微地震监测技术在川南页岩气井水力压裂中的应用

发布时间：2018-07-03 19:33

本文选题：微地震 + 页岩气　；参考：《成都理工大学》2015年硕士论文

【摘要】：我国页岩气资源十分丰富,川渝地区页岩气储量位居全国首位,但相应的勘探开发工作尚处于初级阶段。页岩气藏常被称为“人造气藏”,勘探开发通常需要水平井钻井技术和水力压裂技术改造储层,形成人造裂缝网络才能形成工业生产能力。当前川南地区页岩气开发多采用水平井大型多级体积压裂,相对于传统压裂方式,其裂缝网络形成更为复杂,压裂情况更为复杂多变。常规的压裂监测技术,例如净压力分析、井温测井、放射性测试等方式因其自身技术的局限性不能完全满足对大型水力压裂裂缝形成过程的监测。微地震技术作为新兴的地球物理技术,通过观测水力压裂过程中产生的岩石破裂声发射现象来实现对压裂效果和地下状态变化的监测。其主要通过布设在临井或地面的检波器排列监测来自地下的微地震信号,获取微地震事件的震源信息(空间分布、震级大小)等,进而评估整个裂缝网络的形态特征。本文以川南地区一典型的平台井组大型水力压裂为例,系统阐述了微地震监测基本原理及深井监测的基本流程及方法。其主要包括:基于井况和压裂设计参数的观测系统设计与信号采集技术,获得了高品质的微地震信号,分析了不同强度的微地震信号与背景噪音信号特征;研究应用不同于常规地震勘探的微地震数据预处理技术,偏振分析技术,速度建模及校正技术,非均匀介质下震源-速度联合反演定位技术实现了对微地震信号的精准定位,平均定位误差控制在15m以内;应用微地震技术对此次大型水力压裂进行监测,效果良好,现场实时处理结果对压裂效果给予了初步评价,并对压裂参数调整给出了建议,有效降低了作业成本,规避了压裂隐患;压裂作业结束后,对监测结果进行结合地质、压裂和常规地震勘探成果的综合解释,主要利用微地震事件的时间属性和能量属性,对本次大型水力压裂作业形成的裂缝网络进行了详细描述,获取了裂缝网络几何形态的和压裂改造体积(SRV),为后期的油藏描述及开发工作提供了大量基础资料。本文最后论述了微地震地面监测的基本流程,并将监测结果与井中监测进行对比分析,验证地面监测方式在不具备深井监测的条件下,可基本实现对裂缝网络的刻画描述。
[Abstract]:China is rich in shale gas resources and the reserves of shale gas in Sichuan and Chongqing areas rank first in China, but the corresponding exploration and development work is still in the primary stage. Shale gas reservoir is often called "artificial gas reservoir". Exploration and development usually need horizontal well drilling technology and hydraulic fracturing technology to reconstruct reservoir and form artificial fracture network to form industrial production capacity. At present, shale gas development in south Sichuan adopts large scale multistage volume fracturing of horizontal well. Compared with the traditional fracturing method, the fracture network is more complex and the fracturing situation is more complex and changeable. Conventional fracturing monitoring techniques, such as net pressure analysis, well temperature logging, radioactivity testing and so on, can not fully meet the monitoring of the formation process of large-scale hydraulic fracturing fractures due to the limitations of its own technology. As a new geophysical technique, microseismic technology can monitor the fracture effect and the change of underground state by observing the acoustic emission phenomenon of rock fracture during hydraulic fracturing. The microseismic signals from the ground are monitored by geophone arranged in the near well or the ground, and the source information (spatial distribution, magnitude) of the microseismic events are obtained, and the morphological characteristics of the whole fracture network are evaluated. Taking the large hydraulic fracturing of a typical platform well group in south Sichuan as an example, the basic principle of microseismic monitoring and the basic flow and method of deep well monitoring are expounded systematically. It mainly includes: the design of observation system and signal acquisition technology based on well conditions and fracturing design parameters, obtained high quality microseismic signals, and analyzed the characteristics of microseismic signals and background noise signals with different intensities; The micro-seismic data preprocessing technology, polarization analysis technology, velocity modeling and correction technology, and the combined source-velocity inversion positioning technology in non-uniform medium are applied to realize the accurate location of microseismic signal. The mean positioning error is controlled within 15m, the microseismic technique is used to monitor the large-scale hydraulic fracturing, the effect is good, the field real-time processing results give a preliminary evaluation of the fracturing effect, and some suggestions for adjusting the fracturing parameters are given. After fracturing operation, the monitoring results are interpreted in combination with geological, fracturing and conventional seismic exploration results, and the time and energy attributes of microseismic events are mainly used. The fracture network formed by this large-scale hydraulic fracturing operation is described in detail, and the fracture network geometry and fracturing volume (SRV) are obtained, which provides a lot of basic data for the later reservoir description and development work. In the end, the paper discusses the basic flow of micro-seismic ground monitoring, compares the monitoring results with in-well monitoring, and verifies that the surface monitoring method can basically describe fracture network without the condition of deep well monitoring.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE377;P631.4

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