Research Of Static Correction In Complex Mountainous Area

With the West China becoming the focal point of petroleum exploration, the static correction is always a key and basic step in seismic data processing. The existence of static correction problem affects the imaging of seismic reflected wave directly, which brings on the fake structure in seismic profile, and it makes the seismic interpretation more difficult. So the study of static correction has significant meaning.The complex mountainous region has heavy hypsography, and large vary of the Low Velocity Zone (LVZ) thickness and transverse velocity fluctuation, therefore the seismic travel times in different receiving points are delayed and the time-distance plots of reflected wave are variable, so that a big trouble is appeared in seismic data processing. The static correcting methods for extensive use in current production are all based on the Surface Consistency Hypothesis (SCH). But the geologic situation in the complex mountainous area is complicated, which is different with the SCH. So there is a biggish diversity of the static correcting values between the SCH and non-SCH. In this paper, the static correcting methods for current use are analyzed and discussed, based on the analysis of the surface characteristic of complex mountainous area. Then the principal problems of the static correcting methods based on SCH in the mountainous seismic exploration are analyzed and the difficulties to solve the static problem using static correcting methods based on non-SCH are raised. At the condition not meeting the SCH, using the models and theoretical derivation results, through the study of the various LVZ and structure models, the reasons of the static correcting values error between the actual static correction and traditional static correction are discussed, and the contrast and regularity are summed up. Then the reason of static correction error based on SCH and the relation between this reason and datum plane, shot-geophone distance, velocity of LVZ and base rock, LVZ thickness and depth of reflecting surface are discussed to improve the static correcting methods for current use or obtain a new affective method, as a reference for solving the static correction in complex area, especially in the west mountainous region.