仿生绒囊钻井液煤层气钻井应用现状与发展前景

Application state and prospects of bionic fuzzy-ball drilling fluids for coalbed methane drilling

郑力会

ZHENG Lihui

中国石油大学石油工程教育部重点实验室，北京　102249

The Key Laboratory of Petroleum Engineering of Ministry of Education, Beijing 102249, China

仿照细菌结构开发了含仿生绒囊的钻井液。CLY-A井欠平衡钻井表明，无需附加设备，调整钻井液密度0.8~1.0 g/cm3即可循环；CLY-B井空气钻井表明，空气钻井过程中添加不同绒囊处理剂，可实现空气、雾、泡沫和绒囊不停钻转换钻井工作流体；DFS-C井防漏堵漏钻井表明，分压、耗压、撑压方式可控制钻井液漏失速度；FL-D分支井钻井表明，该钻井液具有低剪切速率下高黏度和高剪切速率下低黏度的特性，能够提高井眼清洁效率和机械钻速；J-E井不同压力系统共存于同一裸眼的井下复杂处理表明，该钻井液可以提高低压井段承压能力，满足动态窄密度窗口地层安全钻井。绒囊钻井液应加强绒囊结构微观研究、绒囊钻井液类型开发和低密度循环极限评价等，满足更多地层条件钻井需要。

The bionic fuzzy-ball drilling fluid was developed by imitating bacteria structure. Bionic Fuzzy-ball drilling fluid for underbalance drilling in well CLY-A shows the density of the fluid can range from 0.8 g/cm3 to 1.0 g/cm3 and it can be circulated without extra equipments. Compressed air drilling in well CLY-B proves that the different bionic fuzzy-ball additives varying drilling phases such as air, mist, foam and fuzzy-ball drilling fluid can be converted smoothly. Bionic fuzzy-ball drilling fluids for controlling and killing circulation loss in well DFS-C indicates it can control the leakage in forms of pressure reduced, pressure lost and pressure supported. The multi-branch drilling process in well FL-D shows both the cases of high viscosity with low shear rate and the low viscosity with high shear rate have good performance in cleaning wellbore and enhancing ROP. In well J-E, different formation pressure coefficients exist in the same open hole. The successful drilling proves it can improve the formation pressure bearing resistance in low-pressure section and help safe drilling in formations with narrow dynamic safe density window. Further study of bionic fuzzy-ball drilling fluid should focus on its microstructure, system type and circulation density, to satisfy more specific needs in drilling process.