The Burgan field, the second largest in the world and the largest clastic reservoir, has been in production for 66 years under primary production from natural water drive. The first phase of water injection has just begun in a small part of Burgan as a precursor to peripheral step-in water injection in the topmost Wara reservoir. Tertiary recovery schemes are being evaluated early in the life of this field with the foresight of reaping maximum benefits through early application before waterflood approaches maturity. Low salinity water (LSW) injection has been identified as a forerunner and apart from being very promising in itself; it will form an important base for the application of polymers and/or Alkaline/polymer/surfactant EOR schemes. Burgan is large enough to have a diversity that will require distinctive solutions for different areas of the field and different reservoir zones. Produced water injection started in Wara formation in 2010 at 60mbwpd with next phase of 670mbwd injection arriving in 2014 to implement peripheral injection in the flanks. This is targeting just 5% of the reserves that will need future water injection. Confidence in the LSW trial will therefore change the course of our future water injection schemes in the remaining zones. Replacing secondary with tertiary recovery schemes early will benefit not just the operating costs of the volume of water handling and disposal/injection; the overall recoveries will be higher. The eyes of the world are constantly on the health of the 2 super giants, Burgan and Ghawar. Potential benefits from EOR will have a huge impact on the extension to the life of Burgan and its strategic importance worldwide. This is the first time that KOC has taken a bold step into the field without extensive laboratory screening. As a result of taking this carefully calculated risk, KOC have soared ahead in experience on EOR in the Greater Burgan Field, within a small timeframe. The presentation will discuss the results of the LSW trial injection into 2 producers and comparisons on Sorw are made of LSW versus High Salinity produced water injection. Key learnings are shared from operating the pilot and modeling of the results. Single well tracers were used to measure the Sorw and its interpretations can be quite challenging. The tests have been analysed using five different methods. From this work, it was concluded that Low salinity water injection reduced Sorw by at least 3 s.u. (23.7% of remaining oil after effluent waterflood) in the best quality rock with the least clay content in Burgan, which would still be sufficient to make it economically attractive. Additional tests are planned for the remaining rock types in Burgan, having higher clay content and the potential for a larger change in oil saturation. Multiple models for evaluating the tracers response provide better insights to the interpretation of the Sorw. Good surveillance during the test and careful control on injection/production volumes are essential when a small response in Sorw is expected. To reduce uncertainty in the results, it is preferable to use downhole pumps rather than gas lift, control the temperature of injected water and invest in lengthy overfishing back to base brine after LSW injection.

Four expandable completion liners (ECLs) have been run in Algeria in two fields-these are the first fully compliant ECLs in Algeria, the first worldwide in gas wells, and the first worldwide in multilateral wells (from Weatherford database). This paper presents the first detailed benchmark study of ECL performance.All systems to date have been run in 8½-in. hole using 5½-in. base-pipe ECL compliantly expanded, and the installations went well. It has been possible to compare ECL performance data against a comprehensive surveillance data set for the two fields where data from existing openhole completions allow meaningful comparisons. The other completions consist largely of slotted liners and some barefoot completions. The tested production rates in each of the wells have been high relative to normal field trends; however, the predominant factor in this is the reservoir character. Pressure-buildup (PBU) analysis indicates that the second well has reduced Darcy skin, while it is considered unproved in the first well (more data over time are needed). There is, however, consistent evidence for a reduction in the rate-dependent proportion of total skin in both wells. This is supported by other studies and a consideration of basic principles.The reduction in the rate-dependent proportion of skin has given an increase in production rate of 5-20% as compared with the computed rate from a slotted liner. This difference assumes no borehole collapse, with analyses and discussion presented of the effect on well performance should borehole collapse occur.The joint venture (JV) is investigating the further use of this technology in smaller hole sizes and possibly in conjunction with fracture stimulation. Reservoir DescriptionsThe In Salah gas reservoirs are sandstones of Devonian and Carboniferous age. They are hard consolidated sandstones with generally low-to-moderate permeability. The fields typically have multiple sands units that are laterally extensive. The gas is dry, comprising 90-98% methane. CO 2 content varies from 1% in the Carboniferous to 10% in the Devonian reservoirs.Teg is a large four-way dip closed structure with few faults. The infill wells are in the Devonian D55 (Emsian-tidal/shallow marine sand), lower D40 (Siegenian-predominantly clean fluvial sand), and upper D30 (Gedinnian-tidal/estuarine sand/shale) sandstones. The Devonian reservoirs are fluvial to shallow-marine sandstones. Reservoir quality is usually good, with porosities up to 27% and permeabilities up to 150 md, and the sands are laterally well connected. Gas in the Devonian at Teg contains typically 90% methane with 9% CO 2 and 11 ppm H 2 S. The dewpoint at 29 bar is -46°C, water/gas ratio (WGR) is 2 bbl/MMscf, and condensate/gas ratio (CGR) is 0 bbl/MMscf. The Reg field consists of a large four-way dip closed structure covering an area of up to 350 km², which is elongated in a northwest/southeast orientation. A 3D-seismic survey acquired by the JV during the appraisal phase over the crest of the field has confirmed that the structure is exten...

Four expandable completion liners (ECLs) have been run in Algeria in two fields - these are the first ECLs in Algeria, the first worldwide in gas wells and the first worldwide in multilateral wells. This paper is the first detailed benchmark study of ECL performance. All systems to date have been run in 8 ½″ hole using 5-1/2″ base pipe ECL compliantly expanded, and the installations went well. It has been possible to compare ECL performance data against a comprehensive surveillance data set for the two fields where data from existing openhole completions allow meaningful comparisons. The other completions consist largely of slotted liners and some barefoot completions. The tested production rates in each of the wells have been high relative to normal field trends; however, the predominant factor in this is the reservoir character. PBU analysis indicates that the second well has reduced Darcy skin, while it is considered unproven in the first well (more data over time is needed). There is, however, consistent evidence for a reduction in rate-dependent proportion of total skin in both wells. This is supported by other studies and a consideration of basic principles. The reduction in the rate-dependent proportion of skin has given an increase in production rate of 5-20% as compared to the computed rate from a slotted liner. This difference assumes no borehole collapse, with analyses and discussion presented of the effect on well performance should borehole collapse occur.

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Thts paper was sebcted for presentation by an SPE Program Commmtee following rewew of mfcfmatlon contained In an abstract Submtfed by Ilw author(s) Contents of tfw paper, as presented, have not bean rewewed by ttw Sc.aety d Petroleum Engineers and are subpd to correctIon by the author(s) The material, as presented does not necas=nfy refled any Posrtronof the SocBtV of Petroleum Emamecus, Its officers, or membws Papers presanted at SPE meetmgs are subjecl to pubhcaton revmw by EdWta! Ccfnmttees of the Souety cd Petroleum Eng!neers Perm!ssrm to cnpy IS restrutd to an abstract of no! more than 300 words Illustrations may not be copied The abstract should c.mtam wnsPIcuous acknowledgment of where and by whom the papar was pfesanled Wnfe Lbranan, SPE, P O Box 833S36 Rlchardscm TX 7S083-3826 U S A, fax 01-214-952-9435 Abstract Due to tubular corrosion of a gas lifted completion on the Arbroath field, the well was unable to flow due to the well shallow gas lifting through holes in the tubing. Since the Arbroath platform is a rigless platform, a full workover was considered a costly operation with prohibitive lead times. For that reason less costly and innovative through tubing repair options were considered to allow the well to be returned to production. After considering several options a coiled tubing straddle insert was chosen as the prefemed repair method to meet the success criteria for the job.The straddle consisted of 3 1/2" coil with hydraulic set packers at either end and was successfully run inside the existing 4 1/2" completion to seal off the corroded section of tubing allowing the well to return to production. This paper describes the repair options considered, the design, planning and installation of the coiled tubing straddle and the subsequent post repair well results.

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