The Research Of Statics Corrections And Its Application In The Sahara Desert

The proven oil reserves in North Africa are among the largest in the world, but the extent and costs of exploration are relatively low, which makes it an important strategic area for future oil and gas exploration and development. Increasing oil and gas exploration and development in this region can make a significant contribution to mitigate the relative lack of domestic oil and gas supply as well as to ensure China’s energy security. But most of the oil and gas resources in North Africa located in the Sahara Desert, whose complex surface conditions make statics a very serious problem which directly affects the quality of seismic profiles and the reliability of seismic interpretation. Therefore, strengthening statics research in Saharan Desert and choosing optimal static correction method to provide reliable static correction for seismic data processing are necessary.This paper first briefly introduces the impact of statics problems for seismic data processing, including statics classification, impact on seismic profile and identification. Then make a simple analysis of the causes of statics problems, followed by details on the basic principle of four most widely used statics methods(elevation statics, surface survey statics, refraction statics and tomostatics). The last part of this paper takes BK block as an example to demonstrate the effectiveness of the above statics methods.In practical applications of statics methods, we first interpret the uphole survey data, and based on that establish the initial near surface velocity model. Then pick the first breaks using a combination of band pass filter and gain control, neural networks first break picking and smoothing method. The practical application in BK block shows the effectiveness of the combination of the above three methods, which can improve the first break picking accuracy and only involves little human intervention, thus basically solved the first break picking problem in BK block which involves massive data with low SNR. This first break picking method has some theoretical and practical value. After first break picking, we sequentially applied elevation statics, uphole data statics, refraction statics, refraction statics constrained by uphole data and tomostatics. After a comprehensive comparative analysis of effectiveness of the above five statics methods, the result shows(by effectiveness): elevation statics < uphole data statics < refraction statics < refraction statics constrained by uphole data, and refraction statics constrained by uphole data is better than tomostatics. Refraction statics constrained by uphole data method is the optimal statics method for solving statics problem in this region, having a certain reference value for statics problem solving in the Sahara Desert.