Zhang Tingshan

Potential and trend prediction of unconventional oil and gas resources based on combination forecasting model of variable weight for multi-factor

In order to increase the potential and trend prediction accuracy of unconventional oil and gas resources, a potential and trend prediction method of unconventional oil and gas resources based on combination forecasting model of variable weight for multi-factor is proposed. First of all, the present situation and trend of oil and gas resources development are analyzed and introduced. It is pointed out that it is influenced and restricted by many factors and external environment, which shows the characteristics of its complexity and non-linear historical evolution trend. Secondly, the optimal variable weights are determined by using the variable weight combination forecasting model and then the potential and trend prediction accuracy of unconventional oil and gas resources is realized to be increased. Finally, the validity of the proposed method is verified by the simulation experiment.

Quantitative study of generated shale hydrocarbon—a case study of lacustrine shale, Yanchang Formation

ABSTRACT Shale hydrocarbon has recently received widespread interest due to its emergence as a type of clean energy. However, calculating the quantity of lacustrine shale hydrocarbon is a challenging issue that the petroleum geologists are currently facing, which results in a poor understanding of shale-hydrocarbon distribution. Using mass conservation law, as well as geochemical and geological rules, this paper tries to establish mathematical models for calculating the quantities of lacustrine shale hydrocarbon. A simple method is also introduced to acquire the target values. The lacustrine shale of the Yanchang Formation in the Ordos Basin is selected to establish the mathematical models and the parameter systems. The method is tested to be computationally efficient and highly practical. The results show that the generated shale gas and shale oil per ton of lacustrine shale of the Yanchang Formation are 1.2 m3 and 0.75 kg, respectively. The lacustrine shale of the Yanchang Formation has a high hydrocarbon potential and is recommended as a favorable target for shale hydrocarbon exploration.

Mineral Composition and Brittleness Analysis of Organic-Rich Lower Paleozoic Shale in South Sichuan and North Yunnan Areas of China

Organic-rich Lower Paleozoic Qiongzhusi, Wufneg, and Longmaxi formations in South Sichuan and North Yunnan areas are the main gas prospecting strata in China. XRD analysis is used to determine the mineral composition and brittleness indexes of three shale suites in these areas. These parameters are important for evaluating shale gas resources, analyzing reservoir-forming mechanisms, and planning prospecting. The investigation results indicate that the three shale suites have a mean quartz content of more than 27% and a mean clay mineral content of less than 37.27%. Their sedimentary environment is euxinic. They passed through a telodiagenetic phase. The mean relative brittleness index of the samples from Qiongzhusi, Wufneg, and Longmaxi formations are 69.54, 67.33, and 60.44%, respectively. Such high relative brittleness indexes imply that the studied shale suites have good fracturability.