Drilling automation

There’s More to Dull Drill Bits Than Meets the Eye

The best way to know how drilling affects drill bits is to visualize the bits. A device that creates high-resolution images for precise measurements is one of three technologies being featured in a JPT series on drilling measurement innovations.

Training people to be experts on bit wear is not easy for companies to do, especially in a fast-changing business. Source: Getty Images

Before a worn drill bit goes back to the rental company, an oil company representative looks it over and grades it from 0—no wear, to 8—extensive damage.

It is a system long used to adjust prices for bit rentals, where the cost varies based on the amount of wear. Lately there is growing interest, and frustration, for those trying to use damage reports to understand bit wear during drilling and how that relates to the drilling parameters and surface data.

Eyeball inspections have been good enough in the negotiated realm of oilfield pricing, but not for people like Nathan Zenero, a senior industry consultant for Teradata. He worked on a study showing that low numerical grades frequently conflicted with descriptions of wear, such as chipped or broken, when he digitally analyzed the reports.

Zenero is working for a data-driven consulting firm that developed a portable device to precisely image and measure bits before and after use, with software that can calculate the shape and dimensions of the losses.

The company is building and testing an affordable device, currently called the BitBox. It needs to be designed for easy and safe handling while taking pictures of bits, and small enough to be stored in users’ office. It must include the electronics needed to help transfer the data to cloud-based systems where the analytical software will be available.

Based on his experience, Zenero knows there are many reasons why visual inspections by oil company representatives, commonly known as company men, have their limits.

Bits often come out of the hole in the middle of the night when the light is bad and those doing the job are tired at end of their shift on duty. Their time is limited because there are a lot of things to do while the rig crew is preparing to drill the next section.

In addition, training people to evaluate bit wear is often not a priority in a tough, fast-changing business. 

Even a quick read of an online bit-rating summary shows there are a daunting number of details and fine points to consider, such as whether the wear extends down to the diamond substrate and percentage of loss on the cutters.

“Even with perfect conditions, it is unlikely that two drillers, or even two experts, would grade the same bit exactly the same way,” Zenero said.

Teradata is trying to persuade the industry that bit assessment is better done with imaging and analysis and that the data and analysis generated will add value. Further, imaging may help in the analysis of wear on other equipment that can be fit inside the box.

Cameras and lights mounted inside the box create high-definition digitized images from all around the bit. Equipment should be imaged before and after use.

This could help answer an old question: Was that reconditioned bit really just like new when drilling started; and new questions: How did the actual wear compare to the wear predicted by the downhole data analysis?

Teradata has partnered with NOV, which is building BitBox prototypes now and will be manufacturing, distributing, and providing field support if it goes commercial.

At this early stage the brand name has not been decided, and Zenero is vague on some design details, such as the number of cameras or images taken.

What differentiates the product is a business plan to build the technology for widespread rig use.

They are competing with camera phone apps already on the market, but those results depend on a steady hand, good lighting, and consistent angles.

Service companies that make bits provide bit imaging and analysis, but that requires shipping the bit to a lab and waiting for results, which limits the usefulness of the information in a fast-moving business.

“The goal is to keep the price of it [BitBox] on the same order of magnitude as a Porta Potty,” Zenero said, adding, “Who cannot authorize the spend of that kind of money?”

The BitBox will be “designed for the typical handling experience in the oil field,” he said. He chose that wording to avoid tempting someone on a rig to test toughness beyond “typical.”


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