A Study Of Accumulation Of Volcanic In Jizhong Depression

In recent years, with the difficulty of exploration increasing, people turn to igneous reservoir. However, less research is made by previous people on igneous reservoir. As a special kind of lithologic reservoir, it has its own special rules of oil accumulation, and has very strong nonuniformity. With the development of the age and the advance of technology, the research on igneous reservoirs has been a hopeful and new field for oil-gas exploration gradually, and more and more people begin to pay attention to it now.Jizhong Depression is a secondary tectonic unit in Bohai Bay basin in Cenozoic. Compared with other depression basin, it has a smaller scale in magmatic activity, with nonuniform distribution and different activity degree. Although there were magmatic activities in the whole Cenozoic, the horizontal distributions were limited and igneous rock even didn’t develop in certain regions except for Langgu Depression and Baxian Depression in the North, and Raoyang Depression and the areas of deep country, Shulu County and Jinxian in the South where magmatic activities were intense in Cenozoic. At present, the researches on many basic geological problems for igneous rock in Jizhong Depression are not enough, and even less researches on the conditions and mechanisms for oil accumulation of igneous rock. Therefore it is impossible to talk about the exploration potential and exploration orientation for igneous reservoir.Based on the research above, this paper researches the igneous reservoir from the aspects of logging, seismic attributes and seismic inversion on the basis of Petroleum geology, Theory and Method of Seismic Prospecting, Geological explanation of logging data, the Seismic Attribute Analysis Technology, Igneous Petrology and Petrography, together with the information of seismic data, geophysical well logging, gravity and magnetic data, coring and analytical experiments data. Then this paper forecasts the conditions for oil accumulation of igneous rock and belts favorable for oil accumulation. Finally this paper assesses the igneous rock traps comprehensively and forecasts the oil and gas resources.Compared with the reservoir of sedimentary rock, the features about reservoir space of igneous rock reservoir is extremely complicated. It has its own features, which are summarized on the following. There are many reservoir spaces. The structure for pores is complicated. The secondary effects are strong. It has shown serious nonuniformity from microcosmic to macroscopic. The pores, holes and fissures of igneous rock reservoir are mingled together, making great diversity and mutability for reservoir function. Reservoir space of igneous rock reservoir in Jizhong Depression is divided into two types: primary pores and secondary pores according to the analysis of core observation and thin section identification. Secondary pores are divided into pore-type and fracture-type, and can be divided into nine micro types further.Igneous reservoirs distribute around hydrocarbon generation center or the migration direction of oil and gas. And it distributes in the area where tectonic activities are strong and faults develop. And it also can be found near plane of unconformity. Igneous reservoirs usually appear in the upper part or under part of one igneous rock. The higher part of the igneous rock is in favor of oil and gas accumulation.