| Anyue gas field is tectonically located in the middle part of the Chuanzhong~Gurung inclined and gentle tectonic belt, which is of gentle structure and theaccumulative area of many sediment origins. For its complex reservoir spreading,complicated controlling factors, strong heterogeneity, unclear enrichment laws of gasand distribution of high-productivity wells in the study area, it is necessary to studyXu2gas reservoir in the region to get comprehensive evaluation of reservoir, whichhas provided necessary geological basis for exploration and further development ofXujiahe formation in study area. Using the data core, logging and production testing,adopting multi-disciplinary theory and technology, this paper has carried on thecomprehensive research, which has made the following understanding:（1）On the basis of previous stratigraphic classification and correlation, withlogging curve being given priority to, taking An8and Tong9as standard well, incombination with core data, applying the key bed and auxiliary marker formation tocontrol layer, this paper has done great work on division and correlation of Xu2gasreservoir.（2）According to the well and seismic data, combining with regional tectonicconditions and the predecessors’ explanation about earthquake, this paper studied thestructure characteristics of research area，which is a gentle monoclinic from south tonorth and develop some palaeohighs and a few small thrust faults.（3）The comprehensive analysis of core facies-log facies and combining thedetailed description of cores and indoor observations and studies of large numbers ofcore slices indicates that the research region’s reservoir in member2of Xujiahe aremainly developed from the underwater distributary channel and mouth bar sandbodiesof the fan-deltaic front, and the research region sedimentary facies model is also constructed. Based on the study of Sedimentary microfacies characteristics, thesandbody distribution characters was studied.（4）The rock types in the reservoir are mainly debris-feldspar and feldspardebris sandstone. The reservoir type are fracture-pore type，and the types of porosityare mainly inter-partical and dissolution pores. The pore throats are mainly of lamellarthroat and necking throat, the reservoir have low porosity, low permeability andultra-low porosity, ultra-low permeability and poor physical properties, whichcontrolled by sedimentation and diagenesis. Subsea river channel and mouth bar sandbody are the mainly distributed facies of reservoir. The constructive diagenesis aredissolution and early rim chlorite cementation while destructive diageneses includecementation and compaction etc.（5） By means of respective parameters, the reservoir is classified into4categories: class one reservoir (better), class two reservoir (good), class threereservoir (bad) and class four reservoir (non-reservoir). Based on the study for theplanar distribution characters of effective sand body, the author classified andevaluated the good reservoir of the research region. The main development types inthe research region are class two reservoir and class three reservoir, but class onereservoir scatters widely. Based on the reservoir classification,combineing witheffective thickness of reservoir and distribution characteristics of gas well, this paperhave done some estimation and prognosticated the excellent gas prone area of thehorizon-talreservoir for the secondary exploration in member2of Xujiahe formationin Anyue gas field. |
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