Key Technology Application Research On Shale Gas Seismic Exploration In Wuxi Area, Sichuan Basin

Shale gas is a natural gas extracted from the shale,and is an important unconventional natural gas resource.Shale gas has become a research hotspot in the field of unconventional oil and gas resources in recent years.Preliminary investigation and evaluation show that the favorable area of shale gas exploration in China is about 88×104km2,and the resource of technology exploitation is about 25×1012m3,which has a very broad prospect.The Paleozoic shale in the Sichuan basin is a highly complex,highly difficult and high-risk exploration field with rich source rocks and rich natural gas resources.The evaluation results of sedimentary facies and actual drilling results of well Wuxi 2 show that the lower Paleozoic shale gas reservoir in Wuxi block of Sichuan basin has favorable reservoir forming conditions and has great potential for exploration and development.Because shale gas reservoir with high natural gamma,physical properties of low speed,high hydrogen quantity,low density and high resistivity of the earth,and the Wuxi regional geological and tectonic evolution is very complex,resulting in shale gas reservoir geological conditions are very complicated,difficult data processing.Generally speaking,in the aspect of seismic acquisition,high signal-to-noise ratio seismic data acquisition technology requires complex mountainous exploration,so as to improve the quality of seismic data;in seismic processing,seismic inversion processing and considering the influence of seismic anisotropy is a hot issue,is the key to further improve the quality of seismic data.Domestic research on shale gas has made some achievements,but it is still in the exploratory stage.Especially,how to use seismic methods to study shale gas has not formed a complete technical thinking and method.Based on the above reasons,the seismic data acquisition and processing of shale gas comprehensive research,summarize the results of previous acquisition and processing aspects,give full play to existing technical potential,through the combination of different methods and procedures to solve the Wuxi area of the Sichuan basin shale gas data acquisition and processing method.Shale gas from the original data based on the analysis of characteristics,based on the common reflection point(CRP)observation design,tomography static correction,surface wide line of prestack noise suppression and high fidelity imaging processing technology,analysis and use of various software and the advantages of multi algorithm,iterative combination of various processes,combined with the acquisition and explain the staff,the wide line observation collection,static correction,denoising and imaging effect is the best,the complex area of shale gas data acquisition and processing,seismic data for other shale gas collection provides important reference and treatment.In this paper,we collect and process the shale gas 2D seismic data in Wuxi area,and summarize a set of data acquisition and processing process suitable for shale gas in Wuxi area.Through the analysis and evaluation of various professionals and experts,and the shallow layer of Upper Ordovician five peak formation and Lower Silurian Longmaxi formation,lower Cambrian shuijingtuo formation of two sets of marine black shale reflection events significantly,smooth and continuous,SNR was significantly increased and imaging.Made a very good effect.At the same time,the earth's abdomen structure and fault distribution in the shale gas exploration area in Wuxi area have also been fully explained.Finally,after three years of study,through the test of shale gas exploration projects in Wuxi area,initially formed a set of complex structure,low SNR,shale gas seismic data acquisition and processing technology and process of imaging difficult,but also the process and ideas applied to the unconventional oil and gas seismic data the project is expected to achieve better results.