Compact Intelligent Completion: A Game Change for Shushufindi Field
Production in the Shushufindi-Aguarico oil field (SSFD), Ecuador, is
from three stacked reservoir sands: basal Tena, U, and T. The SSFD is
considered undersaturated and is characterized as having two simultaneous
driving mechanisms. The first mechanism is associated with solution gas drive,
and the second is associated with an active bottom and lateral aquifer. This
latter mechanism offers high recovery factors that oscillate between 25% and
30% and high water cut in most of the wells, especially in those producing from
the T sand.
The reservoir is compartmentalized by stratigraphic pinchouts with the
result that each of the sands has a different pressure regime: T sand from
2,400 to 2,600 psi, U sand from 1,400 to 3,000 psi, and basal Tena sand from
1,200 psi. The reservoir pressure limits natural flow; therefore, artificial
lift is required.
The dominant artificial lift method is the electric submersible pump
(ESP), which is used in 106 wells. Other methods in the field are hydraulic
pumping in five wells, gas lift in one well, and beam pumping in one well.
The saturation pressure for the U and T sands varies between 1,010 and
1,062 psi. Some wells are exploited with dynamic bottomhole pressure
(Pwf) below the bubblepoint pressure; there are cases where
Pwf is approximately 600 psi.
Originally, the casing used to complete wells in the field was 5 1/2 in
x 17 lbm/ft and 7 in x 26 to 29 lbm/ft. The wells perforated during the last
three years have been completed with 9 5/8-in. x 47- to 53-lbm/ft casing and
7-in x 29-lbm/ft or 26-lbm/ft liner. From the beginning of production in the
field in 1970, a total of 140 ESPs have been run: 17 ESPs in 5 1/2-in casing,
39 ESPs in 7-in casing, 42 ESPs in 9 5/8-in casing, and 42 ESPs in 7-in
Wells are completed as monobore completions, either in the U or T sand,
or have been selectively completed when both sands are to be exploited
sequentially. The latter completion includes a sliding door to allow sequential
production over time. In 2012, concentric dual completions were deployed in
four wells, with some success. This technology involves high risk to the well
operations because of its complexity (numerous accessories), tie drifts, and
lack of flexibility to intervene in the well even with a rigless intervention.
Additionally, this completion technique requires high capex and a considerable
amount of surface equipment. This makes a future workover operation lengthy and
A very important production consideration in this field is that the
hydrocarbons regulatory authority in Ecuador, ARCH, does not allow the
commingled exploitation of the U and T sands because of the issues this raises
with reservoir management and petroleum accounting.
The technical and regulatory challenges are the drivers for considering
intelligent completion (IC) or compact IC for the operator, Consorcio
Shushufindi (CSSFD), and evaluating and testing IC and compact IC completions
for this field are the objectives of the present technical work.
As part of this work, significant advances have been made in increasing
the information that makes up the portfolio for a candidate well; this
information includes a definition of the architecture required, conceptual
simulations to estimate production rate for the sands, operation philosophy,
advantages and disadvantages of the application, and antecedents worldwide. In
addition, technical presentations have been conducted at all levels of
management to explain the technical justification and the benefits of
implementing IC completions in terms of production optimization, reserves
development, reduction of formation damage induced by the effect of well
intervention (recompletions), etc.
Based on early technical meetings with the ARCH, Petroamazonas (PAM),
and the Hydrocarbon Secretary (SH), a pilot test has been approved that will
implement and evaluate IC in five wells in the SSFD field.