English abstract
Petroleum production from oil and gas reservoirs around the world is typically going
through a cycle of early life production, production plateau then production decline till
abandonment phase is reached. Production optimization is a key process to prolong
production from the reservoirs and maximize the hydrocarbon recovery from the targeted
reservoirs. Optimization can have several methods and procedures depending on reservoir
conditions, characteristics and the objective that the professionals are trying to achieve
including drilling infill wells, adjusting offtake from current wells, injecting external
fluids to reservoirs and so on. Since optimization involves remarkable expenditures in
most of the cases, the options of optimization have to be studied thoroughly via the various
methods and tools available in petroleum engineering. One of the recognized tools in oil
industry is the use of material balance equations that are fundamentally based on the fact
that the initial volume must be equal to the summation of the removed volume and the
remaining volume. These calculations can be done by modeling softwares that depend on
material balance concept to study optimization and come up with scenarios that fit the
conditions of the reservoir, safe to operate and economically feasible for operator. This
project studied two cases for brown fields in northeast of Oman producing from, Khufai
formation, a naturally fractured reservoir with different petroleum setups. The first case
study is producing from Khufai formation with aquifer influx that provides proper drive
and pressure support. Through material balance modeling, hydrocarbon volume was
modeled and compared with volume scenarios from static geological model and
sensitivities that affect the modeling of volumes were considered. Options of optimization
via drilling additional wells were investigated and numbers of wells to be drilled were
decided along with prediction of recovery and anticipated project generated revenues. The
second case study is producing from Khufai formation as well but with different drive
mechanisms and with absence of any water influx where the reservoir is going through
severe pressure depletion not allowing continuity of production from the reservoir. Similar
to the first case study, hydrocarbon volumes were modeled and sensitivities that are related
to this particular case were modeled. Volumes were also compared to those from static
geological model. Optimization options through enhancing reservoir pressure were
studied using material balance models. Different sensitivities were considered to cover the
potential uncertainties in the production prediction which is a cornerstone for the
optimization feasibility. All modeled options with their sensitivities were economically
evaluated and screening of optimum options was done by taking into account the
maximum net present value.
