Research and Application of Plugging Technology for Oil-based Drilling Fluid in Changning Platform
In the horizontal section of shale gas in southwest China,anti-collapse and plugging performance of oil-based drilling fluid have always been technical problems faced in field.In this paper,a set of plugging technol-ogy,suitable for Changning area,is developed after a lot of preliminary research and lithology analysis of shale gas target layer in Changning area through laboratory tests.The optimal dosage of plugging agent in the laboratory is 3％CXG-1+3％CXG-2+3％CXG-3+2％NS-6,which has a slight influence on the rheology of drilling fluid.In the laboratory test,the high temperature and high pressure filtration loss decreases from 3.2 ml to 0.8 ml,and the emulsion breaking voltage increases by 140 V.In the field test,the high temperature and high pressure filtration decreased from 2.0 mL to 0.8 mL,and the demulsification voltage increased by 121 V.Field application shows that this plugging technology has good plugging and anti-collapse performance and is well compatible with oil-based drilling fluids.Compared with the four wells drilled on the same platform,the drilling cycle was reduced from 38.1d to 11.4 d and the hole expansion rate was reduced from 18％to 4％,thus reducing the drilling cost and having the value of popularization.
oil-based drilling fluidpluggingemulsion-breaking voltageshale gas
万方数据
维普
