Research On Seismic Sedimentology In Weibei Sag

Weibei sag is a small continental fault basin under the control of the slipping ofthe Tanlu fault belt, which is located in the northwest of the Changwei depression.The north of Weibei sag is the Changbei bulge. They are separated by theGucheng-Weihekou fault. Ludong uplift is to the east of the sag, which is separated bythe Changyi-Dadian fault. To the west is the Changbei uplift and Houzhen sag, whichis aparted by the Tangwu-Gegou fault. The sag is a Subprime tectonic units with areaof about880Square Kilometers.According to the regional characteristics and the characteristics of sedimentaryevolution the Sag can be divided into four of its subprime tectonic units: the northslope belt, the western Wacheng fault terrace belt, the eastern Zaohu faulted nose beltand south ramp zone. Under the control function of the Tulu fault, the internalstructure of the Sag is complicated. The main fracture performance for NW, NE andEW, distributed mainly in the western city of the western Wacheng fault terrace beltand the eastern Zaohu faulted nose belt. The sag is controlled by the Tangwu-Gegoufracture and Changyi-Dadian fracture in the latitudinal direction, with theperformance of dustpan form of "high in the south and north down"Basin began in late Mesozoic era, to the ancient near the hole is main sedimentaryKongdian formation and Shahejie formation. Later because Tanlu fault activity in thebasin, and the overall uplift, the upper part of Shahejie formation geodynamic,keeping only Es₄formation. From then on the sag continue descending and continuereceiving the sedimentary of Guantao Group and Minghuazhen Fm.Through the comprehensive analysis of tectonic evolution law and depositionalhistory of the Weibei sag during Kongdian formation, we come to a conclusion: it’sthe crack of trapped period for the basin in Ek3, with the influence of westernGucheng-Wehekou fracture and eastern Changyi-Dadian fracture, there are mainlymagmatic product.Because lava high temperature, low viscosity, easy to flow, thatcovered the entire area of magmatic rocks, the three sections of the main hole for underwater intermittent eruption and the overflow deposits. Ek2is the fault stage ofthe sag. During this period the overall decline faster, mainly for the Lacustrine Facies.And because of the the humid climate, mainly for the reduction of the sedimentaryconditions products. Ek1is the depression stage, the tectonic effects are relativelyabate, settlement slowly, and the water is shallow, by damp climate more rain becamehot and dry, the sediment mainly for the purple and purple.Through the analysis of the well-log information and log information of98wells inthe project, we make every single well mouth of single well sedimentary facies,mainly for the fan delta, lakes phase, a nearshore subaqueous fan, braided delta fivesedimentary facies. Then use sound waves and density logging on synthetic seismicrecords, through the horizon calibration, will be the single well stratified informationto pitch in seismic data. Use of3d seismic data of seismic facies analysis, andcombined with the single well sedimentary facies analysis result, in the study area tostore all the holes of period for the research of sedimentary facies, and draw thesedimentary phase plane distribution. In combination with the characteristics ofstructural evolution of all times, painted the deposition of patterning.