechanics property chage as a result of acid flooding in different condition by sandstone traumata experiment in different temperatures which combined with rock mechanics triaxial stress experiment.6) Associating damage mechanics with sandstone acidizing, established sandstone damage mechanics model in the foundation of the recognition on the rock mechanics parametric variation which is caused by acid-rock reaction in both macroscopic view and microscopic view ,also demonstrated those processes and quantitative estimated the acid busrt pressure to direct the site operation.更多还原