The objective of this study is to characterize the interlayers within the thick, blocky-like, ultra-low permeability conglomerate reservoir in the Lower Wuerhe Formation, in the Eighth District of the Karamay Oilfield, Xinjiang, and to provide a new theoretical basis for precise waterflooding in the future. Based on the reservoir characteristics of the Lower Wuerhe Formation in the Karamay Eighth District, this study integrates wireline logs, core samples, and production data to describe the interlayers’ types and characteristics precisely, establish their identification criteria and determine their influence on future waterflooding development within the study region. The Lower Wuerhe Formation in the Karamay Eighth district mainly develops physical interlayers, which can be further divided into three categories. Type I interlayer mainly develops at the top of the P2w3 Member and is widely distributed within the study region. Type II interlayer is mainly developed in the P2w4 Member and it thickness is the largest in the middle and northeastern study area, gradually decreasing to the southwest. Type III interlayer mainly develops in the P2w4 Member and is the thickest in the northeast. Interlayers and reservoirs alternately developed in the Wuerhe conglomerate reservoir in the study area. In general, interlayers are well developed across the study area with an average thickness of 8.0–22.0m. The development of interlayers can form a seepage barrier within the reservoir and subdivide the permeable layer into multiple flow units. This well assist future precise water injection adjustments and residual oil exploration in the massive conglomerate reservoir of the mature Karamay Oilfield.