Research On Wellbore Pressure Gradient Distribution Characteristics For Deep Water Multi-gradient Drilling

The corresponding drilling technical problems are also increasingly valued with deep water has become an important potential area in the campaign of international oil and gas exploration and development in recent years.The narrow density window problem is one of the most common problem deepwater drilling.In order to solve this problem,the dual-gradient drilling technology developed.However the use of the dualgradient drilling technology cannot perfectly solve the problem of narrow density window because of it's many limitations.Multi-gradient drilling technology developed on the basis of dual-gradient drilling technology and it is easier to control wellbore pressure.This paper analysis the theory of multi-gradient drilling.The main research content is as follows.Set up empty core ball injection separation device model and simulation analysis its performance;Analyze drilling fluid equivalent density distribution after injection the drilling fluid,then derived the wellbore pressure distribution of multi-gradient drilling.Write the wellbore pressure distribution calculation program of multi-gradient drilling.The purpose of this paper is to research the law of wellbore pressure distribution of multi-gradient drilling and explore new methods in deepwater wellbore pressure control of shallow gradient drilling on the basis of relevant theoretical research of dual-gradient drilling technology.I set up a corresponding key device and deduce the wellbore pressure distribution under multi-gradient drilling system.The research of this paper has reference significance for the exploration of the multi-gradient drilling in the future.