葡浅12-平1特浅稠油水平井钻井液技术

Drilling fluid technology for Puqian 12-Ping 1 ultra-shallow viscous-oil horizontal well

大庆油田首口稠油水平井—葡浅12-平1井位于黑帝庙油田葡浅12区块,区内农田、鱼塘、草场密布,施工目的是开发地面条件受限而难以动用的储量。该井钻井技术难点包括:一开表层?311 mm井眼造斜点浅,开钻20 m即开始造斜,造斜钻遇高渗易漏的流砂层60 m;二开造斜段地层造浆性强,低排量下高钻速、高造斜率与岩屑携带矛盾突出,沉砂卡钻风险高;三开HI2-3层段稠油埋深浅,主力油层砂岩胶结疏松,井眼力学不稳定;施工存在塌、漏、涌同层风险;为便于油层识别与解释,水平段不允许混油。为此,根据室内实验和井身结构为三开确定了3套钻井液体系,现场应用中钻井液流变性合理、润滑防卡防塌能力强,易于发现油气显示,满足该井施工需要。

The ifrst viscous-oil horizontal well of Daqing Oilifeld-Puqian12-Ping 1 well is located in Puqian block 12 of Heidimiao Oilifeld, where there are intensive farmlands, ifshponds and grasslands. The construction aims to exploit the reserves which are hard to utilize due to restriction of ground conditions. Technical dififculties of drilling for this well are as follows.Firstly, shallow delfection points of surface ?311 mm boreholes, and delfecting is required from 20 m after drilling, and delfecting drilling will meet 60 m quick sand stratum which features high permeability and easy leakage. Secondly, the stratum of delfecting segment features high mud formation capacity, and shows severe conlfict between high drilling speed, high delfecting rate under low displacement and the rock debris taken out, thus indicates high risk of drilling tools being jammed by sand setting. lastly, HI2-3 stratum features shallow buried depth of viscous oil, major oil reservoir shows loosen sandstone bonding, and boreholes are in unstable mechanical properties.There are risks of collapse, leakage and surge in the same stratum during construction. To facilitate oil reservoir identiifcation and interpretation, oil mixture is not allowed in horizontal segment. Therefore, 3 sets of drilling lfuid systems are determined on the basis of indoor tests and well structure, and the systems feature reasonable rheological property of drilling lfuid, high lubricating, jamming and collapse prevention capacity, and easy discovery of oil and gas show in ifeld application, thus can meet construction requirements for this well.