Study on Cementing Displacement Efficiency of Highly Deviated Wells in Tarim Oilfield

As an important measure to improve the productivity in Tarim Oilfield, the application scale of highly deviated wells has been expanding in recent years. Cementing of highly deviated wells is characterized by low casing centralization, slurry channeling in the casing and low displacement efficiency, which makes it difficult to guarantee the cementing quality. In order to solve the above problems, a high precision three-dimensional cementing displacement efficiency calculation model considering the channeling in the casing is established. The effects of casing eccentricity, displacement, cement slurry dosage and slurry rheological property on the degree of channeling in the casing and displacement efficiency of wide and narrow sides of annulus in highly deviated wells are explored. The results show that the reduction of casing eccentricity and the increase of cement slurry dosage could greatly improve the displacement efficiency of annulus narrow side in highly deviated wells. The increase of displacement will slightly increase the degree of channeling in the casing, but it could still improve the annulus displacement efficiency to a certain extent. The reduction of the consistency coefficient of drilling fluid and spacer fluid could effectively reduce the degree of channeling in the casing and improve the displacement efficiency of annulus narrow side. The influence of cement slurry rheological property on channeling in the casing is relatively low. The displacement efficiency of annulus narrow side could be improved by properly increasing the consistency coefficient K in addition of the fluidity index n ≥ 0.8. The above research results have been successfully applied in highly deviated well in Tarim Oilfield with excellent application effect. The study effectively solves the problem that the cementing quality of highly deviated wells in Tarim Oilfield is difficult to be guaranteed. It could provide reference for similar highly deviated wells around the world.