Abstract

During the past decade, the oil and gas industry has implemented several new well completion technologies, such as multilaterals and intelligent well systems. These two technologies have independently proved themselves desirable because of their ability to reduce cons and/or increase production. The integration of these technologies into a single well bore offers synergistic opportunities for even greater well construction efficiencies and production optimization. This paper will discuss the merits of the individual technologies. In addition, it will provide two case histories of their combination in drastically different environments in order to show their ability to enhance reservoir value.

Further as multilateral well bores have matured over the time, tri-lateral and quad-laterals have become as common as Bilateral wells. Multilaterals provide a cost effective venue to maximize reservoir contact in singular or multiple zones, while minimizing cost. Moreover, with the on set of acceptance of multilateral technology into the main stream of the oil and gas industry, new issues have arisen; How to control the additional production while maintaining effective reservoir management? Intellegent Well Systems effectively eliminate the much desired but difficult issues by providing a flexable approach to manage the reservoir assets and eliminating costly wellbore interventions. Both technologies are as effective in off shore as they are in on shore applications.

Introduction

Multilateral and IWS technologies have been deployed in a variety of well profiles, from heavy oil, high pressure gas, underbalanced drilling, conventional oil wells, sub sea and deep water. In all of these applications the technologies have proven their value. The Mukhaizna field traditional was a single well horizontal development that was first discovered in 1975. It contained heavy oil with a viscosity of 14-16 ° API, (1500-2000 mPas.s in-situ viscosity). The two oil-bearing sandstones found in this field contained 374 MMm3 of reserves. The technical difficulties posed by heavy oil in unconsolidated sand with a high probability of water break through resulted in high development cost of the field. Utilization of horizontal multilateral has been beneficial as a cost effective method of maximizing recovery these reserves while lowering the cost per barrel produced. In 2000 the introduction of steam and is currently producing 2000m3 / day out of 52 single and 4 dual horizontal wells. The multilateral systems employed allows for either jointed work strings or coiled tubing re-entry into both the lateral and the mainbore. Further, more it accommodates commingled production to an electric submersible PCP pump. Production from the Middle Gharif was controlled using an InForce?HCM Hydraulically Operated Sliding Sleeve. Later, production was initiated using artificial lift. Initial results show minimum vibration of the ES-PCP assembly at less then 1G whereas up to 5G's were expected. Production levels are as expected. (See Figs.1, 1a,1b,1c)

The Glitne field is a sub sea development with of 25,000 bbl/day of oil from five producers and one water/gas injector. To increase production at a lower cost it was decided to utilize multilateral technology.

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