Keywords: coning, cusping, radial flow, productivity index (PI), skin, acidising, routine
production testing, bottom hole pressure testing, drill stem testing, horizontal wells,
cresting, productivity improvement factor, tubing performance curves, perforating, artificial
lift, gas lift, beam pumps, electrical submersible pumps, hydraulic pumps, well completion,
christmas tree, sand control, gravel packing.
Introduction and CommercialApplication: Section 8.0 considered the dynamic behaviour
in the reservoir, away from the influence of the wells. However, when the fluid flow
comes under the influence of the pressure drop near the wellbore, the displacement
may be altered by the local pressure distribution, giving rise to coning or cusping. These
effects may encourage the production of unwanted fluids (e.g. water or gas instead of
oil), and must be understood so that their negative input can be minimised.
The wells provide the conduit for production from the reservoir to the surface, and are
therefore the key link between the reservoir and surface facilities. The type and number
of wells required for development will dictate the drilling facilities needed, and the
operating pressures of the wells will influence the design of the production facilities.
The application of horizontal or multi-lateral wells may where appropriate greatly reduce
the number of wells required, which in time will have an impact on the cost of
development.
Horizontal or multi-lateral wells can also be used to cost efficiently access remaining oil
in mature fields.