Successful Application of System Optimization Technology to Gas Production in a Complex Onshore Gas Field in China

The gathering system in the Sulige gas field is characterized by “simultaneous metering of gas with liquids” and by “multiple inter-connections between wells”. With the large scale expansion of the gas field, the gathering and transportation system has become so complex that it is increasingly difficult to optimize the production of each well or gas source in an integrated manner and simultaneously eliminate pressure bottlenecks in the network. Traditional optimization methods can handle simulations and process calculations for single wells or small local networks, but cannot adequately address the overall system performance as a whole. Consequently, integrated optimization technology has been introduced in the Sulige Gas Field. A compositional model of the entire gas field has been constructed of individual production components, and via comparison of simulation results and measured data, the model has been accurately tuned. Based on the calculated results of the tuned model, several conclusions have been derived which collectively support the field production target of 40 Million m3 per day, representing an increase of 14% per day. These measures include the laying of a new pipeline to relieve pressure bottlenecks, adjustment and optimization of the compressors‟ operational parameters in the processing plant, and choke setting optimization in specific areas. Results clearly demonstrate that the application of optimization technology in the complex infrastructure of the Sulige Gas Field has been successful, and furthermore that it can ensure the gas gathering and transportation system operate in both a stable and efficient manner. Using practical field data and reference case studies, this paper highlights the positive effects of the optimization process via for example pressure data matching, pressure bottleneck reduction and/or elimination, and compression scenario optimization. The application of optimization technology has provided the end-users with both accurate and reliable results which in turn contribute to improved decision making for the field production and development planning. Moreover it establishes a new management model for the large-scale gas field production system such that any modifications are closely associated to calculated simulation results and are supported by an outlook of maximizing production revenues.