Drilling Engineering and Formation Evaluation: An Integrated Approach to Improve Real Time Drilling Optimization

Abstract

In the current market climate, the industry is in a time squeeze and it is crucial for future value generation to reduce the well construction time and cost. Drilling Optimization practices have helped to increase drilling efficiency while reducing the likelihood of downhole failures. To see this effort further, an adequate engineering plan to design the operation strategy, along with the understanding of the geological challenges, assists in establishing a more robust real-time optimization program.

Real-time drilling optimization helps to improve drilling performance by providing early warning detection of downhole drilling events, maximum allowable deviation of planned vs. actual hydraulics and torque & drag measurements, and finding the "sweet spot" by use of drilling parameters. These processes can then further be optimized by the integration of pre-job engineering and formation evaluation measurements. Pre-job engineering seeks to ensure the BHA is able to resist vibration- related events, while the drillstring and bit are selectively examined for optimal hydraulics and resistance to torque and drag related issues. The pre-job engineering also considers ways to improve the rig’s overall efficiency, by eliminating invisible lost time while both in and out of hole. New generation of logging while drilling measurements help to provide reliable prediction of pore pressure for early warning of circulation problems, collapse events, lost circulation, blowout, and kicks. This process involves a depth-by-depth correlation between actual borehole lithology and pre-modeled unconfined / confined compressive strength (UCS/CCS). Optimized mechanical specific energy is evaluated using drilling parameters such as torque, RPM and ROP. The resulting two curves are then defined by calculating the value of MSE/CCS-UCS fraction to derive a drilling efficiency indicator. By correlating these curves, the drilling optimization team can identify geological formations that have the optimum correlation then compute the efficiency indicator for the interval, using it as baseline for drilling each hole section. This workflow guides the operations to make necessary real time adjustments to mitigate potential problems.

The workflow demonstrates the integration from the pre-job engineering design to the automation of the real time integrated evaluation, along with the accuracy of the new generation of Logging While Drilling technologies as a cost-effective solution to mitigate non-productive time and optimize drilling rates through the implementation of a solid drilling optimization program during the execution of ERD, offshore and unconventional projects.