Cementing Techniques of Mono-Bore Well Completion in Yishan Slope of Ordos Basin

In order to improve cementing quality of cement sheath and strength of interfacial cementation during the cementing of the mono-bore well in Yishan Slope of Ordos Basin in Changqing Oilfield,spacer fluid with good shear thinning was chosen to effectively insulate mud and cement slurry.By using low density cement slurry of micro-sphere in cementing non-production interval,the risk of cement loss in the cementing process can be reduced.Latex conventional slurry was applied to ensure high temperature resistance and good gas channeling prevention performance of gas-pay cement sheath.Based on the proper selection of the cementing tools,design of completion string and several cementing solutions, mono-bore well cementing technology was optimized to efficiently solve the cementing problems like high cement plug,over-displacement and poor displacement efficiency.The technique has been applied in 15 wells in Yishan Slope with fully qualified operation in which 66.7% are excellent.Cementing results indicated that the newly developed mono-bore well cementing technology can efficiently improve cement quality of mono-bore well.