中原油田特殊工艺井钻井液的研究与应用

Drilling fluids for special wells in Zhongyuan oilfield.

针对中原油田地层高温(140～180℃)、高压(1.5～1.9g/cm3)、高矿化度(14×104～25×104mg/L)和低渗透率的实际特点,开展了特殊工艺井水基钻井液在流变性、润滑防卡、井壁防塌、储层保护以及现场工艺等方面的技术研究。通过钻井液弱凝胶聚合物流型调节剂、纳米润滑乳化剂、油膜形成剂以及油气层保护暂堵方法的优选,研制开发出了一套性能优良的特殊工艺井钻井液体系。该钻井液在复杂地质条件下具有较强的携岩、润滑和防塌性能及好的储层保护效果,是一种综合性能优良的特殊工艺井钻井液。中原油田10多口井的应用表明,平均钻井周期为50d,比对比井降低了10%,日进尺为84.6m/d,比对比井提高了12.6%,钻井综合成本明显降低。其中桥69平1井是中原油田第一口以开发天然气为目的的三靶水平井,该井水平段岩心渗透率恢复值均大于85%,全井施工顺利,井径规则,生产时效达97.28%,纯钻时效为38.32%,电测均1次成功,产量是对比井的8倍。

According to the geological characteristics of Zhongyuan oilfield such as high temperature, high pressure, high salinity and low permeability, researches on water based drilling fluids for special wells were conducted on such aspects as rheological property, lubrication, pipe stuck prevention, hole collapse prevention, performance protection and onsite maintenance. Based on optimizing the weak gel flow adjusting agent, nanometer lubricating emulsifier, oil film forming agent and relevant formation protection measures, a drilling fluid for special wells was developed. It is composed of 3%~4% bentonite, 0.1%~0.3% AMZ, 0.1%~0.3% JTR-888, 0.5%~1.0% MMH, 8% crude oil, 1%~2% oil film forming agent CMJ-2, 0.5%~1.0% nanometer lubricating agent DNE-1, 0.2~0.5% SMT, 1%~3% PSP, 1%~2% SDX-3, 0.25%~0.5% LV-CMC and 0.5%~1.0% polyalcohol. This fluid system exhibits good cuttings transportation, lubrication and hole swelling prevention. Field using also demonstrated its stable property. Accidents down hole were reduced substantially, the drilling period is shortened and drilling cost was lowered. Moreover, this fluid helped in protecting formation effectively, damage caused by drilling fluid was reduced.