Optimization of Field: Development Strategy with a History Matching Approach

The industry over the past several decades, because of the demand for reliable predictions of reservoir performance. The progress in electronic computing hardware, and the significant improvement in methods of numerical analysis were two important factors in the achievements made in numerical models of reservoirs such models made important contributions to the enhanced oil recovery.

Reservoir models are used for understand and predict reservoir performance. One of the most important activities during the process of developing and managing the petroleum reservoirs is History matching process. The Matched model are fundamental in making reliable future forecasts possible, and give an idea of the level of understanding of the geological and reservoir models. Depending on available field production data, and complexity of a reservoir, the History matching process may be very time consuming. To achieve matched model, some changes can be conducted on the geological and reservoir models, mainly in those attributes with higher uncertainty, for example, relative permeability curves, its distribution through the reservoir, and other parameters with few samples.

One of the objectives of this work is to perform history matching on the Zhaozhouqiao oil field specifically Zh86 Block using Schlumberger’s simulation software Petrel-RE 2014. History matching will be done based on trial and error by modifying some reservoir properties, end point scaling and by modeling and including the aquifer support into the system. The best history match was achieved by modifying the critical water saturation (SWCR) in the system, modeling an aquifer support using Carter Tracy Aquifer model and by modifying the horizontal and vertical Permeabilities of the model. After the history match is achieved two prediction strategies are developed and compared, where we did forward modeling to build some confidence level in the reservoir model. Production indexes; water cut, water production, oil production and oil rate of wells and the field as a whole were forecasted. Results of the indexes were presented against time and analyzed. The results portrayed that Zh86 Block in Zhaozhouqiao oil field is still very promising in terms of production.

An Uncertainty and sensitivity assessment was done on the reservoir model to analyze the impact certain reservoir properties have on the volume calculations and simulation results in the Zh86 Block reservoir model. The impact of uncertainty in our Sw and contact positions on volume calculations in this model can be seen.

The impact of the grid resolution in placing horizontal wells was also studied, a synthetic model of the Zh86 Block was built selecting the varying grid resolutions both laterally and vertically, and then properties were up-scaled to the models and a well-placed below an impermeable shale zone in each model to determine the optimum location. Using a model with a fine grid resolution enables you to place the well in the best position in the reservoir model.