Quantitative Analysis Model and Application of the Hydrocarbon Distribution Threshold

Hydrocarbon source rock obviously controls the formation and distribution of hydrocarbon reservoirs. Based on the geological concept of ＂source control theory＂, the concept of a hydrocarbon distribution threshold was put forward. This means the maximum range for hydrocarbon controlled by the source rock conditions to migrate in the hydrocarbon basins. Three quantitative analysis models are proposed on this basis, namely the hydrocarbon accumulation probability, maximum hydrocarbon scale threshold and reserve distribution probability, which respectively refer to the probability of forming a hydrocarbon reservoir, the possible maximum scale of the hydrocarbon reservoir and the percentage of reserve distribution in a certain area within the hydrocarbon distribution threshold. Statistical analysis on 539 hydrocarbon reservoirs discovered in 28 hydrocarbon source kitchens from seven sedimentary basins and sags of eastern China shows the maximum reservoir scale possibly formed in the hydrocarbon basin, hydrocarbon accumulation probability and oil and gas reserve distribution probability are all controlled by the characteristics of the hydrocarbon source rock. Generally, as the distances from the hydrocarbon source rock center and hydrocarbon discharge boundary get longer and the hydrocarbon discharge intensity of hydrocarbon source rock center gets smaller, there will be lower probability of hydrocarbon accumulation. Corresponding quantitative models are established based on single factor statistics and multivariate analysis. Practical application in the Jiyang Depression shows that the prediction from the quantitative analysis model for the hydrocarbon distribution threshold agree well with the actual exploration results, indicating that the quantitative analysis model is likely to be a feasible tool.

Effects of heterogeneous adoption thresholds on contact-limited social contagions

Limited contact capacity and heterogeneous adoption thresholds have been proven to be two essential characteristics of individuals in natural complex social systems,and their impacts on social contagions exhibit complex nature.With this in mind,a heterogeneous contact-limited threshold model is proposed,which adopts one of four threshold distributions,namely Gaussian distribution,log-normal distribution,exponential distribution and power-law distribution.The heterogeneous edge-based compartmental theory is developed for theoretical analysis,and the calculation methods of the final adoption size and outbreak threshold are given theoretically.Many numerical simulations are performed on the Erdös-Renyi and scale-free networks to study the impact of different forms of the threshold distribution on hierarchical spreading´process,the final adoption size,the outbreak threshold and the phase transition in contact-limited propagation networks.We find that the spreading process of social contagions is divided into three distinct stages.Moreover,different threshold distributions cause different spreading processes,especially for some threshold distributions,there is a change from a discontinuous first-order phase transition to a continuous second-order phase transition.Further,we find that changing the standard deviation of different threshold distributions will cause the final adoption size and outbreak threshold to change,and finally tend to be stable with the increase of standard deviation.

Development of Surface Grating Distributed Feedback Quantum Cascade Laser for High Output Power and Low Threshold Current Density

We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.