巴楚隆起夏河区块风险探井钻井优化设计

Optimal drilling design of wildcat well in Xiahe Block, Bachu Uplift

夏河区块位于新疆塔里木盆地巴楚隆起,夏河1井是中国石化部署在该区块的第1口风险探井,目的层为寒武系盐间灰岩和盐下白云岩。该区块地层岩石可钻性差,易蹩跳钻、断钻具,机械钻速低,深部地层易井斜,裂缝性地层易井漏,盐膏层存在钻井液钙侵污染等。邻近地区钻井周期长,钻井复杂情况及故障多发,安全钻井技术难点多。为实现安全高效钻井,基于工程地质特性和邻区完钻井技术分析,优化设计了夏河1井井身结构、分层段钻头型号、钻井液体系,制定了古生界钻井提速、井斜控制、裂缝地层防漏堵漏、抗钙侵钻井液等针对性技术措施,为安全、高效成井创造了条件。

Xiahe No.1 well is located at the Bachu Uplift of Tarim Basin, which is the first wildcat well in Xiahe Block. The main targeted formation is Cambrian limestone between the salt beds and subsalt dolomite. The extremely complicated geological condition results in the poor rock drillability, drill bit bouncing, low rate of penetration, well deviation, lost circulation and calcium contamination. The adjacent wells drilled have the problem of long drilling circle and multiple drilling complex condition and failure. Based on the research of engineering geological characteristics and drilled well technology analysis, the casing program of Xiahe No.1 Well was optimized, and the drill bit type and drilling fluid were selected carefully. A series of drilling technical measures were applied, for instance, high efficient rock breaking methods, well deviation control, lost circulation control ＆ plugging, anti-calcium drilling flurry, which contribute to the safe and high efficient drilling operation.