低固相超高温水基钻井液研究及应用

冀东油田南堡构造深部潜山储层温度高、压力低、裂缝发育,为满足保护储层和井下携岩的需要,基于开发的聚合物增黏剂SDKP以及对抗高温降滤失剂、油溶性封堵剂、润滑剂、高温保护剂和防水锁剂的优选,优化出一套低膨润土低固相超高温水基钻井液。室内评价结果表明,1%SDKP溶液在165℃老化16h后,表观黏度保持率仍可达20%,表明SDKP的耐温性能好;SD-101和SD-201复配可显著降低1.0%膨润土基浆的滤失量,油溶性封堵剂HQ-10可显著降低高温高压滤失量;该钻井液抗温达235℃,在200℃下的塑性黏度达到15mPa·s,满足携岩需要,抗污染能力强,能抗10%NaCl、2%CaCl_2、10%劣质土污染,抑制性好,膨胀率降低率达78%,页岩回收率从8.24%提高到84.45%,储层损害小。在探井南堡3-82井五开井眼的现场应用表明,该钻井液在220℃井底温度下的流变参数基本稳定,API滤失量不变,携岩性好,顺利钻达井深6037m完钻,自喷求产,产液量为43.20 m~3/d。证明该钻井液可满足现场高温低压储层的钻井需要。

Study and Application of Low Solids Ultra-high Temperature Water Base Drilling Fluid

A low clay content and low solids ultra-high temperature water base drilling fluid was engineered using optimized polymer viscosifier SDKP, high temperature filter loss reducer, oil-soluble plugging agent, lubricant, high temperature protective agent and water block preventer, based on an analysis of the characteristics of the reservoir in Nanpu, Jidong. Laboratory experiments showed that after 16 hours of aging at 165℃, 1% SDKP water solution still retained 20% of its original viscosity. A combination of two filter loss reducers, SD-101 and SD-201, remarkably reduce the filter loss of a 1.0% bentonite slurry. HQ-10, an oil-soluble plugging agent, can remarkably reduce the HTHP filter loss of drilling fluid. This drilling fluid remained stable at 235℃. At 200℃, the plastic viscosity was 15 mPa.s, satisfying the needs for carrying drilled cuttings. The drilling fluid maintained good rheology even contaminated with 10% NaCl, 2% CaCl2, or 10% inert clays. In inhibition test, the percent reduction in core swelling was 78%, and the percent recovery of cores increased from 8.24% to 84.45%. The application of this drilling fluid in the exploration well Nanpu3-82 showed that, at 220℃ (bottom hole temperature), the rheology of the fluid was stable the API filter loss remained unchanged, good carrying capacity of the fluid was realized. Well Nanpu3-82 was successfully drilled to 6,037 m, and had a liquid production of 43.20 m3/d.