Those little islands are called “bushes”. There are oil pumps placed on them. This is a Samotlor oil field near Nizhnevartovsk. The oil deposits are on the bottom of the lake and swamp so there are many artificial islands made on which they drill the well and put an oil pump.
This is how it all looks from the satellite point of view.
And this is a photo from the helicopter
The islands are connected with artificially created roads, the length of which is many hundreds of kilometres, there are long distances here.
Ant this is how those “bushes” look on an oil engineer’s map. There are over a thousand of those wells here.