Rig Computer System Improves Safety for Deep HP/HT Wells by Kick Detection and Well Control Monitoring

Abstract

Abstract A drilling contractor has installed and operated on several offshore rigs, a comprehensive data acquisition and computer processing system for realtime monitoring of drilling operations and post event analysis. The system, which includes post event analysis. The system, which includes "smart alarms" for early warning of problems such as kicks, stuck pipe and drillstring washouts, has been extended to cover recent recommendations of the UK Department of Energy for High Pressure/High Temperature (HP/HT) wells. In this paper we describe the extensions to the system, developed with a major operator, which continuously monitor the return line valve status, mud pumps, choke manifold and BOP stack to ensure that all components are operating within their design limits. Although the smart alarms for early kick detection reduce the size of an influx, the problem of circulating out a kick remains a hazardous procedure requiring close monitoring. The system's procedure requiring close monitoring. The system's existing realtime displays of log and digital data include a dedicated screen for well control to provide the necessary monitoring. provide the necessary monitoring. Additional HP/HT monitors, which continuously display choke position, BOP temperatures and separator pressures as required for the North Sea, have been added. Hard copies for detailed analysis are produced from a workstation linked to the network. The development and operation of this system are discussed, and the benefits in terms of improved safety and environmental protection are demonstrated. Introduction In critical HP/HT wells in the North Sea, the need for the latest systems for improved well safety and efficiency are well recognized. With comprehensive data acquisition and monitoring of all key drilling-related parameters, the Driller is provided with the necessary information to spot and diagnose potential problems as early as possible. possible. The MDS* system from Sedco Forex is a drilling monitoring and alarm network of sensors, computer processing, realtime displays and an offline workstation. It gives the Driller and other key supervisors on the rig the capability to carefully monitor critical drilling parameters in realtime to improve safety, and better analyze recorded data to improve drilling efficiency and planning. planning. By incorporating smart alarms, the detection of events such as kicks has been significantly improved, which helps keep the size of any influx to a minimum. Other smart alarms include early detection of tubular washouts and excessive wellbore friction. Figure 1 shows a schematic of the standard monitoring and alarm system. Realtime color graphics monitors are located in the Driller's console, and in the offices of the copy Representative, Rig superintendent, and Rig Engineer. Phillips Petroleum's concern for safety in Phillips Petroleum's concern for safety in drilling deep, HP/HT wells in the Central North Sea has led to the installation of a new and enhanced version of the system on the Sedco 712, a semisubmersible rig jointly owned by Phillips and Sedco Forex. P. 227