Seismic exploration in desert area of Tarim basin

Abstract

Tarim basin is located in northwestern China and is the one of main basins with abundant oil and gas. Due to existence of thick low velocity-reducing layer in desert area of the basin, it is very difficult to gain good seismic datum. The main problem in collecting data include: 1) Bad shot and receiving situation cause very low signalto- noise ratio and low resolution; 2) Undulant hypsography make complicated static correction; 3) Surface deep sand stratum induce absorption and attenuation of seismic wave. To finish the geologic target, we introduce following methods: 1) Enhancing analysis and investigation of surface structure to perfect surface structure model which will serve for choosing better shot points; 2) Exploding under water table to guarantee enough shot energy, and embed the geophone to get the better receiving condition; 3) Selecting bigger diameter of dynamite to form better point explosive response; 4) Surveying the noise wave to design the best acquisition parameters; 5) Calculating better static correction by surface refraction tomography; 6) Applying the compensation of absorbed energy of seismic wave to gain better information. After these methods are introduced, the signal-to-noise ratio and resolution of main prospecting objective in collecting seismic datum are improved obviously and obtain correct geologic interpretation.