Continental fault-block reservoirs in the Second Member of Shahejie Formation in Dongying Sag of Eastern China are difficult to achieve efficient exploration and development due to the complex geological conditions. This study relates to the in-depth analysis on diagenesis and reservoir quality in such deposits. These deposited sandstones have a wide range of porosity and permeability, which indicate both depositional facies and diagenesis control. Diagenetic processes that influenced the reservoir quality of the study area mainly insist of the formation of carbonate cements, and clay minerals, mechanical compaction, quartz cementation, and dissolution of framework grains. The distribution patterns and mineralogy of cements vary spatially, being relevant to reservoir evaluation. Among the diagenetic menerals, carbonate cements occur as the predominant components in the Shahejie sandstones of the study area. In such settings, the quality-destruction processes include mechanical compaction and carbonate cementation, whereas the quality-generation process is dissolution of detrital grains and calcite cements. The major sequence is eodiagenesis with the types and extent of eogenetic alterations related to the near-surface geological conditions. This study demonstrates diagenesis and related reservoir quality evolution can be linked to fine reservoir characterization, and thereby has an important role on hydrocarbon exploration and exploitation in the continental fault-block reservoirs.

This article describes an approach based on artificial neural network to identify waterflooded zone of continental clastic reservoirs. For the logging sequence of waterflooded zone matching the characteristics of the continental oilfield, the application of artificial neural network algorithm is able to distinguish water layers, oil reservoirs and dry layers among reservoirs of waterflooded zones. The output vectors of the network represent the fluid types. Thus, better results are supposed to be obtained than traditional methods in the crossplot plate after network training. Distribution becoming non-uniform and contact between grains being loose were found after microscopic observation in the waterflooded zones. It has revealed that the waterflooded characteristics are of great significance, and it has also proved the accuracy of identification from another perspective.

Study on the interlayer has developed associated with in-depth exploration and development of oil fields, which is an indispensable part to characterize reservoir heterogeneity. This study relates to a comprehensive research method of interlayer in rhythmic layering in continental low permeability reservoirs. During the process of waterflooding development, distribution characteristics of interlayer in the single well, plane, cross-well, and well group should be analyzed based on identification and genesis of interlayer. And thus the three-dimensional model of interlayer could be constructed in order to reveal its spatial distribution characteristics in continental reservoirs. Practice in continental oil fields has shown that the type and distribution of interlayer play an important role in controlling remaining oil. Mastering the distribution rule of interlayer can better explore the distribution of remaining oil. Through in-depth analysis on the interlayer, better development results could be achieved by taking different measures to trap the potential. Also, utilizations of interlayer results for the analysis of injection connectivity could facilitate petroleum engineers to adjust the injection layers, and thereby increasing the efficiency of oil field development.