The Kuparuk River Field, on the North Slope of Alaska, is an extremely complex system when predicting and managing produced gas and artificial lift gas. Encompassing an area of almost 200 square miles, it is one of the largest full-field waterfloods in the world. On a daily volume basis, it is the second largest miscible gas flood in the world, second only to Prudhoe Bay. The field has approximately 400 gas-lifted wells and a dozen wells on ESPs. Currently, the field is characterized as "formation gas constrained" because wells over a formation GOR of ~6000 scf/bbl must be shut-in. Fluids are processed and gas is compressed at three different processing plants, with some processes being shared between plants, and other processes being independent. Combined with a reservoir that is composed of two distinctly different sands, makes reservoir management and particularly gas management, an extremely challenging task.

In late 1998 a multi-disciplinary team was assembled to develop a framework and implement tactics that would better optimize gas handling at Kuparuk. At the time, several nearby "satellite" fields had just come on-stream that further taxed the existing gas handling capacity and oil prices were such that expansion projects were unattractive. This Gas Management Team was charged with optimizing reservoir, gas lift, and equipment performance. This required developing a better understanding of the leveraging mechanisms and processes, and communicating a set of tactics that could be implemented by the Organization.

This paper discusses the work of the Kuparuk Gas Management Team, composed of EOR, reservoir, optimization, and process engineers. This team studied the various facets of gas injection, gas production, gas storage, and gas lift to establish a plan to optimize this system. Efforts and topics that will be discussed are as follows:

  • More consistent measures of gas handling capacities

  • Methods to improve forecasts of gas production

  • Identification of the reservoir management "levers" that effect gas production

  • Definition of the value of gas lift and the importance of quality data

Results to date show the optimization target was significant, and that much of it was achieved by applying the recommended tactics. This paper should benefit anyone who is working large fields where gas is re-injected for disposal or EOR purposes. It should also benefit those working gas-lifted fields where the value of gas lift must be understood in order to optimize the entire system.

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