Integrated Reservoir Fluid Mapping While Drilling Along High-Angle and Horizontal Wells
- Maria Cecilia Bravo (Schlumberger) | Mirza Hassan Baig (Schlumberger) | Artur Kotwicki (Aker BP ASA) | Nicolas Gueze (Aker BP ASA) | Mathias Horstmann (Schlumberger) | Yon Blanco (Schlumberger) | Chanh Cao Minh (Schlumberger) | Julian Pop (Schlumberger) | Scott Paul (Schlumberger)
- Document ID
- Society of Petrophysicists and Well-Log Analysts
- SPWLA 60th Annual Logging Symposium, 15-19 June, The Woodlands, Texas, USA
- Publication Date
- Document Type
- Conference Paper
- 2019. held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and the submitting authors
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- 121 since 2007
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Identification of hydrocarbon type and fluid contacts and assessing production potential are vital to successfully develop infill reserves. Geosteering decisions must be made in real time to achieve the optimal well path that would drain remaining reserves. Thus, highly flexible data acquisition strategies while drilling are needed to be able to adapt to unpredictable reservoir structures, hydrocarbon saturation, and variable fluid contacts.
Logging-while-drilling (LWD) technology has enabled a step change in well construction from geometric trajectories to those actively steered by formation and fluid characteristics in real time. Depending on geosteering challenges, an LWD bottomhole assembly (BHA) can include tools for deep directional resistivity (DDR), standard petrophysical logs, LWD spectroscopy, nuclear magnetic resonance (NMR), formation pressure, advanced downhole fluid analysis (DFA), and surface mud log gas.
In recent years, DDR measurements have been widely used for their deep depth of investigation to map reservoirs and geosteer the well within the hydrocarbon column. DDR measurements use the resistivity contrast of hydrocarbons to conductive water to map and delineate the top and bottom of the hydrocarbon-bearing zones. However, it does not always differentiate between hydrocarbons as gas or oil because they share similar resistivity signatures. It continuously maps hydrocarbon-water-contact but rarely maps a gas-oil contact (GOC), valuable to be known, since usually to drain remaining oil reserves the well must be placed below the GOC and at a safe distance from the oil-water contact (OWC). Leveraging the short time-after-bit and less exposure to drilling fluid invasion, two measurements have become particularly useful to differentiate gas from oil: advanced downhole fluid analysis and real-time interpretation of petrophysical log data.
In this paper, we discuss an infill reserves development case study of the Boa field in the North Sea where it was desired to place four lateral wells within a thin oil rim. Fluids were continuously mapped along the wellbore trajectory as gas, oil, light oil, and free and irreducible water by using petrophysical logs in real time. Fluid typing from downhole optical spectrometry provided validation points for the petrophysical interpretation. Software and data transmission technologies were utilized to create an integrated answer product of continuous near- and far-wellbore fluid characterization for well-considered geosteering decisions and optimal well placement.
|File Size||2 MB||Number of Pages||13|