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Click here to read
the "General RFI-Insert Installation Steps"
Insert Pump Style
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DHI reserves the right to
change specifications or information appearing
in this procedure without incurring any
obligations for equipment previously or
subsequently sold, leased or installed.
This procedure and its Illustrations may
not be copied without DHI's prior permission.
DHI and its affiliated companies continue
to stress safety as their number one priority.
DHI expects the same dedication to safety
from their independent contractors, and
anyone else at the wellsite. DHI and its
affiliates cannot and do not supervise or
control the manner and means by which DHI's
contractors carry out work assignments,
DHI must rely upon DHI contractors and other
wellsite personnel to adopt, implement and
enforce rules and practice necessary for
the safe performance of the proposed work
outline in this procedure. Therefore, DHI
is not responsible for any harm, loss or
damage caused by following these procedures.
See DHI's Manual of Practice, Appendix B
for safety procedures, protocols and contracts.
In addition, see the terms of the contract
for more information. |
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First, read and understand DHI's safety procedures and take
the proper safety precautions before attempting a DGWS system
installation. For a copy of DHI's safety procedures see Appendix
A, in DHI's Manual of Practice. The DHI technician must always
review the RFI system, equipment checklist and this installation
procedure prior to the RFI installation.
In addition, to DHI's safety procedures understand and insure
that the well has been properly prepared. The well preparation
can consist of testing, scrapping, swabbing, cleaning, logging,
perforating, fracturing, treating, drilling deeper, inserting
casing liners, cementing and etc. See DHI's DGWS well preparation
procedures in Appendix A, and see section 10.0 of DHI's Manual
of Practice. Covering all general re-completion practices
are to numerous to mention in this procedure or in the Manual
of Practice. Therefore, a DGWS installation must be supervised
and or performed by a certified DHI trained technician that
is skilled in the art of re-completing and working over gas
wells.
If able, obtain samples of produced water from the production
zone and obtain samples of water from the disposal zone to
verify water compatibility later if needed. There should always
be a DGWS or equivalent disposal permit for the given well
before the RFI system is installed. See DHI's Manual of Practice
for permitting information. The gas well must always be killed
with appropriate kill fluids to avoid any formation damage.
See DHI's Manual of Practice for more information on appropriate
kill fluids. Before any RFI installation, an injectivity test
must be performed and analyzed. If required by the regulatory
commission, an MIT must be performed on the production casing
to insure there are no casing leaks. In addition, see DHI's
Manual of Practice for more information on injectivity tests.
The DHI technician must perform an accurate daily chronological
report or journal before, during and after the RFI installation.
This report must include every function or task performed
by DHI and notes of what is being performed by other personnel.
Insure that the rig operator/crew, packer technician, well
operator, pumper and any other critical personnel fully understand
the installation and operations of the RFI system. Field training
will be required. See DHI's Manual of Practice for training
aids and information. Before the installation, insure that
the client has provided or will provide all of the necessary
equipment that they have been specified by DHI to provide.
This equipment could be any and all surface equipment, tubing,
rods, packer, pub joints, polished rod, polished rod liner,
pony rods, on/off tool, crossover boxes, couplings, water
trucks, corrosion inhibitor/defoamer and etc.
The DHI technician must always develop a check list of the
tools, training aids, chemicals, lubricants, safety equipment,
testing equipment, parts and other equipment required to take
to the wellsite prior to departing the DHI facilities. This
will eliminate forgetting to take essential parts. DHI must
always take extra parts or extra systems to avoid costly down
time if original parts are damaged and must be replaced.
Prior to any RFI installation, the DHI technician must be
furnished with a complete well file and history along with
RFI specifications, maps and directions to the wellsite. DHI
engineering must always first approve that the well is a DGWS
candidate and have specified a complete RFI system.
Unless otherwise approved, DHI must be present at the wellsite
for every RFI installation and reinstallation.
IMPORTANT NOTES TO KNOW
Swabbing
A swap is a rubber-faced device with a hollow center mounted
on a hollow mandrel with a pin joint on the upper end to connect
to a swab or wire line. A check valve is installed on the
lower end of the swab tool and position to open upward. The
rubber-faced closely fits the inside of the tubing. The swab
tool is pulled through the tubing to lift the fluid and sand
"trash" to the surface from the well.
Swabbing must never be conducted in the tubing string when
the outer section of the RFI system is installed on the bottom
of the tubing. If swabbing was conducted with the RFI outer
section installed, the "trash" would enter the tubing
string through the BSM intake holes and the "trash"
could build up inside of the RFI outer barrel, BSM, and down
into the packer. If water is then flushed into the tubing
after the swabbing was complete, the remaining "trash"
would simply go back out of the BSM intake holes and the "trash"
would settle back down on top of the packer and is ready to
be pumped into the RFI system later. This is if there is not
a larger remaining amount of "trash" that could
settle back into the RFI system. In addition, the "trash"
can become lodged in the outer section of the RFI system if
swabbing is conducted.
Therefore, to properly swab a DGWS well, both the RFI outer
section and packer must be removed.
Swabbing in the casing should be avoided and swabbing should
only be conducted in a tubing string. This will eliminate
the chance for the swabbing tool to become lodged in the casing.
However, before swabbing a casing scraper or another suitable
type of cleaning method may have to be used to clean deposits
(as of scale, iron sulfite, paraffin and etc.) from the casing
inner diameter.
Sand and Other Large Particles
Sand is the product from a disintegrated rock, which is
granular, loose, hard and a siliceous material. The major
constitute of sand is silicon dioxide (SiO2) quartz. All
and any sand must be cleaned out of the wellbore prior to
any DGWS installation.
In DGWS systems, no water is produced to the surface. The
only way that sand can be produced to the surface is when
a liquid (water) is acting as a delivering fluid. Therefore,
sand can't be produced to the surface with a DGWS system.
However, a small amount of sand can be separated from the
gas and water and stored downhole in the rat hole (pilot
hole). Soon as the rat hole is full, the DGWS system and
packer must be retrieved and the sand swabbed out. Therefore,
the rate of sand production compared to the volume of storage
"rat hole" must be considered to determine how
often the storage will have to be cleaned out.
DHI considers sand as another fluid that can be produced
from the production zone along with the gas and water. Since
most sand can't be disposed into a disposal formation then
it must be stored. The size of the sand particles must be
analyzed. If the sand particles are too small, they will
able to enter into and plug the disposal formation. If the
sand particles are large enough, they will not enter the
disposal formation and fall to the storage "rat hole".
As the fluid is being injected into the disposal formation
if these larger particles begin to bridge the disposal formation
the bridge will be held there by the force of fluid motion.
However, when the fluid stops injecting into the disposal
formation (at the top of the upstroke and the bottom of
the downstoke) most or all of the bridge will fall into
storage.
Since the sand is being pumped through the RFI system the
strainer/filter must be sized to allow the larger particles
of sand to enter the pump intake. The sand is produce form
the production zone, falls down on top of the packer where
the RFI pump intake is located, the sand flows through the
strainer and is pumped through the RFI system, the sand
then flows through the packer out the back pressure/check
valve and then falls to the storage "rat hole".
Sand production can be eliminated or reduced in the completion
stage by the use of sand consolidation methods or gravel
pack filters. When drilling and completing a DGWS well the
size and amount of sand production must be considered.
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STEP #1
When transporting a RFI system it is essential to protect
it from bending, dropping or other damage and its extremities
must be covered to prevent foreign matter from entering
into its openings. In addition, insure that the RFI
system is securely fastened down and supported. If using
side racks, be careful not to overload the rack structure.
In the state of Oklahoma, |
if the RFI system is on a side rack and
the system extends from either bumper then a red flag
must be attached to those extended ends. This law also
applies to trailers. In addition, in the state of Oklahoma
there are no illegal extended lengths. However, to prevent
bending, the RFI system should not extend out further
then three feet from either bumper. Check with local
state officials for size and weight limits.
The tubing and rods must be inspected, tested, reconditioned
and clean before entering the wellbore.
It is the responsibility of the operator (client) to
pull or cat in DHI vehicles if lease roads are unassailable
or drivable.
Insure to check and identify the type of wellhead. The
wellhead must be a slip type wellhead so that the tubing
can be set in tension. |
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STEP #2
A RFI system should not be disassembled at the well
site for any reason, nor should it be laid on the ground
prior to running it into the well. If it must be laid
down, it should be supported on 2X4's or stands spaced
not more than six feet apart. However, in remote locations
with the proper tools and DHI personnel the RFI system
can be disassembled.
STEP #3
Prior to running the RFI system, it should be checked
for freedom of plunger action. It must be inspected
to make sure all caps, plugs and or protective wrappings
have been removed. In addition, inspect for shipping
and handling defects or debris.
Do not use any unspecified wrenches on any of DHI's
equipment.
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STEP
#4
At the well site or at a shop facility, connect
both the handling sub and the overshot of the tubing
on/off tool to the RFI system. See figure #1 shown below
in Step #5. Note: that all RFI systems must have a tubing
on/off tool for safety practices.
In, addition, with the packer representative, connect
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the lug nipple of the tubing on/off tool
and the below packer check valve (if required) to the
packer assembly. (See Schematic on Back Page)
If the distance between the pump intake and producing
zone is not critical in the design then a 10' tubing
sub should be used between the BSM and the tubing on/off
tool. This will provide a small amount of volume for
"trash" to accumulate.
CAUTION: Do not over torque any connections. |
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STEP #5
A DHI technician must now tally the length of the RFI
system. See the figure directly to the left for dimensional
datum points. Measure and record the four dimensions.
NOTE: It is the packer representative's responsibility
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lug nipple, packer and check valve assembly. However,
it is DHI's responsibility to insure that this is performed.
All tally tolerances are ± ¼" (overall). |
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STEP #6
Instruct the rig crew to hoist the RFI system (figure
#1) to the side of the well opening. Then lower the
overshot over the lug nipple of the packer assembly.
Note, that the packer assembly must be place on a protected
surface, such as a timber. Insure that the tubing on/off
tool is now properly engaged. The RFI system is now
attached to the packer assembly.
CAUTION: Be careful when picking up the RFI system.
The use of a short tubing sub will help. RFI systems
over 24 feet in length will require special handling.
Always lift or hoist the RFI system in such a manner
as to prevent bending, thus creating a permanent bend
or kink in the tubes.
If there is excessive scale, particles, corrosion or
any substance that has came from the wellbore be sure
to take a sample of it so that it can be analyzed later
if required. |
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STEP #7
The tubing by now should have been tested, inspected,
re conditioned and clean. The tubing can be lowered
through a stripper head to aid in cleaning if necessary.
The rig crew must now lower the RFI system with the
packer into the well (casing) to DHI's specified depth.
This procedure is performed under the packer representative's
supervision. The tubing should be lowered into the wellbore
at a rate no less then 5 second per single joints or
10 seconds for double joints. This will help prevent
particles from breaking off of the casing wall and falling
into the wellbore. It is the rig crew's responsibility
to tally the tubing and relay this information to the
packer representative. In addition, it is always good
practice to have a tally |
witness while tally's are being performed.
Again, all of this is performed under DHI's supervision.
NOTE: Before lowering the RFI system, with packer representative,
note the type of wellhead. This may become critical
when trying to hang off the tubing in Step #9 of this
procedure. The type of well head must be known and the
well head must be prepared before the RFI installation.
CAUTION: When the RFI system and the packer is close
to the predetermined (if possible) fluid level, the
lowing process should be slowed down to avoid a jarring
action when entering the fluid. This slow process must
be continued through the fluid until the pump is properly
located. This will help prevent shearing of the packer
elements. |
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STEP #8
After the packer is properly positioned to the correct
depth, the annulus is flushed with appropriate water
and the packer representative must then set the packer.
NOTE: DHI recommends a Baker neutral set "Loc Set"
packer for all RFI installations. These packers will
be set with between 15k and 30k pounds of axial tension
with on an average of 25k pounds of axial tension. However,
it is the packer representative's responsibility not
to damage the tubing string by exceeding the tubing's
yield strength. DHI is not responsible for the packer
performance or installation.
In wells with a packer depth less the 1500' a tension
packer with 40,000 lbs of shear force can be utilized.
Pre-Inform: DHI must pre-inform the packer representative
of the following: In RFI applications the isolation
packer also serves as a tubing anchor. In RFI systems
the ? force across the packer is different that what
is common in most packer applications. The delta |
force across the packer must be predicted
by DHI and communicated to the packer representative.
The delta force prediction along with the packer depth
will aid in deciding the amount of tension that is required.
If sand or other particles are going to be a displaced
through the RFI system and there is very little rat
hole storage below th e packer then a below packer valve
(BPV) should not be used. See DHI's Manual of Practice
for more information.
After the desired amount of tension is achieved the
tubing is securely fasten "hung off" on the
tubing head. |
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STEP #9
Surface plumbing is now performed to the wellhead. For
example, the flow tee is assembled, valves are attached
and connections are made. All wellhead plumbing configuration
is specified in conjunction with DHI and to DHI specifications.
See DHI's MOP for more information.
Insure that the wellhead is prepared for "running
in" of the insert pump and rods. |
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STEP #10
First, a DHI technician must perform steps 2 and 3 with
the insert section of the pump. The rig crew must now
lower the insert pump down into the tubing and into
the RFI system. A rod wiper disk ring can be used to
help clean dirty rods. The rods must be clean and installed
at the same rate of speed as the tubing was. When the
insert pump is close to the predetermined (if possible)
fluid level, the lowing process should be slowed down
to avoid a jarring action when entering the fluid. This
slow process must be continued through the fluid until
the pump is properly seated. This will prevent bending
of both the rod string and the valve rod.
CAUTION: After the pump is seated, softly jar
the pump two or three times to insure that the top hold-down
is fully engaged. However, do not jar so hard to cause
damage to the pump or the RFI system. |
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STEP #11
With assistance from the rig crew, the DHI technician
must now space out the rod string. However, the rig
operator is responsible for performing this task correctly.
First, mark the top rod accordingly to establish a datum
point. Un-seat the pump and lay out the top sucker rod
(with the datum point) and with pony rods and the polished
rod assemble accordingly to the marked rod. It is recommended
to lay down the polished rod with one extra sucker rod
and then pick up the polished rod with the stuffing
box to pack off and seal the tubing. In addition, this
procedure is very common in completing wells and will
be fairly easy and understood by a technician that is
skilled in the art of completing wells.
Important: Be sure that there is enough length on the
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polished rod to completely reciprocate the plunger
assembly from the very top to the very bottom of the
working stroke. In addition, allow for adjustment
of lowering and rising of the plunger assembly. This
will be very important for leaving room for DHI's
monitoring equipment (load cells) and for eliminating
gas locking in the future.
Important: Before permanently seating the insert pump
into the tubing, flush out the tubing with appropriate
water from a pressure truck with of at least 2X the
volume of the tubing. In addition, use only the appropriate
fluid. First, insure that the pump is un-seated and
completely out of the RFI System.
After the pump is re-seated, softly jar the pump two
or three times to insure that the top hold-down is
fully engaged. However, do not jar so hard to cause
damage to the pump or the RFI system.
When spacing out the down stroke of the rods/pump
plunger one must estimate the amount of rod stretch
that will occur at the end of the stroke. Slowly lower
the rods and allow the top valve rod connector to
tag the top of the DSB at the top of the pump. Slowly
pick the rods/valve rod up the correct distance required
to not allow the valve rod to pound the DSB tool.
Then clamp off at the top of the surface stuffing
box and set the pumping unit at its full down stroke
and clamp off at the bridle. See Step #14 for more
information.
NOTE: Brief tapping is allowed if gas locking is suspected.
However, the DHI technician should be consulted.
CAUTION: Slightly tighten the surface stuffing box.
Note that there will be no surface pressure in the
tubing. This precaution will prolong the life of the
surface stuffing box seals and reduce the polished
rod friction. Note that the reduced friction will
lower the peak load on the pump.
For
anti-gas locking procedures see DHI's Manual of Practice.
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STEP #12
Next, with the insert pump completely seated install
the DHI fill-up connections and tooling/vent to the
tubing head. Connect the water truck hose to the DHI
tooling and begin to fill up the tubing.
With the pressure truck, flush in the treated water
into the tubing string slowly (around a 1" free
flow stream). This can take a long time (30+ minutes).
With the treated water, completely fill the tubing
(top off). The fluid level in the tubing should now
be at the surface with the insert pump seated.
Pressure against the insert pump with 500psi in the
tubing at the surface to insure that the insert pump
is seated and there are no leaks.
NOTE: If using fresh water instead of saltwater then
the fresh water must be treated with 2% KCL.
Important: A pressure truck is required so that the
fluid can be forced down the tubing if required. Note
that up to 500psi in the tubing at the surface may
be required.
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Water Treatment: Treat the water with corrosion inhibitor
(not a scale inhibitor). Treat with a ratio of 1 gallon
of inhibitor to 10 barrels of water. This corrosion
inhibitor is also known as packer fluid or an oxygen
scavenger.
Optional: A de-foaming agent may be required if foaming
is a problem. However, some corrosion inhibitors contain
a de-foaming agent. Check with the chemical company.
Tubing Volumes:
2 3/8" Tubing with ¾" Rods: 0.0033
Bbls/ft
2 7/8" Tubing with 7/8" Rods: 0.0050 Bbls/ft
To order the correct amount of water for this entire
procedure, calculate the volume of the tubing with
the above figures and multiply it by at least 5 times.
In addition, have a pressure truck with the correct
quantity of water at the well site before Step #8
begins.
Time may be required to allow for trapped or dissolved
air to work out of the water. This air volume will
have to be replace with water later.
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STEP #13
Do not stroke the pump with a full working stroke at
high speeds with the rig (long stroke). If long stroking
is desired it must only be performed with strict DHI
supervision and instructions.
CAUTION: Do not unseat the pump.
Install the load cell and any other equipment such as
a polished rod saver, polished rod liner, clamps and
etc. Next, hang off the polished rod by connecting the
rod to the pumping unit and space out for proper operation.
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STEP #14
The DHI technician must now begin the initial start
up procedures for the RFI system. Before the initial
start up check and record the static fluid level. During
the initial operation, be sure to watch and listen for
any signs of improper operation. Be sure that the pump
is spaced properly and not making contact, "pounding"
either at the top or bottom of the stroke. The system
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should be checked periodically to insure
that the traveling and standing valves are spaced as
close as possible without "pounding" the pump.
In addition, the fluid level in the tubing must be monitored
to monitor the performance of the DSB tool and to insure
there are no tubing leaks (see section 8.4 in DHI's
Manual of Practice). Insure that all surface equipment
is set and operating correctly.
NOTE: As the fluid level in the annulus is being pumped
down, as the injection zone is being charged or opened
up and as accelerations change, the net forces on the
plunger will change. This will result in a different
elongation of the rod string. Therefore, the RFI system
must be checked periodically especially at start up
to insure that the traveling and standing valves are
spaced as close as possible without "pounding"
the pump. Always keep in mind that in time the rod string
can elongate once heated if they are installed in cold
weather and or into relatively cold fluids. In contrast,
the rod string can contract once cooled if they are
installed in hot weather and or into relatively warmer
fluids. The RFI system should never be installed and
not started up as soon as possible. This is because
of the following reasons:
- Solids will settle down to the pump intake
(BSM) from the well fluids in the casing annulus
and when the pump is first started up the
system will have high concentrates of solids
to displace. This can be damaging to the DGWS
system.
- Most importantly, a film can build up on
the inner wall of the pump barrel where the
plunger is not resting and when the plunger
begins to reciprocate the plunger will become
lodged in the "dirty" section. This
plunger sticking or hanging up problem is
very common in wells that have been shut down
for a long period. In addition, this is very
damaging to the DGWS system.
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Solutions to this problem is one, don't install the pump
until it is ready to operate it or two, run it for short
periods of time until it operates constantly. |
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STEP #15
Initial monitoring and control of the RFI system is
very important.
See DHI's Manual of Practice for DGWS monitoring and
control. In addition, do not allow for the RFI system
to severely "pump off" and monitor for gas
interference or gas locking.
Important: Only after the RFI system is operating
with no problems (4 to 6 hours) can the DHI technician
leave with the well site with the RFI system operating.
Lastly, insure that the well site is cleaned up and
the proper DGWS notice signs are visibly located.
Performing accurate dynamometer and acoustic surveys
offer viable data that can be analyzed to
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determine the injection pressure and
the performance of a given DWGS system. Using the knowledge
gained from the analysis of the data, DHI will be able
to correct inefficient operations and institute more
efficient procedures, which will result in increased
production, controlled injection pressure, lower operating
costs and longer tool and equipment life. Monitoring
injection pressure is very important and is one of the
keys for DGWS success. Monitoring the following ten
items are important to insure that the given DGWS system
is performing properly.
1. Hall Plot
2. Gas Production and Injection Rate vs. Time
3. Gas Liquid Ratio (GLR) vs. Time
4. Injection Pressure vs. Time
5. Condition of DGWS Strainer/Filter
6. Condition of DGWS Equipment
7. The Surface Pumping Unit is Balanced
8. Insuring that the DGWS System was Designed Properly
9. Insuring that the DGWS System is Operating at an
Optimal Speed
10. Monitoring and Maintaining all Surface Equipment
Most of the common concerns with DGWS equipment failure
are the same concerns as conventional plunger pumping
technology. However, there are differences. See DHI's
Manual of Practice (MOP) for more information.
DHI should at this point discuss a corrosion prevention
program with the operator or filed supervisor.
NOTE: If injection rates begin to fall off or the peak
loads substantially change, the pump or RFI system should
be analyzed first then pulled for inspection and or
repair as soon as possible.For the first 30 days of
operation, DHI must be supplied with a daily report
to insure proper operation. See DHI's Manual of Practice
for an example of a daily report.
This procedure is approved and in DHI's practice as
of July 28, 2002. |
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