Control of Bottomhole Pressure in Managed Pressure Drilling using IMC Controller

Abstract

In this paper we present a simple proportional integral (PI) with internal model controller (IMC) tuning for kick/loss rejection for managed pressure drilling (MPD) process. Arctic regions are very fragile and hence precaution must be taken to avoid any blow out. MPD is a promising technology for well control. Several complex controllers are available in the literature for controlling MPD but design and implementation of such controllers require the knowledge of advanced controls. It would be beneficial to check the suitability of simple controllers for the control of MPD. We propose a switching PI controller with IMC tuning. In order to synthesis the controller the process between the bottomhole pressure and choke opening was identified. It was observed that the process was highly nonlinear for lower choke openings and hence two separate cases of choke openings were considered for controller synthesis. The synthesized controller was used to reject a kick of 100 lpm and it was observed that performance of the controller was reasonable. We also show that the controller will be able to track the setpoint robustly at different choke openings. The proposed controller requires minimal human interference and it is very simple to implement. We demonstrate that complex advanced controllers will be beneficial from a technical point of view and to meet tough conditions, nevertheless simple controllers can also deliver a ressonable performance.

Experimental study on the dissolution characteristics of ethane into oil‐based mud in complex oil and gas wellbore environments

“…Literature reviews 6‐42 show that the solubility data available for ethane in oil‐based drilling fluids are scarce and immethodical, which cannot meet the demand for describing the velocity and pressure profile of wellbore gas–liquid two‐phase flow during the gas kick. The main components of oil‐based drilling fluid are base oil (crude oil, diesel oil, mineral oil, gas oil), water, organic bentonite, and additives.…”