Drilling by the Numbers Demands Better Numbers

Oil wells can produce large volumes of oil, gas, water, and dubious data. For example, a recent study of data from 40 wells found that the measure of the weight on the bit (WOB) was off by 18% in the average well. The big problem was that 69% of the time this key measure of the force applied while drilling was not recalibrated when the weight of the drillstring was increased as pipe was added, which is known as WOB zeroing. Past technical papers on data quality focused on how data were measured, not on whether drillers were regularly zeroing, said Adam Neufeldt, a research engineer at Pason. He delivered a paper (SPE 189636) at the recent IADC/SPE Drilling Conference where multiple papers were generated about the industry’s growing use of data for analysis and control, including some questioning data quality, which could undercut the value of analytics and automation. The demand for better-quality data is rising as operators and service companies build systems to gather and analyze real-time drilling numbers. Representatives of Anadarko, Nabors Drilling, and Occidental all presented papers at the conference describing how they are expanding their ability to gather and analyze more drilling data faster to improve drilling performance. “We have reached the tipping point on the use of this data,” Matt Isbell, drilling optimization advisor for Hess, said during a presentation at the drilling conference about the Operators Group on Data Quality, which was formed a couple of years ago to address the problem (SPE 189626). “The errors are significant and there are huge consequences,” said John de Wardt, president of De Wardt & Co., who is leading an industry effort to create a roadmap for drilling automation systems development. He is working with Southwest Research Institute to develop a validation system to verify sensors and systems for drilling measurement. The Pason paper looking at WOB data shined a light on the central role played by drillers. Errors in the drilling data recorder were likely caused by drillers failing to push the button on the recorder to zero the measure. Several experts interviewed said that if an operation was progressing smoothly, the driller would likely keep an eye on the data but not feel a need to do the update, allowing the error to grow. The study found a similar error rate in the estimates of the differential pressure that measures the force of the fluid flow driving the mud motor, which, like WOB, is used to measure the mechanical energy applied by the drill bit. Failure to regularly zero the differential pressure was a major source of error as well.