VII. Implementación
4. Implementación de “Drawing App”
Introduction
Figure 94 illustrates the differences between EGP and ESS in the case of a 20 API oil reservoir drilled with a 6” open-hole. ESS when installed would have an ID of at least 5” and up to 5.5”. For a GP, the options are to use a 3.5” screen (or a 2.7/8” screen if using shunt tubes). The tubing intake curve (VLP - Vertical Lift Performance) is assumed to be the same for all completion types. The Inflow Performance (IPR) curves for the various ESS/EGP completions indicate the ability of the reservoir to produce through the sand-face completions. A “solution point” is where the VLP and IPR curves intersect and this indicates steady natural flow. The solution points vary by over 4,000 bpd between ESS and the 2.7/8”
EGP completion.
Figure 94: Productivity comparison for a various ESS & EGP completion options in a 6" heavy oil producer
Figure 95 compares the flow contribution of five equal intervals along the length of the well.
The ESS completion clearly has a more even inflow, which of course has several advantages in terms of reservoir management:
• Production rates considerably more than equivalent gravel pack rates
• Reduced and more even draw-down for production along the wellbore length (less prone to sanding and better mud-cake lift off).
• Even production inflow giving more efficient reservoir drainage
• Reduced risk of early water & gas breakthrough
• Well slimming
General Sand Control Information Manual External Revision 1.0 - 106
Figure 95: Flow contribution along well bore of various ESS & EGP completions
These benefits are derived purely from the increased ID available for production. The productivity gains of using ESS in a 6” hole are roughly equivalent to that of a standard EGP in a 8.5” hole, hence the use of ESS allows the operator to slim down his well. This concept is referred to as “well slimming” and is causing much operator interest in this product.
Additionally, there are two further benefits to an ESS deployment. Firstly, the more even draw-down along the well should improve the consistency of mud cake removal along the well bore length. Secondly, there will be some skin improvements in the near well bore area as less fluids will have been pumped with ESS than in an EGP. In horizontal wells, this benefit is less apparent however.
The reduction and elimination of the annulus gives the following benefits:
• Formation sands/clays/fines do not mix in the annulus and plug completion
• Zonal isolation & control is possible
• Increased number of remedial options
• Remedial options still provide a sufficient ID for high rate production
• Production logging data is useful.
ESS
Construction
The ESS is made of metallic components designed to withstand the toughest well environments. It combines four basic elements to deliver sand control in various well conditions while maintaining high reliability, longevity and optimum hydrocarbon production.
Its basic components are:
• Base pipe
• Filtration media (Petroweave)
• Outer protection shroud
• Integral expandable connector
Figure 96: ESS Construction
Filtration Media (Petroweave) Expandable
Base-Pipe
Petroweave attached to base-pipe
Expandable
Protective Shroud
General Sand Control Information Manual External Revision 1.0 - 108 Figure 97: ESS Assembly
Top connector houses the expansion cone.
ESS Joints are normally supplied in 11.6m lengths and are 11.5m when made-up (4.71” make up loss)
Shoe assembly with cone catcher After expansion the cone is left secured in the cone catcher at the base of the ESS assembly.
Base Pipe and connections
The ESS base pipe is a robust Expandable Slotted Tube (EST) capable of expanding up to 80% in diameter, depending on the size of base pipe selected. The base EST provides a very large inflow area for the produced fluids.
The base pipe has the ability to go through short curvature radius making it an ideal choice for deployment in horizontal holes. Because the pipe is slotted, the ESS becomes more tolerant to larger bending moments, displaying class leading flexibility (ie 5-1/2” ESS can be deployed through 30°/30m doglegs; it will fail only at 43°/30m dog legs).
The ESS joints have integral expandable connectors with no blank areas to obstruct flow.
Each joint has both a pin and a box connection, which are designed to provide a mechanical interlock (for strength) during deployment and expansion. The Petroweave filter on the connectors overlap after screwing together the ESS joints, providing a sand tight connection. The connector is a critical element of the ESS system and has been extensively tested to prove sand exclusion capability after expansion.
The flush connectors are made of Super Duplex Stainless steel to provide high tensile and bending strength (ie tensile yield of the 5-1/2” ESS is 230,000lbf).
Figure 98: Stabbing in ESS pin connection
Figure 99: ESS Connections
Filter Medium (Petroweave)
The filter medium Petroweave is a metal weave designed to provide maximum filtration/flow area, thus maximising resistance to plugging effects. The Petroweave is manufactured in both 316L and Nickel Alloy (Incoloy 825) offering compatibility with most corrosive well environments. Following extensive testing to select the filter medium, Petroweave filters with nominal sizes ranging from 150 micron to 270 micron were chosen as elements of the ESS to suit different sandstone types and operational preferences.
General Sand Control Information Manual External Revision 1.0 - 110
The Petroweave is attached to the base-pipe using a process that ensures the integrity and uniformity of the sand exclusion apertures. The filters overlap each other along the length of the base pipe and accommodate the circumference increase during expansion while remaining sand tight. Correct selection of the Petroweave filter should aim to restrain the load bearing grains of the formation sand from passing into the well-bore. These grains will naturally bridge the formation sand against the ESS, controlling sand influx in the process.
Figure 100: Expanded ESS
The sand control capability of the Petroweave is enhanced because the screens are placed in direct contact with the well-bore, reducing movement of formation sands in the annulus.
As a result, the well-bore remains stable throughout the life of the well and risk of hole collapse is decreased. Furthermore, with restricted fines migration, near well-bore impairment is reduced. In cased hole applications, the ESS will outperform traditional screens by eliminating annular fill.
Outer Protection Shroud
The outer protective shroud ensures the filter medium is not damaged when running the screens in hole. It also acts as the encapsulating layer, ensuring the filter media remain tightly sandwiched together following the completion of ESS expansion.
Expandable Isolation Sleeve (For Information)
The Expandable Isolation Sleeve (EIS) is a complimentary product to the ESS designed for use in wells where zonal isolation may be required during the well life. Current practices for open hole zonal isolation involve the use of External Casing Packers, which have proven with time to be unreliable due to cement shrinkage and complex installation procedures. The EIS is constructed in a similar manner to ESS enabling it to be made up in the ESS string in the same manner as the ESS at the correct space out. EIS uses a HNBR rubber coating on the protective shroud, which is energised against the formation during the expansion process preventing annular flow. Should it be necessary later in the field life the EIS may be re-energised against the formation using inflatable packer set inside the EIS.
Expansion Systems
Solid Cone
The solid cone (shown below) is pre-installed in the ESS ETC (Expandable Top Connector), fitted with the standard 7.375” OD tungsten carbide cone ring (to suit 8.500” hole). The solid cone is easily removable from the ETC if so desired. The body is a two part assembly, which holds the cone ring. The cone holder is supplied with a suite of cone rings, to suit irregular hole sizes. On the outer surface of the cone body are four slip segments. These locate in profiles in the EBC (expandable bottom connector) to ensure the cone remains at the bottom of the ESS. Tests have shown that this feature is NOT necessary, but is included as an additional safety feature.
Figure 101: Expansion Cone
To date, the majority of ESS field expansions have been performed using this method. A second expansion method
integrates the cone with the expansion mandrel so that the cone is retrieved. Whatever method is utilised it is essential that the borehole geometry is maintained within the surplus expansion limits of the ESS in order to achieve both full expansion and borehole support.
Expansion Mandrel
The expansion mandrel shown below is deployed on the end of the expansion string on all solid cone, two trip systems. The mandrel passes through the cone body, centralises in the unexpanded ESS and engages with the inner shoulder in the cone body.
Figure 102: Expansion mandrel
Rotary Expansion
A range of Rotary Expansion tools is in development, which can be deployed on drill pipe or coil tubing. Driven by a PDM mud motor, they improve the deployment options and expansion performance of the expandable product line.
The rotary expansion tool is available as a selective device which will pass through restrictions (eg packer bores). Following deployment and expansion
the tool can be functioned to “collapsed mode” allowing retrieval. Experience suggests that the use of rollers for expansion reduces the required expansion forces by 66 – 75 % by eliminating friction, thus extending the length of ESS that can be expanded in extended reach wells. Additionally, this system can be retrieved and reset to a smaller open OD should a restriction in the well be encountered.
Figure 103: First 4” Compliant Rotary Expansion System (CRES) tool as used on Shell Brigantine
Figure 104: Non Compliant Rotary Expansion Subassembly
General Sand Control Information Manual External Revision 1.0 - 112 Figure 105: Compliant Rotary Expansion System
The CRES tools consist of roller cones in the nose which expand the EST to a fixed size.
The balls in the compliant section above then move out under hydraulic pressure and force the EST outwards still further to ensure it conforms to the bore-hole wall. This system is still under intensive development and its first application occurred in October 2000 when it was used to expand 4000ft of 4” ESS in a North Sea well. This first use of the system actually used two trips, the first trip used a “conventional” fixed cone system to expand the ESS out initially as a precaution. The second trip was with the CRES device which expanded the screen out to conform to the well-bore.
The intention is of course for rotary expansion in one trip (two trip deployment) and this should be achievable by year end 2001. Longer term, the intention is to deploy ESS and expand in one trip (single trip deployment/expansion).
ESS Mechanical Properties
TESTED MECHANICAL FIGURES
The following figures are the results of testing to destruction under laboratory conditions.
These figures are for information only and on no account should be quoted for operational issues. A safety factor should be adopted at all times, and as such, the rule of thumb for operations is to divide these figures by 2.
2 7/8" 3.5" 4" 4.5" 5.5"
Tensile Yield (lbf)
100,000 100,000 125,000 175,000Tensile failure (lbf)
134,000 140,000 188,000 230,000Compressive Failure (lbf)
63,000 66,000 107,000 122,000Bend (°/100ft)
53 43 42 43Point load collapse
resistance (psi)
2,240 2240 2240Rotational Torque
(Ft-lbf)
3,500 3,500 3500Expansion Force (lbf)
30,000 20,000 20,000 25,000 35,000Table 27: ESS application limits
ESS
Size (in) Pipe OD Wall
Thick Pipe ID Wt/Ft Box OD Box ID Filter Width
Max Final
OD
2.875 73.03 7.01 59.01 2.67 83.8 59 200 114.42
2.875 0.28 2.32 5.89 3.30 2.32 7.87 4.50
3.5 88.9 5.49 77.92 3.49 99 74.5 120 133.35
3.500 0.22 3.07 7.70 3.90 2.93 4.71 5.25
4 101.6 5.74 90.12 4.2 112.4 87.3 140 158.75
4 0.23 3.55 9.26 4.43 3.44 5.49 6.25
4.5 114.3 6.02 102.26 4.97 124.5 100 160 184.15
4.5 0.24 4.03 10.96 4.90 3.94 6.28 7.25
5.5 141.3 6.55 128.2 6.74 151.5 127 200 232.41
5.56 0.26 5.05 14.86 5.96 5.00 7.87 9.15
Table 28: ESS dimensional data (mm & inches)
ESS Installation Procedures
The ESS system can be installed using either a one-trip or a two-trip system. Note that the one trip system requires further development to allow this to be applied over all ESS sizes and systems. The two-trip system is currently used as standard.
In the two-trip system, the ESS is conveyed in the same manner as conventional non-gravel packed screen, ie below a liner hanger or packer. The ESS and liner hanger can be run with a concentric wash string which allows circulation through the ESS via a wash down shoe string. The wash-string makes the running string stiffer and this factor should be considered in Torque & Drag (T&D) modelling. The use of the wash-string, although a complication, may be required for well control and mud conditioning considerations and this is a drilling &
client decision.
Torque and Drag
Before any ESS installation, it is necessary to run a Torque & Drag simulation to ensure:
• The ESS can be safely deployed to TD without exceeding its mechanical limits or inducing helical buckling into the string
• The ESS can be safely expanded in its entirety without the expansion string exceeding its mechanical limits or inducing helical buckling into the string.
• Hydraulic factors do not limit the activation of key system components, eg liner hangers or expansion cones.
Weatherford Completion Systems make extensive use of the Landmark Torque and Drag software package to determine whether a particular ESS can be safely deployed in the well.
The interval length is not limited by hydraulics as is the case with gravel packing. Rather the limit to the length of ESS that can be expanded using conventional “weight on bit” from the
General Sand Control Information Manual External Revision 1.0 - 114
drill-string (or with mud pump hydraulic power) is limited or dependent on a number of factors:
• The trajectory of the entire well to surface
• The availability of required drill-collars, drill-pipe, etc
• Prevailing hole sizes and friction factors, often dependent on mud types, formation types, casing grades
• The type of expansion mechanism used.
The use of the CRES tools is expected to extend the envelope of possible candidate wells.
Physical testing representative of field conditions is difficult to simulate in test wells as they do not contain long reach sections where achieving WOB is difficult. To date, the validation and fine-tuning of the T&D model has been achieved via observation of expansion performed in real applications. Most wells and certainly all highly deviated or horizontal applications would be modelled when full well data was made available to ensure the appropriate weight on bit (no of drill collars) can be achieved.
ESS Expansion Forces
ESS Expansion is achieved by slacking off weight from the expansion string to lay down weight on the expansion cone. For 5.5” ESS, the following forces can be expected.
• Unlubricated expansion forces, as expected in testing, can range from 35k – 50k Lbf
• Lubricated expansion forces, as expected down hole, can range from 35k – 40k Lbf.
The above information is relevant to a one or two trip system with a solid Tungsten Carbide expansion cone. Tests conducted with the 3.5” roller cone show expansion forces of 4000 lbf, compared with the 12,000 – 16,000 lbf expansion force using a solid cone.
First Trip
Having made up all the T&D pre-determined ESS joints with blank pipe and packer/hanger, the entire system is run to depth on a drill pipe work string. When on depth, the packer is set within the liner, using conventional procedures; ie drop ball, pressure up to set, anchor test and pressure test. The running tools would then be released, and the work string retrieved to surface.
Second Trip (Conventional Cone System)
The expansion string would consist of the Expansion Mandrel and appropriate drill collars and heavy weight drill pipe determined by T&D simulation. Once the Expansion Mandrel is landed on the Expansion Cone located on the top of the ESS, slacking-off weight shears out the locking screws of the Expansion Cone, and the expansion would be initiated. Expansion would continue until the cone lands at the bottom of the ESS. The expansion string would then be pulled and retrieved back to surface.
Typical running time for 150 m of ESS (13 joints) set at 2,500m With the Two-Trip System
OPERATIONS TIME
1. Make-up-up bottom screen joint c/w cone catcher profile and bull plug 2. Make up ESS joints
3. Make-up top joint of ESS complete with pre-installed expansion cone 4. Make-up crossover to blank pipe
3 hrs.
5. Make-up blank pipe space out pipe as required 6. Run inner string/space out
7. Pick up Packer (or liner hanger)
8. Make up inner and outer string connections
2 hrs.
9. Run entire System to depth on Drill Pipe 8 hrs.
10. Drop ball/Carry out setting sequence for Packer
11. Close the pipe rams and pressure test the annulus to ensure packer seal integrity
12. Confirm anchor/test and pressure/test, release running tools
1 hr.
13. POOH with Running tool 5 hrs.
14. Make up expansion string with enough drill collars/drill pipe to provide 35,000 lbs. Net down-hole force and RIH
7 hrs.
15. Latch into expansion cone / shear pins 16. Initiate expansion
17. Expand ESS joints
1 hr.
18. Land out expansion cone to bottom ESS joint 19. POOH with expansion string
20. END
8 hrs.
Total time 35 hours
Table 29: Operation time estimate
General Sand Control Information Manual External Revision 1.0 - 116 Figure 106: Two trip installation: Trip 1 - Set Hanger
1) Make-up screens
2) Make-up Packer setting tool 3) Run in the hole
4) Correlate depth 5) Set packer and test 6) Release running tools
ESS Deployment (Two Trip System)
Figure 107: Two trip installation: Trip 1 - Expand screen
8) Make up Expansion string 9) Run in the hole
10) Engage expansion cone 11) Expand ESS
12) Pull out of the hole
General Sand Control Information Manual External Revision 1.0 - 118
Pre-Installation, Well Prep, Clean-Up & Logging
In order to drill and maintain an optimum hole through the reservoir, it is important that all the relevant personnel have an early involvement in planning the operation and developing the programme. The relevant people should perform hazard identification and develop contingency plans, select the most appropriate fluid, determine the data acquisition requirement, etc, etc.
Hazard identification and mitigation needs to be carried out on the processes required to install an ESS, highlighting the critical issues affecting the installation such as:
• The quality of the reservoir section; require a gauge hole, a clean hole (cuttings free).
• Fluids strategy from drilling to well clean-up.
Proper selection and design of the drilling fluid has a major impact in the success of the operation. The mud type selected must be optimised to achieve the following:
• Aid the drilling of a close to gauge hole, including the prevention of interstitial clay expansion to enable the maximum cone size selection in order to achieve borehole support
• Controlled maximum particle size during the drilling of the reservoir section requiring the use of sized barite or bentonite. Solids control activities should include the use of the finest mesh screens practical to maintain a particle size less than 1/3rd and preferably 1/6th the size of the ESS mesh. The centrifuges typically should be run in barite recovery mode continuously while drilling the reservoir section. It is recommended that while drilling the reservoir section, particle size tests are made at regular intervals to ensure the maximum size is maintained below the pre-determined maximum. Test disks can be provided to allow this to be checked and monitored at the well site.
• To achieve little to no residual cuttings or debris and a thin and tight wall cake, the mud should be treated to provide minimum fluid loss (good mud filter cake), optimum rheology for hole cleaning, optimum solids content and quality.
If any well-bore areas logged indicate potential problem zones, a check trip to TD is recommended to ensure there is a clean hole with no suspected hole problems. A heavy
If any well-bore areas logged indicate potential problem zones, a check trip to TD is recommended to ensure there is a clean hole with no suspected hole problems. A heavy