Halliburton: To Core or Not to Core…
It’s not simple to achieve success in shale drilling, said Peter E. Smith, Product Manager at Halliburton Energy Services, who stated, “There’s nothing easy about it.
“When it comes to the different stages, the service providers often use their success in another shale play – if you are exposed to only that, it may not be suitable to your particular situation. You need to understand your rock,” he said at the Unconventional Gas Forum in Barcelona, Spain, where he spoke about “Modern Drilling and Completion Techniques to Address Unconventional Reservoirs.”
According to Mr. Smith, knowing one’s shale required a holistic view and planning for the frack at the end.
One method of “understanding the rock” was to core it. He said coring had had a bit of resurgence in some areas with some of the unconventional plays.
“When I was a lad, we used to core nearly all the exploration wells,” he recalled, saying, “it’s kind of taken off again. I’m not a coring expert, but coring is defined as the downwell acquisition recovery of the rock, basically, by two methods: full core barrel and wireline coring as well.”
“They both have different advantages,” he continued. “Why would you continue to core in this modern age? You get an actual rock sample to make an effective evaluation of it, a better analysis in the lithology and geochemistry of it – it gives you much more detail about what you’re trying to do with the rock itself, from the reservoir side.”
Mr. Smith noted that there were numerous differences between traditional coring and wireline coring.
“The core quality can be significantly different. In terms of volume, you get much more out with conventional core, but coring shales can be potentially quite difficult – it can be difficult to retrieve them with wireline core where they’re more likely to be broken coming back out of the hole,” he explained.
He recommended working out why one was coring and make sure to choose the right system.
Well spacing and frack design, he said, were also critical.
Mr. Smith also addressed the significant amounts of water used in unconventional gas operations, specifically the hydraulic fracturing.
He showed a photograph of operations at the Barnett shale, with 185 water tanks on site and said, “Each of these frack tanks holds about 20,000 gallons of water, with trucks on the road coming there; in the Eagle Ford, it’s even more – so those are significant amounts of water.”
“To most of us in the industry, it’s just a cost that we have to take care of, but for environmental groups it’s one of the most important things they’re looking at and for regulators it’s a challenge. So it’s important to take a look at water as a resource.”
He added that Halliburton was looking at ways of being very green about this and was trying to make sure that anything it put in water, it could remove. “There are techniques, technologies specifically developed for water management.”