In geological steering, the well path's position is monitored by comparing logs obtained while drilling to logs predicted from a geological model prepared before drilling. Often, important petrophysical evaluation of the logged data needed to refine the geological model is done offsite, delaying full use of the resulting model until subsequent wells are drilled. Furthermore, conclusions drawn from comparisons of logged and predicted data are often presented in geological and logging terms, and are not always explained in clearly defined drilling objectives.

This paper describes a field implementation of an integrated wellsite geological steering service. The service provides timely, useful feedback from real-time logging-while-drilling (LWD) measurements for making immediate course corrections. This service's real-time aspect and its capability to furnish information easily understandable to the geologist, LWD analyst, and driller alike help optimize drilling to the target zone. Visualization is key to this understanding and is provided through interactive multidimensional displays of both the geological and petrophysical properties of formations being penetrated by the wellbore.

This service's true value is realized through incorporation of unique well-planning utilities that automatically incorporate the logged and predicted data and the geological model to help accurately guide the well. As an ancillary benefit, the same computational engine used by the steering service can be employed to sharpen the petrophysical analysis of the logged data used for formation evaluation. This paper briefly reviews forward modeling techniques and describes fundamental principles underlying the new application. Examples illustrate the application of the new service.

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