Abstract

To facilitate field and wellsite optimization, Natural Gas producers have come to rely on the strategic placement of compressors to increase production. Mature fields, with depleting reservoirs and/or low wellhead pressures, are ideally suited for this cost-effective gas recovery solution. The decision process by which the production engineer quantifies the placement of a compressor is of significant relevance. There are several strategies available to the production engineer to identify wellsites best suited for optimization. Total Systems Analysis simulation software, Decision Tree Analysis and Real Time Selection Opportunities (RTSO) enable this process. This paper reviews these decision alternatives and the application of the RTSO Risk Matrix to select ideal well compression candidates.

Introduction

The technology of utilizing field compression has been widely adopted by the Natural Gas industry as an optimization tool. The challenge is to select the optimal field compressor location. Decision-makers can make use of several different methodologies to achieve this result.

Computer simulation allows production engineers to identify locations, and it provides a clear understanding of the dynamic interaction of each component within a gathering system. Hahn, Moss, Sood and Carley1 developed a decision tree that integrates all the necessary parameters to identify wellsite compression candidates. An alternative approach that relies upon a combination of real time data, field operators' input and/or pilot testing has also proved to be an effective process.

This paper reviews these decision strategies and the application of the RTSO Risk Matrix approach to specific case studies in Southern Alberta, Canada.

Decision Strategies

An optimization strategy requires an assessment of the overall field opportunities. It is important to clearly state your optimization objectives in the project scope. The adherence to basic project management principles increases the likelihood of project success. This preliminary review will direct you to the most applicable decision tool.

Table 1 summarizes the main characteristics of each decision strategy. It describes the necessary inputs, the analytical requirements and the final outcome of each solution. Once the requirements for each decision strategy are identified and determined to be available, the decision-maker is able to select an appropriate methodology.

Total Systems Analysis Simulation Software.

Trick M.2 identifies the application of computer models to optimize gas field production and reservoir management. The computer simulator requires information about every component of the gathering system. All this information is entered into a single data file that can be used to evaluate various scenarios or forecasts. Trick also describes the factors that must be included in a model using Total Systems Analysis: Reservoir Performance, Sandface Inflow Performance, Wellbore and Pipeline losses, as well as Field facility performance data.

Simulation software provides an understanding of the dynamic interaction of each component of the gathering system, and facilitates the optimal placement of a compressor.

Decision Tree Analysis.

The selection strategy developed by Hahn et al. identified two key parameters: Gas Well Cumulative Production History (> 28 E6 m3) and Peak Production Rate (> 30 E3 m3/D). Wellsite nodal analysis is then combined with material balance techniques to further the selection process. This methodology has proven to be an effective tool in accurately predicting individual well gas rates.

Total Systems Analysis Simulation Software.

Trick M.2 identifies the application of computer models to optimize gas field production and reservoir management. The computer simulator requires information about every component of the gathering system. All this information is entered into a single data file that can be used to evaluate various scenarios or forecasts. Trick also describes the factors that must be included in a model using Total Systems Analysis: Reservoir Performance, Sandface Inflow Performance, Wellbore and Pipeline losses, as well as Field facility performance data.

Simulation software provides an understanding of the dynamic interaction of each component of the gathering system, and facilitates the optimal placement of a compressor.

Decision Tree Analysis.

The selection strategy developed by Hahn et al. identified two key parameters: Gas Well Cumulative Production History (> 28 E6 m3) and Peak Production Rate (> 30 E3 m3/D). Wellsite nodal analysis is then combined with material balance techniques to further the selection process. This methodology has proven to be an effective tool in accurately predicting individual well gas rates.

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