Study On Reservoir Sedimentary Facies Of The Kalaza Formation Of Upper Jurassic And Cretaceous In Honglian-Shengbei Region

Aimed at the study on the Kalaza Formation of Upper Jurassic and Cretaceous inHonglian-Shengbei region, the paper analyzed the drilling information including rockcores, mud-logging and well-logging etc. The framework and evolution of thedepositional environment in the study area have been revealed using depositional andwell-logging principles, the types and units of depositional system established, thefavorable facies zones and the exploration targets pointed out as well.The study strata consist of the continental clastic rocks, and have fivedepositional systems including alluvial fan, fan delta, fluvial facies, braided fluvialdelta and lake facies. In Kalaza Formation (J₃k), the alluvial fan facies are developedin the Shengbei region, the braided fluvial delta developed in the Lianmuqin region,the fan delta facies developed in the Hongnan region. In Sanshilidadun Formation(K₁s), the alluvial fan depositional system developed in the Shengbei region, thebraided river depositional system developed in the Lianmuqin region, the meanderingriver depositional system developed in the Hongnan region. In ShengjinkouFormation (K₁sh), the ephemeral lake facies developed in the region, and the shorelake facies chiefly developed in Lianmuqin Formation (K₁l), besides the meanderingfacies developed at the No. 3 and 4 tectonic belts of Shengbei region.Reservoir rocks are mainly developed in the end alluvial fan, fan delta, fluvialfacies and braided fluvial delta, which are high-quality reservoirs and widelydistributed. In J₃k, at the Lianmuqin region, southern sand bodies are better than thoseof the north, and the west part is better than the east part. Sand bodies of the Honglianregion are superior to that of the Lianmuqin region, but its indication of oil and gas isinferior to that of the Lianmuqin region. At the Shengbei region, sand bodies of thenorth are better than that of the south, and the east part is better than the west, and theindication of oil and gas is mainly concentrated at the No. 3 and 4 tectonic belts. InK1s, sand bodies developed in three sub-areas, but hydrocarbon shows mainly in theHonglian region, and rarely in the Shengbei region. As a whole, the best sand bodiesdeveloped in the Honglian region, and the second in Lianmuqin, and the third inShengbei. In K1l, point bar of fluvial facies developed at the No. 3 and 4 tectonic beltsof Shengbei region, which showing great indication of oil and gas.According the distribution of sedimentary facies and sand bodies, the authorpredicts the distribution of the favorable facies belts, and points out that delta frontsub-facies of braided river, channel sand and point bar of fluvial facies, sheet-flooddeposit belts of alluvial fan are the best sedimentary facies belts for oil & gasaccumulation.