Near shore oil reservoirs have become significantly depleted, forcing oil companies to explore deep-sea reservoirs with huge investments and the latest technology. However these projects are often very risky. Thus, the optimal solution is to explore shallow sea oil fields before proceeding to deep, high- risk areas.
The Lower Miocene reservoir of White Tiger field is a sedimentary reservoir with high heterogeneity and complex geological characteristics. This reservoir was discovered twenty two years ago. There is an urgent need to study procedures for an increased and maximum oil recovery. A detailed geological understanding of the reservoir along with a reservoir simulation is needed to gain a detailed reservoir description and determine the optimal recovery method for this oil reservoir. These are essential to have successful operations as well as reducing uncertainties and improving the efficiency of oil field management.
With a large database collected from initial production stages of over 50 wells, the authors developed an integrated static and dynamic workflow to forecast oil production under several production scenarios for this reservoir. These integrated results served as input data for simulation with IMEXTM, which will be useful for the economical and technical evaluation of this study. In addition, the authors also introduced history matching and pointed out the main reasons for the significant errors between actual data and simulation results. Based on the reservoir modeling, the authors optimized the wells' network locations and got very good results in oil recovery. The oil recovery factor increased from 24.21% to 37.26% for the Lower Miocene reservoir. Specifically, oil recovery for the Southern Dome Structure was increased from 14.83% to 33.76%.
A good knowledge of the depositional environment of reservoir rocks and the geologic processes is an important key for developing geologic descriptions and building a reservoir model (Aadland et al., 1994). It is very important in successful operations of field management. Especially for complex and highly heterogeneous reservoirs, integrated team consisting of a geologist and reservoir engineer assisted by the latest software tools will develop reservoir model and reduce the risk of successfulness and time. In secondary and tertiary recovery operations, it is more necessary and urgent for an integrated team consisting of geologists and reservoir engineers to analyze the characteristics and behavior of the reservoir. A geologist can provide a good general view of field area like the depositional environment, facies, and sequence boundary, structural characteristic of formation, geometry of sand body, porosity and permeability distribution. Then, the reservoir engineer can combine this geological model and dynamic data to construct a numerical simulation for whole field. The simulation will test the accurate level of geological model and reflect the performance of field in past times. Accurate production forecasting is a critical factor in an oil company's management and decision making. Through history matching, the process of incorporating dynamic data in the generation of reservoir models, and production forecasting simulation may be performed to evaluate present and future recovery strategies.
