This work provides a probabilistic approach to proactively adjust drilling parameters (which can be uncertain) in real time to help ensure the actual drilling path overlaps the target drilling path to the maximum extent. The planned well path is initially adjusted by a probabilistic formation earth model (EM) for maximum production potential and then adjusted to help improve well path smoothness to allow the passage of tubular strings. Drilling parameters and EM data can be updated in real time during drilling operations. Considering the uncertainty associated with petrophysical properties and drilling parameters, the overlap probability between actual and target well paths was computed for current and to-be-drilled locations. All position-related data were described as distributions. The mean value and standard deviation were computed in real time. Overlapping probability (between actual and target well paths) was used as feedback for drilling parameter adjustments. This closed-loop feedback process enables proactive control of the actual well path. Here, it is illustrated using a horizontal well case study from a typical shale field. Based on log data, formation properties [Young's modulus, porosity (Φ), and total organic carbon (TOC)] are calculated using the real-time EM. At the current drill-bit location, those properties are described statistically as normal distributions rather than single values, as are the drilling parameters, including weight on bit (WOB), rotary speed (RPM), and flow rate (Q). Statistical methods are applied to quantify the uncertainty of the predicted actual well path. All position- related data are described as distributions. The drilling path simulation indicates that the trajectory resulting from using this new control method provides better reservoir access and maintains dogleg severity (DLS) at an acceptable level.
展开▼
