Constrained Tomographic Static Correction Technique and Its Application in Complex Surface Area of Western China

Summary Western China’s surface and subsurface geological conditions are highly complex, with mountains, deserts, gobi, and loess plateaus dominating the landscape. In the central Junggar Basin, located at the intersection of deserts and gobi, the surface is mainly made up of sand dunes, gobi, saline-alkali land, and salt lakes. Surrounding the salt lakes are marsh areas. Due to the complexity of the surface conditions, the stability of the refractor layer is poor, and there are significant lateral and vertical variations in the velocity and thickness of low-velocity layers. As a result, static correction becomes the key challenge limiting oil and gas exploration in the complex surface regions of western China. This paper introduces a tomographic static correction method using control point constraints, combining micro-logging and near-offset first-arrival wave data to invert the low-velocity layer’s velocity. The inversion result serves as a constraint for refining the deceleration layer velocity model with micro-logging and medium-to-far-offset data. Additionally, the single-point static correction from micro-logging calibrates the tomographic correction, enhancing the accuracy of medium and long-wavelength static corrections. This method effectively eliminates low-amplitude structures, improving the precision of exploration targets, well placement, and overall exploration success.