Application of Chan Plot in Water Control Diagnostics for Field Optimization: Water/Gas Coning and Cusping

Abstract

A major problem in hydrocarbon depletion is the accompanying water
production. Water production, especially in a deep offshore aquifer
driven reservoir, is inevitable. In the petroleum industry, most active
bottom-water drive reservoirs are completed strategically to handle
produced water problems that may arise during the production of oil
& gas. Water production may come in the form of a tongue, cone, cusp
or a combination of all depending on the location, magnitude and
direction of water movement. Some of the drawbacks include:
decrease in oil flow rate, increase in the volume of water to be
handled thereby increasing the cost of surface installations, reduced
efficiency in the depletion mechanism, increase in water disposal cost
because produced water is corrosive, early abandonment of affected
well & loss of field total overall recovery. The situation is not different
in a monocline reservoir. Edge water coning presents huge challenges
especially when it is unanticipated. Edge water coning is different
from bottom water coning because water encroaches in a sloping bed.
Some of the challenges encountered in a monocline reservoir includes:
difficulty in predicting water breakthrough time and Water Oil ratio
(WOR) performance after breakthrough. Thus, several attenuation
methods have been developed to circumvent excessive water
production as a result of water coning. Among these methods are:
selective water plugging, chemical shut-off, horizontal wells, down
hole oil-water separation (DOWS) technology etc. This research work
deals with the production optimization in a brown XYZ field which is
at primary recovery stage having a number of producing wells. The
main objective of this research is to optimize XYZ field by
understanding the mechanism involved in the water coning process
and presenting a remedy to the coning problem. With the use of a
production plot software, under the direct optimization technique
under the global method. Origin production plot tool was used for
analysis of the brown field. The field is made up of eleven producing
wells and optimization was done on the field 10 years after production
started.