Analysis of borehole factors in synthetic seismogram building and countermeasures

Precise Time-Dpeth relationship derived from synthetic seismogram making is the base of sequence stratigraphic correlation and reservior inversion. Sonic and density logs used for seismogram making are subjected to the influence of factors such as borehole conditions, presence of hydrocarbon, mud invasion, degree of such invasion etc. Caliper log and deep-middle-shallow resistivity logs are proposed to monitor the impact of such factors and necessary corrections should be made before sonic and density logs are used in building synthetics. When a pseudo-acoustic log is reconstructed from a resistivity curve, investigation depths of acoustic and resistivity logs must match each other. Finally when synthetic seismograms are successfully built, the time-depth relationships obtained can help us to check whether the adverse influences of the various factors have been completely eliminated, so as to ensures precise reservoir inversion and target prediction.