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Accurate reservoir description and well placement using distance data, zone logs and depth to fluid contact
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 3rd EAGE/SPE Geosteering Workshop, Nov 2021, Volume 2021, p.1 - 5
Abstract
Summary
We show how distance data derived from inversion of logging-while-drilling directional resistivity (DDR) measurements can be used to constrain both the surfaces confining the reservoir and the well being drilled.
For geosteering, it is important to know where the well is relative to the reservoir surfaces and contacts while their absolute positions in space is irrelevant. DDR measurements provide the perfect data for this. We have used a Bayesian kriging framework to include DDR data directly in predictions of surfaces and wells. Taking into account uncertainties in distance data, surface depth, and the TVD position of the well, this method can be used to continuously update the position of reservoir surfaces and well while drilling,
For a real reservoir, we demonstrate how the prediction uncertainty can be reduced by adding different kinds of well data to the prediction, and how the prediction uncertainty increases when the well path TVD uncertainty is accounted for. We also show how the free water level can be taken into account in the surface prediction.
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