煤层气215.9mm井眼水平井绒囊钻井液技术

Soft Capsule Drilling Fluid Technology for 215.9mm CBM Well and Horizontal Well

EJ2井是位于鄂尔多斯盆地东缘的一口煤层气水平生产井,目的煤层为顶部深度1047.33m、底界深度1056.5m的二叠系山西组5#煤,采用Ф215.9mm钻头,Ф139.7mm套管完井。大井眼、水平井存在携岩困难、井壁失稳等技术难点。采用重晶石加重绒囊钻井液,密度1.15g/cm3,塑性粘度20MPa.s,切力11Pa,6天完钻1961.98m设计井段。因连通未成功,上提至1765.94m侧钻至1961.45mm,与EJV井对接成功,完钻井深1981.45m。水平段钻井周期8天,平均机械钻速5.1m/h。测井顺利,下入Ф139.7mm套管至井深1962m顺利,固井质量优良。

E J2 is a CBM horizontal production well located in eastern fringe of Ordos Basin. The target seam is No. 5 coal seam of Shanxi formation of Permian system, the depth of the top of seam being 1047.33m, depth of the bottom of coal seam 1056.5m. The drill bit used is φ215.9mm, and φ139.7mm casing completion. The technical difficulties met were： carrying out the cuttings from both the vertical and horizontal wells, and insta- bility of the wellbore. Soft capsule drilling fluid with barite was introduced, with a density of 1.15 g/cm3, the plastic viscosity, 20MPa＇s, shear 11 Pa. Drilling of 1961.98m the design section was completed in six days. Due to failure in well connection, the drill bit was then lifted to the depth of 1765.94m, and drilled laterally to 1961.45m and succeeded in connection with EJV well. The depth of completed well was 1981.45m. The horizontal well was finished in 8 days. The average drilling speed of the machine was 5. lm/h. Logging was carried smoothly. Casings of 6139.7mm were lowered to a depth of 1962m successfully, and the quality of ce- mentation was excellent.