ASSESSMENT OF ENVIRONMENT OF DEPOSITION AND RESERVOIR QUALITY OF WELL TMG C-2 IN THE WESTERN NIGER DELTA

Abstract

This research revealed the reservoir quality and the nature of the depositional Environment of the study location in order to have an accurate field development and reservoir update. The objectives are to interpret logs of gamma ray, porosity and permeability, to determine depositional environments from the log motifs, identify reservoir sands, reservoir depth and thickness. Based on the log responses (signatures) of the well that shows the funnel and bell shapes, the major two sand bodies B and C studied in the well TMG-C2 were deposited in shallow marine environments. Sand B was deposited in Fluvial, shoreface and tidal environments. Fluvial environments occurred towards the western portion of the field capping a shoreface environment at the bottom of the well. Sand C was deposited in shoreface and tidal environment (shallow marine environment). Predominantly shoreface environment was capped with minor tidal channel. Tidal environment occurred at the bottom edge of the well capping shoreface. The average effective porosity ranges between 18.64% to 20.8% and permeability between 226.5 to 300.5 millidarcy, which shows that the sands have moderate to good reservoir quality. The facies and the reservoir quality model, show a good sand development with better porosity and permeability while area with poor sand development have lower reservoir quality. The effective porosity and permeability variation suggest possible changes in depositional processes such as change from laminar to turbulent flow and change in sediment source leading to variation in sorting and porosity.