| Well leakage is a common complex phenomenon in the process of drilling.Although a variety of plugging process and technology have been developed in recent years,well leakage still happen from time to time,causing a great threat to the completion quality and construction period of drilling engineering.In Dagang Binhai block,formation leakage happened frequently at special layer.It is necessary to carry out a suitable plugging technology for this block to improve the current situation effectively.In recent years,a physical method of plugging while drilling in Zhongyuan and Tahe Oilfield has been basically applied and achieved good results.Compared to the conventional plugging technology,this technique has better plugging effect with higher drilling efficiency and lower cost.What's more it also has a good applicability to the leakage of fractured and permeable formations in Dagang Binhai block.However,there hasn't been any specific design for block application yet.In this article,leakage layer and its leakage mechanism are analyzed on the basis of the field investigation,including geology,drilling,well logging and mud logging data from Dagang Binhai block.Combining with statistical data and the relationship between drilling speed and drilling pressure,hydraulic rock breaking contribution is separated from the total amount during drilling process,and the hydraulic jet rock damage threshold pressure of easy leakage layer is calculated,providing the basis for lateral hydraulic parameters design of plugging tool while drilling.Under the normal drilling condition,the reasonable pump pressure and displacement are selected and hydraulic parameters of lateral jet tools are calculated.Then a appropriate model of the lateral jet tool is established by numerical simulation method to optimize a set of suitable hydraulic parameters for Dagang Binhai block.At last,the obtained results of this paper are applied in the Dagang Binhai block plugging while drilling test,which presents a successful effect. |
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