Research On Sequence Stratigraphic And Sedimentary Facies Of Ordovician Penglaiba Formation In Tahe Area, Tarim Basin

Tahe area is located in the northern Tarim basin, and research purpose layer is the ordovician Penglaiba formation.According to the theory of sequence stratigraphy, seismic stratigraphy and sedimentology related theory as the instruction, logging, drilling and seismic data analysis, on the basis of single well sequence stratigraphic classification, synthetic seismogram calibration, and seismic data interpretation result compare, calibration, established the sequence stratigraphic framework in this district, and plane distribution of sedimentary facies Tahe. Summarizes the Tahe area section of sedimentary evolution characteristics of target layer.Penglaiba formation in the Tahe area can be divided into three level 4 sequence, respectively for Peng1 member, Peng2 member and Peng3 member. Peng2 member largest segment thickness. Identify the Penglaiba formation top bottom(T78, T80) and two level 4 sequence interface(PLB1, PLB2), it is summarized in the logging and seismic recognition characteristics in the Tahe area. According to each level 4 well logging and seismic reflection characteristics of sequence interface, clear each single well the position of the upper sequence interface, divided into single well sequence, on this basis, through the Tahe of the comparison of each single well, prepare well tie sequence stratigraphic profile established sequence stratigraphic framework in the Tahe area. With four sequence as a unit, the seismic stratigraphic framework, drawing exhibition layout, seismic stratigraphic thickness to determine the thickness of Penglaiba formation paragraphs formation development trend.Using Landmark software to level 4 sequence as a unit, paragraphs geometric structure seismic attribute extraction of Penglaiba formation, and optimization. With seismic attributes the graph is the basis, combined with the feature of paragraphs seismic layout, summarizes seismic facies distribution regularity, compared with drilling rock phase calibration, clear the geological significance of seismic facies represents, in turn, to perfect the seismic phase diagram, for subsequent plan provides the basis of the division of sedimentary facies.Research shows that the Tahe area Penglaiba formation ping and main development in beach subfacies. Primary identify a cloud ping ping and phase and grey set of microfacies, the beach and the phase is to identify sand beach and algal mat microfacies. According to the logging curve characteristics of different microfacies and seismic section the reflection characteristics of compiling the Penglaiba in quaternary sequence set of sedimentary facies distribution plan.Peng1 member to Peng2 member sedimentation period, water rising quickly, the sediment gray matter composition is rapidly increasing, grey set distribution change is wide, the beach development became more, good water circulation. Peng1 member to Peng3 member sedimentary period, water falls, the Peng3 member sections of grey set development than Peng1 member is less, the beach number decreased, but compared with peng, peng three bodies of water cycle, the sea is also higher. Overall, the sedimentary period of the Penglaiba formation in the Tahe area into a rising sea level.