尤拉屯No.15井超高密度聚磺复合盐水钻井液技术

Ultra-high Density Polymer Saltwater Drilling Fluid Technology for Well No.15 in Yunatu,Turkmenistan.

土库曼斯坦古诺尔塔·尤拉屯气田No.15井完钻井深为4 500 m,四开地层岩性以石膏、盐岩为主,压力系数为1.98～2.31,地层流体活跃,盐膏层易蠕动,周围有12口报废井。研究出的超高密度聚磺复合盐水钻井液具有流动性好、滤失量低、润滑防塌能力强等特点。现场应用表明,全井最高钻井液密度为2.38 g/cm^3,压井浆最高密度为2.70 g/cm^3,没有因盐膏层的缩径、坍塌、塑性流动等而引起井下复杂或事故;该钻井液具有较强的抗盐抗温稳定性和抗各种污染的能力,流动性较好,在遭遇严重的盐水侵、石膏侵、气侵等污染时流变性变差,但经过及时的处理或维护后很快好转;通过控制Cl^-含量不小于18×10~4 mg/L,同时使用盐重结晶抑制剂,有效地抑制了盐层溶解;维护处理工艺简单,性能稳定周期长;钻进、起下钻、电测、下套管顺利,为该地区高压盐膏层段钻井奠定了坚实的技术保障。

A high density polymer saltwater drilling fluid was used to drill the fourth interval of well No.15 in Yunatu gas field in Turkmenistan.The fourth interval of the well(4,500 m in depth) penetrated a series of gypsum and salt formations with formation pressure coefficient in a range of 1.98～2.31.Field application showed that the polymer mud,treated with some sulfonate had strong resistance to saltwater, gas and solids contamination,and stable rheology.The maintenance of the fluid property was easy and simple.This application of the high density polymer mud greatly helped the drilling operation.