玛湖油田玛18井区体积压裂对钻井作业干扰问题的探讨

Discussion of Frac Interferences during Volumetric Fracturing in Drilling Operation of Ma 18 Well Area in Mahu Oilfield

玛湖油田玛18井区油井进行体积压裂后,相邻中深水平井三开钻进时出现井下复杂情况的次数增多,为了分析其原因并解决该问题,分析探讨了体积压裂对钻井作业干扰的问题。从复杂情况类型、处置案例、阶段性防控技术修正等方面入手,结合该井区中深水平井三开井段钻遇地层的地质特性,分析了受体积压裂影响正钻井发生井下复杂情况的主要原因:受体积压裂影响,侏罗系与三叠系地层交接处形成了窜漏点,导致在此处易出现井漏、溢流等井下复杂情况;斜井段与水平段的泥岩井段易出现井眼失稳和垮塌。对此,提出了针对体积压裂所造成的动态窜漏以及定向井段、水平井段泥岩地层井眼失稳的处理措施。研究认为,玛18井区中深水平井三开钻进防控体积压裂造成井下复杂情况的要点,是做好裸眼井段窜漏点封堵与泥岩段井壁的支撑工作,可为玛湖油田同类型水平井钻井提供借鉴。

The goal of this study is to solve the problem of frac interference in an area with many downhole complexities.After volumetric fracturing in Ma 18 well area of Mahu Oilfield,numerous downhole complexities were experienced in the third spud section drilling of middle-deep horizontal wells.In order to analyze the causes and solve the problems,the interferences of volumetric fracturing in drilling operation have been analyzed.From perspectives of complicated event,disposal cases,and phased prevention and control technical modification,combined with geological characteristics of different strata in the open-hole section of the middle-deep horizontal wells in this area,the main reasons leading to drilling complexities under the influence of volumetric fracturing were analyzed.Due to the influence of volumetric fracturing,leakage points were formed at the junction of the Jurassic and Triassic strata,which led to complex phenomena such as lost circulation and overflow The mudstone intervals in the deviated and horizontal sections were prone to wellbore instability and collapsing.Hence,the countermeasures for the dynamic leakage caused by volumetric fracturing,and the wellbore instability in the mudstone intervals of directional and horizontal sections were proposed.According to the research,during the third spud section drilling of middle-deep horizontal wells in the Ma 18 well area,the key elements for controlling the downhole complexities caused by volumetric fracturing were a consequences of plugging the leakage points in the open hole section,and supporting the wellbore in the mudstone intervals.These countermeasures could provide reference for drilling the same type of horizontal wells in Mahu Oilfield.