CONTROL OF WELL DRILLING SYSTEM BY USING ESTIMATED BOTTEM HOLE PRESSURE

When difficult reserves are discovered to drill well safe and efficient, advanced technology is required. The subject considered in this paper is the problem of keeping the bottom hole pressure under control during drilling by control of top side choke flow control by using an observer for estimating bottom hole pressure and bit flow rate. Without loss of generality a simple model of well is used. After that by using a simple observer, the bottom hole pressure can be estimated. Then a PI-controller is designed to keep the bottom hole pressure under control