复杂深井高密度阳离子钻井液体系优化研究与应用

Optimization study and application of the high-density cationic drilling fluid system for complex deep wells

关键词:  酒东油田  复杂深井  高密度  阳离子钻井液

Key words:  Jiudong oilfield  complex deep well  high density  cationic drilling fluid

摘要:

针对玉门酒东油田白垩系深部井段钻井液在高密度、高井温、高矿化度条件下流变性不易控制、现场维护难度大、钻井复杂事故多、完井电缆测井成功率低等问题,室内优选出了钻井液封堵剂JHS-01和抗高温降滤失剂JY-1B两种钻井液处理剂,优化形成了改进型高密度阳离子钻井液配方。室内评价表明,该钻井液在密度2.00 g/cm³时的漏斗黏度为77 s、动切值为7 Pa、终切值为8 Pa,120 ℃ HTHP滤失量为10 mL,黏切值低,封堵造壁性能良好,抑制性、抗温、抗污染等性能符合要求。现场应用表明:该钻井液与改进前邻井相比,漏斗黏度由88～110 s降至78～86 s、动切值由23～28 Pa降至12～20 Pa、终切值由14～26 Pa降至6～16 Pa,钻井液流变性明显改善,120 ℃ HTHP滤失量9～11 mL,泥饼薄(2.5 mm)且致密,封堵造壁性能良好,钻井无复杂事故,电缆测井一次成功,满足酒东高密度复杂深井钻井要求。 

Abstract:

There are problems of uncontrollable rheological characteristics, difficult site maintenance, frequent occurrence of complex drilling accidents, and low success rate of wire-line logging after well completion at deep wells segments of Cretaceous System in Yumen Jiudong oil field, where the drilling fluid has a high density, high well temperature and high mineralization level. This paper selects two kinds of drilling fluid treatment agents indoors, which are drilling fluid plugging agent JHS-01 and anti-high temperature filtrate loss reducer JY-1B. Through optimization, a modified high-density cational drilling fluid formula was formulated. The laboratory evaluation shows that the funnel viscosity of the drilling fluid is 77 s, the dynamic shear value is 7 Pa, the final shear value is 8 Pa at the density of 2.00 g/cm³, the HTHP filtration at 120 ℃ is 10 mL, the viscosity shear value is low, the plugging and wall building performance is good, and the inhibition temperature resistance and pollution resistance meet the requirements. The field application shows that as the funnel viscosity of the modified drilling fluid drops from 88-110 s to 78-86 s, its yield point drops from 23-28 Pa to 12-20 Pa, its ten-min gel strength drops from 14-26 Pa to 6-16 Pa, which means its rheological characteristics have been improved significantly compared with the unmodified ones in neighboring wells. Moreover, the HTHP is 9-11 mL at 120 ℃, the mud cake is thin (2.5 mm in thickness) and compact, showing a good plugging and wall-building property, being free from complex drilling accidents, and capable to complete wire-line logging in one go. Therefore, this drilling fluid is able to meet the requirements of high-density complex deep wells drilling in Jiudong oilfield.