The Research Of Seismic Geomorphology In Tianchi Area Of The Ordos Basin

The geomorphology and cave of Palaeokarst’s identification and prediction are alwaysthe hot and difficult research of carbonates. Marine carbonates weathering crust of the OrdosBasin’s Ordovician has the predominant geological conditions of the study of the Palaeokarstand its controlling factors.In this paper,4main aspects of the results obtained by sdudying carbonate rockpalaeokarst seismic geomorphology deeply, identifying and characterizing the geomorphologicunits of the Ordovician palaeokarst in Tianchi of the Ordos Basin and investigating the maincontrolling factorsof palaeokarst based on3D seismic data, core and logging data,identification of the drilling and logging of palaeokarst geomorphologic units, fine seismicinterpretation, seismic forward modeling and a variety of analysis of seismic attributes:(1)Carbonate rocks mainly developed ancient rivers, karst pits, tower karst, caves, canyons, hillsand other geomorphic units and a model of the Ordovician carbonate rocks palaeokarstgeomorphology is establishied in the studying area;(2) Logging respons of the Ordovicianpalaeokarst in the studying area are: expansion of caliper, increasing or jumping of acoustictime, reducing of GR, SP and DEN dropping of LLD and ILs;(3) By studying the forwardmodeling, respons of seismic waves of carbonate rocks palaeokarst in the study area can befound are: weak amplitude and weak continuous reflection in the top of karst,some reflection,messy reflection, strong amplitude, weak coherent, strong discontinuity and low speed in thecave;(4) the main controlling factors of the formation of carbonate rock palaeokarst cave inthe study area are favorable hiatus, Palaeotopography, ancient water system, lithology andstructural conditions factors.It is expected to promote the understanding of developed and distribution law ofcarbonate palaeokarst, and provide geological basis.for lateral prediction of Ordovicianpalaeokarst reservoir through the study of seismic geomorphology of the Ordovician carbonateof the Tianchi in the Western Ordos Basin’s...