Abstract
This Field is a Cretaceous fractured oil bearing reservoir in the south of Iran composed of tightly packed limestone characterized by high porosity but poor permeability and it is seems to be oil wet. The oil is relatively heavy with API of about 21.3 degrees, viscosity of about 6.85 centipoises and solution GOR of 250-280 scf/stb.
The reservoir energy is limited to fluid expansion and water in flux. The strength of which will be weak because of the low permeability of the rock, as a result the reservoirs are considered to have very poor flow potential. Our studies focused on characterization, modeling and simulation of different production scenarios.
A model was constructed using a three-phase, three-dimensional, dual porosity simulator (ECLIPSE). Because of Existence of uncertainties in SCAL data understanding of two key issues are addressed, Reservoir rock typing and rock wettability. This study emphasized detailed analysis of relevant parameter to these issues which estimated using combination of core, log data and wireline formation tester measurements by developing a numerical model. Several studies were conducted after successfully matching performance of built model with production history of DST results. Eventually the model was applied to run a series of sensitivity simulations for optimization of injector locations, Water injection and gas injection (miscible and immiscible) to increase reservoir oil recovery.
Based on simulation results for different scenarios water injection outperform the others. Miscibility experiments performed in PVTi showed that the minimum miscibility pressure (MMP) is around 12000 psia.
Immiscible gas injection process suffers from unfavorable mobility ratio and high producing GORs, which makes sweep efficiency to decrease and eliminates possibility of ESP usage occurs. This study provides Guidelines for any future development plan in this field.