Research And Application Of Fine Calibration With Well And Seismic Data

In actual seismic exploration,seismic calibration has an important effect on the accuracy of filed velocity modeling and the seismic interpretation results.Usually,the time-depth relationship of VSP data is considered to be the most accurate,and using VSP data for joint seismic calibration can improve the accuracy of calibration results.When there are large dip angles in the subterranean strata,there is a difference of time-depth relation between the VSP data and the actual case,directly using this time-to-depth relationship for seismic calibration will produce errors.This article conducts in-depth research,focusing on the time-depth relationship of zero-bias VSP in inclined formations,fine matching of well-seismic data,and accurate inversion of seismic layer velocities,improves the modeling accuracy of the average velocity field based on the fine calibration of wells and lays a foundation for the fine structural interpretation of the work area.In this paper,the time-depth relationship of VSP in inclined strata is studied.The correction methods of tilt angle are given for simple strata and complex strata,respectively,and the superposition recording of zero offset VSP corridors for slant strata is realized,which improves the accuracy of time-depth relationship in VSP data.On the basis of velocity dispersion and scale matching of logging data,the precise calibration of well seismic data is realized by dynamic time warping,and the matching accuracy of log synthetic record and well by-pass is improved.On the basis of well seismic data combined with fine calibration,VSP travel time and representative seismic axis travel as control points respectively,and accurate logging velocity is obtained under seismic scale.The mapping relation between the velocity of the seismic layer and the velocity of the seismic layer is established as the velocity of the target,and the matching factor of the two velocity matching factors is interpolated to establish the matching factor field of the whole area,so as to provide technical support for obtaining the three-dimensional precise velocity field of the work area.Based on the research background of a sea area,the fine calibration of 242 wells is carried out in the18381km² exploration area.On the basis of well seismic combined fine calibration,the layer interpretation,section fracture and plane fracture interpretation of the target layer 250m*250m grid density are realized.7 pieces of first grade fracture of section fracture,more than 110 pieces of two grade fracture and 4000 secondary faults are established,and well seismic combined with fine velocity field is established.The three-dimensional velocity field with strong transverse continuity and higher precision is obtained.On this basis,the depth domain structure map of the exploration area is obtained by time depth conversion,and the error on the well point is obtained.Obviously,the T₀ layer 190.3km² trap has been obtained,which provides more accurate structural information for oil and gas exploration in the sea area,and is of great practical significance to the design of the subsequent oil and gas exploration well.