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1 SPE First Installation of an Openhole Expandable Sand Screen Completion in the Iranian Oilfields Leads to Operational Success and Production Enhancement - A Case History A. Hooshmandkoochi and F. Ghorbani, National Iranian Oil Company Copyright 2007, Society of Petroleum Engineers This paper was prepared for presentation at the 2007 SPE Production and Operations Symposium held in Oklahoma City, Oklahoma, U.S.A., 31 March 3 April This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented. Write Librarian, SPE, P.O. Box , Richardson, Texas U.S.A., fax Abstract Expandable sand screens were developed to overcome the shortcomings of both existing sand control techniques, while also providing some unique benefits. The first commercial application of this technology took place in January Since then, their use has spread quickly to all parts of the world and in many diverse applications. As of June 2005, over 340 installation of expandable sand screen (ESS) had been run in over 700 years of combined production. The productivity performance of the ESS has been shown to be very good, with an average skin of 0.3 being achieved in recent openhole applications. ESS completions generally perform better than the baseline models. Where field comparisons were possible, they also performed better than alternative sand control completions. However, its introduction and acceptance into the Iran has been slower in coming. It was not until in 2005 that National Iranian Oil Company (NIOC) decided to complete its Mansuri oilfield, well MI-34 sidetrack, using openhole expandable sand screen for sand control, thus making it the first such completion in the Iranian oilfields. This paper will provide a brief overview of expandable sand screen, its construction and advantages and will describe some of the issues addressed in this well completion. It will provide details of the installation procedure, the fluids employed and well production results achieved. It will conclude that the use of expandable sand screen as an alternative to conventional sand control methods in the Iranian Oilfields is viable. Introduction Mansouri 34 is the first application of openhole ESS (Expandable Sand Screen) technology within Southern Iran. NIOC awarded the contract of sand control solution as a part of Mansuri oilfield development project to Weatherford Completion and Production Systems. There were some wells completed with ESS in southern Iran before but they all were cased hole, hence make this job the first time of its own. The deployment and expansion of the screens was carried out as per the Weatherford guidelines without any problems. An openhole completion strategy was selected in order to boost well productivity, with the reservoir section lined with ESS in order to provide borehole support and optimize production rates still further and more importantly allow them to be sustained for a longer period, improving ultimate reservoir recovery factors. The operation began with the setting of a whip stock. A window was then milled in the 7 liner. The kick off point was at m. A total length of 64m of 6-1/8 openhole was drilled. This produced a 52m reservoir section between 2168m and 2220m. The formation was then acidized to remove the mud cake. Following the acidization, the casing was scraped. This ensured the deployment packer had no problems setting, and there was nothing in the well that might damage the ESS. The EXP hanger-packer was set in the 7 29 lb/ft liner with the expandable sand screens across the Asmari Formation. The ESS was then expanded using the Axial Compliant Expander Tool (A.C.E. tool). The back pressure generated by pumping through a bit nozzle in the tool nose ensures the sand screens are expanded to fully contact the borehole, even in irregular hole geometries. Background Well History- The well was drilled in 1993 in the axial structure of Mansuri field and in 800 meters NW of well MI- 15 and 1300 meters SW of well MI-6. The formations were drilled without a major problem from Aghajari formation in surface to 2294 m TD in Asmari formation. The cap rock is determined at 2164 m, drilling through Asmari formation was reported with slight losses. The well was producing from sandstone layer 3 of Asmari formation. Objective of Sidetrack and Re-Completion- The objective of sidetrack and re-completion in this well was to increase production from layers 1 & 2 of Sandstone Asmari formation as well as cut the sand production with installing a sand control device in the well. NIOC decided to use expandable sand screen (ESS) as the most profitable sand control method over existing sand control solutions for this well.

2 2 SPE Expandable Sand Screens Technology Previously published papers have discussed the development of the expandable sand screen in detail [4], but a brief overview of the concept is discussed here. Expandable sand screen is a relatively new technology that is rapidly gaining industry acceptance. The difference between ESS and other expandable tube technologies lies in the slotted basepipe. The slotted basepipe allows expansion ratios up to 80% greater than the original diameter. This provides both a larger inflow area and larger flowing I.D. than conventional sand screens deployed in similar wellbore geometries. ESS is constructed of three sandwiched layers; the basepipe, the filter media, and the outer protective shroud (see figure 1). The basepipe and outer shroud slots open during expansion to accommodate the change in diameter, while over-lapped layers of filter media slide across each other to maintain sand integrity. The entire length of the ESS joint is expanded, including the connectors. This allows flow along the entire ESS completion without any blank sections. Several methods have been designed to expand ESS. The simplest method is to push a fixed O.D. cone ring through the ESS. This method results in a minimum screen I.D. equal to the cone ring O.D., plus an additional 4%. This method is considered non-compliant, as the O.D. of the ESS is able to conform to the wellbore (casing or openhole) by only a 4% variation. Two methods of compliant expansion have been developed. The first was the CRES (Compliant Rotary Expansion System). This CRES has been replaced by a more reliable and more easily operated system, known as ACE (Axial Compliant (Fig. 2). The tool is compliant in that the pistons can extend or retract if an increased or decreased hole diameter is encountered. This allows the ESS to expand fully to give improved wellbore contact, thus providing improved hole support and eliminating any microannulus. Activation of the compliant roller/traveling piston assemblies is achieved by generation of a back-pressure within the ACE tool. This back-pressure is a result of flow through an integral drill bit jetting nozzle directly in front of the compliant section. This system was used to expand the ESS string in well MI-34. Whipstock Setting and Casing Window Milling The window that was milled in the casing represented a significant risk to the success of this job. The main concern was that it would not be properly dressed, and the ESS would be damaged while running in hole. The window was dressed with a watermelon mill when the window was cut. However, if the window was properly dressed with the 6-1/8 water melon mills, it occurred before the openhole section was drilled (with a 6-1/8 tri-cone bit). All the work dressing the window was undone when the bit was run to drill the reservoir section. The bit may create burs, which may cause tears in the ESS as it is run through the window. A better method is as follows: Set the whip stock and mill the window. Drill the openhole section. Perform polishing run with two water melon mills. Tail pipe can be run below the mills. Hence this trip will perform two tasks. Polish the window and check the openhole section. Also we can go further to suggest that the casing scrapper also be run on this trip. If the window is not properly polished the ESS could easily be torn. Tears in the petroweave will allow sand production. If the recommendations above are considered, we can achieve two things; a reduction of the chance of failure during installation, and save time through combining trips that have previously been run individually [3]. Well Details Well details are tabulated in table 1. Also figures 3 to 5 illustrates MI-34 Final well schematic, MI-34 Openhole ESS deployment string configuration, MI-34 Openhole EST expansion string configuration [3]. Fluid Data Deploying expandable sand screen in good, well-conditioned, clean fluid is very important. The fluid should be free of any particles that may plug the screen. This is an important part of all ESS operations. For this installation the well was displaced to brine. This made fluid conditioning much easier. Time was also spent conditioning the fluid over 100 micron shakers. This is the correct size for 270 micron ESS. As with all openhole ESS installations the fluid was checked with a mud flow through tester. No problems were encountered with these tests. Losses have been a common problem with workover operations in the Mansuri field. On this installation however, losses were almost zero. Initially after the acidizing of the formation the losses were 5bbl/hr. However this rate declined to zero at the time of installation. The low rate of losses should limit formation damage, and result in high flow rates from the well, once production commences [3]. Deployment and Expansion Deployment and expansion of the 4 ESS was carried out as per Weatherford procedures. On the final check trip before running the ESS, TD was tagged approximately 5m high. This is believed to be due to sand. When the ESS was run, we tagged TD 4 m high (at 2216m instead of 2220m). Attempts to work the string deeper and to wash the string down were unsuccessful. Once the EXP packer was set, it was confirmed with three tests: a 10K lb over-pull, a 10K lbs slack-off, and a 500psi annulus test. All tests passed. One issue worth discussing here relates to the rat hole left for ESS operations. Here there were left with no rat hole. The formation extended all the way to TD. This presents two problems. Firstly we have to expand to the bottom of the ESS and into the Expandable Bottom Connector (EBC). It would be preferred to have the bottom of the formation above the EBC by one or two meters. This means that even if there is a small error on our pipe tallies, we can ensure the entire reservoir is covered with the sand screen, and we don t risk tagging the EBC. Secondly it is difficult to set the packer at the correct depth with no rat hole to work in. General practices when running completions is to pick up to setting depth. This takes any buckling out of the string and makes the depth more accurate. This cannot be done without a rat hole. In this well the formation stopped us from having any rat hole, however, in future wells it is something that should be available. One area where some small improvements can be made relates to picking up the ACE tool. Due to the short length of this item, it is difficult to make up on the rig floor. Significant rig time could have been saved if the ACE tool and one joint of drill collar were torqued

3 SPE together before the job. This details all the events associated with system deployment, EXP setting, and ESS expansion in general terms. However, a more detailed description of the expansion observations are shown in Table 2 [3]. 4. P.D. Metcalfe; The Development of the First Expandable Sand Screen OTC 11032, 1999 Offshore Technology Conference, Houston Post Completion and Production Well fluid was displaced by gas oil and the well was flowed into different choke sizes. The well is now producing 6000 BOPD without sand production which impressed the operator. Conclusions 1. Screens and Liner Hanger were run in hole without any unexpected problems. 2. The Liner Hanger / Packer was set at the required depth and in complete adherence to its specifications as per the Weatherford running and setting procedures. 3. The entire length of screen was expanded without problem, and within the typical weight on- bit range. 4. The application of an integrated completion using expandable sand screens as the primary sand control completion technique proved to be an enhanced economic solution when compared to other conventional sand control solutions. Recommendations 1. One joint of drill collar be sent to service company base before each installation. This means that the ACE tool and stabilizers can be torqued together before the job. 2. Procedures relating to dressing / polishing of the casing window should be reviewed. In particular the water melon mills should be run after the openhole section is drilled. 3. The dog leg severity must be limited to 7 deg/100ft (in this well we had deg/100ft). 4. The hole should be 5-7/8 or 6. The 6-1/8 hole is too big for 4 ESS. The 4 screen is good for a maximum hole size of only Acknowledgement The author wish to acknowledge NIOC for permission to publish this paper, and to the many other involved whose efforts contributed to the success of this job. References 1. Bobby D. Sanford, Clinton Terry, Michael J. Bednarz, Chris Palmer, and Doran B. Mauldin, Case History: First Installation of an Expandable Sand-Screen Completion in the Gulf of Mexico, OTC 13282, OTC conference, Houston, Texas, May C. Jones, M. Tollefsen, P. Metcalfe, J. Cameron, D. Hillis, and Q. Morgan, Expandable Sand Screens Selection, Performance and Reliability; a Review of the First 340 Installations, SPE 97282, SPE/IADC Middle East Drilling Technology Conference and Exhibition, September 2005, Dubai, United Arab Emirates. 3. Mansuri Project Weatherford, MI-34 work over completion report, NIOC Mansuri field development reports, 2006.

4 4 SPE Figure 1. ESS Construction Filter Medium Figure 2. Compliant Rotary Expansion System (CRES) and Axial Compliant Expansion (ACE).

5 SPE Figure 3. Final Well Schematic Figure 4. Openhole ESS Deployment string configuration

6 6 SPE Figure 5. Openhole EST Expansion string configuration Table 2. Expansion sequences ACE Tool Expansion Event Joint 1 (8 m of Joint 2 (9.5m of Joint 3 (9.5m of Joint 4 (9.5m of Joint 5 (9.5m of Joint 6 (9.5m of Joint 7 (4m of WOB (Klbs) Pump Rate/Pressure (spm & psi) Rate of Expansion (ft/min) / / / / / / / Table 1. Well Details Liner Size / Weight : 7 29 lb/ft (N80) 7 : m m MD Max Deviation : 250 (Note: build angle was deg/100ft) TD : 2220m MD Fluid Type / Weight : Brine / 70 pcf Liner Hanger Type : Weatherford EXP 7 x 5.5 FLJ Setting Depth : Center of elements m MD ESS Size / Type : 4 ; 316L Stainless Steel Top of ESS : 2156m MD Bottom of expanded ESS : 2116m MD Amount not expanded : All expanded Expansion Force : Variable (20-35 Klbs)