Abstract
We have investigated the use of a novel smart steamflood pattern in San Ardo field, California to minimize steam override and thus enhance oil production and reduce steam injection costs. The smart steamflood pattern consists of a vertical injector placed at the center of the pattern and a smart horizontal producer placed on each of two (parallel) sides of the pattern. The horizontal section of the producer is fully open initially, but after steam breakthrough only one-third (heel-end) is kept open.
Using an 8-component thermal compositional model, we compared the performance of the smart steamflood pattern (under steam- and steam-propane injection) against the conventional 9-spot inverted pattern in the Lombardi reservoir, San Ardo field. A 16×16×20 Cartesian model was used to represent one-quarter of the typical 10-acre pattern in the field. Main results of our investigation are as follows.
First, under steam injection at 1200 BPDCWE, oil recovery after eight years is significantly higher with the smart steamflood pattern (61% OOIP) compared to that with the conventional steamflood pattern (51% OOIP). Second, when steamflooding follows cyclic steam injection, the smart steamflood pattern recovers 53% OOIP in eight years compared to 46% OOIP with the conventional pattern. Lastly, steam-propane injection accelerates the first oil production peak by 10% and the second by 24% when compared with pure steam injection using the smart steamflood pattern.
