Integration of Geology and Petrophysics for the Characterisation of a Sandstone Reservoir

Abstract

Abstracts Poor reservoir characterization poses unique problems for exploration and production when the complex variation in lithology and diagenetic history that result in heterogeneous reservoir quality are not addressed. Optimizing field development requires a level of reservoir description that adequately defines vertical and lateral variations in reservoir quality. An accurate reservoir description is a key to improved field development planning and management. This study shows how integrating petrophysics and geology helps in reservoir characterization. This is illustrated with data from Niger Delta reservoir sandstone. Introduction One of the most challenging activities in reservoir modelling is the integration of all available data. Ability to integrate all available data improves understanding of reservoir characterization in a field development project2. Subtle characteristics within a subsurface formation can reveal important features, from regional geology to detailed local reservoir properties. Since investment decisions for future field development are commonly based on future field performance predicted from static and dynamic models, their accuracy usually dictate the decision quality. Challenges to reservoir characterization areidentifying what types of reservoir heterogeneities are most relevant to fluid flows so that the right types of data can be acquired anddetermining how to build robust reservoir models with limited subsurface information, and often times typically in a short time frame3,4. This paper focuses on the integration of all available data in the characterization of a reservoir in the Niger Delta. We have chosen the X-reservoir of Abia field because it is hydrocarbon bearing and the wells are producing. This provides a good candidate for integration of geology and petrophysics for reservoir characterization. Data Availability The reservoir being studied is drained by seven wells. Available data include: Deviation data, Well surface locations, lithologic data, and property logs. Sidewall core data is available but not detailed. Regular production tests were performed on the Wells and a satisfactory historical production data, fluid samples and pressure data were also available.