油气井压裂开采裂缝系统的声探测方法的机理和应用研究

Unconventional oil and gas field with low permeability has become the focus of exploration and development, which has met with many difficulties. Fracturing and acidizing technologies are frequently used to achieve economic results. However, our ability of detecting and charactering the fracture systems is still very limited. An economic and effective evaluation technology is vitally important in this area. Based on the wave scattering theory in the heterogeneous medium, parallel 3D finite difference modeling and physical experiment, this project will study the borehole elastic wave field characteristics caused by wave scattering and reflection from fracture system. This study will understand the mechanism of acoustic interaction with the hydraulic fracture system, the key acoustic characteristics and parameters for the borehole acoustic measurement, establishing a borehole acoustic response function for the fracture characterization. With this approach, we analyze the sensitivity of controlling acoustical parameters to the fracture system. On the basis of the theoretical study, we will further study engineering applicability of acoustic detection technology in the detection and evaluation of the fracturing systems. The results will be an effective acoustic detection technology for detecting and evaluating oil and gas well hydraulic fracture systems, providing a key technological support for exploration and development of unconventional oil and gas reservoirs.

非常规低渗油气田是目前勘探开发的重点，但同时也是难点，需要对储层进行压裂、酸化等改造，才能实现经济开采，然而，目前对于油气井压裂开采裂缝系统的探测能力还十分有限，寻求经济有效的声探测技术和评价方法成为研究的关键。本项目拟基于波在随机介质中的散射理论和并行化的三维有限差分方法，结合物理实验，系统研究非均匀离散型网状裂隙所引起的散射波和断裂型裂缝系所引起的反射波的井孔声场变化特征，揭示井中声源在地层中激发的弹性波与开采压裂裂缝系统的相互作用过程和机理，提取对裂缝系统属性变化敏感的声学特征参数，建立测井环境下反映裂缝属性的井内声场响应函数，分析各声波特征参数对裂缝探测的灵敏度。在此基础上，进一步研究声探测技术在压裂裂缝探测和效果评价方面的工程适用性，建立压裂效果的评价标准，最终形成一门有效探测和评价油气井压裂裂缝系统的声波探测应用技术，为非常规低渗油气田开采中压裂效果评价提供关键技术支持。