Avoid damage to casing
Al-Khafji Joint Operations (KJO), a collaboration between the Aramco
Gulf Operating Company Limited and the Kuwait Gulf Oil Company, encountered a
challenge with one of its water disposal wells.
Water disposal wells in Khafji, Saudi Arabia, are completed with
fullbore 7-in fiberglass-lined casing.
With kill brine in the well, only one barrier was in place during
nippling down the drilling BOP and nippling up the wellhead. However, KJO
safety standards dictate that two wellbore barriers are required to perform the
operation safely. Thus, KJO needed a high-expansion retrievable packer that
Protect fiberglass lining
The anchors of standard slip-type packers would likely damage the soft
fiberglass lining. The unique slat-design anchoring mechanism of the
Schlumberger CoilFLATE through-tubing inflatable packer distributes the
anchoring force over a large surface area; therefore, no damage is done to the
fiberglass coating of the casing.
Field test results showed that no damage was observed on the fiberglass
lining after setting and retrieving the CoilFLATE packer. As a result, the
CoilFLATE packer was selected as the best candidate for this application.
CoilFLATE packers are mostly deployed via coiled tubing (CT), which
allows for accurate surface control of tension and compression forces on the
CoilFLATE element during the inflation and anchoring process. While it is
operationally safer, it takes additional time to rig up a coiled tubing unit
(CTU). Consequently, KJO requested to develop the process and procedures to set
CoilFLATE packers on drillpipe.
The risks associated with setting and retrieving the CoilFLATE packer
with drillpipe were mitigated and action plans were executed. A yard test to
use a CT BOP to cut the drillpipe was performed and a rig-up stack on top of
the wellhead was provided to enable the retrieval of the CoilFLATE packer with
drillpipe, in compliance with KJO safety standards. Later, an optimization of
the rig-up procedure was implemented to further reduce rig time.
Rig time saved
Four CoilFLATE packer jobs were performed on RKH water disposal wells. A
CoilFLATE packer was deployed with CT on two of the wells, RKH-06 and RKH-07.
On the other two wells, RKH-08 and RKH-09, a CoilFLATE packer was deployed with
A large amount of savings in rig time was achieved on those wells that
deployed the CoilFLATE packer with drillpipe instead of CT. Rig time was
reduced from 126 hours on the first wellwhich used CTto 17 hours on
the fourth well, which used drillpipe. An average of 60 hours of rig time was
saved per well by using the CoilFLATE packer with drillpipe versus CT.