RE: Reservoir question30 Jun 2019 00:52
Wulbert,
(I've got knocked out of my habitual online poker tounament befor the pay, so am back here!)
"When people talk of "the reservoir got damaged" do they mean just the part where the drill entered the reservoir? Surely the whole reservoir would not be "damaged" or compromised by an area of collapsed rock & mud (or whatever) around the penetration point of the drill? "
People don't talk about 'the reservoir got damaged'. The technical phrase is 'formation-damage'. I mentioned the possibility of this when the Halifax story started getting long, but with no RNS, and was pilloried by a number of people for having used such a term. But was subsequently vindicated, when the company used it themselves.
(I'd like to say here that it was pure intuition on my part, with a lot less 'networking' and availability of rumours.)
'Formation damage' generally applies to 'near-wellbore'. It does not apply to the reservoir as a whole. It's important to understand this. Halifax was not a 'dud'. Far from it. However various regulatory constraints due to its 'exploration' staus, especially regarding drilling-fluid ('mud') densities, immediately limited the chances of successful DST due to 'clogging' of the fracture matrix by fines, and possible chemical interactions with minerals interspersed within the rock.
This is 'near-wellbore'.
The wellbore at that depth is only 8-1/2 inches diameter. And never think about oilwell drilling as being intersecting some sort of underground cavern like Carlsbad Caves, filled with oil. It ain't.
Think instead about drilling a hole in your wall (for whatever reason), with your Black and Decker, and maybe the thing getting stuck because you haven't 'reamed it' a bit, or whatever.
Really, the principle is the same. But a bit more complicated. I really loved the analogy someone posted a couple of days ago about directional drilling being like decorating the bedroom from outside in the street, and through the letterbox. But it's a tad more difficult than that. And this is where Wellwell's 'no oil ' argument falls flat on its face. Because while drilling the horizontal, they were using sophisticated (read rocket-science to make things simple) LWD in tandem with the navigation tools. (LWD=Logging-While Drilling.)
They know what they've got, they're not wasting time, but moving on. Can't wait for the RNS.