Analysis on the Characteristics of littoral delta Sediment in Kalamkas Oil Field in the North Ustyurt Basin of Central Aisa ——An example from J2-C sand group

Previous studies suggest that sedimentary environment of J2-C sand group in Kalamkas Oil Field is marine delta plain. This study uses the data of core, well logging, laboratory analysis and other information，through study of... [ view full abstract ]

Previous studies suggest that sedimentary environment of J2-C sand group in Kalamkas Oil Field is marine delta plain. This study uses the data of core, well logging, laboratory analysis and other information，through study of the plane distribution of sand morphology, the combination of lithology and lithofacies，the color of mudstone and sandstone, the curves of Well logging and the sedimentary background，confirmed that sedimentary environment of J2-C sand group in Kalamkas Oil Field is front deposits in littoral delta，the study suggests that J2 - C sand group mainly develops sedimentary microfacies such as underwater distributary channel, mouth bar, distal bar, beach sand and so on.On the basis of a comprehensive study of core data、 well logging, combined with the high resolution sequence stratigraphic theory and techniques, this paper can divide the front deposits of J2-C sand group in marine delta in Kalamkas Oil Field into three types: ultra-short-term, short-term, medium-term three datum level cycle sequence. The sedimentary evolution of J2 - C is a complete set of medium-term cycle. Small layers of J2 - C_2 is a rising half cycle, because the overall sea level is rising, and the marine transgression of sedimentary environment, sand body is in retrogradational stratigraphic units. During maximum flooding period, sediments in the front of estuary dam frequently be washed by the waves and forms the beach sand deposits；small layers of J2 - C_1 is a drop half cycle, because the overall sea level is down, and the marine regression of sedimentary environment, sand body is in aggradational stratigraphic units 。 Finally ，this paper get the conclusion that the ultra-short-term cyclic sequence’s sedimentary sequence, tacking pattern and the distribution pattern of J2 - C sand group in Marine delta front provides a a basis for the further research of fine geology of J2 - C sand group.
Keyword：marine delta front facies，sedimentary micro-facies，the high resolution sequence stratigraphic，sedimentary cycle，tacking pattern