高石梯—磨溪构造龙王庙组优快钻井技术研究

Optimized and Fast Drilling Technologies for Longwangmiao Formation,GaoshitiMoxi Block,Sichuan Basin

高石梯—磨溪区块位于四川盆地乐山—龙女寺古隆起磨溪潜伏构造带,在须家河组、嘉陵江组、龙王庙组、灯影组地层都有较好的油气显示,特别是龙王庙组及灯影组,是四川盆地近20年勘探取得重大突破层系,目前是重要的勘探前景区。针对该区块上部垮塌、缩颈、泥包、地层压力梯度大,二叠系地层易井漏、地层研磨性强等钻井难点,应用了高扭矩螺杆+PDC钻井技术、个性化钻头技术、优化钻井液性能、强化钻井参数、控制井眼轨迹等多项技术措施。在磨溪20井提速效果明显,该井创下高石梯—磨溪区块行程周期最短、平均机械钻速最高,311.2 mm井眼行程周期最短,仅用4只PDC钻头就钻完311.2 mm井段等多项纪录。

Gaoshiti-Moxi block is situated at the Moxi buried structure belt of Leshan- Longnvsi palaeo- uplift, Sichuan Basin.Good oil and gas show appears at Xujiahe, Jialingjiang, Longwangmiao, and Dengying formations. During the recent two-decade exploration, both Longwangmiao and Dengying formations have made major breakthrough, and become an important prospect in Sichuan Basin. However, there are some problems occurring in drilling, including collapse in upper part, necking down, bit balling, high formation- pressure gradient, lost circulation in Permian strata, and strong abrasiveness. So, some drilling technologies are adopted and many measures are made, for example, high-torque screw + PDC and personalized bit; and to optimize drilling-fluid property, to reinforce drilling parameter, and to control well trajectory. After their application to Moxi-20 well, an obvious effect of fast drilling was obtained, and some new records were also created, i.e., the highest average ROP, the shortest drilling cycle of 311.2mm borehole, and drilling interval of 311.2mm by only 4 PDC bits.