A single drill bit lasted about 4 hours, which was enough to drill between 7 and 10 meters. In comparison, raising and lowering the drilling column took up to 18 hours.
It also mentions that due to the core samples being saturated with hydrogen, they turned to a fine dust unless they were raised very slowly to allow the gas to dissipate.
"It is rumored that at some point the drilling rig began to vibrate unnaturally, as if someone were jerking for it from below.
When the well reached a mark of about 12,000 meters, scientific equipment recorded sounds resembling the cries and groans of thousands of martyrs emanating from the depths."
Now there’s a fun moral dilemma. Is it ethical to generate electricity with the torment of the damned if it replaces polluting power plants and they’d be tormented anyway?
No boreholes are perfectly straight and vertical. In most cases, you're twisting the drillstring at the top, so it naturally "wants" to corkscrew. Furthermore, anisotropy in the rock causes things to deflect (deviate in drilling terminology). Usually you don't know exactly where the well went until you run a directional survey afterwards (basically, you lower a gyroscope down the hole).
At the scale of a well, the steel drillstring is more like cooked spaghetti. You don't "push" down, you use the weight of fluid (drilling mud) for pressure. The drillstring is only meant to transmit torque. It's easy for it to bend over long distances. (You can even turn things entirely around and use fluid pressure to turn the bit, in which case the drillstring is basically a steel hose that's stored coiled up.)
It is pumped, but the pumps are there to force circulation and keep things under control rather than to provide the pressure directly.
You need a steady gradient of pressure. The pressure you need at the bottom of the hole will fracture the rock in the shallow section. Pumps add a constant pressure, so there's no way to get the right pressures at each depth with a pump.
Instead, drilling exploits gravity to do the hard work. The drilling mud is very dense (almost as dense as the rock) so that the pressure at the bottom of the borehole from the weight of the mud is just a bit less than the pressure from the weight of the rocks.
I think even if they had no rock formation or the whole layer was uniform, they would still deflect. It's similar to walking in a straight line blindfolded.
Those are sidetracks. Sidetracking is done when there are problems with the borehole (it starts to collapse/deform or something gets stuck inside it) or different work needs to be done on a section (e.g. going back and coring a section that you've already drilled through to get samples). In this case, they most likely sidetracked to core, as they'd want direct samples and borehole stability is less likely to be a major problem in crystalline rock.
As far as how they do it, it's conceptually simple (these days there are "fancier" options with steerable drillbits). You put a tool down the borehole that you can expand and lock in place at the desired depth. When it's expanded, it forms a ramp towards one side of the wellbore. You then lower the drillstring, and when the bit hits the ramp, it's deflected in the direction you want it to go.
-I would guess (mind, guess, I don't know the first thing about gas drilling) that as they needed to take great care retrieving the core samples slowly to allow the hydrogen to evaporate without damaging the sample (as per @abcd_f's comment above), the rate of hydrogen release from the rocks is simply too low for it to make any sense to drill for it.
After all, if hydrogen is slow to escape from the core sample, it stands to reason it will be slow to escape from the surrounding rock, too.
(Given a bit of electricity, we can easily get lots and lots of hydrogen from water, anyway.)
Good catch, may be the work was too exhaustive and the exhaustion led to depression once you realize that whatever you do it does not matter at the end, everyone is paid the same, even all the credits go to the "united workers of the world", not you.
Edit: from the Russian version of the page -
A single drill bit lasted about 4 hours, which was enough to drill between 7 and 10 meters. In comparison, raising and lowering the drilling column took up to 18 hours.
It also mentions that due to the core samples being saturated with hydrogen, they turned to a fine dust unless they were raised very slowly to allow the gas to dissipate.