Greater Burgan Basin

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Introduction

The Greater Burgan Basin lies within the Arabian basin and in the State of Kuwait, an independent emirate situated in the northeastern part of the Arabian peninsula at the western side of the head of the Persian (Arabian) Gulf. Kuwait is bounded on the east by the waters of the Gulf; on the north and west by the Republic of Iraq; and on the south by the Kingdom of Saudi Arabia. Although small in size, with a surface area of only 17,820 km2 (6880 mi2), Kuwait contains a number of important oil fields, including the Greater Burgan, Raudhatain, Sabriyah, and Minagish fields. The Greater Burgan field, located at lat. 29° N, long. 48° E, is by far the largest of these. The Greater Burgan field lies in southeastern Kuwait in typical desert terrain a few miles inland from the Gulf shoreline, at elevations ranging from 75 to 115 m (250 to 385 ft). The field encompasses a surface area of 780 km2 (300 mi2) and, with recoverable reserves of at least 75 billion bbl, is certainly among the very largest producing oil fields of the world. The Greater Burgan field was ranked as the second largest known by Halbouty et al. (1970) and by Carmalt and St. John (1986).[1]

Depositional History

During lower to middle Albian times, the Raudhatain/Sabiriyah area was an offshore environment. The paleostrand line is interpreted as having a general northwesterly orientation to the southwest of the two fields. The middle Burgan member was deposited at this time and is dominated by a thick section (140–160 ft) of stacked progradational muddy shorefaces. During the middle to upper Albian, this muddy shoreface environment evolved into the complex upper Burgan member. Core and wireline log correlations indicate that the upper Burgan was deposited in a complicated alternation of depositional environments that included major marine-influenced channel and estuarine settings, and occasional periods of relatively high sea level as recorded by thin marine mudstones and/or shoreface sandstones. Although there is positive evidence of estuarine processes, the more regressive, hence more constructional, lower part of the upper Burgan may have been partially deposited by tidally influenced deltas. Estuarine conditions would have been more prevalent during the retreat of the entire depositional system, and so would become more dominant in the uppermost part of the upper Burgan member. There is abundant evidence of channel sandbodies cut into marine mudstone in the uppermost part of the upper Burgan and micropaleontological data suggest that some of the enclosing marine mudstones were deposited in water depths of a few tens of meters. This provides good evidence of significant drops in relative sea level that facilitated channel incision. The channel-fills at the top of the upper Burgan are true, although small, incised valley-fill deposits. The major channels are believed to have northeasterly trends based on paleocurrent directions obtained from image log analyses. As relative sea level continued to rise overall, marked retrogradation occurred. The final extinction of the clastic-dominated depositional system during a continued rise in relative sea level resulted in the establishment of carbonate deposition and the accumulation of the carbonate-rich Mauddud Formation.[2]

File:GreaterBurganMap.jpeg
(Fig. 1) Map of Greater Burgan Basin.[3]
(Fig. 2) Simplified tectonic map of the Greater Burgan Basin.[4]

Primary Geological Risks and Uncertainties

There are multiple risks and uncertainties affiliated with hydrocarbon exploration and production. Many candidate surfaces were identified in the Greater Burgan using extensive core coverage throughout the Burgan Formation. This process was extremely significant as the sedimentological and palynological data indicate that many shale sections within key parts of the upper Burgan reservoir are of marginal-marine (specifically estuarine) origin. It also demonstrated that channel incision had eroded marine mudstones in many places. Hence, there are inherent risks in correlating estuarine shales that are likely to be discontinuous, and even some of the key marine shales are commonly missing through erosion and could not be identified in all wells. The surfaces used for regional correlation are a subset of the candidate surfaces, and are based on well-to-well correlation across both fields.[5] Many rapid facies changes were identified by the interpretation of log facies in the uncored sections of cored wells and throughout an additional 50 key wells. Naturally, facies changes in uncored sections are less certain. Marked changes in log facies were calibrated as far as possible with neighboring cored wells, and field-wide correlation proceeded on this basis. The wireline signatures, such as inflections, of correlatable surfaces in cored wells are the basis for identifying equivalent surfaces in surrounding wells.[6]


Petroleum Elements

Source Rocks

Ayres et al. (1982) suggested that the oil in late Early to early Late Cretaceous (Albian to Cenomanian) reservoirs in northern Sa'udi Arabia had its origin in source rocks of Early Cretaceous Berriasian-Valanginian age. In southeastern Kuwait, (Greater Burgan) it is reasonable that these sediments might have provided a source for the oil in the "Minagish oolite zone," which is of similar Early Cretaceous age. The Berriasian-Valanginian sediments are less satisfactory as a possible source for the oil in the main Albian to Cenomanian reservoirs at Greater Burgan, owing to the presence of the thick and apparently competent shales of the Ratawi Formation, lying between the Minagish reservoir and the Albian to Cenomanian clastics (Burgan and Wara formations).[7]

Seal

Despite being the largest oil reservoirs in Kuwait, the interbedded shale within Burgan Formation efficiently plays as a seal for the two major sandstone reservoirs (Third and Forth sand members).[8] Paleozoic and Jurassic organic-rich source rocks of the Arabian-Persian Gulf (hereafter, Gulf) region form two of the most prolific petroleum-producing systems in the world (fig. 1); these systems also include regionally extensive reservoirs and seals and large structural traps that combine to form many supergiant oil and gas fields.[9]

(Fig.3) Events chart for conventional oil and gas in the Greater Burgan.[10]

Trap

The majority of traps in the Greater Burgan Basin are structural traps. Several geological factors are responsible for the prolific hydrocarbon reserves in Kuwait and the Greater Burgan Basin. The tectonics, subsidence histories, and the diagenetic processes that prevailed, on the eastern part of the Arabian Peninsula during its geological history, are the main drivers for the exceptional geological conditions. These geological conditions are manifested by the widespread geographic distribution of rich, mature source rocks, high-quality reservoir rocks, and highly efficient seal rocks. Along with the formation of large structural traps during or after oil and gas generation, which helped in the formation of multiple petroleum systems in Kuwait. There are more than 20 oil fields across the country, however, most of the hydrocarbon production comes from the Greater Burgan field. These fields resemble very gentle four-closure anticlines interpreted as drape structures over deep-seated faults or as growth structures related to salt tectonics.[11]

Migration

The extremely large oil reserves in the Greater Burgan field result from the presence of oil conditions necessary for hydrocarbon generation, migration, entrapment, and preservation. The large volume of reserves is due to the simple geologic setting of the field, no major faulting, being adjacent to a large area of thermally mature source rocks to the northeast, great thickness of the reservoirs rocks, and their wide horizontal extension which allows horizontal migration of the fluids from the source rocks to the reservoirs and existing traps.[12]

(Fig. 4) Hydrocarbon migration model of the Greater Burgan Basin.[13]
(Fig. 5) Reservoir thickness of the Greater Burgan Basin. Reservoir thickness maps display the best areas in a given field and can demonstrate any well's long-term performance within the basin.[14]

Reservoir

The Greater Burgan is part of the world's largest siliciclastic reservoirs. The Greater Burgan’s oil producing zones are six Cretaceous-age reservoirs: (1) Wara (topmost) including First and Second Sand (as initially called); (2) the Mauddud limestone; (3-5) The upper, middle and lower units of Third Sand of which the middle unit is a quartz-rich, multi-Darcy porous sand unit and has produced over 75% of the field’s oil; and (6) Fourth Sand (lowermost), which is also quartz-rich and porous. The Third and Fourth Sands belong to the Burgan Formation. This Albian-Cenomonian succession of sediments, about 410m, was deposited in near-shore, shallow water (deltaic, littoral to lagoonal) environments on the gently subsiding continental shelf of the Tethys Sea that once covered the northern margin of Gondwana. A detailed study of sedimentary facies in the Burgan field by Christian Strohmenger and her colleagues (AAPG Memoir 88, 2006) show that the sediments have stacks of low-stand, transgressive, and highstand sequence sets controlled by sea-level changes. The Cretaceous play is capped by the Ahmadi Shale on the top of the Wara Formation and is sourced probably from the organic rich shale units of the Lower Cretaceous at the base of Fourth Sand. The generation and migration of oil occurred during Miocene-Pliocene times.[15]

Porosity and Permeability

Carbonate lithofacies comprise mostly limestone and dolomite, plus transitional lithologies such as dolomitic limestones or calcareous dolomites. Reservoir quality is considered poor with an average porosity of 18% and permeability ranging between 0.1%-10% mD in average.[16]

Resistivity

There are 777 wells in Greater Burgan field. Openhole well log data for these wells varies, as might be expected, from early spontaneous potential and resistivity data that were hand plotted, to modern digitally recorded logs. The predominant log suite in the field during initial development was a gamma ray, resistivity and neutron log combination, Modern log suites that include compensated density and neutron data are available for only about 14~0of the wells. Much of the digital data was lost during the Gulf War. Archived paper log copies were digitized, but information was only recorded for many wells from the Ahmadi formation to just below the original oil water contact. During 1996 and 1997 a formation evaluation project was undertaken to reprocess all openhole well logs in the field. Lithofacies prediction has been successful in analogous sediments of the Wasia formation in Saudi Arabia using a suite of five well logs.zo Our ability to define log facies, which are tied to core, and then predict lithofacies in uncored wells is limited because of the scarcity of weI1s with modern log suites. Pulsed neutron logs are a valuable data source that are used for tracking water movement in the reservoir, as discussed later and, through a normalization technique, for porosity estimation in the early wells drilled in the field.[17]

(Fig. 6) Porosity types and reservoir chracterization within the Greater Burgan Basin.[18]

Engineering Aspects

The Greater Burgan Basin produces over 1,200,000 barrels per day (~6.0×107 t/a). The current production of gas is about 550×106 cu ft/d (16×106 m3/d). The Greater Burgan Basin's peak of production (oil) is around 2,410,000 barrels per day (~1.20×108 t/a). The Greater Burgan Basin's estimated oil in place is around 44,000 million barrels (~6.0×109 t) with the producing formations being Upper Cretaceous Wara.[19]

Future Petroleum Prospects

The Greater Burgan Basin has been pumping oil for 65 years or so, and like any other oil field, be it large or small, it will eventually be abandoned, but that day will probably be several decades hence. The Cretaceous play in Burgan is still a supergiant field. And with the application of improved recovery techniques, more of the oil in place can be produced. Moreover, the deeper Lower Cretaceous (Thamama Group) and Jurassic oil and Permian (Khuf) gas plays, which are proven and rich productive horizons in the Persian Gulf region, are yet to be rigorously explored in the Great Burgan field.[20]

Potential Exploration Areas

1. In the Arabian Gulf offshore, very few exploration wells have been drilled and therefore the large Hydrocarbon potential of the stratigraphic traps remain untested. With the structural traps and sandstone reservoir, it should not take more than 5 years for production potential offshore southeast of the Greater Burgan Basin.

2. The anticline traps in the northern part half of the Greater Burgan with depths up to 3000m, could host potential exploration and production wells given the colossal size of the Greater Burgan Basin.

3. The Cretaceous sandstone salt-domes in the southern half of the Greater Burgan Basis. This potential area is a mature exploration and production area and still hosts potential targets for exploration.

References

  1. https://www.researchgate.net/publication/240780205_Characterizing_the_Greater_Burgan_Field_Use_of_Geochemistry_and_Oil_Fingerprinting
  2. https://pubs.geoscienceworld.org/geoarabia/article/6/2/179/566723/Upper-Burgan-Reservoir-Description-Northern-Kuwait
  3. https://assets.geoexpro.com/legacy-files/2012%20-%20Vol%209/No%201/Burgan/BurganFig2_Map.jpg
  4. https://www.researchgate.net/publication/354810336/figure/fig1/AS:1071506679406592@1632478508973/A-The-location-of-Kuwait-state-in-the-northeastern-part-of-the-Arabian-peninsula-and.png
  5. https://pubs.geoscienceworld.org/geoarabia/article/6/2/179/566723/Upper-Burgan-Reservoir-Description-Northern-Kuwait
  6. https://pubs.geoscienceworld.org/geoarabia/article/6/2/179/566723/Upper-Burgan-Reservoir-Description-Northern-Kuwait
  7. https://archives.datapages.com/data/specpubs/fieldst3/data/a015/a015/0001/0100/0103.htm
  8. https://link.springer.com/chapter/10.1007/978-3-031-16727-0_6
  9. https://pubs.usgs.gov/bul/b2202-h/b2202-h-508.pdf
  10. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.geoexpro.com%2Farticles%2F2012%2F05%2Fthe-great-burgan-field-kuwait&psig=AOvVaw01KUrM6VMdRZ4N2jSG7ur0&ust=1670364335514000&source=images&cd=vfe&ved=0CA4QjRxqFwoTCPC_opi-4_sCFQAAAAAdAAAAABAE
  11. https://link.springer.com/chapter/10.1007/978-3-031-16727-0_6
  12. https://www.searchanddiscovery.com/abstracts/html/1989/annual/abstracts/0428c.htm
  13. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hydrocarbon-migration
  14. https://link.springer.com/article/10.1007/s12517-018-3995-3/figures/3
  15. https://www.geoexpro.com/articles/2012/05/the-great-burgan-field-kuwait
  16. https://watermark.silverchair.com/iptc-17471-ms.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAvkwggL1BgkqhkiG9w0BBwagggLmMIIC4gIBADCCAtsGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMbYToG8srKuc9YWwcAgEQgIICrDLXcQN5GER8v9q2L5cZiMC85-pSMm-fXQhTN-TyjEY_unt7fEaxQyKTrR5ANCmsQpzla9GOVOqp7NTatCsvXgT6MBjeaoyQltBQvVs6Ugf7uXwlHODZuJGrEF5VdDYv-DUe5DbHMb1MIXwqlAGiahzmpMPIm7Laq5oyc-NtP0JvXj_9yed14IKuWS0-O3GaaKktHyg0jQxWNLSXzeF2ayBPyhCENH-V1nCJWms9B9g5z-9BYK-CGHfpVBqykX7kMnjyTbSCs_nsAZNhiLIdS_E7sMPhwKOXgaYjPaa5o5GEPJ2NZzZUaiqM1rvfY6_jlYb_IVFj1UaWIjKB9YNbD4HvX8kNOL86VEYDoQXDzGRJrFBfiDOJ-nw0kUj98dSug6UHe7BN-KzpJKme3in8jRIlAmYXYAECLDOiJjeYrsYWnevvhBTT0g7LUmPk6_UGpr1_bLcaZTZYXbqjh4M58rZWK7G6w4VZew6b4h4KI5qhuAvqByxoRcnLHZQa_SjdXKq_StFQbtve1Zv2TeXNVETDWdcDn847IryPzbcEHtxEiyrv_FBjp7Mu8JelxKfVcCNbY20dHqo3QnvXU0OEAWEqL21_YyPQ4yh0P7o5ehr750-Z4lYjPl1ziOQavPsJN6AxaF8a4x5DO-aba2KXZbsaHIdLvcpzJThQzrhgRGCL3Wil0lI62tTCcCmc2uVzH838IC_UMmqd1gRI9bzoYqE30j87RUm3Zj6TdPcwX1U8dvJ6iGXFDiU6SCF7TYHjh6rftHzrLrPjuxbp5IqRoaNe4975TYKohNC8EJ2uHti88mUHvmosDd9mAQKaN95yjLjM6OWs7YeWOlMzeV4TWzI3D7Z-_EKmmYKe8kWPTGfCSmnX6zoXGeCkrkEvD8OlT6RkqqZWrnCeqEfiVg
  17. https://watermark.silverchair.com/spe-49214-ms.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAu0wggLpBgkqhkiG9w0BBwagggLaMIIC1gIBADCCAs8GCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMjmKGnooSUtbbkBSKAgEQgIICoEZs378Bf2l5pz1eVpzduBPJuHR9lg9YLNDfJSJFIJjyUGimKgt0O4jUgo5s_VDHBgSFLNmVWkFFHsdh0Y0OqKcm_eNAcmgVPRzrEWNcof6-Bwne8-AvBg7wv9EHUHO-vHFoyJyRaiYcW7-_2V4MeCb0tn6_lXT4_3iiXGWVS4O1oJy_kmffECCM-A3-SuyMvctrYusLbnhA1YWRIkFxrr3-2k5X-4KWAM0bCZxf_CI8GxX789EYEM4FbT-nbHundNNVNtShBftAwPxWCaV1CsqTrhWsYB0dDvyI6gynuxYmN1qDQjKfM5szGo_3wO-SE_Uia_2BJmVYiNjyGJw7qctmjAWjO0iWoveuhVYg-Fj3nwK2nZ2zYAF1NeJYamYBWeN2ZH2ssxfb8T-4oX2r6WUzm4Iik9PYGoizEbTMVAG1oHVBiXkj_2VYfdgpjc_6VsHX_P2xTG5LyMoAsUfl8F6R6wRxZcl5N7Y3LuGwxbaoC5aG7TLFOFrOhw0Rik7eA4lhGKqkD-266PsB6pJEcer9UtLYYs8dEKaZ9PGkE-nK5xn99njjfQQZT0m7DKxZuDBRct-gzoigt4TYESwCA3WGQsbfccmfZcpYULtvxTUsoCLBOlVteanLv0o20iX3csX0AMhJBN2LkpGsU9d1KZV1VN_y8jgRb_z5k9I91hfTsiMNixm56mv3d3aSEWsf_w6w4RZLzvYIbuu8t37dhTCRg4fFEgFVLHuzFkeEn0V6avT1wEAQn9rntsdYho5FTyxy4ffjOpJ3t6qxr6JN_A4-L-LQfgRYCYWnXLghURmbtV9j5pc-9TgNf7wOEPEG99X3a_iXc6MzUV-_ba8FOMsqJSVjkWC6pkb1hee_QuvxZC_optYHIIx-elKtCRUoEw
  18. https://ars.els-cdn.com/content/image/1-s2.0-S0920410518310222-fx1.jpg
  19. https://petrowiki.spe.org/Burgan
  20. https://www.geoexpro.com/articles/2012/05/the-great-burgan-field-kuwait

Additional References

1. Jones, R. W. 1997. Biostratigraphy of the Upper and Lower Burgan reservoir in cored wells in the Raudhatain and Sabiriyah fields (North Kuwait). Unpublished BP Sunbury report for Kuwait Oil Company.

2. Aladwani, N.S., Alenezi, A. & Diab, A. Investigation of the Cretaceous total petroleum system using wireline logs, core, and geochemical data in Bahrah Field, Northern Basin, Kuwait. J Petrol Explor Prod Technol (2022). https://doi.org/10.1007/s13202-022-01556-4

3. Kirby, Robert H., Carr, Brian S., Al-Humoud, Jamal, Safar, Ahmed I., Al-Matar, Dawood, and Waleed Naser. "Characterization of a Vertically Compartmentalized Reservoir in a Supergiant Field, Burgan Formation, Greater Burgan Field, Kuwait; Part 1: Stratigraphy and Water Encroachment." Paper presented at the SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, September 1998. doi: https://doi.org/10.2118/49214-MS

4. E. Ravier, J.-F. Buoncristiani, in Past Glacial Environments (Second Edition), 2018

5. Naqi, M., Alsalem, O., Qabazard, S., Abdullah, F. (2023). Petroleum Geology of Kuwait. In: Abd el-aal, A.ea.K., Al-Awadhi, J.M., Al-Dousari, A. (eds) The Geology of Kuwait. Regional Geology Reviews. Springer, Cham. https://doi.org/10.1007/978-3-031-16727-0_6

6. Adasani, M., 1965, The Greater Burgan field: 5th. Arab Petroleum Congress, p. 7-27.

7. Alzankawi, Omran , Al-Houti, Reham , Ma, Eddie , Ali, Farida Ali, Alessandroni, Mauro, and Mariana Alvis. "Mauddud Fractured Reservoir Analysis, Greater Burgan field: Integrated Fracture Characterization using Static and Dynamic Data." Paper presented at the International Petroleum Technology Conference, Doha, Qatar, January 2014. doi: https://doi.org/10.2523/IPTC-17471-MS