Coiled Tubing Cleanout, Diagnosis, And Remediation of Sand Control Failures

Published on June 2016 | Categories: Types, Presentations | Downloads: 55 | Comments: 0 | Views: 470
of 43
Download PDF   Embed   Report

Coiled Tubing Cleanout, Diagnosis, And Remediation of Sand Control Failures

Comments

Content















Through Tubing Cleanout, Diagnosis and
Remediation of Sand Control Failures


Prepared by:
Bryan Stamm

November 15, 2006





















Introduction:

This document describes the Schlumberger technologies available for:

• Cleaning out sand control failures
• Diagnosing the location of the failure
• Repairing such failures

The described technologies are based on general sand control screen failures in both cased
hole and open hole applications. Attached to this document are several brochures with the
descriptions of the available technology and also case histories.

Assumptions:

The screen types described in both well cases assume that the screen in composed of base
pipe and screen jacket. The screen jacket can be premium (Dutch weave, sintered laminate,
etc.) or wirewrapped (including pre-packed).

Attached below are pictures representative of a premium and wire wrapped screen.



























Premium Screen
Wire Wrapped Screen
Pre-packed Screen
Although Schlumberger does not manufacture expandable screens, the techniques
described in this document also apply.

Of more importance than the type of screen is access to the screens (minimum restriction
above). The ODs of the cleanout, diagnostic, and remediation tools are provided so that
their application different size wellbores is well defined.



Clean out:

Although not specified, the assumption is that a failed sand control well will have been shut
in or the production rate substantially reduced upon the detection of sand at the surface
detector or production facility. This action was taken to prevent any damage to the
wellbore or production hardware.

For the purpose of this document, it is assumed that some fill may need to be removed in
order to gain access to the potential areas from which the sand was produced.
Schlumberger does not recommend attempting failure diagnostic work prior assuring the
wellbore is free of sand / gravel, as the risk of sticking the diagnostics tools is very high.

Prior to beginning any cleanout operations, a clear identification of the sand produced
should be provided to Schlumberger. The size and type of formation sand or gravel will
allow for potential identification of the location of the failure, and may allow estimation as
to the amount of material potentially in the wellbore. The type and size of sand will also be
important in establishing the cleanout techniques (rates, fluids, etc).

The issue of bailing the sand with slickline while mobilizing additional equipment often
arises. It is Schlumberger’s experience is that trying to remove sand from a failed gravel
pack with bailers can often lead to damage of the upper completion hardware if multiple
runs are made. A few bailer runs to establish the depth of the fill may lead to a decision not
to rig up CT if complete access is possible (i.e. sufficient rat hole as in well type one).
Also identifying the fill depth will allow CT washing operations to commence at the fill
depth rather than higher up the well, saving cleanout time.

The use of coiled tubing (CT) for through tubing remedial services after installed gravel
pack completions fail is viable and efficient solution. The coiled tubing equipment is small
modular equipment and can be mobilized quickly.

For the purposes of this report, horizontal and vertical wells with 5 ½” production tubing
and also 5 ½” screens were examined. However, well completions of any size can be a
challenge depending on the following.

- Maximum crane lift capacity offshore
- Deck space and deck loading capacity of the location
- Well depth
- The maximum inclination of the wellbore
- Bottom hole pressure and temperature
- Type and size of solids that fill the wellbore


Wellbore Solids Removal
With the challenges described above in mind, Schlumberger can design an efficient
cleanout using their PowerCLEAN services. PowerCLEAN is the engineering approach to
efficient wellbore cleanouts. The service is a combination of the following aspects.

- Software modeling program
- Special design cleanout wash nozzle
- Suite of cleanout fluids to fit the well conditions
- Solids monitoring device at surface
- Fluids and solids handling equipment for separation and re-cycling of fluids


Horizontal wellbore across the sandface:

This well is placed horizontally into the pay zone with a length of approximately 3,000
ft. cleaning out horizontal wells required high annular fluid velocities and good
carrying capacity of the fluid used. The challenges in this wellbore profile are the long
horizontal section and the fairly large tubing ID. This well can be cleaned out using the
following coiled tubing string sizes.

1.75” OD Coiled Tubing
- Sweeping technique back up to 7,000 ft taking 50 ft bites
- Cleanout speed 5 ft/min
- Fluid rates 3.0 bpm
- Specialized cleanout fluid with high carrying capacity and low pump pressures


2.00” OD Coiled Tubing
- Sweeping technique back up to 7,000 taking 100 ft bites
- Cleanout speed 12 ft/min
- Fluid rates 4.0 – 4.5 bpm
- Specialized cleanout fluid with high carrying capacity and low pump pressures

2.375” OD Coiled Tubing
- Circulating wash technique 500 ft bites (Not POOH back to 7,000 ft for each bite
length)
- Cleanout speed 17 ft/min
- Fluid rates 5.0 – 5.5 bpm
- Specialized cleanout fluid with high carrying capacity and low pump pressures

2.875” OD Coiled Tubing
- Circulating wash technique 500 ft bites (Not POOH back to 7,000 ft for each bite
length)
- Cleanout speed 12 ft/min
- Fluid rates 6.0 bpm
- No specialized fluids required. Fresh water or light brines can be used

Looking at the different available scenarios described above it will be possible to clean
the wellbore from solids. The PowerCLEAN approach will help to identify the most
efficient cleanout procedure within the limitations of the well and the location.


Vertical wellbore across the sandface (with exposed casing):

This wellbore is a vertical and is completed with 5 ½” production tubing. The
completion is placed in sections leaving voids back to casing ID. The challenges in this
type of wellbores are the already large ID of the tubing and the additional extreme large
casing ID between the different sections of the production tubing. After a brief review
of the well description and using the PowerCLEAN approach, this well can be cleanout
using the following coiled tubing sizes.

1.75” OD Coiled Tubing
- Sweeping technique back up to 10,500 ft taking 200 ft bites
- Cleanout speed 5 ft/min
- Fluid rates 3.0 bpm
- Specialized cleanout fluid with high carrying capacity and low pump pressures

2.00” OD Coiled Tubing
- Sweeping technique back up to 10,500 taking 500 ft bites
- Cleanout speed 8 ft/min
- Fluid rates 4.0 – 4.5 bpm
- Specialized cleanout fluid with high carrying capacity and low pump pressures

2.375” OD Coiled Tubing
- Circulating wash technique 1000 ft bites (Not necessary to POOH back to 10,500
ft for each bite length)
- Cleanout speed 12 ft/min
- Fluid rates 5.5 – 6.0 bpm
- Specialized cleanout fluid with high carrying capacity and low pump pressures

2.875” OD Coiled Tubing
- Circulating wash technique 1000 ft bites (Not necessary POOH back to 10,500 ft
for each bite length)
- Cleanout speed 12 ft/min
- Fluid rates 6.0 – 6.5 bpm
- No specialized fluids required. Fresh water or light brines can be used

Looking at the different available scenarios described above it will be possible to clean
the wellbore from solids. The PowerCLEAN approach will help to identify the most
efficient cleanout procedure within the limitations of the well and the location. As
described the wellbore was simulated as a vertical drilled well. Changing the directional
path of the wellbore will influence the cleanout efficiency of each coiled tubing size
described. Also increasing the length of the large ID voids in the completion will
complicate an efficient cleanout.

For both wellbore types, Schlumberger is able to supply the coiled tubing strings and fluids
required for the most efficient cleanout scenario. The specialized PowerCLEAN fluids that
we offer have the following technical parameters.

- Density range: 8.34 ppg – 15.5 ppg
- Temperature stable up to 300 F
- Compatible with high density brines
- Fluid recycling possible

To improve the cleanout procedures on location is real-time Schlumberger offers the DPS2
services, which enables engineer on location to adjust the cleanout schedule based on real-
time recorded downhole data.

When the Coiled Tubing size able to be mobilized onto the location is limited due to
logistical or location limitations, Schlumberger can offer reverse circulating techniques to
remove solids from the wellbore. This technique is a proven cleanout technique in several
parts of the world. To perform this cleanout technique the standard dual check valve
assembly can not be run to enable flow up the coiled tubing string. For well control
purposes Schlumberger is currently looking into engineering solutions for reversible check
valves.

It is recommended that all CT cleaning operations be performed with the well in a slightly
overbalanced condition. This will minimize the amount of fluid lost to the formation
during washing operations (reducing damage) while preventing the well from flowing
while will introduce more solids into the wellbore. Fluid losses should be controlled with a
solids free pill (VES, HEC, or X-linked HEC fluid loss control pills). Calcium carbonate
should be avoided as it may interfere with the subsequent diagnostic operations.

Attached are some case histories of CT cleanout operations utilizing the PowerCLEAN
“integrated approach to fill removal” under similar of more demanding environments than
the two wellbore types given.

Also attached is information on CT TComp, which will allow for a safer and faster CT rig
up on all rig types, but provides active compensation when necessary on floating rigs and
platforms.




Also SPE 81729: Record Depth Coiled-Tubing Sand Cleanout and Gauge Retrieval should
be reviewed as it highlights the methodology, techniques, and design philosophy employed
by Schlumberger for CT cleanout operations of failed gravel packs.

















Diagnosing the Sand Control Failure:

Once the wellbore is deemed free of sand, diagnostic operations can begin. Traditional
methods and technologies as well as other potential methods to locate the sand control
failure will be presented. Locating the source of the failure can be summarized using one
or more of the following techniques:

1.) Gravel pack logs which may indicate voids in the gravel pack
2.) Production log (spinner) to identify locations of anomalies in fluid flow. However,
it is recommended to not flow the well during the diagnostics to prevent the
possibility of sticking the diagnostic tools. Therefore, the spinner log is proposed
to be run while injecting into the well.
3.) Multi-arm caliper to detect anomalies which may be a result of erosion on the ID of
the screen basepipe
4.) Outside base pipe measurements (i.e.screen jacket) to detect anomalies which are a
result of screen jacket erosion.

Wireline tension modeling would need to be performed with the exact wellbore geometry
and trajectory to identify the type of cable required, as well as identify the need for a
wireline tractor.


• Gravel Pack and Production Log

The SLB PSP (Production Services Platform Tool) + RST (Reservoir Saturation Tool) is
used to measure the following log responses in gravel packed wells:

1. GR/CCL is used for correlation
2. 4 arm caliper + relative bearing is used to determine cross sectional area and also
for determining low side of the casing or screen. (pictured below)
• 4 arm caliper can be used to detect any unconformities in the gravel pack
• The advantage over multifinger is that it the arms are thicker. Less issues
getting stuck in a “split”
• Spinner response can also be used to identify voids.

3. RST tool is deployed to measure the SIGMA of the formation for in-situ water
saturation monitoring. On the same descent, a gravel pack log is logged for
determining the quality of the gravel pack. The latter measurement is important for
two reasons:


• Qualifies the spinner response versus flow contribution. ie.. the spinner
response is in the base pipe, but how do you know its not a void or is it
really flow contribution? If the well is making sand, it may be better to run
the tools in “Injection” mode. This will minimize risks of “sanding up” the
tools.





















2)




• The gravel pack log also gives the completion engineer assurance that the
pack is good to minimize possible “Hot spots” or future erosion points. This
log is more representative of the gravel pack because the well has flowed
and the pack has settled . The conventional memory tool run with the
washpipe is run immediately after the gravel placement and may not be
representative of the gravel pack after things settled out. (see figure 2)



The PSP toolstring (minus RST) can also be run in memory mode deployed with either coil tubing
or slickline. The RST tool cannot be run in this mode because it requires surface power for the
minitron operation. The primary log responses for identifying failed screens would be the 4 arm
caliper, temperature, and the spinner response.











Figure 1: PSP + RST Tool
4 arm caliper + spinner shown in detail



















































Figure 2:
Example of a
gravel of a gravel
pack logging
procedure using
the PSP-RST
Explanation of the
RST silicone
activation gravel
pack technique

Multi-arm Caliper

For initial measurement of screen damage the mechanical caliper (PMIT Tool) combined
with the Production Services Platform (PSP) is the most suitable option.

The PMIT is normally used to determine casing or tubing condition but can be used to
identify whether sand production has caused damage to the screen base pipe. There are two
versions of the Sonde available a 1-11/6” with 24 arms and a 2-3/4” with 40 arms. Both
Sonde’s can be used in horizontal or high deviated wells providing tools are centralised.

Screen base pipe perforation size and spacing must be examined with respect to the PMIT
arms to prevent sticking or damaging the PMIT tool.


Outside the Base Pipe Measurements (i.e. screen jacket)


• PSDT

This is the PSDT - an experimental sonic tool based on the SCMT (Slim CBL tool Segmented
Cement Mapping Tool). It uses a bandpass filter to differentiate fluid/sand flow.

• Image Behind Casing (IBC Tool)

The new Cement Evaluation Tool (IBC) Image Behind Casing is used to detect the “2
nd
” interface.
(Figure 3). The example below is from a GoM well where the 9 5/8” casing and 13 5/8” casing
were logged with the IBC tool. The same principle could be used with a gravel pack screen using a
smaller 3.56” OD tool. (See figure 4)






























How do we prove the IBC could work to analyze failed screens?

1. Sample screen could be placed in the vessel to analyze various anomalies.
2. The IBC tool would be rotated inside the sample screen to determine if an accurate
image could be made to evaluate a failed screen. ie.. assume the base pipe is intact, but
the outer mesh is damaged.
3. In the case of a base pipe failure, the tool would detect it with the inner diameter.
4. The IBC tool can detect imperfections as little as 1” and measures around the pipe
every 5 deg.
13 5/8” casing
9
5/8”
Figure 3: IBC tool showing the
inner casing and the outer casing


The test vessel shown here was used for evaluating deepwater cement jobs using
LiteCrete, heavy wall casing, and heavy SOBM. (SPE paper 83483). The vessel has been
used to evaluate many different type of casings + well bore fluids to assure log quality
signal to noise ratio.





































Figure 4: Pressure Test vessel, the
USIT or IBC transducer requires
5000 psi for the transducer to
measure.
3.56” OD
Small
IBC tool
Sample
screen to
evaluate
could be
placed here
• Multifrequency Electronic Thickness Tool (METT)


The METT tool works on the principle of electromagnetism. It sends out a uniform
magnetic field. Any disruption to the field is caused by metal thickness or geometry
changes.

With this technique, the exact “as built” drawing of each screen joint would be required to
differentiate hardware changes from holes in the base pipe. The beginning and end of each
screen joint, as well as centralizers and connections would show up as disruptions in the
electromagnetic field. However, disruptions in the middle of the screen joint where there is
only the screen jacket would indicate the potential failure location of the screen jacket.

The functionality for the METT tool has been replaced by a variety of other Schlumberger
logging tools







Remediation of the sand control failure:


Schlumberger can provide a number of through tubing mechanical and chemical repair
solutions. Schlumberger would also like to have the opportunity to discuss potential
changes to the initial wellbore design which would subsequently make repair of a failed
gravel pack screen easier.

Chemical Repair

SandLOCK V is a gravel / epoxy resin system that sets up in the perforation tunnels and
wellbore (internally catalyzed). In many cases, it needs to be drilled out of the casing or
repaired screen or at least a small pilot hole drilled to allow unrestricted flow up the
wellbore. Compression strength is very high (> 2000 psi). SandLOCK V resin has also
been used to fix failed gravel packs. Reference SPE 52192.

K300 is a furan resin that is injected into the matrix, consolidating the formation near the
wellbore. It requires an HCl overflush to externally catalyze the resin. Many times an HCl
(or HCl followed by HF) is used ahead of the K300 in order to increase near wellbore
permeability and allow the resin to inject into all perforations. Reference SPE 39435.

The OrganoSEAL-R gel provides, in a single stage treatment, flexible formation
consolidation that eliminates formation failure due to reservoir depletion, repeated
drawdown cycles or fluid flow. The system works by forming a continuous rigid, but
flexible, gel in the pore spaces of the formation; the gel network prevents the production of
formation sand. The pore filling nature of OrganoSEAL-R does not require bonding
between the gel and the formation sand thus eliminating a pre-flush stage. The simplicity
of the OrganoSEAL-R system and the ability to use a diverting agent, coupled with the
flexibility of the crosslinked gel, gives effective consolidation with only 1 ft of penetration.

In the techniques mentioned above, the key is coverage across the failed screen area with
undiluted chemical. Placement technique and procedure has much to do with the success
of the treatment.


Mechanical repair

Straddle Technology: Straddling is a method by where blank pipe are placed between two
packers that ‘straddle’ across a failure to prevent further sand production. The setting of a
straddle system is accomplished by a number of runs. Firstly it requires the bottom packer
to be set on either on wireline or coil tubing; then a composition of snap latch / screen or
blank and the top packer to be snapped into the bottom packer on a second run. Placing a
straddle assembly in the lower completion has the same effect as a choke ie production will
depend on the straddle length and exact location of production intervals. Schlumberger can
provide packers and assemblies to straddle 5” and 5-1/2” screens.


Insert Screens: Schlumberger can provide insert screens for all size screen failures in a
variety of mesh configurations. Depending on the application, these can be used as “stand
alone” repairs or in conjunction with internal gravel packs.

Isolation plugs: In the even that the sand control screens failure was determined at the
bottom of the well, a mechanical isolation plug could be set. It is recommended that this be
set across a screen coupling to allow complete isolation. Schlumberger can run 3
rd
party
isolation plugs on e-line or CT.

PatchFlex:























































Summary:

Please contact Schlumberger for additional details of clarification on any of the information
provided in this document. We look forward to developing a relationship to provide fit for
purpose cleanout, diagnostic, and repair services in the event of a sand control failure.





Sand Production Occurs
Log to locate and
identify failure
Failure
Length short
( < 2 ft )
Set Isolation Plug
When failure is situated
at a distance of up to
5 % of open hole length
from shoe
Failure at
Toe of Well
Total Failure
Top To Bottom
Chemical Treatment
Placement with Coiled
Tubing and Inflatable
Packer
Repeat
Treatment
Test Well for
Sand
Production
Insert Screens
When failure is situated
at a distance between
5 % - 20 % of open hole
length from shoe
Chemical Treatment
Placement with Coiled
Tubing and Inflatable
Packer
Failure at Top
or Middle of
Screened
Section
Chemical Treatment
Placement with Coiled
Tubing and Inflatable
Packer
Tubing Patch
Consider
Tubing Patch
Straddle

Abandon & Sidetrack
Cut blank pipe above
screens and fish packer
and blank pipe . Place
cement plug .
Failed Sand Control Screen
Repair Flow Chart

Yes No
Yes No
Yes No
Yes
No
Return well to production
Well Still
Produces Sand

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close