Are We Really Listening?
- Carel Hoyer (Weatherford International)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- July 2009
- Document Type
- Journal Paper
- 18 - 20
- 2009. Copyright is retained by the author. This document is distributed by SPE with the permission of the author. Contact the author for permission to use material from this document.
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It is often said that there is a reason we have two ears and one mouth. Similarly, most would agree that things would go a lot easier during well construction if both operators and service entities spent more time listening and trying to comprehend and less time talking. All this talking makes me wonder—who is really listening to what the well is trying to tell them while it is being drilled?
Old habits are a poor excuse for allowing drilling hazards to eat up a budget. But that is the case for many “conventional-wisdom” well construction and fluid programs, where 10 to 40% of expenditures are still spent drilling trouble zones and large contingency funds are the norm. Given we have likely already drilled most of the “easy” prospects, unless we change our approach, drilling-related nonproductive time will no doubt continue trending upwards.
From one well to the next, “the way we’ve always done it” often trumps lessons learned. The magnitude of the resulting spending—particularly to combat known and predicted hazards—makes a harsh point. For instance, an analysis of Gulf of Mexico data from James K. Dodson Company shows that wellbore instability accounts for more than 31% of total nonproductive time in nonsubsalt wells and 41% in subsalt wells. For a 20,000-ft well, extrapolated losses add up to the millions of dollars.
However, it has also been shown that these trouble zones can be effectively and efficiently drilled or even avoided if new drilling practices are considered, applied, and combined with proven drilling technologies, products, and processes.
The very earliest wells were drilled “underbalanced.” Hydrocarbons flowed to the surface until events like Spindletop in 1901 created environmental and safety challenges. It was only from the desire to reach greater depths that drilling fluids were weighted up and “overbalanced drilling” was invented.
Imagine if a rotating control device (RCD) and automated choke manifold had been invented instead, and all wells had been drilled underbalanced to the present day? Imagine the difficulty in trying to persuade long-time reservoir engineers or drillers to now commence drilling their wells overbalanced, pumping foreign chemicals and particulate into their wellbore to get to total depth (TD) and then being given the “solution” by the service companies to pump expensive stimulation treatments to try and remove or bypass the damage, before handing over to the completion group. Or the need to start running multimillion dollar tools with nuclear sources downhole to indirectly measure rock properties and try and deduce, using complex software, where the oil might actually be located with the very real risk of leaving some of these expensive tools downhole.
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