3D Reservoir Architecture of Alluvial Fan; Christies Beach Formation, Sellicks Beach
Aadil Al Shekaili, 2013
Bachelor of Science (Honors) (Petroleum Geology & Geophysics)
Australian School of Petroleum
University of Adelaide
The studies of outcrops are used as analogues of hydrocarbon fields (Collinson, 1970). Good analogues are those that have excellent 3 dimensional exposures over an area to obtain sufficient scale of heterogeneity and they are also comparable to the system being studied. Hence, outcrop analogue studies play a vital role in improving the architecture and distribution of facies.
Accurate 3D models are needed to illustrate the geobodies continuity. Connectivity of geobodies is one of the vital controls on petroleum production and preservation (Pringle et al., 2004a; Larue & Friedmann, 2005). Software, such as Schlumberger's Petrel can represent and simulate the subsurface in 3 dimensions. This paper will show how newly adopted digital data capture techniques - digital geometry acquisition by laser rangefinder and high resolution outcrop photography using a gigapan photographic mosaic capture device - aids a geologist by collecting accurate and precise data that can be used to condition or calibrate reservoir model development.
Understanding of the subsurface is essential for hydrocarbon exploration and ground water aquifers characterisation. Alluvial fans are considered to form a complex facies system. Many studies of modern-day alluvial fan systems and their deposits have identified surface geometries and various sedimentary environments of an alluvial fan (although the stratigraphy is not well understood). The 3-dimension model of alluvial fan facies provides predictions of geobodies connectivity, hence production potential.
The aim of this project is to build the 3D architecture of conventional reservoir and non-reservoir elements recognized within alluvial fan sediments of the Christies Beach Formation adjacent to Sellicks Beach in South Australia, including geobodies recorded within them. This work will assist to build a detailed reconstruction of past fan surface landscapes and eventually post flood event simulation (Bunch, 2013, project proposal). Both sheet-floods and debris flow deposits will be investigated through sedimentary analysis and interpretation of depositional processes to determine the style of these alluvial fan sediments.
In addition the 3D model will be a useful analogue for ancient terrestrial fault-front sedimentary successions that host viable reservoir systems in the subsurface. It is also thought that ‘pay' characteristics of the Christies Beach Formation will provide a proxy for the ratio of conventional reservoir to non-reservoir sediment volumes that accumulated basinward.