页岩储层原始地应力场仿真与局部人工扰动规律研究

The critical success factor of shale gas reservoir development is the perfect combination of horizon well techniques and fracturing technology. Improving single wells' gas drainage area intensively is the starting point of all theories and techniques; therefore horizon well optimization and reservoir reconstruction technology has become key theoretical issues to be solved for shale gas reservoir development。Make clear about the shale reservoir's original stress distribution and the artificial disturbance of local stress field are the breakthrough points to solve the problems above. The project starts from shale rock mechanics parameter test and field well logging data interpretation，aims to build a 3D geological model of shale reservoir rock mechanics parameters ,which reflects the real geological situation。And based on the well known of site geology and engineering knowledge ,straightening out the thought of shale reservoir original ground stress field simulation technology, and guide the optimization of shale gas reservoir horizontal well spacing。Through the establishment of heat - flow - solid coupling mathematical model of the local stress field disturbance, combining the theory of "stress shadow" key parameters to optimize horizontal well sectional fracturing construction, as much as possible to improve single well dynamic reserves of shale gas Wells. Resolve the shale gas development "bottleneck" that exists in the process of technology from the source, provide strong technical support for a more rapid, economic and efficient development to shale gas industry.

页岩气藏开发的成功关键就是水平井和水力压裂技术的完美结合，尽最大可能提高单井泄气面积是研究理论和工艺的出发点，因此水平井布井优化和水平井增产改造技术已成为页岩气藏开发亟待解决的关键理论性问题，摸清页岩储层的原地应力分布和局部地应力场人工扰动是解决上述问题的突破点。本项目从页岩岩石力学参数试验和现场测井资料解释入手，致力建立一套反映实际地质情况的页岩储层岩石力学参数三维地质模型；并在现场地质和工程认识基础上拟定页岩储层原始地应力场仿真技术思路，进一步指导页岩气藏水平井的优化布井；通过建立热-流-固耦合的局部地应力场扰动数学模型、结合"应力阴影"理论优化水平井分段压裂施工关键参数，尽最大可能提高页岩气井的单井动态控制储量；从源头上解决目前页岩气开发过程中存在的技术"瓶颈"，进一步为我国页岩气产业快速、经济、高效的开发提供强有力的理论与技术支撑。

页岩气藏开发的成功关键就是水平井和水力压裂技术的完美结合，尽最大可能提高单井泄气面积是一切理论和工艺的出发点。受物性、断层、人工裂缝等多种因素干扰，局部地应力场在局部有较大的扰动现象。当水平井段与最大主应力方向为30°夹角时，泄气面积下降50%.因此准确掌握试验区块地应力场分布是水平井分段压裂施工优化设计的技术关键，也是页岩气藏快速高效开发的基本保证。本课题从页岩岩石力学参数试验和现场测井资料解释入手，通过中横波关系构建、岩石力学弹性参数、强度参数、地应力参数测井计算和动静参数校正，获得单井岩石力学参数测井解释模型。结合变差函数分析和分布概率函数分析，基于高斯序贯理论形成了一套反映实际地质情况的页岩储层岩石力学参数三维地质建模方法。在岩石力学参数三维模型基础上，通过参数粗化、数据转换与输入、模拟物理模型建立、应力边框处理、地应力参数输入与模拟、结果输出等步骤实现页岩储层原始地应力场仿真。在开发过程中，多种因素会对原始地应力场形成人工扰动，课题组建立了水平井钻井成孔诱导应力场、注入流体诱导应力场、人工裂缝诱导应力场、温度诱导应力场数学模型，形成了热-流-固耦合的局部地应力场扰动评价模型。并在此基础上形成了基于真实岩石力学参数和地应力参数环境的人工裂缝启裂与延展评价方法；结合井网井距评价方法和数值模拟方法，形成页岩气藏布井优化方法和分段压裂施工关键参数优化方法。本课题的研究成果为我国页岩气产业快速、经济、高效的开发提供强有力的技术支撑，同时对于保护资源、加快国民经济建设等具有十分重要的现实意义和深远的战略意义。