Application of an Intelligent Well
Completions (IWC) in optimizing
production from oil rim reservoir
Faculty mentor: Mr. Chandan Sahu
CHIRAG VANECHA
ROLL NO. 16BPE137

What is an Oil Rim reservoir??
 The oil part of gas/oil or oil/gas/condensate deposit, the size and geological
reserves of which are significantly smaller than of the gas part of the two-phase
deposits.
 An oil rim reservoir is a saturated reservoir with an oil column of limited
thickness, less than 90 feet, overlain by a gas cap with a thickness of more than
250 ft and underlain by an aquifer.
 and despite their low pay thickness they can still contain substantial volumes of
hydrocarbon-in-place.

Intelligent well completions
 An intelligent well is defined as an advanced well equipped with
intelligent completion technology. An intelligent well completion is a
system equipped with sensors and special valves installed on the
production tubing, which provides the operator with continuous
monitoring and adjustment of fluid flow rates and pressures.
 It is challenging to increase oil recovery from reservoir with thin oil rim
and more gas after a long depletion of gas cap.
 Judicious selection of intelligent completions will increase oil recovery
and constrain unwanted water and gas production from the reservoir.

 IWC reduce CAPEX and OPEX and help in increasing additional
productivity than conventional completions.
 The nature of oil rim reservoirs makes long horizontal wells an attractive
option for increasing well-reservoir contact and reducing drawdown.
 It can be achieved by using Inflow Control Valves (ICV) installed on the
production tubing. The production of oil and gas is highly dependent on
types of ICDs and ICD configuration.
 Therefore, choosing the best ICD is a key point to maximize the oil
production.

Challenges while production
 Among the various challenges encountered in producing oil rim reservoirs, water
and/or gas coning and breakthrough is the most prominent.
 The production of unwanted well fluids, such as water or gas, impacts well and
reservoir performance and its financials. Inter-well connectivity, formation fluid
movement and understanding whether unwanted fluid comes from the formation or
nearby wells play an important role in different reservoir development planning
stages.
 Water and gas breakthrough occurs majorly due to heel-toe effect and reservoir
permeability variations. Inflow control devices (ICDs) were deployed to mitigate the
heel-toe effect thereby delaying the water and gas breakthrough.

Water and gas coning
 Coning is a rate-sensitive phenomenon generally associated with high producing
rates. Strictly a near-wellbore phenomenon, it only develops once the pressure
forces drawing fluids toward the wellbore overcome the natural buoyancy forces
that segregate gas and water from oil.
 The change in the oil-water contact profile as a result of drawdown pressures
during production.
Fig 1: (b) a producing well subject to
gas and water coning
Fig 1: (a) a producing well with no
coning

Coning (ctd.)
Fig 2: (a) coning in a vertical well Fig 2: (b) coning in a horizontal well

Factors affecting coning
 Density differences between water and oil, gas and oil, or gas and water
(gravitational forces)
 Fluid viscosities and relative permeabilities
 Vertical and horizontal permeabilities
 Distances from contacts (oil-water/gas-water) to perforations.

Heel-Toe effect
Fig 3: Heel and toe part in the production tubing

Heel-Toe effect (ctd.)
 Increasing the horizontal wellbore length leads to some production challenges. In
a long horizontal well with open hole completion, the drawdown in the heel
section of a well is much higher than the drawdown in the toe section.
 This is because of higher cumulative frictional pressure loss in the heel section
than the toe. Thus, higher production in the heel section than the toe section is
expected.
 Consequently, the inflow from the reservoir to the well and water/gas
breakthrough are non-uniform. This phenomenon gives partial water or gas
breakthrough and lower oil recovery and sweep efficiency.

Fig 4(a): coning in horizontal wells Fig 4(b): even drainage with ICD
The area close to the heel will produce more hydrocarbons, resulting in coning of the
water-oil contact or the gas-oil contact. Over the time, this leads to reduction in oil
production and more water disposal problems.

ICV- inflow control valves
Fig 5: Intelligent well completion with Autonomous ICDs

How do ICVs or ICDs work?
 As it is shown in figure 4 by arrows that fluid first flows along the base pipe
and enter through the outer screen then flows through nozzles and comes in the
wellbore.
 After passing through the screens, it goes to the chamber then flows since flow
rate is controlled by orifices present over there. This controlled flow by
orifices and sensors comes under ICDs.
Fig 6: channel ICD schematics

 Sensors send heel toe effect reduction in the form of non-linear, second order
ODE. And solutions must allow one to estimate that: 1)ICD design parameters
that reduce heel-toe effect at required level and 2) impact of ICD’s on the well’s
inflow performance relationship.
 ICDs or AICDs generally have hydrophobic part in them so these devices keep
away water to enter in the wellbore. So multiple ICDs throughout the horizontal
well length keep water level at some distance and help in producing only oil.
ICVs (ctd.)

Autonomous Inflow control device

References:
 Ali Mojaddam Zadeh et. Al., “Optimal inflow control devices configurations for
oil rim reservoirs”, 2012.
 I. Chaperon., “Theoretical Study of Coning Toward Horizontal and Vertical Wells
in Anisotropic Formations: Subcritical and Critical Rates”
 https://www.iprojectmaster.com/MARINE%20ENGINEERING/final-year-
project-materials/application-of-intelligent-well-completion-in-optimizing-
production-from-oil-rim-reservoirs
 Bernt S. Aadnoy et. Al., “Analysis of Inflow control devices”, 2009, SPE
international
 Schlumberger oilfield glossary, Wikipedia and Petrowiki