The use of GPR to image three-dimensional (3-D) turbidite channel architecture in the Carboniferous Ross Formation, County Clare, western Ireland

Abstract

Petroleumreservoirmodelsarecurrentlybuiltfrom two-dimensional( 2-D)i nformation. Anunderstanding of boththe large-scale and internalthree-dimensional( 3-D)architectureo fturbiditechannel deposits isimportantforbothh ydrocarbon exploration and production. Aground penetrating radar(GPR)surveyw asu ndertaken on astudys itee xposing UpperCarboniferous Ross Formation deposits in westernIreland. Bothchannel marginsand intrachannel fill wereimaged in 3-D.Constant-offset,2-Dreflection sectionswerecalibrated byverticalradar profiles.GPR datawerei ntegrated withsedimentary and surveydatatop roducea3-Dmodel of the studys ite.Inp etroleumreservoirs,highlydetailed,downborehole information constrainsnear-well geology, but onlyavery small amountof the reservoiris sampled. Wherespacing between wellsisrelatively large (typicalvaluesin the NorthSeab eing 1000 m,Henson pers.comm.),the inter-well volume ispoorlyu nderstood. Conventionalseismic datasets overr eservoirs cani dentifylarge-scale sedimentary features,suchas15-25m-thicksand bodiesobserved on moderate-quality twodimensional( 2-D)seismiclines(Weber1993

3D high-resolution digital models of outcrop analogue study sites to constrain reservoir model uncertainty: an example from Alport Castles, Derbyshire, UK

“…These horizons were noted within channels on the outcrop face (Fig. 2d); 3D shale horizon dimensions were obtained from a similar study on the Carboniferous Ross Formation turbidite channels described in Pringle et al 2003a. The 3D shale horizon data from the Ross Formation study were scaled to fit the Alport Castles turbidite channel dimensions, being of similar Upper Carboniferous age and deposited in a medial turbidite environment.…”

“…Ground Penetrating Radar (GPR) equipment has begun to be used to acquire shallow subsurface, high-resolution datasets (c. 0.25 m spaced beds to depths of 10 m+) on ancient outcrop analogues (see Stephens 1994;Corbeanu et al 2001;Szerbiak et al 2001;Pringle et al 2003a). Whilst electromagnetic reflection amplitudes are controlled by changes in bulk electrical properties, rather than by lithology boundaries (Davis & Annan 1989), Vertical Radar Profiles (VRPs) acquired down outcrop cliff faces allow GPR reflection events to be correlated with observed cliff-face sedimentary horizons (see Pringle et al 2003b).…”

Lateral juxtapositions of channel and lobe elements in distributive submarine fans: Three-dimensional outcrop study of the Ross Sandstone and geometric model

“…Gill (1979) interpreted the erosional surfaces above the Ross Slump as slip scars related to slumping. In Lien et al (2003), Pringle et al (2003), Pyles (2008), and Pyles and Strachan (2015), the erosional surfaces were interpreted as the lower bounding surfaces of submarine channel elements.…”

An introduction to ground penetrating radar (GPR) in sediments

“…This data can also be used to provide both qualitative and quantitative data for petroleum and hydrogeology reservoir modelling (Thompson et al 1995;Jol et al 1996b;Corbeanu et al 2001). In Pringle et al (2003a), outcrop sedimentary and topographic data are combined with GPR to produce a 3-D model of turbidite channel deposits. The aims of the study are to complement conventional outcrop data and improve the data available for hydrocarbon-reservoir modelling and the results include a quantitative 3-D volumetric model suitable for hydrocarbon-reservoir modelling.…”