First EOR Trial using Low Salinity Water Injection in the Greater Burgan Field, Kuwait

Abstract

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.

From Mineral Surfaces and Coreflood Experiments to Reservoir Implementations: Comprehensive Review of Low-Salinity Water Flooding (LSWF)

“…In light of these, low-salinity water injection has become an established EOR method for Endicott field. , Robertson analyzed historical production data from fields that have been waterflooded with about 1000 ppm low-salinity brine and observed that their recoveries were higher than those under high-salinity injection. Patil et al, Vledder et al, Seccombe, Abdulla et al, and Zeinijahromi et al all reported substantial recovery increments ranging from 4–15% oil-in-place. Conversely, less than encouraging field cases have been observed.…”

A review on low salinity waterflooding in carbonates: challenges and future perspective

“…Low salinity waterflooding projects/field trial/pilots reported in the literature have been dominated by those projects which have been implemented in sandstone reservoirs. Researchers (McGuire et al 2005;Eric Robertson 2007;Skrettingland et al 2011;Abdulla et al 2013a;Erke et al 2016;Al Qattan et al 2018;Katende and Sagala 2019) have reported field implantation of low salinity waterflooding in sandstone reservoirs. On the other hand, studies which discuss low salinity projects in carbonates are scarce.…”

Brine-Dependent Recovery Processes in Carbonate and Sandstone Petroleum Reservoirs: Review of Laboratory-Field Studies, Interfacial Mechanisms and Modeling Attempts

“…In addition, the low content of organic acid in the Snorre oil ensured that the reservoir was already close to optimum wetting conditions, such that low saline water could not significantly improve recovery [36]. Furthermore, Abdulla et al [225] documented two recent SWCT tests conducted in the giant Kuwait Burgan oilfield. The tests were implemented in two reservoir formations with the least clay content and good quality rock.…”