The Detailed Study Of The Sequence Stratigraphy And The Reservoir Of The Changxing Formation In The Northeast Of The Sichuan Basin

In this paper , under the guidance of the Sequence Stratigraphy,Seismic Stratigraphy,Sedimentology and Carbonate Reservoir Geology, this thesis has taken the strata of Permian,Changxing formation in Northeast of SiChuan Basin as the main targets of the study and has carried out detailed research work on sequence stratigrapy,sedimentary faces and reservoir characteristics by taking the full advantage of files about core ,well drilling,logging and testing etc.Based on the former study, by referring to the geological survey reports, observation of the outcrops, and the data of the wells, and so on, it is known that the sedimentary framework of the Changxing Foramation take on"two platform-two trough", the Kaijiang-Liangping trough links southwardly to the ocean, the platform in the east of which is isolated.Based on the knowledge of the sedimentary framework, using the principle and methods of the sequence stratigraphy, by means of the analysis of the lithology- sedimentary in the outcrops, the core, and the well-logging, the Changxing Formation in the northeast of the Sichuan Basin is divided into 2 3rd-order sequences, 8 4th-order sequences, and 15 5th-order sequences. Furthermore, the frameworks of the 3rd-order sequence and the high-frequency sequence are built for the study area and the Puguang Oilfield.By integrating the outcome of the sequence stratigraphic study in the wells, and the research on the seismic facies in the Puguang area and Yuanba area, which make it clearly that the evolution disciplinarian of reef and shoal in the frameworks of the sequence is different between platform margin and platform inner.By means of the modern analytical technology of rock and mineral, by integrating the study of the lithology and geochemistry, it is revealed that the reservoir of the Changxing Formation in the northeast of the Sichuan Basin suffered many kinds of the diagenesis, the sedimentary compaction,the cementation, the dissolution, and the dolomitization played an important role in the formation and quality melioration of the reservoir. the syngenesis dissolution by the meteoric water is the chief formation mechanism of the reservoir, the burial dissolution react greatly on the scale-up of reservoir and the melioration of reservoir quality, and the dolomitization can promote the quality of the reservoir greatly.Through the research of the reservoir diagenesis, by recognizing the reservoir in well section and contrasting the reservoir sections between the wells and by integrating the outcome of the sequence stratigraphic study in the wells, it is known that the reservoirs of the Changxing Formation mainly distributes in the platform margin and its distribution was controlled by the reef and tidal flat facies,and that the reservoirs of the Changxing Formation occur mainly in the HST of the upper sequence, singularly in the HST of the lower sequence and the TST of both sequence.By integrating the analysis of the physical property of the reservoir and the study of the reservoir parameters by the well-logging, the controlling factor of quality of reservoir has been discussed on the aspects of the changing disciplinarian of the porosity and permeability of the reservoir which distribute in different types of rock,in different sedmentary facies and in different sequence.At the last,the quality of reservoir in some important area such as Puguang area,Yuanba area and so on,have