The Greater Burgan field is the largest sandstone reservoir system in the world, and its complexity requires the state of art technology for a sound reservoir management practice. This paper will discuss our methodology to maximize the production plateau length of Burgan field using parallel reservoir simulation, waterflood efficiency algorithm, streamline visualization, and ensemble-based optimization method.
With a reservoir dimension longer than 48 km, parallel reservoir simulation becomes necessary for an integrated Burgan field study. Through history matching of 60-year production data, we quantified billions of barrels vertical fluid migration between major reservoir units, and fluid migration is a major concern in making reservoir management decisions. To optimize future development plans, an economic analysis package was developed to evaluate various operating scenarios, and Net Present Value (NPV) is used as an objective function. The scalability data of parallel reservoir simulation are discussed.
The waterflood efficiency algorithm was based in injection efficiency or remaining oil recovery, and the input could come from finite-difference simulation, streamline simulation, and field surveillance data. The algorithm utilized the injector-producer connectivity relationship realized from streamline analysis, and it calculated the amount of water injection for each injector in order to achieve maximum sweep efficiency.
The alternative method to optimize the waterflood is based on the ensemble method in which hundreds of simulation models with different operating settings are automatically submitted to run. Results of all models are gathered and analyzed by co-variance. A better setting will be proposed for each model and the next batch of simulation is then launched. At the end, all models will converge to an optimized operating setting.