延长油田复杂区块水平井钻井液优化与应用

Optimization and Application of Drilling Fluid for Horizontal Wells in Complex Block of Yanchang Oilfield

延长油田以靖边、定边和吴起区块为主,该区水平井技术发展迅速,侏罗系延安组和三叠系延长组作为主力层位开发已经有较大规模。但部分区块地层炭质泥岩和泥页岩较为发育,工程情况较为复杂,水平井钻井过程中,漏失和坍塌问题特别严重。延长油田水平井钻井技术,特别是钻井液技术研究显得尤为关键。现阶段延长油田水平井钻井所用的K-PAM聚合物钻井液体系存在流变性不佳、封堵和抑制性不足等缺点,室内通过对地层岩性和钻井技术难点分析,优化形成了新的水平井钻井液体系,并指出水平井钻井液性能要求。针对延长油田实际情况,提出水平井钻井液应用基本原则和主要优缺点。以定边井塌为例,对定边水平井坍塌问题进行深入探究,给出具体集体措施,现场应用效果较好。

The Yanchang oilfield is dominated by Jingbian,Dingbian and Wuqi blocks.The horizontal well technology in this area has developed rapidly.The Jurassic Yan’an Formation and the Triassic Yanchang Formation have been developed as the main layer.However,carbonaceous mudstone and shale in the formation of some areas are relatively developed,the engineering situation is more complicated,leakage and collapse problems in the horizontal well drilling process are particularly serious.Horizontal well drilling technology for Yanchang oilfield,especially drilling fluid technology research is particularly critical.At this stage,the K-PAM polymer drilling fluid system used for drilling horizontal wells in oilfields has shortcomings such as poor rheology,plugging and insufficient inhibition.Through analyzing the lithology of the formation and the difficulty of drilling technology,optimized drilling fluid system was developed.And the performance requirements of horizontal well drilling fluid were pointed out.Based on the actual situation of the oilfield,the basic principles and main advantages and disadvantages of horizontal well drilling fluid application were proposed.Taking Dingbian well collapse as an example,the collapse problem of horizontal wells in Dingbian block was deeply explored,and specific collective measures were given.The field application effect was better.