Diagenesis And The Favorable Reservoir Prediction Of The Target Layer In The Qiong Dongnan Basin

since "75",The reservoir studies in the Qiongdongnan basin have been among the leading domestic level, for long-term and high-yield oil field has made a great contribution. However, like other fields, most of the past, the method used, the traditional geological methods, mainly static, unable to hydrocarbon generation, migration, accumulation process and the evolution of the reservoir together, it is difficult to meet the needs of oil and gas exploration. In order to as soon as possible to a major breakthrough in oil and gas exploration in the Qiongdongnan basin, this study attempts to research the context of over-pressure high-temperature diagenetic mechanism, based on the application of diagenesis numerical simulation technology, the establishment of a regional diagenetic Qiong Basin frame of the forecast of reservoir porosity and effective distribution of reservoir, so that a more practical and scientific study of the reservoir for the accumulation kinetics and the Qiongdongnan Basin oil and gas exploration and provide a scientific basis.Analysis and test data, and thin section results of the Qiongdongnan basin show that the high-temperature thermal fluid to promote the formation of carbonate cements to accelerate the transformation of clay minerals and organic matter thermal evolution; super-repressed system, carbonate cementation, quartz and secondary increase, slow clay mineral transformation and thermal evolution of organic matter, inhibit dissolution and mechanical compaction. Two diagenetic zones and 39 single-well diagenesis diagenetic stages of research and results of the Qiongdongnan basin show that the Qiongdongnan basin has a "strong east west weak" law of the regional diagenetic This is the ground temperature, pressure, the result of an integrated stratigraphic age. The lower the geothermal gradient, the greater the formation pressure, formation of new era of Vietnam, diagenesis weaker. In addition, the petrologic characteristics of diagenesis also affected the more coarse grain size, cementation weaker.The gas layer of Qiongdongnan basin are mainly distributed in the diagenetic stage A₂ sub-period of the medium-term corrosion phase and period of the late diagenetic stage B soluble phase. Although diagenesis stronger, but is favorable reservoir facies is still to contain gas. By inference, diagenesis diagenetic stage than in the A₂ sub-period of weaker reservoir properties will be better. The diagenetic phase analysis of Qiongdongnan basin showed that the yellow stream group is currently in early diagenetic stage - in the diagenetic stage A₂ sub-period, diagenesis is not strong, reservoir, cap rock development is conducive to accumulation. Meishan Group Qiongdongnan Basin in the western region into the diagenetic stage B period, diagenesis strong, growth relative to the late dissolution, and other areas are still in early diagenetic stage - in the diagenetic stage A period of reservoir compaction cementation in the early - morning, mid-soluble phase, material is better. Sanya group a (T52) Lingshui group a (T61) only a small part of the western region has entered the late phase cementation, diagenesis strong, most of the other regions are still good reservoir properties. Lingshui group of bis (T62) and the following strata, a large area in the western region late cementation facies, diagenesis strong, is not conducive to oil and gas accumulation, poor reservoir properties; but not too strong in other parts diagenesis, in the early diagenetic stage - in the diagenetic stage B period, if the development of favorable sedimentary facies, still has a certain reservoir properties.The history simulation results of Qiongdongnan basin show porosity, with a layer of digital reservoir porosity since ancient times, gradually reducing the flow of Qiongdongnan basin to thermal activation period in the huangliu, the reservoir porosity decay rate of speed.