新型抗高温油包水乳化钻井液体系的研究与应用

Research and Application of New High Temperature-Resistance W/O Emulsion Drilling Fluid System

针对高温下,传统油包水乳化钻井液黏度高、切力低、携岩能力差等问题,自主设计并合成了抗200℃油包水乳化剂,通过各种处理剂优选得到低黏高切油包水乳化钻井液体系,配方为油水比90:10,6.5%主乳化剂DQGC-II+2.2%辅助乳化剂DQNS-II+4%4号有机土+1.5%石灰+6%降滤失剂DQHA。室内评价结果表明,该体系抗温达200℃,稳定性强,破乳电压ES达1644 V,流变性良好,塑性黏度PV 19 mPa·s,动切力YP8 Pa,动塑比0.42,尤其低转速条件下的黏切适当,高温高压滤失量8.6mL。该体系在大庆油田GS-3井进行了现场应用,钻完井过程中未发生井下复杂,平均井径扩大率5.83%,保障了后续施工的顺利实施,可以替代麦克巴泥浆公司的VersaClean体系。

Due to the problems of traditional W/O emulsion drilling fluid, such as high viscosity, low gel and worse cuttings carrying capacity under high temperature, a new 200℃-resistance W/O emulsifier was designed and synthesized. A new W/O emulsion drill- ing fluid system with low viscosity and high gel was obtained after optimizing various agents, and the formula was： 90：10 oil-waterratio, 6.5% primary emulsifier DQGC-II, 2.2% secondary emulsifier DQNS-II, 4% No.4 organic clay, 1.5% CaO and 6% fluid loss control DQHA. This system showed good characteristics in lab including high electricity stability（ES 1644 V）, heat stability, good rheology, especially appropriate viscosity and gel under a low speed with 19 mPa. s PV, 8 Pa YP, 0.42 YP/PV, 8.6 mL HTHP filter loss. The new drilling fluid system was applied in GS-3 well of Daqing oilfield, there was no downhole complex. The ratio of overcut in average was 5.83%, and the following construction went smoothly. This new W/O drilling fluid system could replace the Ver saClean system ofM-I SWACO.