XRF Core Scanning – A Time-efficient Tool for Non-destructive, High-resolution Element-geochemical Analyses of Drill Cores

Matthias Forwick

Inorganic geochemical analyses of drill cores recovered for hydrocarbon exploration are typically destructive, time-consuming and expensive. Furthermore, they are performed at steps of meters to tens of meters, thus, providing only sporadic information about the chemical composition of the recovered sediment sequences. We performed element-geochemical measurements of drill cores from the Barents Sea using an Avaatech X-ray fluorescence (XRF) core scanner with the purpose of testing whether or not this method provides a useful tool for chemo-stratigraphy and core correlation. XRF core scanning is an energy-dispersive method, meaning that atoms exposed to X-radiation emit a secondary radiation with energies of certain characteristics for each element of the periodic system. The intensity and amount of the secondary radiation are identified and counted by a detector. The method is time efficient and non-destructive allowing qualitative element-geochemical analyses of surfaces with spatial resolutions exceeding those currently applied in hydrocarbon exploration. XRF core scanning has developed to a standard method within scientific drilling during the last decade, but has – to our knowledge – not been systematically applied in correlations of cored strata so far. Our test measurements were performed on IKU/SINTEF shallow stratigraphic cores from different parts of the southwestern Barents Sea containing a large variety of lithologies of the Triassic succession. The analysed area was 10 mm x 12 mm and data were typically collected at a spatial resolution of 2-30 centimetre intervals. Three runs were carried out at each point in order to identify light (Mg-La), medium (Ni-U) and heavy (Cd-Ba) elements. Our settings allowed us to obtain data from more than ten depths within less than 15 minutes. We will present information about the principle of XRF core scanning, our experiences from the test measurements and discuss the potential of this method for chemo-stratigraphical analyses and correlation of cores drilled for hydrocarbon exploration. We regard XRF core scanning as a method having great potential of becoming a standard method for geochemical analyses of drill cores recovered in hydrocarbon exploration.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013