Decision Analysis for Long-term and Short-term Production Optimization Applied to the Voador

Abstract

Optimization of oil production may be performed on different time horizons. Long-term optimization (which is typically performed over timescales of years) is usually conducted by reservoir engineers, whereas short-term optimization (which typically concerns days or weeks) is performed by production engineers. Long-term objectives focus on finding the best strategy to drain as much oil as possible from reservoirs. However, in reality it is often short-term goals such as maximizing daily oil rates that dictate the operational strategy. Unfortunately, these goals may be in conflict with each other. Therefore, incorporating long-term goals into short-term objectives is crucial. We present a novel approach to systematically combine long-term and short-term production optimization. The approach is based on a priori articulation of preferences, i.e., the decision maker is allowed to specify preferences that may be articulated in terms of goals or the relative importance of long-term and short-term objectives. The approach is adopted from multi-objective optimization method in which the solution is not a single point but rather a collection of points. To this end, we introduce the upper and lower bounds of the objective function such that the objective function can be written in a different form, whereas in reality, the short-term and longterm optimization are performed with the same objective but different methods. The idea is then to solve a bi-objective optimization problem using an adjoint-based method for the upper and lower objective functions and project the solution onto the original objective. The approach is tested on a simplified reservoir model of the south wing of the Voador field, which is located in the Campos Basin in Brazil. The results are presented as Pareto-like plots that can be used for decision support to balance long-term and short-term goals.

MRST-AD – an Open-Source Framework for Rapid Prototyping and Evaluation of Reservoir Simulation Problems

“…The Voador field is located in the Campos Basin, approximately one hundred miles off the coast of Brazil. It is a solution-gas-drive field in which the pressure has been depleted to below the bubble point, see (Hasan et al 2013). The field consists of two non-communicating reservoirs.…”

“…In the schedule, the injector is controlled by water rate, while the producers are controlled by oil rate. A simplified two-phase version of this simulation model was used by Hasan et al (2013) to study the combination of long-term and short-term production optimization. Likewise, a shorter period of the three-phase, black-oil model was used by Raynaud et al (2014) to study upscaling and adjoint methods for production optimization.…”

Derivative-free trust region optimization for robust well control under geological uncertainty

“…For Thiago L. Silva thiago.silva@sintef.no Extended author information available on the last page of the article. the most part, these objectives involve maximizing profit, e.g., increasing either the net present value or other more sophisticated economic targets [4,20]. However, objectives can also include other performance measures and costs, e.g., improving water-flooding sweep, reducing topside energy consumption and environmental objectives.…”

Output-feedback stabilization of the Korteweg-de Vries equation

“…In the infinitedimensional backstepping, a Volterra integral transformation is used to transform the original system into a stable target system. Different with other approaches that require the solution of operator Riccati equations e.g., optimal control method (Hasan et al, 2013;Hasan and Imsland, 2014), backstepping yields control gain formulas which can be computed using symbolic computation and, in some cases, can even be given explicitly in terms of Bessel function (Krstic and Smyshlyaev, 2008) and Marcum Qfunction (Vazquez and Krstic, 2014).…”