Abstract:

Because of the strong heterogeneity and complex modal pore structure, the develop dynamic of the conglomerate reservoirs are more complex than those of the sandstone reservoirs. At present, the conglomerate reservoirs in Xingjiang have been in high water cut stage. It faces the problems such as the serious water channeling, low recovery rate, and great production difficulty,so it is necessary to carry out the polymer flooding evaluation experiment of the conglomerate reservoirs to provide references for designing the later development in maturing field. Taking the lower Karamay formation in No. 7 reservoir in east district of Karamay Oilfield as an example, we choose different heterogeneous models for the displacement experiments to analyse the effects of interlayer heterogeneity on the recovery and polymer channeling. The results prove that the producing reserves in the medium-low permeability cores of the strong heterogeneity model are very low, and the oil recovery in the experiment is mostly from the extraction of the high permeability core. There is still a large amount of oil remaining in the core. During the displacement, the serious polymer channeling exists in all test groups, which greatly reduced the sweep efficiency. It is a challenge of dealing with polymer channeling in the future development of the conglomerate reservoir.

Key words: conglomerate reservoir, interlayer heterogeneous, recovery, polymer channeling