中文摘要：

为获得适合页岩气水平井的低油水比下性能优良的油基钻井液,利用Turbiscan Lab型分散稳定性分析仪研究了油水比对油包水乳状液的粒径及稳定性的影响,考察了油水比对油基钻井液性能的影响。研究结果表明,油水比由90∶10降至60∶40时,油包水乳状液的平均粒径由5.65μm增至8.21μm;随着油水比降低,乳状液的背散射光强度值变化幅度逐渐增大,油包水乳状液稳定性变差。在处理剂加量不变的条件下,油水比由90∶10降至60∶40,热滚后的油基钻井液的塑性黏度由16 m Pa·s增至55 m Pa·s,动切力由7 Pa增至30 Pa,破乳电压由1211 V降至303 V。通过提高乳化剂加量、降低有机土加量在低油水比条件下获得了性能优良的油基钻井液,并成功用于焦页54-3HF、焦页25-2HF、焦页54-1HF等多口井的现场施工。

英文摘要：

In order to obtain oil-based drilling fluid with excellent performance at low oil-water ratio suitable for shale gas horizontal wells,the effect of oil-water ratio on the particle size and stability of water-in-oil emulsions was studied by using Turbiscan Lab type dispersion stability analyzer,and the effect of oil-water ratio on the performance of oil-based drilling fluid was researched. The research results showed that particle size of the water-in-oil emulsions increased from 5.65 μm to 8.21 μm when the oil-water ratio decreased from 90∶10 to 60∶40,and the variation range of the reflected light intensity indicated the poor stability with decreasing oil-water ratio,which meant that the stability of the water-in-oil decreased with the decrease of the oil-water ratio.At the same dosage of additives,the plastic viscosity and yield point of the aged oil based drilling fluid increased respectively from16 m Pa·s to 55 m Pa·s and from 7 Pa to 30 Pa,the emulsion breaking voltage decreased from 1211 V to 303 V,when the oil-water ratio decreased from 90∶10 to 60∶40. Through increasing the amount of emulsifier and reducing the amount of organic clay,an oil-based drilling fluid with excellent performance at low water-oil ratio was formed,which had been successfully used in well Jiaoye 54-3HF,well Jiaoye 25-2HF,well Jiaoye 54-1HF,and so on.