神木双山三开优化水平井钻井液技术应用

Application of Drilling Fluid Technology in Shenmu Shuangshan 3rd Spud Optimized Horizontal Well

神木双山区块作为长庆气田主要产建区块之一主要指榆林周边的区域。神木双山区块具有延安组地层易缩径,延长下部和纸坊上部地层易垮塌,刘家沟地层承压能力低易漏失的地质特点,三开优化水平井的井身结构虽然在一定程度上解决了上部坍塌和刘家沟容易发生井漏的问题,但是,斜井段和水平段在同一裸眼段,又带来一系列新的问题。最为突出的是,大斜度井段和水平段在同一裸眼段,浸泡周期长,井壁容易失稳,后期钻井施工摩阻扭矩大的问题。加上该区块的层垂深浅,直井段的钻具重量相对轻,加重了这些难题。针对这些特点与难点,通过理论分析和现场实验,初步形成了相对应的一套钻井液技术方案和措施,结合现场实际应用出现的一些问题,总结了经验,改善了措施,完善了神木双山区块三开优化水平井的钻井液技术。

Shenmu Shuangshan Block,as one of the main production and construction blocks of Changqing Gas Field,mainly refers to the area around Yulin.The Shenmu Shuangshan block has the geological characteristics of easy shrinkage of the Yan'an Formation,easy collapse of the lower and upper Zhifang formations,and low pressure bearing capacity and easy leakage of the Liujiagou formation.Although the optimized wellbore structure of the Sankai horizontal well has to some extent solved the problem of upper collapse and easy leakage of the Liujiagou formation,the inclined and horizontal sections in the same open hole section have brought a series of new problems.The most prominent issue is that the highly deviated and horizontal sections are in the same open hole section,with a long soaking period and easy instability of the wellbore wall,resulting in high friction and torque during later drilling construction.In addition,the vertical depth of the target layer in this block is shallow,and the weight of the drilling tools in the vertical section is relatively light,which exacerbates these difficulties.In response to these characteristics and difficulties,a corresponding set of drilling fluid technology schemes and measures have been preliminarily formed through theoretical analysis and on-site experiments.Combined with some problems encountered in on-site application,experience has been summarized,measures have been improved,and the drilling fluid technology for the third optimized horizontal well in the Shenmu Shuangshan block has been improved.