DIVISION AND EVALUATION OF FLOW UNITS IN LOWER MEMBER OF TRIASSIC AKEKULA FORMATION IN TAHE 9 AREA TARIM BASIN

In this study, a division method of flow units of the massive reservoir sand bodies of the Triassic Akekule Formation in the Tahe 9 area is proposed by the construction of comprehensive indexes of heterogeneity (IRH). Furthermore, the heterogeneity of the reservoir and the potential for remaining oil are elucidated. The results show that the comprehensive index of homogeneity (IRH) method can be effective used to determine the flow units of the superimposed thick sand layers. The preferred reservoir parameters include porosity, permeability, seepage coefficient, storage coefficient, effective thickness, permeability coefficient of variation, liquid production capacity, and configuration unit. The flow units of the superimposed massive fluvial delta sandstone reservoirs are divided into I, II, III, and IV types. The quality of the flow units in the vertical direction gradually become poor upward, and they have the characteristics of regular rhythmic distribution; and its plane distribution is strictly controlled by the northeast-trending reverse faults and its seepage barriers such as lateral abandoned channels, inter-distributary bays, and channel edges. Various types of flow units can be clearly distinguished. The RQI, FZI and R35 index values of the Type 1 and Type 2 flow units are higher, the reservoir quality is better, the microscopic porethroat structures is better, and the seepage capacity is strong. However, due to the formation of water flooding channels in some high-permeability reservoirs, the water flooding process is non-uniform, and the final water flooding efficiency becomes poor.