ALBERT

Description: Reservoir Compartmentalization - the segregation of a petroleum accumulation into a number of individual fluid/pressure compartments - occurs when flow is prevented across ‘sealed’ boundaries in the reservoir. These boundaries are caused by a variety of geological and fluid dynamic factors, but there are two basic types: ‘static seals’ that are completely sealed and capable of withholding (trapping) petroleum columns over geological time; and ‘dynamic seals’ that are low to very low permeability flow baffles that reduce petroleum cross-flow to infinitesimally slow rates. The latter allow fluids and pressures to equilibrate across a boundary over geological time-scales, but act as seals over production time-scales, because they prevent cross-flow at normal production rates - such that fluid contacts, saturations and pressures progressively segregate into ‘dynamic’ compartments. Thus, reservoir compartmentalization impacts the volume of moveable (produceable) oil or gas that might be connected to any given well drilled in a field, which restricts the volume of reserves that can be ‘booked’ for that field. Booking of reserves is tightly regulated by government authorities because it is a key measure used by stock analysts and investors to value an oil company. This places reservoir compartmentalization studies, and the predictive science and technology applied to them, at the heart of company valuation. Unexpected compartmentalization can also seriously impact the profitability of a field: with more data acquisition, more study, more wells, more time being required to produce less oil and gas than was originally anticipated. In extreme cases, this might even lead to early...