Ministry of Oil and Minerals Petroleum Exploration & Production Authority BLOCK 85 (Al Uqlah North) The Al Uqlah North Block (85) occupies an area of 597 km 2 in the Sabatayn Basin in the province of Shabwah in central Yemen. The petroleum system of the Sabatayn Basin has been confirmed by the discoveries of the Many oil and gas fields. To the west lie the Exploratory Block (6) and the Exploratory Block (20) - with many oil & gas discoveries. To the south lies the Producing Block (S2) with many oil discoveries.
Block's Location on the Oil Producing SAB'ATAYN Sedimentary Basin
GENERALS Block Name Al Uqlah North Block N 0 (85) Province Shabwah Basin Sabatayn Basin Area (Km 2 ) 597 PREVIOUS EXPLORATION ACTIVITIES Company Period Activities Russian 82-90 Gravity 2D seismic CGG 76-77 Aeromagnetic Occidental 90-96 2D seismic Drilling (2) wells Preussag / OMV 98-07 2D seismic Previous Work DRILLED WELLS WELL NAME COMPANY DATE TD TD FM 2136 m West Riyam#1 Occidental 1993 Lam 1910 m West Riyam#1 Occidental 1993 Basement SHOWS STATUS Dry P & A Oil & Gas shows P & A HABBAN Field producing (34 o API) oil with rate of 18,000 bopd (with plan to reach 60,000 bopd) from the BASEMENT RESERVOIRS in BLOCK S2 - directly to the south of the Block 85
The entire surface area of Block 85 consists of flat sandy desert with some sand dune ridges in the western and northern parts of the block. Overall altitude of the block is around 800m amsl. In the eastern part of the block some isolated hills occur, representing outliers from the Hadramauwt Plateau. The Sabatayn Basin is a typical rift graben bounded by fault systems. The Sabatayn Basin consist of a series of discrete late Jurassic sub-basins which form a horseshoe shaped basin, with an opening to the southeast. The basin is surrounded to the north and east by basement highs with little sedimentary cover. Each of these highs comprise shallow basement, unconformably overlain by Tawilah Group sediments. In the depo-centers the sedimentary section reach up to 6,000m. The Shabwah depression is a part, together with the Wadi Hajar basin to the E and the Marib al Jawf basin to the NW, of a NW- SE trending sedimentary basin (about 560 km long and up to 140 km wide) generally referred to as Sab'atayn Basin. the Sab'atayn Basin formed as a consequence of a Late Jurassic (Kimmeridgian-Tithonian) extensional phase related to the initiation of spreading that led to separation of India- Madagascar from Afro-Arabia. The Shabwah Basin consist of a series of discrete late Jurassic sub-basins which form a horseshoe shaped basin, with an opening to the southeast. The basin is surrounded to the north and east by basement highs with little sedimentary cover. Each of these highs comprise shallow basement, unconformably overlain by Tawilah Group sediments. In the depo-centers the sedimentary section reach up to 5,000m. The Marib-Shabwah Basin has a thick oil-prone source rocks, which charge potential and excellent quality clastic and carbonate reservoirs. Open fractures within crystalline basement form the key element to the play. Open fractures in the basement have been proven by several wells in the Shabwa Basin. ossible charge mechanism include: Downwards migration from Madbi where it directly overlies the basement. Lateral migration in areas of Madbi onlap or cross fault juxtaposition. The most favorable route involves up-fault migration into structurally highs areas with hydrocarbons having reached the fault via bed-parallel migration within the Madbi (or within the basal part of Lam where the Madbi has lapped-out).
PETROLEUM SYSTEM TRAPS AND PLAY FAIRWAYS Structural and stratigraphic. SOURCE ROCKS Late Jurassic Lam/Meem Fm sh TOC > 5%, locally 10-20 Cretaceous SAAR, Late Jurassic SABATAYN or NAIFA high organic content clays and carbonates effective source rocks where they are mature. RESERVOIR Intra-Salt and Lam Carbonates & Clastics Naifa/Sarr, Madbi & Shuqra Carbonates Kuhlan Clastics The fractured Precambrian Basement can be good reservoir. Block 85 Prospects
Play concept
The Ma Rib-Al Jawf-Shabwa sub-basins are interpreted as a result of a failed arm of a triple junction that occurred in late Jurassic (Kimmeridgian). After Jurassic rifting, sediments filled the grabens from earliest Cretaceous (Berriasian) through late Cretaceous. A second phase of rifting and associated transpressional and transtensional structures were related to the opening of Red Sea and Gulf of Aden during Oligocene and Miocene. Block 85 is located close to the accommodation zone between Ma Rib-Al Jawf and Shabwah sub-basins. In this area plays are characterized by different possible reservoirs located in the following formations: Qishn sands shallow marine transgressive sands, unproven in Marib/Shabwa basin. In the Block 6 area, Qishn Fm. is too shallow. Naifa (Azal mbr) Main reservoir above the salt, composed by limestones and dolomite with interbedded shales and sands. (Naifa - Azal mbr has a discovery in nearby block 3) Alif Sandstones The Alif sands are an intra salt member within the lower section of the Sabatayn Gr. The Alif sands are well developed in the Ma'arib-El Jawf where they are considered a good reservoir. Sand units are SE prograding sand bodies, representing lowstand deltaic systems. The hydrocarbon entrapped in that reservoir requires vertical migration from Lam and Meem source rock through fault carriers rejuvenated by the Tertiary rifting. (The Alif sands producing in nearby blocks 18, 20 and S1). Lam - The Lam Fm is represented by thick deep water basinal shales with thin interbedded distal turbidites and thin limestones. The sequence was deposited during the main rifting phase. The sandstones are basically turbidites and occur as thin beds within the argillaceous sequences (producing in nearby block S1). Shuqra Limestone - Fractured carbonates, marginal marine (producing in nearby block 4). Kohlan - Fluvial sandstones occupying pre-rift topographic lows (producing in nearby block S2) Basement Fractured/weathered basement discoveries in nearby S2, 3 & 7 blocks.
Alif Play - Intra-salt Clastics in Block 85
Regional Sourcing Migration
Conclusions Sabatayn Basin is a proven hydrocarbon generating basin (with more than 20 oil fields carrying 2500 mmbbl of recoverable oil has been proven by many companies in many blocks. Block 85 is located on the structural margin of a hydrocarbon-rich basin with proven production to the East and West. The drilled wells confirmed the presence of reservoirs in many levels. Wells in the region which encountered significant oil and gas shows are associated with regional highs and Tertiary reactivation of bounding structures. BASEMENT SOURCING MODEL (in Sabatayn Basin)
Hazmi New Prospect in Block 85