Abstract:

Low porosity and low permeability sandy conglomerate heavy oil reservoirs in the Permian series of the Lukeqin oilfield in Turpan-Hami basin are usually fractured for recovery due to their poor physical properties, strong heterogeneity and low natural productivity. The induced fractures and reservoir heterogeneity lead to poor water injection effect. In order to solve the problems encountered in the development such as prominent areal contradiction, low efficiency, and ineffective areas, water injection is used to replenish the formation energy for increasing single-well production, but the effect in single wells is quite different. The reservoir wettability and water injection process for energy replenishment were studied through physical simulation experiments. The results show that the Permian reservoirs in the Lukeqin oilfield are water-wetting. Fracturing is conducive to the imbibition between fractures and reservoir matrix, which can effectively replenish the formation energy to improve single-well production. The faster the water is injected, the faster the formation energy can be recovered; the higher the well soaking pressure, the higher the oil increment. Combining numerical simulation and in-situ conditions, the injection parameters were optimized. As a result, the effect of water injection was good, with the effective rate reaching 88%.

Key words: Turpan-Hami basin, Lukeqin oilfield, Permian, low porosity and low permeability, sandy conglomerate, heavy oil reservoir, water injection for energy replenishment, influencing factor