Girasol oilfield is the first oilfield of Mansarovar Energy Colombia Ltd. (MECL) employing horizontal wells. With first well drilled in 2004 and commercial development started in 2008, this typical heavy oilfield have been produced for 10 years, but the current recovery factor is only 5.09%, and that is much lower than that of similar oilfields.

Girasol oilfield is at the medium stage of the cyclic steam stimulation (CSS) with 5.3 cycles and remaining reserves of 40.54 MMbbl. Based on characteristics of typical mid-shallow inter-bedded reservoirs with heavy oil in Girasol oilfield, by applying methodology of reservoir engineering and numerical reservoir simulation, the development status of Girasol oilfield is analyzed through full utilization of the geologic, logging and production performance data, and etc. Five potentials for production enhancement are researched including (1) Potential for well pattern improvement: except layer A12 and A9-Upper, other layers exist 30%~70% of uncontrolled regions in transition part between vertical and horizontal wells, nearboundary, low permeability areas; (2) Potential for well infilling: the well spacing is about 150m, while heating radius is about 50m, so there exist oils hard to exploit between wells. Numerical simulation shows the average heating area is only 33.07%. (3) Potential for CSS parameter optimization: compared with other similar blocks, the steam injection parameter is not suitable and the steam injection intensity is too low, and there is a good potential for optimized steam injection parameters; (4) Potential for horizontal lateral optimization: the current horizontal lateral of 600m on average is too long for thermal production because it will leads to high heat loss, un-uniform steam adsorption and poor steam injection effect; (5) Potential for steam flooding: as the reservoir geological conditions meet the screening criteria of steam flooding reservoir, there is a good potential for converting of steam flooding from CSS.

This paper constructs a framework and technical route for fullfield EOR enhancement design of heavy oil reservoir from potential analysis, sector simulation to fullfield scale implementation. Comparison of injection parameters and production performance among similar reservoirs in different countries is another highlight.

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