塔河油田潜山录井技术

Mud logging technology for Tahe oilfield buried hill

塔河油田奥陶系碳酸盐岩潜山,地层复杂,非均质性强,风化面上下存在两套地层压力系统,上古生界和中生界为相对高压系统,下部奥陶系为相对低压系统,致使钻井过程中风化壳卡取困难,井漏、井涌等工程事故频发。针对潜山录井工作中风化壳地层的卡取、工程预报与油气层评价3个关键环节,从地层对比、过渡带识别和现场措施制订等方面总结了卡取风化壳的经验,介绍了井涌、井漏等工程事故的预报方法,将潜山在纵向上分为地表岩溶带、渗流岩溶带和潜流岩溶带,按带归纳出岩性、电性特征,并进一步形成了塔河油田潜山油气层评价的专家系统,实践证实应用效果较好。

As to the Ordovician system carbonate buried hill in Tahe oilfield, the formation is complex and the heterogeneity is high, two sets of formation pressure system exist above or under weathered surface, the upper Palaeozoic and Mesozoic are the relatrvely high pressure systems, the lower Ordovician system is the relatively low pressure system, this made stick weathering crust difficult, thus leading to lost circulation, kick and other engineering accidents frequently to happen. In view of the three key points during buried hill mud logging, that is, formation weathering crust sticking, engineering prediction and pay zone evaluation, the paper summarized the weathering crust sticking experience, introduced the methods for forecasting engineering accidences of lost circulation, kick and so on from the aspects of stratigraphic correlation, intermediate zone identification, on-site measures establishment and so on. The buried hill was divided into surface karst zone, osmotic karst zone and underwater current karst zone in the vertical, and induced the lithologic and electrical behavior characteristics according to the zones, thus further forming Tahe oilfield buried hill hydrocarbon reservoir evaluation expert system. The system got better results through the practice application.