Complex Surface Static Correction Applied Research

The Tarim Kuqa foreland basin is rich in oil and gas resources, and it is the key area ofTarim in oil and natural gas exploration for a long time. After the consistent seismicexploration research in the last several years, we attained remarkable achievements includingthe seismic data quality improvement and tectonic framework of Keshen structural area withbillions gas resources. Keshen structural area has a wide range of surface types includingmountains, Gobi, farmland, villages, rivers and so on, which are very complicated in surfacelayer geological conditions. In the past, we carried out surface layer surveies using smallrefraction and static correction method base on surface layer model, which led to severeproblems in static correction and also affect the imaging results of the seismic profiles,restricting the thorough exploration.There are many methods for near-surface investigation. Micro-logging is a mostlyapplied method, and sometimes shallow refraction is also used. Usually, the density of controlpoints in near-surface investigation is constant according to experience, but it will lead toscarcity and excess for certain areas which is surely a waste of resource, and has bad influenceon the accuracy of near-surface modeling. Interpolation is commonly used for near-surfacemodeling. With explanation result of control point, the modeling is carried out within the line.Since only in-line direction is interpolated, and only result from control point is taken intoconsideration, other factors like first-arrival, tomography, are not used. We have to correctthese to improve the quality of surface modeling and statics-correction.This thesis embarked on the regular of geological variation for near-surface. Thefeasibility of near-surface survey methodology is analyzed and the best one is chosen toensure the accuracy of the model. Depending on the lithologic characteristics of the work area,the staging areas are divided for different modeling methods and the key and difficult pointsof the work of near-surface survey are carried out and modeled. Scientific methods are used tohelp to ensure the reasonable density of near-surface survey. Many kinds of geologicalinformation are integrated and the surface modeling method is developed with arrivalconstraints.3D modeling method is used to establish3D surface model with high accuracy.On this basis, comprehensive statics-correction method is used to improve the imaging accuracy of the profiles. This study solved the problem including the distribution of thenear-surface survey control points in mountain area, the modeling methods for regolithhuge-thick near-surface and choosing the optimal method from the different surfacestatic-correction methods. For the complex mountainous, this thesis formed correspondingmethod including near-surface survey, modeling and statics-correction, preparing forfollowing mountain exploration.