Research On Integrated Seismic Recognition Methods Of Deep Rift Structure In Gulong Area

The area of gulong faulted depression is8900km2.Natural gas resources are2429×108m3.It possesses a large gas resources conditions,and exploration potential isbig.Mid-shallow acquisition of seismic data in the deep shows the weak reflectedenergy,low Signal-to-Noise,and inadequate deep offset distance,which causes deepimaging difficult,leading to a unclear understanding of the basement structural andstratigraphic distribution characteristics;There is no basis on reservoir prediction ofgulong faulted depression.Deep buried reservoirs, complex lithology,low seismicresolution,less drilling data, the difficult prediction of favorable volcanic reservoirsand gas reservoir result in unclarity of favorable exploration zones and series ofstrata;Shahezi Formation is deeply buried and lack of drilling data,leading to a unclearunderstanding of the distribution of source rocks.After nearly three years of continuingresearch,we achieve some results of deep rift structure of changjiaweizi-gaotaizi workarea.（1）Changjiaweizi has favorable conditions of gas accumulation.Accumulationis mainly controlled by gas generating intensity, fracture, reservoir and structure;（2）Subtraction multiple suppression and advantages offset the weightedsuperposition improve the image quality of the basal reflection of research district ofgulong faulted depression;（3）The project explores the small offset deep imaging technology.It improvesthe quality of deep reflection of the work area in changjiaweizi-gaotaizi andpunan-xinzhao;Different offset imaging test on the two-dimensional seismic dataanalyzes that large-offset data is conducive to deep volcanic imaging;（4）The project explores the comprehensive fault-depression structure identification methods,such as imaging, inversion,gravity and magnetic data.Studiessuggest that the depth of faulted basement is large in well Gu1and stratigraphicthickness is big in rift epoch.Well Gu1is the deep natural gas exploration area in thenext step;（5）Prestack elastic parameter inversion method has a lot of great value in theexploration of lithologic reservoirs and subtle reservoirs.This method has highcomputational efficiency, simultaneous inversion of elastic parameters and a strongpracticability.