SEGMENTATION CHARACTERISTICS OF LANLIAO FAULT IN NORTHERN HEZE UPLIFT AND ITS CONTROL ON KARST GEOTHERMAL RESERVOIR

Based on the seismic, drill logging and other production test data, the qualitative analysis and quantitative study are used for inversion of the growth process of Lanliao fault in northern Heze uplift, as well as its control effect on karst geothermal reservoir. The results show that the evolution of Lanliao fault can be divided into three stages, characterized by segmentation in early stage and linkage in late stage. In the early sedimentary stage of Shahejie Formation, the fault segmentation began to appear. Through the depositional stage of Sha-3 Member, each fault segmentation was obvious with the displacement characteristics of independent normal fault. To the depositional stage of Sha-2 Member-Dongying Formation, the fault segmentations grew laterally and eventually connected as a large fault. The difference of fault segmentation characteristics is significant to control the spatial distribution, heat transfer and productivity of karst geothermal reservoir in the study area. During the evolution of the faults, the total vertical displacement of No. 2 fault system in the middle is larger than that of No. 1 fault system in the south and No. 3 fault system in the north, showing a rolling half-graben structure association pattern in a forward arrangement in the profile, and the rise of Heze uplift is more obvious with serious bedrock denudation partially. The karst geothermal reservoir in the area is characterized by shallow burial, developed karst fracture, high average geothermal gradient of cap rock and good productivity, which is the most favorable for geothermal exploration and development.