Diagenetic facies types and main controlling factors for the high quality reservoirs of the Kalazha Formation in the middle part of the southern margin of Junggar Basin
The southern margin of the Junggar Basin has the potential for oil and gas exploration,as evi-denced by the high flow of oil and gas in the Kalazha Formation reservoirs of its middle section.Howev-er,the factors responsible for the high-quality reservoirs are still unclear.By analyzing and testing methods such as thin section identification,scanning electron microscopy,and physical property testing,combined with drilling data such as logging data,the diagenetic process types,intensity,and evolution-ary characteristics of the Kalazha Formation reservoir in the middle section of the southern margin are analyzed.And the controlling factors of high-quality reservoirs are identified.The results show that Kalazha Formation mainly consists of lithic sandstone with low compositional maturity and medium structural maturity,with residual intergranular pores dominating the reservoir space.The reservoirs of the Kalazha Formation are controlled by sedimentary factors,diagenetic facies,and lithostatic pressure-temperature conditions,sedimentation is the foundation for the development of high-quality reservoirs,diagenesis is the key factor in reservoir modification.Four diagenetic facies can be identified and classi-fied within this section:medium-compaction and weak cementation,medium-compaction and medium cementation,medium-compaction and strong cementation,and strong-compaction and dense.The medi-um-compaction and weak cementation facies had the best physical properties and was the most favorable reservoir,it was mainly developed in the underwater distributary channels microfacies.The medium-compaction and medium cementation facies had the second-best physical properties and was mainly de-veloped in the mouth bars microfacies.On the other hand,the medium-compaction and strong cementa-tion and strong-compaction and dense facies had the worst physical properties and were non-reservoirs;anomalously high pressure and a sustained decrease in geothermal gradient effectively reduce the impact of compaction and are important factors in preserving reservoir properties.The results provide guidance for the future exploration and development in the study area.
diagenetic faciesdiagenesisreservoir controlling factorKalazha Formationsouthern margin of Junggar Basin
万方数据
维普
