A Study on Wellhead Backpressure Automatic Control System of Coalbed Methane Drilling

摘要

During coalbed methane drilling operations , Downhole pressure has to be controlled accurately for reservoir protection . The downhole pressure can be controlled by restricting the drilling fluid flow through a choke valve at the top of the well. This paper presents a closed-loop wellhead back pressure antomatic control scheme based on a low order wellhead backpressure control model . The researching and simulation results show that the wellhead backpressure automatic control system can meet the requirements of coalbed methane drilling.