Sumbat ZakirovOil & Gas Research Institute, Russian Academy of SciencesMoscow
Horizontal wells operating under critical gas-free rates permit the development of gas and oil reserves more efficiently.
These wells drain a larger area with fewer wells. Each well will have a greater cumulative oil production than a vertical well, but ultimate oil recovery from the reservoir can be less.
For a given formation zone with fixed reserves and number of horizontal wells, the location of these wells does not significantly influence cumulative oil production and ultimate oil recovery factor.
It should be remembered that total liquid rate, not just the oil rate, influences gas breakthrough