Improving models of the Earth’s magnetic field for directional drilling applications

Abstract

8Over the past twenty years, directional borehole drilling has become increasingly important for 9 improving the optimal extraction of reserves from challenging targets, for extending the reach of 10 fixed platforms and for reducing wellbore collisions. Very long wells drilled using borehole steering 11 methods can take weeks to months to complete and rely on accurate models of the Earth's magnetic 12 field which necessarily include a parameterization of its time variation. Earth magnetic field models 13 used in the hydrocarbon industry, such as the BGS Global Geomagnetic Model (BGGM), are 14 computed from data collected by a network of ground-based magnetic observatories and from low-15Earth orbiting satellites. Magnetic field models provide snapshots looking back in time, but to be 16 useful to industry, they also need to predict how the field will change in the future. Previously, 17 predictions of magnetic field variation have been based on relatively simple extrapolation of the 18 observed changes. We introduce a physics-based technique to forecast the changes in the field by 19 deducing large-scale flow of the iron-rich liquid at the top of the outer core and use this to advect 20 the present magnetic field forwards in time. We demonstrate that this method produces valuable 21 improvements in the accuracy of the BGGM. 22 23 3

A Study on Monte Carlo Simulation of the Radiation Environment above GeV at the DAMPE Orbit

“…As the inputs of our simulation, we use the measurements of the AMS02 for the incoming fluxes of various GCR components, and only three GCR components of the most interest are considered, namely, protons (Aguilar et al 2015b), helium nuclei (Aguilar et al 2015a) and CREs (Aguilar et al 2014). We consider in our simulation a full 3D description of the Earth's atmospheric (NRLMSISE00 atmospheric model, Picone et al 2002) and magnetic-field (IGRF-12 geomagnetic field model, Beggan et al 2015) configurations using the latest available models. The NRLMSISE00 model describes the atmospheric density, composition and changes over time from sea level to 1000 km altitude.…”

A földi mágneses mező forrásfolyamatának gépi tanulás alapú rekonstrukciója

“…Végül de nem utolsó sorban a modellek mágneses mezőjét általában a földköpeny aljáig (KMH) tartó térrészben számítják ki, élve azon feltételezéssel, hogy a (8) feltétel a földköpenyen belül is mindenhol teljesül, azaz a köpenyt szigetelőnek tekintik, aminek további fontos következményei vannak. Hamilton, 2014).…”