C2133侧钻小井眼水平井钻井液技术

Drilling fluid technology for the horizontal side-tracked slim hole in well C2133

针对彩南油田西山窑组储层裂缝发育,产量大幅度递减、含水量上升较快、注采矛盾突出等问题,在C2133井侧钻,以增加泄油面积。该井侧钻点井深为2120 m,采用聚磺暂堵钻井液,在不同井段采取了不同的钻井液技术措施。即:在套管开窗井段,提高钻井液悬浮携屑能力,保证铁屑及时返出地面;磨铣时,钻井液密度为1.10 g/cm3或略增高,以保持侧钻地层井壁稳定。造斜井段,提高钻井液的抑制能力,防止岩屑床的形成;加入SMP-1、KT-100和QCX-1改善泥饼质量,降低滤失量;加入足量的KWR和RH101降低摩阻,控制固相含量。水平井段。在钻井液中加入1.5％FB-2、2％QCX-1、1％WC-1,保持磺化沥青含量为3％～5％,使钻井液具有较强的抑制性、稳定性和良好流变性。现场应用表明,聚磺暂堵钻井液保证了C2133侧钻小井眼水平井不同井段的钻井施工,钻进过程中井壁稳定,未发生井下复杂事故。该井前期日产油量约25 t,比邻井产量高3～5倍,收到了明显的经济效果。

To cope with the problems of reservoir fracture development, severe production declining, water content ratio rising in Xishanyao group of Cainan Oilfield, a side-tracked slim horizontal hole has been drilled in Well C2133 to enhance the drainage area. The KOP is located at 2120 m, and poly-sulfonate temporary plugging drilling fluid has been used in the well. Different drilling techniques have been used in different section in the well. i. e. , in the window killing section, improving the suspension property and solids-carrying capability of drilling fluid to ensure the timely return of iron cuttings to surface; during milling, high density drilling fluid of 1-10 g/cm3 or more was used to stabilize the hole; in the build-up section, improving the inhibition of drilling fluid to prevent cuttings beds form settling, improving mud cake quality and reducing the filter loss with additives of SMP-1, KT-100 and QCX-1, reducing friction drag and controlling solid content with additives of KWR and RH101; in horizontal section, using the additives of 1. 5% FB-2, 2% QX-1 and 1% WC-1 to ensure the content of sulfonated asphalt between 3% and 5% and keeping the drilling fluid at higher inhibition, stability and good rheology property. Field application indicated that polysulfonate temporary plugging drilling fluid satisfied the drilling engineering requirements in the different horizontal section of well C2133. The borehole wall was stable and no accident took place in the down hole during drilling. Its early production rate was 25 t/d which was 3-5 times of the adjacent wells, remarkable economic benefits has been obtained in the well.