05.07.2009
Method developed first in the UK which provides a way of funding major capital investment, often large infrastructure projects, without having recourse to the public purse. Private consortia are contracted to design, build, and in some cases manage new projects. Contracts typically last for 30 years.
When certain consumers receive priority allocation of gas, for instance when Russia cut off gas supplies to the Ukraine, home consumers received priority allocation of gas over industrial users. Priority allocation can be used in cases where demand is greater than supply
The first stage of hydrocarbon production, in which natural reservoir energy, such as gasdrive, waterdrive or gravity drainage, displaces hydrocarbons from the reservoir, into the wellbore and up to surface. Initially, the reservoir pressure is considerably higher than the bottomhole pressure inside the wellbore. This high natural differential pressure drives hydrocarbons toward the well and up to surface. However, as the reservoir pressure declines because of production, so does the differential pressure. To reduce the bottomhole pressure or increase the differential pressure to increase hydrocarbon production, it is necessary to implement an artificial lift system, such as a rod pump, an electrical submersible pump or a gas-lift installation. Production using artificial lift is considered primary recovery. Thus, primary recovery produces oil and gas using the natural pressure of the reservoir as the driving force to push the material to the surface