A method for calculating the overpressure of hydrocarbon source rocks based on the pressurization equation of oil generation

Abstract

A method for calculating the overpressure of hydrocarbon source rocks based on a pressurization equation of oil generation. Based on the oil generation of source rocks in petroliferous basins and theintrinsic relationship among kerogen, crude oil and pore water in terms of mass, volume and compression coefficient, a model of oil generation boosting calculation is established to calculate the overpressure and to improve the accuracy of overpressure value calculation, and technical support is provided for improving petroleum geological evaluation. The invention proposes an overpressure calculation method based on the pressurized source oil in accordance with the pressurized source oil model in China, which can effectively utilize the calculation formula and improve the calculation accuracyof the overpressure value.

Description

technical field [0001] The invention belongs to the geological evaluation technology in the oil and gas exploration and development technology, in particular to a method for calculating the overpressure of source rocks based on the oil generation pressurization equation. Background technique [0002] The overpressure characteristics of oil and gas-bearing basins are currently a difficult research point, and have become an indispensable part of basin analysis, playing an increasingly important role in the process of hydrocarbon accumulation. Overpressure in oil and gas bearing basins is closely related to oil and gas generation, migration and accumulation. The formation of overpressure is related to many factors, including compaction disequilibrium, pore fluid thermal expansion, clay mineral dehydration, structural extrusion and hydrocarbon generation, etc. [0003] At present, there are relatively few quantitative studies on source rock oil generation pressurization at home...

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Problems solved by technology

In 2011, Guo Xiaowen proposed a calculation model for the supercharging of organic matter in oil generation. Based on the two principles of material conservation and space conservation, the model reveals the magnitude of the overpressure generated by organic matter in the oil generation process. However, the model has two main shortcomings. One shortcoming is that the calculation of geological parameters into the formula model sometimes results in negative values, because the equation only considers the compressibility of oil, and does not take into account the oil's underground distribution due to the large amount of dissolved gas in the actual geological situation. The density is smaller than that of the surface, so the underground volume of oil with the same mass is larger than the surface volume. Therefore, the overpressure calculated by Guo Xiaowen’s formula is smaller than the actual overpressure. The second deficiency is that there are no relevant parameters in the formula that can reflect the residual pore water. As the source rock is compacted, the pore water is continuously discharged, and the water content gradually decreases. If it is considered that a part of pore water still exists when the source rock generates oil, the actual overpressure generated is greater than the overpressure calculated by Guo Xiaowen’s formula

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