C&C Reservoirs’ latest content release is now available in DAKS.
This includes 86 Reservoir Evaluation Reports from across the globe.
Hall-Gurney (USA) – Onstream since 1931, light oil (36 °API and 3 cP) has been mainly produced from the Pennsylvanian, multi-layered limestones by solution-gas drive, aided by continuous water injection. A CO2 miscible flood pilot was conducted but proved uneconomic.
Iwafune-Oki Field (Japan) – Offshore Niigata Basin, began production in 1990. Light (34-38 °API) oil is produced from fine- to coarse-grained sandstones interbedded with mudstones deposited in a submarine-fan environment. Strong solution-gas drive led to a 6-year plateau. The production decline thereafter was eased by gas lift, miscible gas injection and WAG injection.
Jujo (Mexico) – Onstream since 1980, volatile oil (38 °API and 0.15 cP) has been produced from a thick sequence (~1100 m) of Upper Jurassic and Lower Cretaceous fractured dolomites by solution-gas and aquifer drives. Matrix acidization is necessary to achieve initial production and maintain economical offtake levels. Hydrocarbon gas injection rejuvenated production in a pilot area, while fieldwide nitrogen injection proved ineffective.
LD 10-1 Field (China) – Offshore Bohai Bay, onstream since January 2005, producing 18 °API oil from the Oligocene Lower Dongying Formation delta-front sandstones, reached the peak in July 2005 under natural drive. Ineffective water injection starting in May 2005 prompted early polymer flood pilot, followed by fieldwide implementation since April 2007, leading to secondary peak in October 2010. Cumulative recovery to October 2015 had reached 28% and ultimate recovery factor exceeds 40%.
Marun (Iran) – This field, in SW Iran, began production in 1966 and had a STOIIP and EUR of 50 BBO and 23.4 BBO with recovery factor of 47%. Massive, fractured carbonates of the Asmari Formation hold most of the oil resources (with a >1500 m oil column) with a dual-porosity system and production mainly from fractures within a dolomitized matrix. Crestal gas injection began in 1978 and was expanded in 1996. In 2003 sour gas injection was converted to sweet gas following increased H2S production levels. In 2020 the field was producing at 600,000 BOPD.
Varg (Norway) – In the Norwegian North Sea, Varg came onstream in 1998 and had an EUR of 103 MMBO. Multiple oil pools in Ula Formation sandstones are trapped within a faulted anticline overlying salt ridges and diapirs. Production was by solution-gas drive supported by gas injection and later by water and WAG injection. Various strategies have been used to maintain production including infill drilling, reperforation, selective perforation of wells, profile modification and sidetracking owing to issues with sanding and scaling. Gas blowdown began in 2013 and the field was decommissioned in 2016.