Global distribution of the hydrocarbon Golden Zone

Abstract

The presence of sedimentary sequences located at temperatures ranging between 60 and 120 °C has permitted the identification of hydrocarbon accumulation patterns of economic importance. This thermal range is identified as the “Golden Zone”, where there is a potential co-existence of the petroleum system elements that supports a minimal degree of degradation or transformation of hydrocarbons generated from source rocks, mainly in the hydrocarbon expulsion zone from approximately 120 °C–200 °C. The Golden Zone distribution can be represented on maps to help distinguish regions of relevant hydrocarbon potential.This work presents global Golden Zone distribution maps, estimated using a global geothermal gradient model obtained using the Curie Point Depth (CPD) distribution constrained with geothermal gradients from direct wells temperature measurements and a global model of sedimentary thicknesses obtained from data reported by a diverse array of institutions. The Golden Zone maps show the variations in different geotectonic environments. The depth interval for the Golden Zone varies between 500 m and 3000 m for the top and from 1000 m to 5000 m for the base, with thicknesses ranging between 5 and 3000 m.The Golden Zone distribution estimated shows that along active tectonic margins, the sedimentary sequences tend to be thin, located with abrupt contrasts of the basement, and where one or both isotherms that define the Golden Zone are below the basins, preventing its proper development. Exceptions to this trend are in the forelands and some intermountain basins. In contrast, the passive margins are characterized by Golden Zone regions in which the sedimentary sequences present a wide range of thicknesses within basins of diverse ages and extensions.