Formation Process And Evolution Mode Of Petroleum Controlled By PVT

Petroleum generation and evolution process in the source rocks of the petroliferous basins is the complicated interaction of geology and geochemistry, which is controlled by geology and boundary conditions of the physical chemistry. It has not only relationship with the inner influence factors of the petroleum formation such as the kerogen type, total organic carbon, but also with the exterior influence factors such as the temperature, pressure, rock mineral, fluid medium, pore space et al. To describe the petroleum generation process, quantitatively estimate the petroleum generation potential and satisfy the requirement of the detail oil and gas exploration, large numbers of pyrolysis simulation experiments for the source rocks controlled by the PVT-t-L (P:pressure; V:pore space; T:temperature; t:time; L:fluid)conditions are carried out according to the actual geology conditions in the sample areas such as burial history, thermal history, paleo-temerature and pressure in the key timing of the hydrocarbon and so on to analyze the effect of formation water phases and pressure, rock mineral property, pore space in the source rocks on the hydrocarbon process of organic matter and thermal cracking rate of hydrocarbon by the combination of the fluid in the pore space, rock mineral, physical chemistry characters of organic matter in the source rocks, discuss the reaction mechanisms of the petroleum formation with the interaction of the high temperature and pressure liquid formation water, rock mineral and organic matter, and establish the dynamic quantitative evolution mode of the petroleum formation and oil and gas generation potential estimation methods of the source rocks. The selected source rocks with various organic abundant, kerogen types (type Ⅰ and Ⅱ), lithology(mudstones and marlite) and formation water samples are from the typical faulted basins in the eastern China and the lower paleozoic marine strata in the southern China. The following conclusions can be drawn:(1) We designed and manufactured the formation pressure pore space hydrocarbon generation and expulsion simulation experiments machine which has several nationality patents authorization, establish the pyrolysis simulation experiments methods controlled by PVT, discuss the effect of the boundary conditions such as the temperature, time, fluid pressure, formation water, pore space and so on. The research results indicate that the temperature is the main control factors on the hydrocarbon generation and the other experiment conditions can not ignore, which imply that more reasonable simulation the petroleum formation process in the laboratory need to take into account multiply influence factors.(2) Hydrous pyrolysis simulation of hydrocarbon generation controlled by PVT system for the different lithology, kerogen types and initial maturity of the source rocks are carried out based on the summarization of the hydrocarbon generation pyrolysis simulation experiments machines and experiment conditions to analyze the relationship between the vitrinite reflectance (Ro) and the generation rate of H2, CO2, hydrocarbon gas, pyrolysis oil and total oil and gas in two pyrolysis systems. The research results indicate that the modes of source rocks pyrolysis simulation experiments have important influence on the rate of the source rocks pyrolysis products, composes and evolution process.(3) The solubility of the formation water with oil, oil with formation water, and the mix of N2, CO2and CH4with oil and water on the coexistence of the oil, gas and water with high temperature and pressure are measured using the self-designed and manufactured high temperature and pressure petroleum solution and release simulation experiment machine by the combination of the the water phase figure and near critical physical chemistry characters with high temperature and pressure. The effect of formation water state in the pore space of the source rocks on the petroleum formation are discussed by the combination of the relationship between the porosity and maturity during the source rocks burial. Source rock pyrolysis simulation experiments with High pressure liquid water and low pressure balance state water are carried out based on the formation water phase in the source rocks to analyze the effect of the formation water phase and fluid pressure on the composes and generation rate of the nature gas, oil and total hydrocarbon generation rate, maturity and residual potential of petroleum generation.(4) The marine and continent source rocks mineral characters and the effect on the organic matter occurrence conditions are studied. The pyrolysis simulation experiments for the source rock with different mineral controlled by PVT and dissoluble organic matter with different mineral are carried out to analyze the products characters of the pyrolysis simulation experiments and discuss the effect of rock mineral on the petroleum formation.(5) The continuous increase pyrolysis experiments methods controlled by PVT are established on the base of the deficiency of the estimation the source rock hydrocarbon generation potential by Rock-Eval. On the base of the pyrolysis experiments, the hydrocarbon generation process of the type Ⅱ kerogen are described detailedly and the parameters of the estimation source rock hydrocarbon generation potential are suggested in this study. The new estimation methods of the source rock hydrocarbon generation potential are also suggested by the combination of the generation rate characters of the dissoluble organic matter (oil with different characters) thermal cracking into the gas. The reaction mechanisms of the petroleum formation with the interaction of the high temperature and pressure liquid formation water, rock mineral and organic matter are discussed on the base of the integration previous study on the mechanisms of the petroleum formation. The dynamic quantitative evolution mode of the petroleum generation for the type II kerogen source rocks are established by the integration large numbers of the pyrolysis simulation experiments results controlled by PVT.