Fan Dalta Sedimentary Characteristics And Reservoir Evaluation Of Bei301 Block In Halar Basin

Bei 301 Block was located in Huhe-2 structure, Surennuoer structural zone, Beier sag, Hailar Basin. This block was developed above an uplift of the basement. During the deposition of Nantun Formation, this area was presented as fault-subsidence, where NE faults were active. The provenance of the 2nd Member of Nantun Formation was mainly come from the Qagan uplift in the west, with sufficient supplement, leading fan-delta deposited rapidly. After 14 year's exploration and development, this block has entered into the stage of infilled well pattern development, where conflicts of rapidly rise in aqueous and rapidly decline in production emerged out gradually. In order to improve the development of the study area, on the basis of core observation and description, types of sedimentary facies and distribution features of the 2nd Member of Nantun Formation has been studied in this thesis by combining well logging and seismic data. And then, combined with production performance of the oil field, reservoir evaluation has been conducted to predict the distribution of favorable reservoir and oil/gas, providing foundations for the comprehensive adjustment of the oilfield.Several conclusions have been gained in this thesis:I. On the basis of study on sequence stratigraphy of former scholar, stratigraphic demarcation of oil/water wells in the study area has been inspected one by one by using well drilling, well logging and seismic data. Adjustment for stratigraphic demarcation in wells that weren't suitable has been made. A reasonable isochronal sequence stratigraphic framework has been established, providing basis for the sturdy of depositional system.II. Based on integrated study of regional geology and core observation, sedimentary facies of this study area was confirmed as fan-delta of prograded-type. Eight types of sedimentary micro-facies have been identified. They are Braided bar, braided channel, mouth bar, overbank sand, beach sand, sheet sand, flooding shale and shallow lacustrine shale.III. A new depositional parameter, Percentage of predominating sand, has been submitted in the first time during the study of sedimentary micro-facies. Combined with the thickness of sandstone, the distribution of sedimentary micro-facies in Bei 301 block have been described, which broken the traditional analysis route of sedimentary facies and provided a more reasonable relation between depositional parameters and distribution of sedimentary facies. Density of preponderant sand can reflect the depositional environment and types of sedimentary micro-facies objectively, which can play a controlling role of division of facies belts, especially in the situation where the affection of sand thickness map towards sedimentary facies (micro-facies) was weak.IV. A method that combined with dynamics and statics for reservoir continuity and connectedness study has been established to predict favorable sand-bodies of target horizons. Types of sedimentary micro-facies, structural location, physical properties and etc were the main factors in static reservoir evaluation, while different locations of pay zones, situation of oil/water production in different time were the main factors in dynamic reservoir evaluation. And then, prediction for favorable sand-bodies among wells has been conducted by combining dynamic and static data. Based on the study of sedimentary characteristic after in-filled and relationship between oil and water, five favorable areas have been submitted for future adjustment.Integrated above research results, 9 wells have been newly deployed, where oil has been gained in 8 wells and commercial oil flow has been gained in 5 wells.