Oilrig (as_oilrig) is an unpopular map that has fallen into obscurity.
Oilrig was never a popular map, mainly due to the weapon restrictions that force players to use only certain weapons. Moreover, there is only one VIP escape zone in which the Terrorists can easily guard.
The map is also quite dark and has numerous camping spots. Snipers are more than just inclined to defend certain areas. Some can get aggressive and may even use the vents to eliminate the VIP and gain a large bonus.
Combat is always intense in this area. If there are Terrorist snipers, they can pin down the CTs and/or assassinate the VIP if he is left unprotected.
Some players may jump into the water to avoid fall damage but enemies can see them and throw grenades or shoot at the only ladder.
As a Terrorist player, one can find a vent opening from the stairwell and access a sniper nest. While this place does not seem to serve any more benefits, there is another use. You can go through the window and jump across. This can allow you to corner the VIP if he is still in the CT Spawn Zone.
Although the elevator can allow the VIP to reach the top faster, it will often alert the Terrorists and they can simply camp above when they are certain the VIP is on the elevator. Usually, this is forgivable for the CTs in pistol rounds but using the elevator is far too risky if enemies are armed with rifles.
Terrorists spawn here, sometimes, in the tower or even on the rooftops. Snipers are always tempted to hide around the upper sections. In fact, a few spawn points are located on "inaccessible" sections (e.g. a rooftop with no ladder) and the CTs will struggle to counter.
One Terrorist can spawn here and he can guard the outside and the escape zone, if he has a sniper rifle.
As such, the tower is ripe for at least one sniper and offers the highest position in the map.
Rarely, a CT sniper can control this section and ensure the evacuation of the VIP and prevent the remaining Terrorist force in reaching close contact.
Although in normal situations permit you to be fully defended from enemies, a CT may be able to kill you from behind (especially, when they know a sniper is inside the tower). Instead, it is more recommended to jump on a ledge and you can gain more cover.
In pistol rounds, the VIP can use this area to ascend to higher ground within a short time. In later rounds, this section may be avoided, especially by the CTs.
Bots will mostly rush through this area to reach the VIP escape zone. Terrorists will often have the advantage as they will always maintain higher ground in Oilrig. Players with rifles (sometimes, including the AWP) can ambush the VIP if he is alone.