Analysis Of Shale Gas Resource Potentiality Of Niutitang Formation Of The Lower Paleozoic In Jin Yang-Wei Xin Area

On the basis of previous research,guided by sedimentology,petrology,reservoir geology, gas geology,oil and gasgeochemistry,logging geology theory,combined with the data of field section survey,logging,physical properties analysis, scanning electron microscopy,organic geochemistry,etc.,Niutitang Formation shale’s distribution, sedimentary facies,petrological characteristics,organic geochemical characteristics, physical characteristics,gas-bearing characteristics and its main controlling factors have been studied. At the same time, main parameters to estimatethe geological resources of shale gas have been analyzed and multi-factors superposition method is used to select favorable areas for shale gas exploration and development.The analysis of core observation,logging data and organic geochemical characteristicsshow that the sedimentary facies of Niutitang Formation in the study area are mainly shallow shelf and deep shelf phase.Effective shale have large thickness and stable distribution, and its bottom buried depth is moderate,mainly between 1000-4000 m. Shale contents high organic carbon,with type Ⅰ organic matter and higher maturity,sapropel-type kerogen dominant,in high to mature maturity stage.The main mineral composition of Niutitang Formation shale is clay minerals and quartz,feldspar and carbonatite secondary,meanwhile,there is a small amount of pyrite, etc.The content of clay mineral is between 8%-47%, the average is 23%.The content of brittleness mineral is between 21%-87%, the average is 62%.The mainly pore in shale samples are nanometer pore,micro pore and micro cracks,porosity between 0.92%-1.91%, the average is 1.50%,permeability in 0.0107×10-3μm2-0.2011×10-3μm2, the average is 0.0396×10-3μm2. Overall,the reservoir property of Niutitang Formation shale is poor.Favorable area for shale gas exploration has been prediced based on the parameters of Niutitang Formation gas-bearing shale such as thickness,buried depth, organic carbon content,organic maturity,etc.The conclusion has been drawn that Yi Liang-Da Guang-Yan Jin region is the favorable area for shale gas exploration, covering an area of 6902.92km2,and the expectations of shale gas’ s geology resources is 0.54×1012m3.