Well-to-seismic tie of Amangihydrocarbon field of the Niger Delta of Nigeria

Abstract

In this paper we performed seismic-to-well tie and wavelet extraction that would subsequently be used for inversion. We took cognizance of the key factors that make for accurate well-to-seismic tie and ensured that the borehole seismic and the surface seismic at the borehole trajectory look as similar as possible. This was possible through quality control of the well log and seismic data, timing and log calibration, well tie location, seismic bandwidth and signal-to-noise ratio and the use of well tie diagnostics that underlie a successful close well tie. The data were processed to zero phase and the dominant loop in the resulting seismic wavelet was delayed and corresponds to an increase in P-impedance. The delay on the seismic data was removed and the wavelet converted to zero phase. The ties are generally good and accurate. With this success we were able to relate directly the horizons picked on the 3D anisotropic seismic data to the well logs. We estimated the wavelets needed to invert the seismic data to impedance and rock property indicators.This was achieved by careful simultaneous analysis of the results at the wells to derive one average wavelet each for the near, mid and far angle stacks.