Stimulation Technique for MECL Heavy Oil Reservoirs in Colombia

As the development of heavy oil reservoirs of Mansarovar Oilfield in Colombia entersits the middle and late stages, some problems have emerged, such as a severe production decline in old wells, the inadequate productivity of new wells, poor thermal recovery effects, increasingly high water cut in wells in the field, and less than ideal stimulation effects.After conducting laboratory tests to select the optimal foaming agent and nitrogen/steam injection ratio, the technologies of foam profile control and nitrogen-assisted steam huff and puff were optimized.Through production analysis, the optimal timing chart of turn cycle steam injection was developed for heavy oil reservoirs in different blocks, and the water shutoff test was practiced in high water-cut horizontal well.For 8 wells with foam profile control, the average single-well oil production was 4.4 t per day, cumulative oil production was 4 575 t, and the total increased oil production was expected be over 8 000 t.For 11 wells with nitrogen assisted steam huff and puff simulation, the average single-well oil production was 2.4 t, cumulative oil production was 3 124 t, and the total increased oil production was expected to be over 5 000 t.In the Girasol Block, the optimal turn cycle steam injection resulted in a diminishing rate of 18.5% to 15% and a three-month cumulative oil increased by 5 680 t.In Well A9 after water plugging, the water cut decreased from 100% to 65%, and oil production increased by 303 t.Field application showed that the simulation technique was applicable for heavy oil reservoirs of MECL and they could yield significant results.