Real-Time Formation Evaluation Using a Well-Site Data Management System to Integrate MWD, Surface Measurements, and Enhanced Mud Logging Data: ABSTRACT

With the advent of measurement while drilling (MWD), a new source of quantitative data became available during the drilling process. The availability of wireline log-type data while drilling has led to a need that traditional mud-logging methods be augmented and enhanced to provide more quantitative correlative data sources and benchmark standards for the lithologic normalization of MWD data. Together these data can be integrated within a single well-site data base to provide effective formation evaluation while the drilling process continues. The data base may be so structured that later available data, such as wireline logs, may be input to provide confirmation and refinement of real-time evaluations. Similarly, the data base may be primed with geophysical and geological pronoses prior to drilling. Case histories show the effective real-time determination of true total and effective porosities, fluid saturations, and estimates of formation characteristics, such as mineralogy and permeability. In each example, when departures between early and late data sets occur (e.g., wireline logs or formation tests), the data variation results from changes in downhole conditions, and the data can be used to enhance formation evaluation by adding a dynamic component.