A RE‐APPRAISAL OF THE APPLICATION OF ROCK‐EVAL PYROLYSIS TO SOURCE ROCK STUDIES IN THE NIGER DELTA

Thirty four shale samples from the Tertiary Agbada Formation were analysed for TOC and Rock‐Eval pyrolysis parameters in order to evaluate the effect of oil‐based mud contamination on source‐rock characterization. The samples were obtained from five wells in the offshore Niger Delta over a depth range of 5,460ft to 11,580ft. The results indicated that the raw (unextracted) samples were dominated by Type III kerogen. However, after extraction, both Types II/III and III kerogen were identified, consistent with previous studies. These results demonstrate that it is essential that shale samples should be extracted prior to TOC and Rock‐Eval pyrolysis for accurate source‐rock evaluation.