Detailed Study Of Putaohua Layer In Maoxing Area

Pupaohua oil layer is one of the main producting layers in Maoxing area, and great breakthroughs have been made on it during the exploration process. It has great potential for further exploration. The thesis is guided by structural geology, petroleum geology, sedimentology and sequence stratigraphy, synthetically utlizing regional geological data, seismic data, logging data, core data as well as the research achievements of former researchers, and the thesis makes tectonic explanation. Besides, combined with the distribution features of sand bodies, oil-water distribution features and sedimentary facies distribution features, the thesis analyses the structural characteristics and predicts the effective zones of Pupaohua oil layer.The interpretation is based on high definition 3-D seismic data. With the help of section interpretation and fault interpretation, the thesis has completed the map of top structure of Putaohua oil layer. Through the analysis of 3-D seismic interpretaion, faults were well developed in the target area. However the faults are small in size, and most of them are south-north and east-west normal faults with steep fault plane. The morphologies of fault plane are basically plate and shovel, which formed the step faults and Y faults combination and graben and horst combination. The faults in the target area were formed mainly in three periods, in which most faults form dure Qingshankou depositional period, while faults develop in Yaojia and Nenjiang periods were relatively less.After synthetically utlizing core, logging and seismic data and analysing the sequence stratigraphy and sedimentary characteristics of Putaohua oil layer, the thesis then divides the Putaohua oil layer into three middle-term stratigraphic base level circles. The research uses middle-term stratigraphic base level circle as stratigraphic correlation unit to correlate formations, then sets up layer sequence stratigraphic framework of th research area. On the basis of stratigraphic division, the thesis analyses sedimentary characteristics of Putaohua oil layer, which is the delta front facies formed in transient regression of the whole transgression setting. During the depositional stage the lake expansed, and the water deepened, the research area deposited delta front subfacies and offshore-shallow lake subfacies, which is an integrated sequence with an entire fining-upward sequence. The delta front subfacies can be further divided into five microfacies:underwater distributary channel, mouth bar, sand sheet, underwater distributary between bay and underwater crevasse-splays.On the basis of the analysis of the accumulation conditions and reservoir types of the research area, the thesis uses the achievements of structural explanation and seismic oil and gas detective techonologies, uniting with sandbodies distribution features, sedimentary facies distribution features, oil-water distribution features and trap conditions, then studied Reservoiring Pattern in Maoxing area.