Submarine fans are important to the petroleum industry for their reservoir and source‐rock potential. There are a variety of fan types that can be characterized by different fan models. In assessing which model, if any, is appropriate for a particular area or field it is important to evaluate the controls that operate to determine the type of fan developed. Most present‐day fans that have been studied are deep‐water oceanic; more work is required on modern examples of shallow‐water, small‐basin fans which are particularly relevant to hydrocarbon exploration.
Jurassic and Tertiary objectives are important in the North Sea and include both nearshore‐sandstone and submarine fan reservoirs. The Brae oilfield is an Upper Jurassic reservoir on the western faulted margin of the North Sea Central rift system. Detailed core, electric log, dipmeter and seismic data have been examined. The Brae field comprises at least three small overlapping submarine fans that form a sediment apron along the scarp margin and that were deposited by a variety of gravity‐flow processes in a shallow basin below wave base. Tectonic control on fan development has resulted in up to six fining upwards megasequences (50‐150m) within the overall fining upwards basin fill (300–600 m). There has been a large intermittent supply of coarse detritus across a narrow littoral zone and down a steep slope. Short, sedimentladen rivers supplied mud and plant débris, and a complex interdigitation of coarse‐and fine‐grained facies has resulted.
The Brae fans are an important example of the fault‐controlled, shallow, small‐basin type and are most closely analogous to the Jurassic fans of East Greenland. Reservoir characteristics are dependent on diagenesis, facies and fault distribution, and vary markedly along the fault margin. A clear understanding of the controls and models is essential for continued exploration and development in this part of the North Sea.
The late Miocene submarine fan complex of the Tabemas basin, SE Spain, consists of three distinct fan systems including a mixed sand/mud system, an isolated channel complex and a sand-rich system. The latter has been extensively studied and provides excellent insight into the reservoir characteristics of a high net:gross sand-rich system.
TX 75083-3836, U.S.A., fax 01-972-952-9435.
AbstractIn Salah Gas is a joint venture between Sonatrach and BP that will deliver 9 billion cubic metres per annum (bcm/a) from eight gas discoveries in the Ahnet-Timimoun Basin of Central Algeria. Prior to the sanction of this project in early 2000 an exploration and appraisal programme was completed to reduce uncertainty in gas volumes and deliverability, prove additional reserves and demonstrate commerciality of the development.Uncertainties were identified and ranked by quantitative assessment of alternative appraisal options and their impact on project value (Value of Data analysis). The analysis was used to help define objectives for the exploration and appraisal programme that comprised acquisition of 2D and 3D seismic data plus the drilling of 9 wells.Key objectives of the appraisal activity were to assess the connectivity of conventional Devonian reservoir intervals, evaluate tight gas reservoirs, assess the contribution of fractures to well deliverability and gain an understanding of Carboniferous reservoir distribution using 3-D seismic imaging. 4 Extended Well Tests (EWT's) were a key part of this programme.Optimisation of the exploitation and sequencing of the 7 fields' development led to significant cost savings. A modelling tool jointly developed by facilities, wells and subsurface teams ran multiple development options providing ranked options with deliverability assurance.As part of Sonatrach and BP's commitment to reduce greenhouse gas emissions, the vast proportion of produced CO2 (400Bcf) will be re-injected at the cost of the project. Two or three dedicated horizontal wells will be drilled to dispose of the CO2 and infrastructure will be put in place to facilitate disposal of CO2 from all eight fields.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.