Study On Hydrocarbon Content And Hydrocarbon Accumulation Capacity Of Shale In Shaxi And Shahejie Formation Of Dongying Depression And Its Significance To Porosity Of Organic

In this study we research around one of today’s shale gas exploration and evaluation systems difficult problems on the determination of organic shale porosity characteristics and its evolution. Using the technical that developed for the field of macromolecules, swelling theory, that allowed us discussing organic pore structure characteristics and the tolerance and expulsion capacity from the molecular level. On this basis, we select the samples of the shale in the lower Es3and the upper Es4in the Dongying Sag of the Bohai Bay Basin. By using the swelling experiments, we access to the different levels of the reservoir space of kerogen in different maturity levels. Thus achieving the goal of evaluating the organic shale porosity quantitatively.The porosities of organic shale account for about0.2%to3.28%overall volumes of hydrocarbon source rocks in the Shahejie Formation in Dongying Sag. The porosities of organic shale in the upper Es4are larger than that in the lower Es3. As the mature stage of the organic matters get higher and higher, the organic porosities reflect a trend that increases first then decreases, which differs from the conventional view of the positive correlation between porosity and thermal evolution.Within a certain range, there exists an excellent correlation between organic abundance and porosity, however the organic matter seems not forming pores for the shale with high abundance. And there is no correspondence between the porosities of the organic matter and the organic maturity during the hydrocarbon generation processes as previously described. By the results of the experiment by swelling and swelling experiments deduction, we studied the relationship of organic shale reservoir space with burial depth, organic maturity and TOC. And discussed the relationship of organic shale reservoir space with hydrogen to carbon ratio, carbon-13isotope and the selective solvents. And it offers a new understanding from the aspects of how the organic structure effects the shale reservoir space from the molecular level. Understand the organic shale porosity preservation conditions by study the mineral environmental analysis and expulsion mechanism, efficiency and momentum. That provides a new effective way to evaluate the shale organic matter system.