Abstract

Improving the design and operation of gas lift systems to obtain optimum production (within the limits of existing facilities) is very attractive with low investment and a corresponding acceleration/increase in reserve recovery to maximise profit. This paper discusses the studies conducted and methods used to increase oil production and optimise the gas injected/fluid produced ratio in the Barrow Island Field by utilising the existing compression capacity and field staff. This multi-stage optimisation program used on Barrow Island (BWI) can be readily adapted to other producing areas, even those with limited remaining field life. During the first stage, emphasis was placed on:

  1. individual well optimisation;

  2. improving gas lift design techniques;

  3. converting to intermittent gas lift (IGL), gas assisted plunger lift (PL) or sucker rod pumping when continuous gas lift (CGL) was no longer efficient;

  4. improving system diagnostics;

  5. field personnel training, and;

  6. enhancing Operations / Engineering communication.

After the first stage is completely implemented and results evaluated, fieldwide optimisation is planned and will be actively pursued. Performance results indicate a very attractive return from a low risk investment. Significant improvements have been obtained in:

  1. individual well profitability;

  2. optimising injection gas usage;

  3. well monitoring, and;

  4. the amount and quality of collected well data.

Additional intangible benefits have come from the much closer well surveillance, such as faster detection and diagnosis of problems, and quicker response to failures. The results demonstrate the potential that exists in producing areas similar to BWI for maximising economic return through the application of sound engineering and operating principles. A united effort from Operating and Engineering personnel that is strongly supported by Management, along with an effective communication and training program can improve gas lift system efficiency quicker and more consistently to minimise costly errors and/or delays.

Introduction

Barrow Island is located about 1,300 km north of Perth, 56 km off the Western Australia coast between Port Hedland and Onslow (Fig 1). The nearest port, Onslow, is about 88 km south. BWI is the second biggest island off the Western Australia coast. Its elongated oval shape covers approximately 233 sq km with the highest point rising to about 65 m above sea level. Prior to oil exploratory and producing activities, the island was uninhabited by man. BWI was declared an "A" class reserve (highest classification of protection) by the W. A. government in 1910. Wildlife has remained undisturbed by man and alien influences which have affected the mainland, and it is environmentally unique. There is a strict ban on firearms, exotic plants and animals being brought in and all contact with vessels is carefully controlled. Destroying or molesting wildlife, and unnecessary damage to plants is specifically prohibited.

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