An Improved Method for Evaluating Hydrocarbon Generation of Shale:A Case Study of the Lower Cretaceous Qingshankou Formation Shale in the Songliao Basin

Because of the influence of hydrocarbons,especially adsorbed hydrocarbons,on the detection of cracked hydrocarbon(S2)and total organic carbon(TOC),the hydrogen index(HI)-based hydrocarbon generation model deviates from actual practice.In this study,the shale in the first member of the Qingshankou Formation in the central depression of the Songliao Basin,where in northeastern China,was taken as the research object and a correction method for S2 and TOC was established.By correcting the experimental results of different maturity samples,the actual hydrocarbon generation model has been revealed,the differences before and after correction compared,and the evolutionary characteristics of the adsorbed hydrocarbon content were clarified.The results show that the organic matter enters the hydrocarbon generation threshold at R_(o)-0.5% and reaches the hydrocarbon generation peak at R_(o)-1.0% and that the hydrocarbon generation process ends at R_(o)-1.3%.The hydrocarbon generation model established based on the measured values has a‘lag effect’compared to actual values,and this extends the hydrocarbon generation window of organic matter and delays the hydrocarbon generation peak.With the increase of maturity,adsorbed hydrocarbon content shows the characteristics of‘first increasing,then stabilizing,and then decreasing’,and reache s the most abundant stage at Roof 0.9%-1.3%.

Corrective Plate With a Gradient Index Media in the Catadioptiric System

In this paper a gradient index media plate is described. The media plate has some properties similar to the Schmidt aspherical corrective plate. In the catadioptiric system,Duncan T. Moors has studied a axial gradient index corrective plate and gave a better result. His plate,in fact,is a zero power plate with two Spherical surfaces of different radius of curvature. However ,my plate is a parallel plate designed forth a shallow radial gradient index media. The spherical aberration of the gradient index corrector with parallel plane ed eliminate the spherical aberration of the spherical primary mirror in the catadioptiric system. In this paper the aberrational correction is analyzed. In the conventional optical systems,this gradient index plate is used to provide the precorrectional quantity of the spherical aberration of the optical lee systems. The refractive index in such a media in the lens systems is given in the same way.