Lithological Hydrocarbon Reservoir Type, Distributing And Forecasting Of Mesozoic Group In Shengbei Of Tuha

Shengbei sag is located in the west of Taibei depression in Tuha basin. According to many years' exporation, it is Pubei gas-oil field, Shengbei gas-oil field, Honglian gas-oil field, Huobe gas-oil field which all belong to structural reservoirs that have been discovered. But proved reservoir of these gas-oil fields is less than 20% of total source reservoir.Based on the comprehensive study of sequence stratigraphy and sedimentary system, first through the comprehensive analysis of geology, logging and seismic and so on, it is found that residual abundant gas-oil resource is rich in lithological hydrocarbon reservoir. And types and distribution of Shengbei lithological hydrocarbon reservoir have been analysed, and technology and method of lithological hydrocarbon reservoir exploration have been put forward. At last comprehensive evaluation was finished and favorable exploration direction has been pointed out.Major results include as the following:1. Mesozoic group in Shengbei sag has advantage factor of forming lithological hydrocarbon reservoir. Alluvial fan and fan delta developed in escarp region of the north of the sag, and river-delta farmed in ramp belt of the south. These sediment bodies are characterized by sandstone pinch out, which is the base of lithological hydrocarbon reservoir.2. lithological hydrocarbon reservoir types in Shengbei sag have slope belt frontal sandrock onlap type, delta frontal sandstone anaphase tilted type, and delta frontal sandstone offlap type.3. Method of identifying and valuating of lithological hydrocarbon reservoir is pointed out by multi-parameters of seismic.4. Primary controlling factors and distribution features of every lithological hydrocarbon reservoir type is put forward. Slope belt frontal sandrock onlap type lies in the north slope of Huoyanshan structure in Shengbei sag, which presents ribbon fabric. Delta frontal sandstone anaphase tilted type is in the east slope of Pubei structure belonged to the west of Shengbei sag. Delta frontal sandstone offlap type lies in the slope of Shengbei structure standing in the north of the sag.5. Five special aspects about explorating lithological hydrocarbon reservoir in Shengbei sag are pointed out.6. Three favorable exploration directions are predicted, which are the north slope of Huoyanshan structure, and the south slope of Shengbei structure, and the east slope of Pubei structure.