The paper is continuation of SPE-175682 and SPE-182963. This work illustrates horizontal well placement optimization studies conducted on a Cretaceous complex carbonate reservoir with thin oil column and strong water drive reservoir. A further complication for the well placement is the presence of some thin high permeability streaks intervals with permeability value of up to 1 Darcy. Early water breakthrough encountered in the existing oil producers is a serious problem which results in lower oil production rates, lower oil recovery, and increased lifting cost. In addition, premature water breakthrough would leave behind bypassed oil zones. Hence determining the optimum location of the wells is a critical and crucial decision to be made during a field development plan.
In this study, we apply integrated geosciences, geostatistical, and flow simulations to assess options for well placement. Base case porosity, permeability, and water saturation realization was selected from multi-realizations performed in the static model which was then used for sensitivity in fluid flow simulations. Flow simulation was used to analyze the performance of the well considering horizontal wells length, well azimuth, well inclination, wells position relative to the reservoir top as well as its position relative to the water contact. In addition, multi-scenarios of well placement relative to the high permeability intervals were created to see the impact on the oil rate, plateau, and water breakthrough time.
The flow simulation results show that the 4000 feet horizontal well that penetrating the upper high permeability streak gives the best performance in most of the cases. In contrast, the performance of the horizontal wells deteriorated rapidly once the well hit the lower high permeability streaks.
Some producers in the studied reservoirs have been drilled using the multidiscipline study recommendation. Actual property derived from the newly drilled wells displayed a very reasonable match to the expected property from model. In addition, production test and well commissioning result also showed comparable match with what was expected from dynamic simulation.