Design and Fabrication of Test Facility for Longevity

Proceedings of the ASME 2012 International Mechanical Engineering Congress & Exposition IMECE2012 November 9-15, 2012, Houston, Texas, USA

IMECE2012-93145 DESIGN AND FABRICATION OF TEST FACILITY FOR LONGEVITY TESTING OF ELASTOMER SEALS SZ Qamar, T Pervez Mechanical and Industrial Engineering Department, Sultan Qaboos University, Muscat, Oman; [email protected] M van de Velden Senior Well Engineer Concept and Design, Shell Oil, Seria, Brunei FJ Sanchez New Technology and Projects, Petroleum Development Oman, Sultanate of Oman ABSTRACT The oil and gas sector has witnessed a marked inclination worldwide towards enhanced oil recovery (EOR) in recent years due to diminishing easy oil in many fields. One of the more popular EOR strategies is the workover method of converting existing weak horizontal producers to maximum reservoir contact (MRC) wells, or dead vertical wells to single horizontal producers or power water injectors. This attempt at maximum well productivity and total oil recovery is based on installation of downhole smart systems to control flow from each lateral. Expandable liners and swelling elastomers are the key drivers enabling this type of zonal isolation. Enhancement and maximization of hydrocarbon recovery is also being attempted through intelligent and multilateral wells. These well systems cannot succeed without proper zonal isolation and compartmentalization of the reservoir. Compared to conventional methods, swelling elastomer packers maintain good zonal isolation in even the most complex environments, yielding major savings in rig time and cost. As yet, no data is available from designers or manufacturers about the durability or service life of swell packers under actual well conditions. A full-scale rig has therefore been designed and fabricated at the Sultan Qaboos University (SQU), in collaboration with a regional petroleum development company, for longevity testing of water-swelling and oil-swelling elastomers. The test battery includes packers made from different swelling elastomer materials, exposed to actual crude oil or water of different salinities, maintained at different temperatures, and subjected to high pressure. Different

conceptual designs of the test setup (for longevity testing over a 5 year period) were developed and later evaluated. Detail design of the best concept was carried out and assessed for reliability, manufacturability, assemblability, etc. Salient features of the final design include thermal systems for selected packers, able to continuously maintain temperature over the 5year period; recirculation system to maintain the desired salinity in some packers; elaborate system for measurement and observation of upstream and downstream temperature and pressure in all tubes; a system for pressurizing the tubes (to 1000 psi) once the elastomers have swelled and sealed. Daily log of readings have been maintained over the last few months. Several months of testing has shown that packers exposed to low salinity and higher temperatures have sealed earlier, and water-swelling elastomers have sealed faster than oil-swelling ones. Three units have not sealed yet, one tube has desealed after initial sealing, one packer has shown seal failure after pressurizing, and two units are exhibiting good sealing under high pressure. Most of these results are in line with material behavior of swelling elastomers observed in earlier laboratory tests. The whole test battery will be monitored over five years, reporting seal temperatures, pressures, seal deterioration or failure, etc. This study can provide direct feedback to field engineers about the lasting capability of different elastomer types under various actual field conditions. This not-as-yetavailable information will be valuable in proper selection of swell packers, and may also help in improvement of packer design.

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Copyright © 2012 by ASME

INTRODUCTION Swelling elastomers are advanced rubber-like polymers that show dynamic swelling when exposed to liquids such as water or oil [1]. In petroleum applications, the term swell packer refers to swelling elastomer section/s mounted onto petroleum tubulars [2]. Production of oil and gas from aging reservoirs goes down significantly due to formation damage leading to water production and similar other problems. Deployment of swelling elastomer packers has proven to be successful in getting profitable production from previously abandoned or dwindling wells [3]. By segmenting horizontal wells, swell packers have been used to shut off unwanted water and gas, thus increasing the recovery from old wells [4]. Apart from these remediation tasks, swelling elastomer seals have reduced development costs and rig size through cementless completions [5], or well completion together with cement jobs [6]. For proper design and selection of swelling elastomer applications, it is important to have reliable knowledge of the material response of an elastomer under varying field conditions. Effect of different drilling fluids on the performance of some elastomers used in drilling equipment was studied by Kubena et al. [7]. Al-Yami et al [8, 9] investigated the behavior of certain water-swelling and oil-swelling elastomers when exposed to differential pressures and temperatures. Qamar et al [10, 11] reported the effect of exposure on the amount of volume and thickness swelling, compression set, tensile set, and other properties of water-swelling elastomer. Performance and suitability of some elastomers in gasoline environment (different hydrocarbon concentrations) was reviewed by Ertekin and Sridhar [12]. Qamar et al [13, 14] performed material testing and characterization of a water-swelling and an oilswelling elastomer used in drilling operations, with and without acid induction. Current Work As mentioned above, various types of swelling elastomers are being used by regional petroleum development companies around the world in the form of packers and sealing elements in zonal isolation and other downhole applications. As material property data under actual well conditions and after different stages of swelling is not generally available from vendors, an elaborate facility for elastomer testing and characterization has been set up at the Sultan Qaboos University for water/oil swelling elastomers under different conditions of temperature and salinity, using laboratory-size elastomer samples. One major issue of interest is the service life of elastomer seals and packers. No information in this regard is available from service providers or other published sources. Attempts can be made to forecast the service life based on the theory of accelerated testing, but it will not be very reliable in the case of swelling elastomers as their material behavior is quite different from normal rubberlike materials. In collaboration with a regional petroleum development authority, a project was thus undertaken for service life testing of actual full scale packers over a 5 year long period. This paper describes the design, fabrication, and commissioning of a test facility for longevity assessment of two types of water-swelling and one oil-swelling elastomer, under low and high-salinity water, and at ambient and 50⁰C temperature, using actual packer sections swelling against actual casing sections.

DESIGN SPECIFICATIONS A thorough study was conducted about the different waterswelling and oil-swelling elastomers being deployed in regional oil and gas wells for development and remediation work, and the existing well conditions (water salinity, crude type, temperature, pressure, etc). After various rounds of discussions with well engineers, a test battery for longevity testing of swelling elastomers was proposed with the following major specifications: Test setup will include 10 units, 9 actual packers inside actual casings, and one demonstration unit with a Perspex outside-tube, showing the inside details that are hidden in the other units because of outside steel casing. Outer casing will be actual 7 inch steel tubulars in all cases. Tube diameter will be 3½ inch for four packers, and 4½ inch for the other five packers. Elastomer type in six units will be water-swelling, while 3 units will be oil-swelling. Water-swelling packers will be exposed to brine solutions of two salt concentrations; 0.5% representing low-salinity wells in two tubes, and 12% representing high-salinity wells in four tubes. Actual crude oil from two different oil wells in the region will be used in three tubes. Testing will be done at two temperatures; ambient temperature corresponding to shallow-aquifer type wells, and 50⁰C temperature symbolizing average-depth wells in the region. Four tubes will be pressurized to 1000 psi (typical pressure range in many regional wells) to test the strength of the elastomer seal. Total testing time will be 5 years. Actual material identification numbers for the elastomers tested have to be withheld for reasons of confidentiality, using the labels W1 and W2 for low-salinity and high-salinity, and O1 for oilswelling elastomers respectively. TEST RIG DESIGN Various conceptual designs were developed, discussed, and evaluated. Salient features of the design are mentioned here. A circulation system (water heaters and containers, circulation pumps and control units, circulation pipes) was required to maintain salinity in water-swellable packers. A thermal system (thermal blankets, insulation, control system, temperature gauges) was needed to maintain 50⁰C temperature in some pipes. A high-pressure system (pressure-manifold, highpressure source, high-pressure pipes and connections, pressure gauges) was required to pressurize the pipes once sealing was achieved. A base frame was needed to support and house all the test and demonstration units. A basic decision matrix was used for concept evaluation; safety, reliability, and 5-year life being the driving concerns. Some of the major design tasks and evaluation criteria were: All valves, fittings, welded joints, etc were to have a pressure rating of at least 100 bar (safely above the design requirement of 1000 psi or 70 bar). A circulation system was needed to maintain water salinity in tubes containing saline water; without circulation, salt would precipitate out and salinity would drop down. A thermal system was required to maintain 50⁰C temperature for each highertemperature unit (swell packer inside outer casing). The test rig should have the capability of monitoring temperature and pressure for each unit, inside the packer and between the packer and the casing. A detection system was needed to indicate when sealing in each packer is completed (due to swelling of elastomer against the outer casing). Another detection system 2


had to be in place for indication of when each seal breaks (after seal failure).

Circulation pipes Circulation tanks

1

5

2

8

6

3

7

4

9

sreP xrp Perspex unit

Fig. 1: Layout of the longevity test setup

Steel casings at 50⁰C

Circulation pumps and controls

Final layout of the test setup is shown in Fig-1. Each unit is identified by a number, and brief descriptions of the units are given in Table-1. Figures 2 and 3 show schematic drawings outlining the final layout of the test facility (configuration and major components), after completion of detail design based on the best conceptual design. Table-1 Elements of the longevity test setup Unit #

Elastomer Swelling Type Medium 3½-in swell packer inside 7-in casing 1 W2 12% brine 2 O1 Crude oil 3 W2 12% brine 4 O1 Crude oil 4½-in swell packer inside 7-in casing 5 W2 12% brine 6 O1 Crude oil 7 W2 12% brine 8 W1 0.5% brine 9 W1 0.5% brine Perspex demonstration unit 10 W1 -

Temperature controllers

Top drain

Temperature

Room temp Room temp 50⁰C 50⁰C

Bottom drain

Fig. 2: Schematic diagram of the test facility showing test and demonstration units; circulation system (tanks, pipes, pumps, and controllers; thermal system and controllers; and top and bottom drain systems

Room temp Room temp 50⁰C Room temp 50⁰C Room temp

FABRICATION AND ASSEMBLY Three types of elastomer-mounted tubulars (low-salinity water, high-salinity water, and oil swelling) and casing pipes were provided by a regional oil and gas development company. One-meter sections were cut out from these tubulars and properly sized and trimmed to form the three types of swell packers and the outer casings. One end on the packers, and both ends on the casings were beveled for later welding; Fig-4. Flanges for packers, and blind flanges and bottom end plates for casings were fabricated. Eight pitch circle bolt-holes were drilled in both flange types to join the packers to the casings. Four corner holes were drilled in the bottom plates to attach the casings to the base frame. Six carefully spaced out threaded holes were drilled in the top flanges for installation of pressure and temperature gauges. Top flanges and bottom plates were welded to the packers and casings; Fig-5.

1. Pressure manifold; 2. Drain system; 3. Pressure gauges; 4. Nuts and bolts; 5. Flanges; 6. Temperature gauges; 7. Casing tubulars; 8. Bottom plates; 9. Base frame; 10. Elbow joints; 11. Circulation pipes; 12. Circulation pump controllers; 13. Circulation pumps; 14. Water heaters/tanks; 15. Temperature controllers; 16. High pressure system; 17. Perspex demonstration unit

Fig. 3: Schematic assembly drawing of the longevity test setup 3


joined to the casings (flange to flange, with pressure sealing in between), and pressure gauges (for all test units) and temperature gauges (for 4 higher-temperature units) were fitted to the top flanges; Fig-9.

Fig. 4: Sizing and beveling of elastomer packers packers

Fig. 5: Welding of flanges and bottom plates to packers and casings

Fig. 7: Fixing of casings to base frame, and placement of packers inside casings

Fig. 6: Fixing of drain valves to bottom plates A single hole was drilled in the center of each bottom plate to fix the drain valve. Ten bottom drain lines were installed on each test unit, including ½ inch stainless steel (SS) ball valves and ½ inch SS plugs; Fig-6. Similarly, 10 top-side drain lines were fitted to top flanges of each test unit (including SS highpressure ball valves and 100 bar pressure gauges). A steel baseframe was fabricated to support and hold all the test units and the Perspex demonstration unit. Casings were bolted on to the base frame, and packers were placed inside the casings; Fig-7. Thermal system (electrical thermal blankets, temperature control units, and insulation blankets) was imported from a company specializing in custom-designed heating units. These heating systems were assembled in-house and fitted to 4 test units that needed higher temperature; Fig-8. Packers were

Fig. 8: Thermal system components and winding of thermal blankets on casings

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The demonstration unit was imported from a company that fabricated the Perspex casing and flange system exactly to the drawings supplied. Except that the outer casing and the blind flange were made of Perspex, this see-through demonstration unit had all the components and was assembled exactly as the other test units; Fig-11.

Fig. 9: Joining of packer and casing flanges (with gaskets), and fixing of pressure and temperature gauges To subject the test units to high pressure, a manifold system was fabricated and installed, with valved connections to each unit; Fig-10. This pressure manifold consisted of a 1 inch SS pipe to be later connected to a high-pressure nitrogen gas cylinder, with 9 outlets that were fabricated and hooked up to the test units: 9 lines including nine ½ inch SS high-pressure needle valves and eighteen 100 bar pressure gauges. A highpressure multistage nitrogen regulator and other fittings were installed on the nitrogen cylinder to control pressure flow into the manifold and test units.

Fig. 11: Perspex demonstration unit showing internal construction of other test units To maintain salinity in water-swelling packers, a circulation system was fabricated and installed on 4 units. This included two 50 ltr water heaters, 4 circulating pumps, 4 pump pressure controllers, 4 non-return valves, 4 filling ports with valves, 4 air vents, and 4 running-hour meters, all connected together by copper lines; Fig-12.

Fig. 10: High-pressure manifold with connections to test units Fig. 12: Ambient and hot water circulation system 5


Filling-and-checking systems were installed on all 9 test units (including SS ball valves at inlet and outlet ports) to determine whether sealing between swell packers and casings was achieved or not. All the elements of the test setup were finally assembled together; Fig-13.

Fig. 13: Complete assembly of the longevity test setup Major fabrication operations included cutting, trimming, beveling, drilling, threading, bending, and welding. Stainless steel and PVC pipes, flexible hoses, valves, pressure and temperature gauges, circulation and heating system, etc were fitted in required locations. Forty sets of M16 x 100 hex bolts and 80 sets of M16 x 80 hex bolts (together with nuts, washers, and spring washers) were used for various types of connections: packer blind flanges to flanges on outer casings; bottom end plates on casings to base frame; etc. COMMISSIONING AND PRELIMINARY TESTING After all fabrication, construction, and final assembly work was completed, pilot test runs were conducted to check out the water circulation system, the thermal blanket system, and the high-pressure manifold system (using plain water). After various trial runs, the system was ready for commissioning. To fill out each unit (completely from inside the swell packer, and to a reasonable height above the elastomer section in the space between the packer and the casing), about 25 ltr of liquid was required per unit. Huge amount of distilled water was prepared (25 ltr for each of the 6 water-swelling units) using water purification facilities in the Environment Lab of the university. This distilled water was then used to prepare salt solutions of 0.5%and 12% salinity as required. Enough amount was prepared and stored in large storage canisters to fill out the test tubes initially, and for later re-filling if required after leakage tests. Collection, packaging, and transportation of actual crude oil from two different regional oilfields to the test facility was a daunting task (25 ltr for each of the 3 oil-swelling units). Testing for all units (water-swelling and oil-swelling types) had to begin at the same time. Once the crude oil and the two brine solutions were in place in required quantities, actual commissioning and testing of the test facility started.

INITIAL PROBLEMS Water Filling 12% salinity water was filled in 4 units, and 0.5% salinity water in 2 units as required. Filling was initially carried out manually, but it took a very long time to fill a single unit. There was apprehension that if the process took several days (practically more than a week), then elastomer seals in some units would be swelling earlier than the other units. Small pumps were therefore used to speed up the filling process for all the water-swell units. This was only a pre-commissioning problem. Once all the tubes were completely filled out, and testing started, only minor amounts of water need to be added after each checkup for sealing. And once sealing has been achieved, no water addition is required for the remaining 5-year test period. Oil Filling Manual oil filling was nearly impossible, as the crude oil was too thick to go through the filling ports under normal pressure. On the other hand, pumping oil using regular watertype pumps was also a very difficult task. Repeated priming and re-filling was required all through the operation. This did not only slow down the process, but 3 pumps were burnt out before oil filling could be completed. Just as for the water-swelling units, this oil filling problem was significant only in the initial pre-test period. Very little oil needs to be refilled after each sealing check, and none at all after complete sealing has been achieved. Circulation System Problems As mentioned above, a circulation system was needed to maintain salt-concentration in the 4 high-salinity (12%) units. Small leakages repeatedly occurred in various portions of the circulation system, causing some rusting of the tubes, flanges, and other fittings because of the high salt concentration. The system had to be monitored on a daily basis, and clean-up, retightening and re-sealing operations had to be frequently carried out. Another problem was recurrent shutting down of circulation pumps because of air gaps forming in the system due to minor leaks, etc. Immediate refilling and bleeding was required to remedy this problem, so that circulation system could work without significant downtime (to maintain salinity). This also required vigilant daily monitoring of the test facility. These circulation problems existed only in the initial phase. Once all higher-salinity (12%) tubes were sealed, the circulation pumps were not needed any more; pumps were switched off and the circulation system was deactivated for the rest of the 5-year longevity testing period. Maintaining Temperature Though the thermal blanket system had control units to maintain the temperature at a pre-set value (50⁰c in our case), temperature often dropped a little (may be due to minor thermal leakages to the base frame, environment, etc). Close watch had to be kept at the temperature gauges on a daily basis and the temperature-setting dial had to be slightly adjusted from time to time. Once the system was monitored for a couple of months, and minor temperature adjustments were needed on a recurring 6 Copyright © 2012 by ASME

basis, an additional control system was designed. This secondary control unit (including temperature sensors, thermal relays, etc) is being currently installed on the 4 highertemperature tubes. INITIAL TESTING AND MONITORING Detailed log of temperature and pressure readings on all tubes, and of any uncommon occurrences is being maintained. This was done on a daily basis initially, then every 2 days, and then once per week. Seal Check Initially, daily checks were done to see if any tube had sealed. Obviously, earlier sealing was expected in low-salinity water, then in high-salinity water, and then in oil. Also, faster sealing is expected for higher temperature packers [10, 11]. After some time, when quick sealing was not observed, the sealcheck duration was changed to 2 days. Circulation pump would automatically stop for a tube once it was sealed; therefore seal check was carried out every time a pump stopped. When it was found that sealing was not complete, refilling and bleeding was carried out to re-start the pump. High-Pressure Testing It was initially planned that the 4 high-pressure units would be pressurized to 1000 psi at the same time after sealing was completed in each tube. However, when it was observed that some tubes had not sealed even after several months, it was decided to pressurize tubes individually after sealing. A highpressure nitrogen cylinder was connected to the pressuremanifold. The tube selected for pressurizing (which had already sealed) was re-checked for sealing. If seal was still intact, highpressure inlet valve (for this tube ) on the manifold was opened and the tube was carefully pressurized in steps of 10 bar to avoid any possible sudden failure or other problems. The tube was observed for 5-10 min at each pressure step. Once the full pressure of 70 bar (about 1000 psi) was reached, the tube was observed for 15-20 min before closing the manifold valve and disconnecting from the nitrogen source. A 10-20 bar pressure drop was observed in the pressurized tube within a couple of days. It was then re-pressurized to 1000 psi. The pressure drop may be due to absorption of some nitrogen into the saline water or a little into the elastomer itself. PRELIMINARY RESULTS AND DISCUSSION It should be pointed out again that the whole purpose of this elaborate setup was in-situ longevity testing of actual-size swell packers under conditions very close to the actual environment in different regional oilfields. Lab testing for mechanical behavior and material characterization of various water-swelling and oil-swelling elastomers, using small test samples rather than full-size packers, has already been carried out by the authors in earlier studies [10, 11, 13, 14]. The main objectives of this longevity investigation are to see (a) if actual swell packers (made of different swelling elastomer materials) will seal properly when exposed to saline water of various concentrations, or crude oil from different fields, held at different temperatures; (b) if the seal formed due to swelling will survive very long exposure (up to 5 years), and if the seal integrity will not be affected by problems such as elastomer softening, leaching, etc; and (c) if the seals will remain intact

even at higher pressures (up to 1000 psi), as experienced in medium-depth oil and gas wells. Pressure and temperature readings for all units are being maintained in a log, to ensure that test conditions remain the same, and to adjust for minor variations. This log also contains records of important events such as stoppage of circulation pumps, completion of sealing in a tube, pressurizing of a sealed tube, etc. Some notable results in the first few months of testing are discussed below. Incomplete Sealing Three units (#1, #2, #6) have not sealed until now. If sealing has not been achieved within the first week or two, the packer is useless for the oil industry, as the well has already lost too many days of production. Though apparently discouraging, the results provide useful information for field engineers (to avoid selection of improper packer types for a given set of field conditions), and are in line with observations from earlier lab tests. Tube #1 has a 3½ inch packer inside a 7 inch casing, exposed to 12% saline water at room temperature. Unit #2 is also a 3½ inch packer inside a 7 inch casing, but the elastomer is exposed to crude oil at room temperature. In earlier works by the authors, it has been noted that elastomers swell more in lower-salinity brine; water-swelling elastomers swell more and faster than oil-swelling elastomers; higher amount of swelling takes place at higher temperatures; and that elastomers developed for lower salinity may not perform well in higher salinity environment [10, 11]. For the longevity setup, elastomer-casing gap for the 3½ packer (#1 and #2) appears to be larger than the maximum possible thickness swelling of the elastomer under conditions that do not favor large amount of swelling (higher salinity water, and crude oil at low temperature). The other packer that has not sealed yet (#6) even though it had a smaller gap to seal is a 4½ inch packer inside a 7 inch casing. As mentioned above, oil-based elastomers have a lower tendency for swelling, especially at lower (room) temperature, and this particular crude oil had a very high viscosity. This elastomer type may be suitable only for deeper wells where temperature is at least 50⁰C. Desealing One tube (# 5) had earlier sealed, but has recently desealed. Though swelling conditions were not favorable (higher salinity of 12% and lower room temperature), the packer was designed for high-salinity conditions (elastomer W2) and sealed because of the small gap (4½ packer). However, after long exposure (several months), the sealing failed. Even after very careful material design and strictly controlled polymerization process, it has been observed in earlier lab tests that some samples show material deterioration such as excessive softening, rupture, and leaching, all of which can cause desealing. That is why in many actual petroleum applications, packers have several swelling elastomer sections in series, so that if one element fails, the others provide the necessary sealing backup. Seal Failure under Pressure One tube (#7) has de-sealed after pressurizing to 1000 psi. This high-salinity elastomer (W2) was showing consistent sealing capability under favorable conditions: higher temperature (50⁰C) and small sealing gap (4½ inch packer). 7


However, failing when pressurized to 1000 psi suggests that this packer can be good for shallow-aquifer or similar wells where the pressure is not in excess of about 500 psi. Good Seal Performance Seals in two tubes (#3 and #8) are intact after pressurizing to 1000 psi. Unit #3 is a high-salinity elastomer at high temperature and large sealing gap, while tube #2 is a lowsalinity packer with small sealing gap at room temperature. This performance is encouraging for deployment in actual highpressure wells: packer #3 for both small and large sealing gaps in medium depth wells of higher temperature, and packer #8 for small sealing gaps in shallow-aquifer type wells with low salinity and ambient temperatures. As intended, these observations (and others to come as testing goes on) are of direct utility for field engineers in selection and prequalification of certain packers for certain wells, and for application developers in improving packer design. CONCLUSIONS A test facility has been designed, fabricated, and commissioned for longevity testing (over a 5 year period) of two water-swelling and one oil-swelling elastomer being used by the regional petroleum industry. Actual packer sections placed inside actual casing sections are being studied for swelling performance under low and high-salinity water and crude oil, at ambient and 50⁰C temperature. The test setup has 10 units, 9 actual packers inside actual casings, and one demonstration unit having a see-through Perspex outside tube. Four packers have 3½ inch tube diameter, 5 packers are mounted on 4½ inch diameter tubes, while the outer casings are all 7 inch diameter tubulars. Six units have water-swelling elastomers, while 3 units are oil-swelling. Brine solutions of low salinity and medium-high salinity (0.5%, and 12% salt concentration, respectively) are used in 6 test units, and two types of actual crude oil is used in 3 tubes. Tubes are maintained at ambient temp (representing shallow-aquifer type wells), and 50⁰C temp (representing medium-depth wells in the region). Two different water-swelling elastomers and one oilswelling elastomer make up the different packers. Some of the packers are being tested at high pressure (1000 psi) to emulate medium-high well pressures. Results obtained so far are generally in line with swelling elastomer behavior observed in earlier studies. Some early failures that have occurred can provide helpful pointers to field engineers and application designers. ACKNOWLEDGEMENT The authors gratefully acknowledge the support of Petroleum Development Oman and Sultan Qaboos University for this work. REFERENCES [1] Brooks RT (2011) “Merging Coiled Tubing and Swellable Packer Technologies,” SPE Paper # 142422, SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, Woodlands, Texas, 5-6 April 2011 [2] Rivenbark M, Dickenson R (2011) “New Openhole Technology Unlocks Unconventional Oil and Gas Reserves

Worldwide,” SPE Paper # 147927, SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia, 20-22 September 2011 [3] Al-Douseri KMM, Barnes C, Young D, Smith PE (2010) “Swellable Packers Provide a Brownfield Water Management Solution in Open and Cased Hole,” SPE Oil and Gas India Conference and Exhibition 2010, OGIC, Mumbai, India, 20-22 January 2010 [4] Mahrooqi MA, Hinai G, Marketz F (2007) “Improved Well and Reservoir Management in Horizontal Wells Using Swelling Elastomers,” SPE Paper # 107882, SPE Annual Technical Conference and Exhibition, 11-14 November 2007, Anaheim, California, USA [5] Rogers H, Allison D, Webb E (2008) “New Equipment Designs Enable Swellable Technology in Cementless Completions,” SPE PAPER # 112302, IADC/SPE Drilling Conference, 4-6 March 2008, Orlando, Florida, USA [6] Cooper K, McVey A, Schafer D, Cox JD, Hilleary N, Parker D, Crooks J (2008) “Completion of a Horizontal Well with Swellable Packers to Control Water Production,” SPE PAPER # 116263-MS, SPE Annual Technical Conference and Exhibition, 21-24 September 2008, Denver, Colorado, USA [7] Kubena Jr E, Ross KC, Pugh T, Huycke J (1991) “Performance Characteristics of Drilling Equipment Elastomers Evaluated in Various Drilling Fluids,” SPE Paper # 21960, SPE/IADC Drilling Conference, 11-14 March 1991, Amsterdam, Netherlands [8] Al-Yami AS, Nasr-el-Din HA, Al-Saleh SH, Al-Humaidi AS, Al-Arfaj MK, Awang MZ, Al-Mohanna KS (2008) “Lab Investigation of Oil Swelling Elastomers for Smart Well,” SPE Paper # 19403, Offshore Technology Conference, 5-8 May 2008, Houston, Texas, USA [9] Al-Yami AS, Nasr-El-Din HA, Al-Humaidi AS (2008) “Investigation of Water-Swelling Elastomers: Advantages, Limitations, and Recommendations,” SPE Paper # 114812, SPE Asia Pacific Oil and Gas Conference and Exhibition, 20-22 October 2008, Perth, Australia [10] Qamar SZ, Hiddabi SA, Pervez T, Marketz F (2009) “Mechanical Testing and Characterization of a Swelling Elastomer,” Journal of Elastomers and Plastics, Vol. 41, No. 5, September 2009, p 415-431 [11] Pervez T, Qamar SZ, van de Velden M (2011) “Comparison between Fresh and Exposed Swelling Elastomer,” Journal of Elastomers and Plastics, Vol. 44, No. 3, May 2012, p 237–250 [12] Ertekin A, Sridhar N (2009) “Performance of Elastomeric Materials in Gasoline-Ethanol Blends ─ A Review,” SPE Paper # 09533, Corrosion 2009, 22-26 March, 2009, Atlanta, Georgia [13] Qamar SZ, Pervez T, Al-Kharusi MSM, Akhtar M (2011) “Material Characterization of Water-Swelling and OilSwelling Elastomers,” 15th International Research/Expert Conference on Trends in the Development of Machinery and Associated Technology (TMT 2011), 12-18 September, 2011, Prague, Czech Republic [14] Qamar SZ, Pervez T, Akhtar M, Al-Kharusi MSM (2012) “Design and Manufacture of Swell Packers; Influence of Material Behavior,” Materials and Manufacturing Processes, Vol. 27, No.7, p 721-726 8 Copyright © 2012 by ASME