THE 3
rd
INTERNATIONAL SCIENTIFIC CONFERENCES OF STUDENTS AND YOUNG RESEARCHERS
dedicated to the 99
th
anniversary of the National Leader
of Azerbaijan Heydar Aliyev
64
that, there is a restriction at the depth of 3733m which restricts passing of
tools with more than 95mm OD. This is what limits the application of most
tools in this well because limited access is present to the zones to be isolated.
Water shut-off
In general, there can be 2 approaches to close zone 1, and produce from
zone 2.
1. Bridge/cement plug can be set above zone 1 to isolate both zones, and
then drill a new bore to the gas producing zone (preferably sidetracking).
This is not the best option for the company considering its cost and other
technical issues.
2. Isolate zone 1 in such a way that this isolation doesn’t prevent production
from zone 2. This can be achieved by using total permeability blocker
gels,
cement squeeze operations,
setting straddle packers, casing
patches and BISN plug. However, an internal restriction will make most
of these tools inapplicable. The main limitations are as follows:
a. Wellbore inner profile is irregular (118.6mm original casing ID above
and below the restriction.
b. Zonal isolation tool must not be greater than 95mm OD initially, while
being able to expand and seal around the wellbore at the target depth.
Considering
these limitations, it has been
decided to run and set a
swellable packer in between 2 zones to achieve zonal isolation. A swellable
packer seems to be the best option that has low initial OD, but provides high
expansion ratio being able to seal around the wellbore of 118.6mm ID without
getting stuck at the restriction. A detailed analysis before and depth matching
during the packer running/setting is needed because swellable packers are
permanent in the well once they are set.
References
1. [Abdullah Taha and Mahmood Amani. (2019). Overview of
Water Shutoff Operations in
Oil
and Gas Wells, Chemical and Mechanical Solutions]
2.
[https://www.rigzone.com/training/insight.asp?insight_id=353&c_id=]
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