The Analysis Of Forming Conditions Of The Oil And Gas Reservoir In Part Of The South Hurenbuqi Sag In Erlian Basin

The paper aims to determine forming conditions of the oil and gas reservoirs in part of the south Hurenbuqi sag by using theories and approaches in petroleum geology, Sedimentology, reservoir geology, field development geology and reservoir engineering and other disciplines. Series of achievements and understandings in oil and gas exploration have been achieved making use of drilling, logging, testing oil, and seismic data in part of the south Hurenbuqi sag in Erlian Basin.1,The study indicates that the Bayanhua Group of Lower Cretaceous for the main stratigraphic of Hurenbuqi sag is Aershan Formation, No.1 & No.2 Member of Tengger Formation and Saihantala Formation from Bottom to up.lt is a set of gray sandstone, conglomerate, mudstone lake sediments. Stratigraphic thickness is about 4000m.2,No.1 Member of Tengger Formation and Aershan Formation is mainly developing depositional system of fan delta～lake, it is river→fan-delta plain→the front of fan-delta→shallow lake→semi-deep lake→deep lake, its source mainly derived from the west and the other from the east. Western gentle slope is mainly developing fan delta and eastern steep slope developing underwater fan.3,The reservoir is mainly the front of fan delta, submarine fan sand. The reservoir has highly heterogeneous that the main reservoir types is the follower reservoir porosity permeability, the high porosity and permeability in the reservoir less. Reservoir properties is No.2 Member of Tengger Formation relatively best, followed by No.1 Member of Tengger Formation and Aershan Formation worse which porosity is 7.4-13.1%, permeability is 6.4-36×10-3μm2. The main types of primary porosity are primary.intergranular pore, secondary porosity and intragranular fracture pore.4,The part of south Hurenbuqi sag show the east off and the west over for structural framework. Main trap type is small block, small broken nose, anticline, long nose, lithologic pinch and stratigraphic complex cut by early, middle and late fault.5,No.1 Member of Tengger Formation has the best oil generation index in Erlian Basin, The average content of organic carbon is 3.01%, chloroform bitumen"A"is 0.22%, total hydrocarbon is 1307ppm, potential hydrocarbon S1+S2 is 114.39mg/g, the type of parent materials is mainlyⅠ-Ⅱ2, the depth of maturity threshold of organic matter thermal evolution is1000m.The potential resource of the whole sag is 1.49～2.24 million tons, in the part of south Hurenbuqi sag is 1.02～1.52 million tons. The exploration potentiality target is estimated great.