油砂SAGD水平井钻井液体系

针对SAGD水平井在油砂开发过程中井壁失稳、托压易黏附卡钻及沥青沾染钻具和固控设备等难题，室内通过核心处理剂的优选，研发了一套强抑制高润滑水基钻井液体系。室内性能评价表明，该钻井液抗温180℃，抗沥青20%，抗钻屑25%，岩屑滚动回收率为91.7%，润滑性能与油基钻井液基本相当。强抑制高润滑水基钻井液在麦凯河区块5对（10口） SAGD水平井施工过程中性能稳定易调整，润滑效果突出，机械钻速高，无任何复杂事故。结果表明，强抑制高润滑水基钻井液完全满足浅层油砂SAGD水平井施工工艺的技术需求，具有推广应用价值。 

Drilling Fluid Formulation for Oil Sand SAGD Horizontal Wells

Wellbore instability, inability to exert weight-on-bit and adhesion of asphalt on drilling tools and solid control equipments are diffcult problems associated with SAGD (steam-assisted gravity drainage) horizontal drilling. A water base drilling fluid with high inhibitive capacity and good lubricity has been formulated, based on additive selection through laboratory experiment, to resolve these diffcult problems. This drilling fluid in laboratory experiment showed good properties, such as high temperature resistance (180℃), resistance to contamination caused by 20% asphalt and by 25% drilled cuttings, and percent cuttings recovery of 91.7% in hot rolling test. The lubricity of the drilling fluid is equivalent to that of oil base mud. This drilling fluid was used on 10 SAGD horizontal wells in Block Maikaihe, showing stable and easy-to-control properties, and good lubricity. High ROP was obtained with the use of the formulation. Ho downhole troubles have ever been encountered during drilling. This water base drilling fluid of strong inhibitive capacity and good lubricity fully satisfed the needs of shallow oil sand SAGD horizontal well drilling, and is worth spreading.