Quantitative characterization of diagenetic reservoir facies of the Karamay alluvial fan in the Junggar Basin, western China

The distribution of the remaining oil in developed oilfields is primarily influenced by the existing diagenetic reservoir facies (DRFs), which encompass the effects of both the sedimentary environment and the local diagenetic processes on the reservoir quality. We divided the Lower Karamay Formation reservoir samples into nine DRFs according to characteristics such as porosity, permeability, diagenetic intensity, and rock type. After applying the sequential indicator simulation methodology, we were able to create three-dimensional (3D) geological models of the DRFs. Based on these models, we can see that, during phases A and B of eodiagenesis, the prevailing DRF is a sandstone/sandy conglomerate that is moderately to weakly dissolved, moderately cemented, and characterized by moderate porosity and permeability values. The highest quality DRF, which emerged during the early stage of mesodiagenesis, is a sandstone/sandy conglomerate that is weakly compacted/cemented, moderately-to-strongly dissolved, and characterized by very high porosity and permeability values. By providing high-quality analyses of the DRFs in Block 6 of the Karamay oilfield, we provided vital information that allowed the operation to more efficiently target and extract oil from reservoir units that are already in production.