Sedimentary Stratigraphic Sequence And Prediction For Favorable Areas Of Silurian In Tazhong Area, Tarim Basin

The oil-bearing properties of the Tarim Basin have attracted more and more attention of Chinese Petroleum Industry, especially exploration of the TaZhong Area which is the most important part of the Tarim basin. Silurian reservoir is one of the key stratum series in the Basin. However, the large majority of the traps here are subtle such as lithologic, stratigraphic and structural-lithologic. Therefore, it is necessary to make research into Silurian characteristic.The latest theory and method of sequence stratigraphy, sedimentology, reservoir geology are adopted in this thesis. By using the data of core information, log data, seismic data,the framework of sequence strata and sedimentary facies in the area of Tazhong in Tarim are analyzed and studied deeply, also the favorable reservoir's features are researched primarily. The results can be described as follows:1. Sequence stratigraphic framework of Silurian in Tazhong Area is marked clearly. According to the data of seismic, well logging, cores and the principles of well correlation, the Silurian stratum is divided into three third-order sequences, six system tract and fivç–¤?urth-order sequences are distinguished.2. The sedimentary facies features, and sedimentary system distribution features of Silurian in Tazhong Area are definiteness. The Silurian has the following characteristics: dominated by barrier-free clastic tidal facies, tidal facies are divided into three subfacies: supratidal zone, intertidal zone and subtidal zone. The intertidal zone are recognized by intertidal sand flat, sand-mud-mixed flat, and intertidal mud flat microfacies.3. Silurian reservoir is mainly composed of litharenite. In the Silurian, compaction is relatively strong, the main style of grain-to-grain contact is lineal contact. The cementation with carbonate cement, siliceous cement, kaolinite cement is well-developed. Dissolution is generally weak. Compaction and cementation have had a significant impact on reservoir quality, also reservoir quality is controlled by grade and composition of the clastic rock.4. Based on the integrated study of the sequence, sedimentary facies and reservoir's features in the Tazhong area, the advantageous targets for petroleum exploration are given.