A Literature Review on Smart Well Technology

Abstract

Abstract Smart well technology is one of the most significant breakthroughs in production technologies during recent years. It enables operators to actively monitor, remotely choke or shut selected zones with poor performance without intervention. During early stages of development, electrical control systems and electronic sensors were applied. However, the service companies abandoned these earlier systems due to their poor reliability. Recently, innovation in fiber optic sensors and hydraulic control systems has significantly improved the reliability, and the market adoption of this new technology is accelerating. This paper describes the typical components of smart well systems from the major service providers. Several typical field applications are reviewed, including cases in North Sea, offshore England, and offshore Brunei. 1. Introduction During the past 10 years, decline rates have doubled. At the same time, reservoirs are becoming more complex. They are smaller, tighter and more remote. As a result, reservoir recovery rates are less than 35%. The goal of many operators is to advance recovery rates to 60%. Consequently, the aggressive development of cutting-edge technologies has become essential. Wells equipped with permanent downhole measurement equipment or control valves, and especially those with both, are nowadays known as smart well or intelligent completion. Since the first intelligent completion was installed in August 1997 at Saga's Snorre Tension Leg Platform in the North Sea, over 300 such systems have been installed globally, from mature land assets to deep water off the coast of Brazil. However, like other new technologies, the adoption of smart wells has not been easy. Prior to the introduction of permanently deployed in-well reservoir-monitoring systems, the only available method to obtain downhole information was through the use of intervention-based logging techniques. Interventions would be conducted periodically to measure a variety of parameters, including pressure, temperature and flow. Although well logs provide valuable information, an inherently costly and risky well-intervention operation is required. As a result, wells were typically logged infrequently. The lack of timely data often compromised the ability of the operator to optimize production. Initial smart well systems, using permanently installed downhole electronics, provided real-time pressure and temperature measurements from gauges deployed close to the sand face. As these systems proved their value, the industry developed follow-on systems for monitoring additional parameters, such as flow rate and water content. These downhole sensors were complemented by the initial development of electro-hydraulically actuated flow control systems. The oil field environment in general and downhole temperatures specifically, have presented a fundamental challenge for these electronic systems whose failure rates approximately double with each 18°F (10°C) increase in temperature. Since smart well systems are essentially inaccessible once deployed, their value is directly linked to their longevity. Those early systems were soon abandoned due to their low reliability. For a smart well to realize its true value, the permanent monitoring system must function for the life of that well. If downhole gauges fail prematurely, there is little point in having the ability to use hydraulically operated in-well flow controls to adjust flow profiles and optimize reservoir recovery throughout field life. Service providers would have to develop a technology solution aimed at expanding the market by lowering costs and improving reliability.