PC-Based System Optimizes and Increases Bit ROP

Abstract

Abstract This case-history paper shows how use of a personal computer (PC)-based sensing, calculation, and display drilling enhancement system (DES) allows drillers to take advantage of years of knowledge accumulated by their predecessors to accurately control weight on bit (WOB) and rate of penetration (ROP) in land-based and offshore drilling operations. Use of the system in more than 100 wells over a 2-year period has resulted in approximately 20% improvement in ROP. Significantly, the drillers achieving this record represented various drilling contractors, cultures, disciplines, and experience levels. At the heart of the system is statistical process software that analyzes and optimizes WOB and ROP by showing the driller two graphical lines. One line shows what WOB should be (target WOB) and one line shows the actual WOB. The driller manipulates the rig brake to match the actual WOB with the target WOB (a process known as "stitching the line"). Traditional training methods required the driller to learn to "feel" the rig vibrations and sense other signals to attempt to optimize penetration. Gaining the skill to be an efficient driller naturally required a great deal of time and potentially great expense in bit damage and excessive rig time. A second set of displays available at the rig enables the company man to monitor WOB and ROP from the doghouse. The software samples data often enough to mathematically forecast optimum WOB in real time for any operating condition. A digital recorder system furnishes input to the DES and feeds data to an analytical tool that gives drillers and company men a method of recognizing trends and anticipating coming events. Lessons learned from each job are archived to be used as input to company training. The paper presents operational details, illustrations, lessons learned, and case histories that show the utility of automated WOB/ROP control and trends analysis as dual means of "managing the challenges of a cyclic industry."