Matching water cuts of production wells is one of the most challenging tasks in the history matching process. When conducting history matching with a finite difference simulator, one of the challenges is how to define a suitable region for the permeability modifier to obtain a good match, and yet, retain major geological description. In the case of large models, the presence of several wells in a region where permability is adjusted makes simultaneous matching for these wells almost impossible.
Commercial streamline simulators are best in reducing the mismatch in water cuts; however, it is cumbersome to include other uncertainty parameters such as water-oil contact, relative permeability, pressure-volume-temperature data, etc., during the optimization process. To combine the power of finite difference simulators and streamline technology, an in-house developed reservoir simulator was linked to a customized streamline tracing software package. This solution is capable of generating streamlines that represent a snapshot of the flow pattern within the reservoir, and providing well drainage region information and injector-producer relationships.
This paper presents an automatic process in which the reservoir simulator is run via the control of a commercial optimizer, the simulation results are transferred to the streamline tracing package, which also tags the simulator cells to be modified by the optimizer without running a full streamline simulation. The optimizer then uses a global minimization method to fine-tune the permeability modifiers for reducing the water cut errors. This approach was verified by using two synthetic models in which the solution is known. Excellent results were obtained. Therefore, this approach makes it possible to employ the power and flexibility of finite difference simulators and optimization algorithms, with the crucial fluid flow information provided by streamline technology.