The Study Of Mechanism Of Hydrocarbon Reservior In Heidimiao Area Southern Songliao Basin

Study area of this paper is the Heidimiao region southern Songliao Basin. The aim is to use the drilling, logging and seismic data through tectonic history research, trap types analysis, influence of faults to oil reservior, Laser Raman composition analysis technology and the homogenization temperature of fluid inclusions technology to study hydrocarbon accumulation period, mechanism and pattern of reservior.Tectonic history study is a basic study of mechanism of reservior, including formation buried history and tectonic subsidence history. Denuded amount calculation is an important part of buried history study. In this paper, using the Acoustic Travel Time method and Sedimentation rate method calculate the denuded amount of Mingshui formation and Nenjiang formation in the Hei62 well etc. By taking Drilling data and well log data, use backstrip method to restore stratigraphy buried history in the hei62 well and other six wells.then make two profile section which based on the buried history. Tectonic history results show that there has been three tectonic subsidence periods and two tectonic uplift periods in the area since Qingshankou stage. The first tectonic uplift period is later Nenjiang stage and the second tectonic uplift period is later Mingshui stage.Coupled with Denuded amount and sedimentation rate study,the result shows that tectonic uplifts hadn't important impact to the configration of study area but had improtant influence to the shaping of anticline and nose structure ,distribution and maturity of hydrocarbon source rock ,migration and accumulation of hydrocarbon.We study the the times and stages of hydrocarbon reservior filling in Heidimiao area Songliao basin according to the application of homogenization temperature of fluid inclusions and composition analysis technology, burial history and evolution of ground temperature. The result show that there were tow main stages of hydrocarbon reservior filling and a minor stages of hydrocarbon reservior filing, the ground temperature was between 90℃to 100℃during the fist main stage when there occurred Nenjiang tectogenesis which was bad for petroleum accumulation; the ground temperature was between 120℃to 130℃during the second main stage, but during this time the construction of the area was becoming stable to provide enough oil trap for hydrocarbon reservior filling, so the sencond main stage is most important for hydrocarbon reservior filling; the minor stage is short and not important, during this time the ground temperature was between 140℃～160℃, so we infer that the reason of origin of the minor stage is that deep hydrocarbon migrated into the stratum through faults.It has been proved by oil and gas exploration that the vertical and horizontal composed mode of hydrocarbon source rock,reservoir rock and seal rock is the important condition of oil and gas accumulation, particularly large oil and gas field.The source-reservior-seal association mode is important to great oil and gas field ,good association mode have the power to drive oil and gas migrate to reservoir more effectively and seal the oil and gas in the reservoir to becom a great oil and gas field. There are three source-reservior-seal association modes in the bed of interest of study area, they are injection migration mode, self-generating and self-preserving mode and lower generating-up reservioring mode.Generally speaking, trap is classified into structural traps, stratigraphic traps, lithologic traps, water driving traps and complex traps. structural traps, lithologic traps and complex traps has been discovered in the study area. Structural trap include anticline traps and faulted nose traps; lithologic traps include sand lens traps and up dip wedge-out traps; complex trap include structure-lithology traps and fault-lithology traps. the fault-lithology traps are main exploration goal. Because of delta and shallow lake dam deposit, a lot of lithologic traps had developed in study area. When a fault broke off across the lithologic traps, it became a fault-lithology trap. There are so many NNW-trending faults in the area that there may be many fault-lithology traps in the area.Faults have great influence to development of hydrocarbon reservoir and play an active role in the performance of the two main aspects, first, they are the pathway between source rocks and reservoir rocks and the efficiency of hydrocarbon migration is far higher than the general pathway; Second, mud rocks can be apartment of the trap by the affect of faults.We establish the hydrocarbon reservoir mode by integrated study, and then consider that fault-lithology reservoir is the most hopeful reservoir and Putaohua reservoir is the favorable exploration goal reservior.