| Jing 51 block,which tectonic setting is situated on the southern tip of He Xiwu fault in Langfang-Gu’an depression, is a kind of condensate gas reservoir with low condensate oil. This gas storage was discovered by finding industrial gas flow when Jing51 well was tested in 1986. From December 1990 when it was put to use to the end of 2005, it has produced gas 0.8 ×108 cubic meter, oil 1.72×104 ton, water 195cubic meter, with 6.07MPa formation pressure. However Jing51 gas storage’s injection and production ability is lower in recent years not forming effective working gas production rate. The geological complexity and poor reservoir property of Jing51 gas storage need to be re-recognized in combination with the dynamic and static data of new wells. So that the working gas production could be raised. Basing on the assessment of effect on the storage capacity and injection-production ability, some measures for potential exploitation and suggestions will be offered in order to improve the working gas production rate. Basing on sequence stratigraphy,reservoir sedimentology, petroleum geology and combining with well, seismic, other geological data, fine structure and reservoir will be analyzed. The change laws of sequence stratigraphy and sedimentary microfacies will be analyzed and a fine geology model will be established. So that the characteristics, such as changed multilateral sand, strong reservoir heterogeneity, complex structural configuration, etc, will be analyzed accordingly.The core, seismic and well data have been analyzed to summarize the characters and recognition marks of each sequence boundary. The lower Es4 submember strata are dicided into a long cycle, three middle cycles and eleven short cycles by high resolution sequence stratigraphy. At the same time, the isochronous stratigraphic framework was established. Jing51 block is controlled by Ban Jiehe fault and complicated by the fault. Basing on three-dimensional seismic data and combining with the many three-dimensional interpretation method, the areal configurations and the distribution of roomage have been determined from macro to micro dimensions. Through the artificial fault interpretation detail by detail, Jing51 block is cut by NE fault rather than controlled by four faults forming trapezoidal horst block. The advantageous reservoir is predicted by the guide of phased theory. Basing on core observation and single well facies analysis, the NE channel sand of Jing51 well developed better. Combining seismic attribute technique with well constrained seismic inversion technology, effective sand bodies are identified with the analyzing of the inner development characteristics of the them. Through the research of sedimentary microfacies and the distribution law of the reservoir, it is determinated that there are delta plain and front subfacies in the lower Es4 submember of Jing51 gas storage. With the analysis of sequence stratum and sedimentary microfacies, the strata physical property of lower Es4 submember in Jing51 block has been evaluated including the distribution and the connectivity. The average porosity is 21.76% and the permeability is 78.23×10-3μm2. It is belongs to middle porosity and middle permeability reservoir. The heterogeneity degrees of surface, within and inner reservoirs are medium-serious. The distribution of interlayer is stable with 2-7 metre thick. The intercalations are scattered and reservoie types are mid-fine. The fine geological model of Jing51 block, established by phased modeling technology, includes reservoir three-dimensional fine structure model, the sedimentary facies model and physical property model. By these,the distribution diagram of flow unit is mapped including the thickness of each sand body, physical property. Suggestions for the optimized expansion goals and drilling location are put forward on the basis of these geological results. |
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