| Jiyuan sag is located in the northwest of Henan, in the Cities of Jiyuan, Qinyang, Mengxian, Wuzhi and Boai. And it is south of the Yellow River, north of Taihang Mountain. The depression is extending from east to west, as an area of about 2800km2. It is part of the south of North China Basin, located in the west of Jiyuan-Huangkou depression belt. It is the Mesozoic and Cenozoic superposed basin with a nearly East-West tectonic framework.In this paper, based on a large number of collection of sedimentary characteristics and tectonic evolution of Jiyuan sag and hydrocarbon source rock evaluation research, using the drilling, logging and testing data, we have studied the hydrocarbon source rocks, reservoir cap combination and trap forming conditions in the study area. Studies show that has good hydrocarbon source condition in this area:three Permian Tanzhuang group hydrocarbon source rock is better in Ⅱ2, the nest type is Ⅱ1, the second is the lower Jurassic anyao formation and Middle Jurassic Maao group, belonging form a good to poor source rock, in Ⅱ2 and Ⅱ1 times, and the maturity of those hydrocarbon source rocks have reached the mature to high mature degree.At the same time, in the hydrocarbon source rocks and oil gas chromatogram of saturated hydrocarbon, saturated hydrocarbon GC-MS analysis foundation, respectively from the hydrocarbon source rocks and oil distribution of n-alkanes, steranes and terpanes and steranes and terpanes parameters characteristics of several aspects of oil source correlation, the study area that Deng 2 well for mixed crude oil sources, namely Tanzhuang formation hydrocarbon source rock and the anyao formation are the source of oil.On the basis of the temperature data of source rocks and geochemical analysis results, we use the thermal history simulation software to simulate the thermal evolution of Jiyuan sag, and then simulate the Maturity History of Mesozoic hydrocarbon source rock. The results of hydrocarbon source rock thermal history and hydrocarbon generation history shows that the recovery of heat flow values from ancient times to the present, the overall change trend of first increased and then decreased, by the end of the Middle Jurassic is about 60mW/m2, and then the heat flow values increase under the influence of Yanshan movement, to the end of Early Cretaceous rises to about 80mW/m2, then enter the rift subsidence basin, the heat flow values began to decrease. At the end of Oligocene, it falls to about 55mW/m2, then the heat flow value tends to be stable, the current is 45-50 mW/m2. The first hydrocarbon generation time is in 165-163Ma, reached the peak of hydrocarbon generation in 157Ma, and it terminate in 156Ma. Second hydrocarbon generation time is in 115-100Ma, to reached the peak of hydrocarbon generation in 105-98Ma, due to uplift hydrocarbon is interrupted in 96Ma, Tan Zhuang group hydrocarbon source rock in the local area can be three hydrocarbon, reached the peak of oil in 26Ma, as the second episode of Himalayan movement, hydrocarbon is interrupted in 23Ma, and the maturity of source rock is generally present in the central uplift belt to the two sides (Wenxian sag and Qinyang sag) evolution degree tended to increase.Using the measured data of fluid inclusions in filling period of oil and gas, we find that there have three kinds of hydrocarbon inclusions fluorescent color in the research area:yellow green, blue green and blue. It reveals that there are three acts of oil and gas filling at least. At the same time, some samples are detected in the solid bitumen, indicating the early filling reservoir has suffered damage. Finally, combined with the oil source correlation analysis, we study the accumulation time by the projection of fine burial history and thermal history. The first phase of the accumulation time is about 163Ma, but may have been damaged; second accumulation time is 101-95Ma, the hydrocarbon source rocks is the result of two hydrocarbon generation; third accumulation time is 27-23.8Ma. |
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