How to be predictive with low net-to-gross reservoirs: a Triassic case study

LUIS MIGUEL YESTE; AUGUSTO NICOLÁS VARELA; NEIL MCDOUGALL; FERNANDO GARCÍA-GARCÍA; JAVIER JAÍMEZ; CÉSAR VISERAS

GEOGACETA

Sociedad Geológica de España

Lugar: Madrid; Año: 2020 vol. 67 p. 39 - 42

0213-683X

The ability to be predictive in exploratory geology (hydrocarbon prospecting or hydrogeology) is very important when dealing with a highly heterogeneous reservoir rock and with a low net-to-gross ratio. A Triassic example is presented in the succession informally known as TIBEM (south central Spain) corresponding to a very distal fluvial flood plain that is studied in outcrop and in cores and well logs of wells made behind the outcrop (OBO characterization, Outcrop / Behind Outcrop). It is shown that there are characteristic patterns of 1D data from gamma ray and distribution of tadpoles acquired in wells that allow as to accurately locate the well within the detail sedimentary model of the ancient floodplain. In this way, from the 1D data, inferences can be made about the 3D disposition of the sandstone sedimentary bodies corresponding to the channel and the crevasse-splay lobes, as well as the interconnectivity between these and their potential permeability barriers and baffles. The usefulness of this workflow when it comes to making robust models is evident.