Comparative studies of pre- and post-drilling modelled thermal conductivity and maturity data with post-drilling results: implications for basin modelling and hydrocarbon exploration

Abstract

The primary objective of this paper is to demonstrate the successful application of maturation modelling using velocity-based thermal conductivity in the whole cycle of hydrocarbon exploration (frontier, developing and mature) on the Halten Terrace, Offshore Norway. This seismic geochemical method, used as a critical technique for selecting a favourable block in the early stages of exploration in the early 80s, enabled Conoco and its partners to make the first oil discovery and the subsequent discovery of the giant Heidrun Field in the area north of the 62nd parallel.Additional data (modelled and measured) on the thermal conductivity and Ro values are now available, and provide an excellent opportunity to compare the original (pre-drilling) basin models and related modelled results of the early 80s with 1990s (post-drilling) state-of-the-art data and models. The results of the comparative study indicate that the velocity-based conductivity compares very well with measured data, particularly in an overpressured area where conventional porosity (modelled) based thermal conductivities were inadequate. The pre-drilling predicted values of heat flow, geothermal gradient and vitrinite reflectance (based on Arrhenius equation) and oil window limits also compared favourably with post-drilling measured results. Thus, the method of calculating thermal conductivity from seismic data provides a useful tool to integrate geochemistry and geophysical (seismic) data, to calibrate maturation models, and to enhance the value of geochemistry and basin modelling in hydrocarbon exploration.for basin modelling and hydrocarbon exploration.

Inversion of needle‐probe data for sediment thermal properties of the eastern flank of the Juan de Fuca Ridge

“…Accurate knowledge of the thermal properties of marine sediments (thermal conductivity, heat capacity, and thermal diffusivity) is necessary for examination of many geothermal problems such as calculation of heat flow in sedimentary basins [e.g., Hyndman et al , 1979; Villinger and Davis , 1987], estimation of heat flow in shallow seas by removal of effects of bottom‐water temperature variation from subbottom temperatures [e.g., Kinoshita et al , 1996; Hamamoto et al , 2005], reconstruction of a bottom‐water temperature history from subbottom temperatures [ Nagihara and Wang , 2000], evaluation of the effects of sedimentation on heat flow at the surface [ Hutchison , 1985], modeling the thermal structure of a subduction zone accretionary prism [e.g., Hyndman et al , 1995; Wang et al , 1995], transport of heat and fluid in sediments [e.g., Goto et al , 2005], maturation and transport processes of hydrocarbons [e.g., Ho et al , 1998], and accumulation of methane hydrates [e.g., He et al , 2006]. To date, thermal conductivity data for marine sediments have been reported in many papers.…”