高性能环保水基钻井液的研究与应用

Study and Application of Environmentally Friendly High Performance Water Base Drilling Fluid

针对高性能水基钻井液体系配方复杂、性能调控难度大、生物毒性与重金属超标等技术难题,采用疏水缔合与接枝复合改性方法,设计、研发了一种基于天然高分子/无机纳米复合材料的环保降滤失剂EFR-1,并对其性能进行评价。结果表明,EFR-1的抗温可达170℃,在饱和盐水中API滤失量仅为14.8 mL,生物毒性EC50值为96500 mg/L,生物降解性BOD5/CODCr为18.56%,较好地解决了降滤失剂抗温、耐盐与环境友好性能相互制约的问题。构建了抗高温为170℃的高性能环保水基钻井液体系HPHB,该钻井液的流变、滤失性能稳定,配方组成简单,高温高压滤失量仅为7.8 mL,生物毒性EC50值为56800 mg/L。目前高性能环保水基钻井液体系HPHB已在胜利油田、新疆准中区块等现场应用20余口井,施工顺利,实验井段的井径扩大率≤5%。在显著提升钻井液工程性能的基础上,实现了绿色无毒,为深层超深层、海洋深水、非常规等复杂油气藏的绿色开发提供了技术支撑。

In the field application of high performance water based drilling fluids,several technical problems have been encountered,such as complex composition,properties difficult to adjust and control,as well as excessive biotoxicity and heavy metals.To solve these problems,an environmentally friendly filter loss reducer EFR-1 was developed with a natural high molecular weight polymer and an inorganic nanocomposite through hydrophobic association and grafting modification.Laboratory evaluation of the EFR-1 filter loss reducer showed that EFR-1 is able to function normally at high temperatures up to 170℃.Saturated saltwater drilling fluids treated with EFR-1 have filtration rate of only 14.8 mL,EC50(biological toxicity)of 96500 mg/L and BOD5/CODCr(biodegradability)of 18.56%.The use of EFR-1 helped solve the mutually restraining problems such as temperature resistance,salt resistance and environmental friendliness.A high performance water based drilling fluid HPHB was developed with EFR-1.HPHB,a drilling fluid of simple composition,has stable rheology and filtration property in field operations,its HTHP filter loss is only 7.8 mL and EC50 of 56800 mg/L.HPHB has been successfully used on 20 wells drilled in Shengli Oilfield and Zhunzhong block in Xinjiang.Hole sections drilled with this HPHB drilling fluid have percent hole enlargement of less than 5%.The HPHB drilling fluid is not only technically feasible,but also environmentally friendly,it has provided a technical support to the“green”development of complex oil and gas reservoirs buried in deep/ultra-deep formations and in deep waters,as well as the“green”development of unconventional oil and gas reservoirs.