Natural Water Drive
‘Natural water drive’ being one of the most effective driving mechanisms for the production of oil and gas, are we really able to achieve the maximum use of natural water drive, whereby a reservoir engineer would be able to predict the performance of an aquifer under a variety of production schemes that may be proposed for the reservoir?
Are we able to secure all the required rock and fluid properties that essentially dictate the aquifer behavior?
During drilling, whether the wells really penetrate the porous strata of the aquifer (which would help us in deducing quantitative information regarding porosity, permeability and water compressibility)?
Feasible to delineate the actual physical location of the aquifer boundaries and its associated flow conditions at these physical boundaries?
Which one of the following remains to be closer to reality?
(a) Knowing the pressure history at the inner boundary, and then, determining the quantity of water influx into the reservoir (the constant-terminal-pressure solution); or,
(b) Knowing the history of water influx into the reservoir, and then, estimating the resulting pressure history (the constant-terminal-rate solution).
What are the practical field-scale constraints that we have towards
(a) determining the amount of water that would flow out of an aquifer in response to a pressure decline at the inner boundary (how easy would it remain to get the efflux response function in this case?); and
(b) determining the amount that the pressure at the inner boundary would decrease in response to a withdrawal of water?