Applications of Advanced Downhole Fluid Analysis and Interval Pressure Transient Test for Improving Oil Reservoir Characterization
A case study from the east coast of Trinidad
Data acquisition of reservoir information in exploration campaigns for offshore oil reservoirs are a continuous challenge in today’s operations. Reservoir fluid properties and reservoir parameters characterization are fundamental for the accurate reservoir description for field planning and facilities design.
This work presents a case study of an exploration well in an offshore Trinidad and Tobago oil field. The formation is unconsolidated sandstones with medium oil and the main objective is to acquire early and quick identification of the oil prospect for appraisal/development wells planning.
The wireline formation tester dual packer module was deployed to perform an interval pressure transient test (IPTT) at the interval of interest with the presence of oil for key reservoir parameter estimation such as vertical and horizontal permeability, damage skin, reservoir pressure, among others in the near wellbore in addition to recover a fluid sample.
Downhole fluid analysis (DFA) was performed to identify the reservoir fluid properties includes oil and water fraction, fluid composition, gas-oil Ratio, density, viscosity, fluorescence, reflectance and resistivity at multiple depths in real time. Also, the real time insitu fluid characterization allowed to make decisions about where and when to take the sample in an optimal amount of time. Additionally, single probe wireline formation tester was used to take fluid samples as well as to obtain formation pressure, used for determining pressure gradient. DFA was combined with pressure profiles to improve the determination of zonal connectivity and contacts across the reservoir. IPTT and real time downhole fluid analysis was used to improve the description of the oil reservoir. This paper will present the job design, planning, results and its applications for reservoir characterization.