微地震技术在稠油油藏蒸汽吞吐汽窜前缘监测中的应用

The Application of Micro-seismic Technology in Monitoring Steam Channeling Front during Steam Stimulation in Heavy Oil Reservoir

摘要: 为了更好地认识蒸汽吞吐过程中蒸汽前缘的扩展状况，以河南井楼油田楼1725井为例，利用微地震技术对蒸汽前缘进行监测，分析该井附近蒸汽流动通道的扩展情况，确定注汽前缘的优势方位和蒸汽波及范围，分析该井的汽窜特征。微地震监测结果显示，楼1725井的注汽优势通道主要位于北偏西与东偏南方向。蒸汽吞吐过程中，注汽前缘的宽度略有增加，注汽前缘的长度有增加的趋势，说明地层中存在蒸汽指进特征，呈现明显汽窜现象。随注入蒸汽量的增加，注汽压力升高，蒸汽波及区域有进一步扩大的趋势，平面上储层动用程度有所提高。但由于储层非均质性比较严重，无论是注汽初期、中期或末期，平面上均存在吸汽不均匀、平面矛盾突出的问题，严重影响了蒸汽吞吐的开发效果。微地震汽窜监测能够实时了解蒸汽吞吐过程中蒸汽在地层中的运移特征，精确掌握汽窜方向及汽窜通道尺寸，为后期措施调整提供了参考依据。

Abstract: Cyclic steam stimulation (CSS) was the main method to develop heavy oil in Jinglou Oilfield in Henan. To have a better understanding of steam front expanding condition during the CSS process, the steam front of Well L1725 was monitored by micro-seismic technique. The expansion of steam channels near Well L1725 was analyzed, the dominance orientation of steam flooding and its sweep area were identified, and its channeling characters were analyzed. The monitoring results showed that the dominance orientation of steam flooding of L1725 was mainly located in the northwest and southeast. During the CSS process, the width of steam front slightly increased, while the length of steam front tended to be increased, indicating that there existed steam fingering phenomenon and it evidently had the phenomenon of steam channeling. With the continuous injection of steam, steam injection pressure increased, steam sweep area further expanded, and the reservoir producing level rose in plane. But micro-seismic monitoring indicated that reservoir heterogeneity was noticeable and steam absorption in plane was uneven whether it was at the early stage, or middle and late stage. There existed a severe contradiction in plane, which seriously affected the effect of steam flooding. The micro-seismic monitoring technology can be used for real-time understanding steam expansion in reservoir and mastering the channeling direction and the size of steam channeling path, which can provide guidance for the adjustment of measures in the later period.