Wei Depth Of 4 To Changdedong The Deep Layers Of Sequence Stratigraphy

Based on the data of seismic, well logging and well drilling, and guided by the theory ofsequence stratigraphy, this paper makes a sequence stratigraphic research in the area betweenWeishen 4 and eastern Changde. The target strata studied in this paper include HuoshilingFormation, Shahezi Formation, Yingcheng Formation and Denglouku Formation. Of thestudied target strata, this paper focuses the main research objective on the strata of DengloukuFormation, and also makes a groping research into the volcanic rock strata of the first segmentof Yingcheng Formation.On the basis of carefully analyzing and referring the research fruits, by means of thestudy on the seismic data, logging data and drilling data, the author divides the target stratainto four super-sequence. It is believed that the interface of each Formation of the deep stratain the studied area is a super-sequence boundary, and accordingly each Formation forms asuper-sequence. Meanwhile it is also deemed that the strata of Denglouku Formation instudied area developed Deng-2 Segment, Deng-3 Segment and Deng-4 Segment, andaccording to the characteristics of their boundaries, the strata of Denglouku Formation can befurther divided into three sequences. Based on the above cognitions, an isochronousstratigraphic framework of the deep strata in studied area is built by means of tracing andcorrelating the well-tie seismic sections and of combining the well data and seismic data.Through the analysis of the sequence controlling factors such as tectonic subsidence,climate change, supply of sediments and lake level change, this paper clarifies the influencesof the above various controlling factors on the development of sequences. It is deemed thatthe structural subsidence is the main factor of controlling the development of stratigraphicsequence during the faulting stage, while the climate change is the leading factor ofcontrolling the development of stratigraphic sequence during the depression period.On the premise of analyzing the evolution of sedimentary facies and sedimentaryenvironment for the strata of Denglouku Formation inside the isochronous stratigraphicframework, this paper predicts the distribution of reservoir for each segment of DengloukuFormation strata by using various geophysical attributes. As a result, it is concluded that thetypes of sedimentary facies of Denglouku Formation are dominated by fluvial facies, andmoreover, the fan-delta deposition can also seen in the stratum of Deng-2 Segment.Meanwhile, it is also pointed out that the channel sandbody of Denglouku Formation is themost type of reservoir in the studied area.According to the analysis and the study on the seismic, logging and drilling data of thevolcanic rocks from the first member of Yingcheng Formation, the author thinks thelithofacies types of the volcanic rocks in the studied region mainly include volcanic channelsfacies, eruptive facies, effusive eruption facies and volcanic-sedimentary rock facies. Based onthis cognition, the author analyzes the planar distribution features of volcanic lithofacies,predicts the porosity and permeability of the volcanic reservoir, and moreover, further predictsthe favorable reservoir developed area of the volcanic rocks in the studied region.At last, the favorable exploration zones in the studied area are pointed out by making anintegrative consideration of various ingredients such as source rocks, reservoir rocks, caprocks and traps.