Petrophysical Evaluation and 3D Geostatistical Reservoir Modeling of Okati Field for Development, Shallow Offshore, Niger Delta

摘要

In order to ensure optimal hydrocarbon recovery and sustained production, it is imperative to carry out reservoir characterization and modeling, that is aimed at facilitating a holistic field evaluation geared towards effective development strategies and optimal field performance. Okati field located on the continental shelf in water depths of 210-250 feet in shallow Offshore, Eastern Niger Delta, was investigated to determine the petrophysical properties of the reservoirs, and model the 3D spatial distribution of the properties of H3 reservoir using geostatistical techniques. Well logs, core, and pressure data were analyzed and interpreted in order to assess the hydrocarbon potential of these reservoirs. The structural 3D grid surface and models were generated with inputs of the interpreted petrophysical parameters using Petrel and Interactive Petrophysics. These parameters were upscaled to provide discrete facies and continuous properties. The reservoirs (H1, H2, H3, H4, H5 and H6) have good effective porosities that range from 12 to 27%, high net-to-gross values that range from 55 to 89%. It was deduced that, the field has very good hydrocarbons saturation (range from 55 to 88%). The porosity and permeability models built indicate that, wells 2 and 3 have better storage and flow capacities relative to well 1. The fluid contact and water saturation models however, show that, well 3 is close to the oil-water-contact and has high water saturation which makes it a poor candidate for completions to avoid early water breakthrough. The volumetric assessment indicates 38.4MMBO of STOOIP. It is concluded that, apart from H1, all the other five reservoirs have good petrophysical properties, hence, from a petrophysical standpoint; they are prospective candidates for future completions and development.