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  4. Microfracturing VS DFIT

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- [Instructor] Here's a comparison between microfracturing versus Diagnostic Fracture Injection Testing, some pluses and minuses of each of these approaches. Microfracturing is a actual in-situ measurement. It is typically acquired in vertical pilot holes, and you can run an image log before microfracturing, and after microfracturing. And by comparing the two images, you can identify the magnitude, orientation, location, and fracture height. You can also get up up to 20 measurements per run, just by filling the fuel packers across multiple holes. And you also have multiple attempts to identify fracture closure pressure, instead of doing this experiment multiple times at the same place. So, the drawbacks of microfracturing are that the volumes tend to be pretty small, we are talking about just a couple of gallons of fluid, there's some risk of tool sticking, that item will reach the tool pressure limitation prior to fracturing, and there are known problems with deflating packers as well. DFITs, by contrast, are typically performed in the first stage of the lateral, and if you think about it, in most cases that decision, about the first stage, is totally a challenging decision. You get information about the rock species, but it's very hard to tie that in with any popular mythology. It is less risky than microfracturing, the volumes tend to be very large, there's many more vials of fluid, so you can also get from the fracture fluid efficiency, leak-off coefficient, and if you wait long enough, you can measure the reservoir perm as well. Another drawback of DFIT is that the pressure is measured at the surface, so just think about it, if I will see when this fracture is closing the hole, in the first stage, and your pressure gage is located all the way on surface, maybe a few miles away, you have changes in day and night temperatures, compressibility of fluid, all that is affecting the noise in the measurement. It's also a single measurement per hole, single attempt to identify closure, and it takes a long time to measure, could be anywhere from a week to a couple of weeks. DFITs are more popular in US land and commercial, compared to microfracturing, because you can do this test a lot cheaper. In most cases, companies can perform DFITs without using a drilling rig, without having a line crew, so the cost and the economics come out fairly lucrative. By contrast, if you're doing a DFIT offshore, the rig cost is the biggest expense, which in turn means time being the biggest expense, so doing a microfracturing job offshore becomes more economic.