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Technical Paper: Advanced Downhole Fluid Analysis

Society: IBP
Paper Number: 3075
Presentation Date: 2010
Download: Advanced Downhole Fluid Analysis (0.58 MB PDF)

 

Abstract

Downhole fluid analysis in a vertical and areal reservoir scale prior to oil or gas production is essential in order to design production strategies and production facilities. In addition, reservoir compartmentalization and hydrocarbon compositional grading magnify the necessity to map fluid properties vertically and laterally in the reservoir prior to production.

This paper describes the Downhole Fluid Analysis (DFA) process with the latest fluid sensors for improved reservoir management. DFA is a unique process that combines fluid identification sensors, which allow real time monitoring of a wide range of parameters as GOR, fluid density, viscosity, fluorescence and composition (CH4, C2, C3-C5 and C6+, CO2), free gas and liquid phases detection, saturation pressure, as well WBM & OBM filtrate differentiation and pH.

We examine two field cases in which compartmentalization and fluid variations were observed with both downhole fluid analysis measurements and pressure gradients. Fluid modeling is used to describe the fluid column according to a fluid equilibrium model and then compared to field pressure gradient to check the appropriateness of the pressure gradient models that accounts for the fluid density changes observed. The results of the modeled fluid and pressure analysis are compared to actual downhole measurements of the pressure profile and in-situ fluid logs. In particular, pressures and densities calculated from the multiple sources of information, pressure, and fluids are compared to direct actual measurements and integrated with the petrophysical model to support the vertical and areal reservoir modeling.

The combination of Downhole Fluid Analysis mapping together with pressure measurements and petrophysical data shows to be very effective for compartmentalization and reservoir characterization.

Using this method we present field DFA and pressure gradient data and its integration into numerical simulation modeling to conceptually evaluate the impact of fluid composition / properties gradation and compartmentalization in the productivity of some reservoirs.

Technical Paper presented at 15th Rio Oil & Gas Conference, held on Sep 13 -16th 2010 at Rio Centro/RJ.

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