超高密度钻井液技术研究

新疆准噶尔盆地南缘地区安集海河组存在超高压、强造浆、强坍塌应力、溢、漏、塌、卡、复合离子污染等钻井问题,使用的钻井液密度最高在2.5 g/cm3以上,钻井液在超高密度条件下性能极难调控.分析了该地区易塌层段地质特点和地层中的粘土矿物组分以及存在的钻井液技术难题,有针对性地研制出了JAB高密度钻井液体系.评价了JAB体系在超高密度条件下的流变性、抗污染能力、抗温性、抑制性及润滑性等.结果表明,该钻井液体系在超高密度(2.5 g/cm3)下,具有良好的抑制造浆、稳定井壁、润滑防卡能力和抗可溶性盐污染、流变性好等特点,能满足准噶尔盆地南缘地区复杂地层钻探的需要.提出了该体系现场维护处理的几点建议.

Study on a ultra-high density drilling fluid

In Anjihaihe Group formation of Xinjiang oilfield, the presence of ultra-high pressure, strong mud-making behavior, strong collapse stress, and problems experienced such as well kick, lost circulation, well slough, pipe sticking, several ions pollution, make drilling fluids difficult to conditioned onsite at ultra-high density(more than 2. 5 g/cm3). Based on analyses of geological characteristics of easy slough section, clay mineral components and present drilling problems, a ultra-high density drilling fluid JAB was studied. In lab, the JAB system was evaluated on aspects of rheological characteristic, anti-pollution ability, thermal stability, inhibition and lubrication. Results showed it satisfied requirements of drilling in complex formation in Zhunger Basin. Some suggestions were put forward on in-situ conditioning for this drilling fluid system.