Images of the benioff zone in the lithosphere using electromagnetic energy released from stress in tectonic plates
Different manifestations of electromagnetic phenomena have been reported in the scientific literature for many years, linking them with seismic events, from large to even 3.0 Ml earthquakes. Examples are pre-seismic and co-seismic luminescence, various forms of electric charge displacement and magnetic fields, stress generated electromagnetic pulses, radio wave generation by accelerated charges at different frequencies and even strange animal behavior. In this paper, we report several events of electromagnetic pulses associated with seismic events and registered by magnetometers and analyze several cases of EM phenomena leading to the determination of the physical morphology and other physical aspects of the lithosphere from passive reception of pulses associated with earthquakes.
Toward a unified solid state theory for pre-earthquake signals
Many different non-seismic pre-earthquake signals have been reported but there is great uncertainty about their origin, their correlation to each other and to the impending seismic event. The discovery of stress-activated electric currents in rocks provides a possible explanation. Stresses activate electronic charge carriers, namely defect electrons in the oxygen anion sublattice, equivalent to O− in a matrix of O2−, also known as positive holes. These charge carriers pre-exist in unstressed rocks in a dormant, electrically inactive state as peroxy links, O3Si-OO-SiO3, where two O− are tightly bound together. Under stress dislocations sweep through the mineral grains causing the peroxy links to break. Positive holes, thus generated, flow down stress gradients, constituting an electric current with attendant magnetic field variations and EM emissions. The positive holes accumulate at the surface, creating electric fields, strong enough to field-ionize air molecules. They also recombine leading to a spectroscopically distinct IR emission seen in laboratory experiments and night-time infrared satellite images. In addition positive holes interact with radon in the soil, affecting the radon emanation.
Prevention of Barite Sag in Oil-Based Drilling Fluids Using a Mixture of Barite and Ilmenite as Weighting Material
Drilling high-pressure high-temperature (HPHT) wells requires a special fluid formulation that is capable of controlling the high pressure and is stable under the high downhole temperature. Barite-weighted fluids are common for such purpose because of the good properties of barite, its low cost, and its availability. However, solids settlement is a major problem encountered with this type of fluids, especially at elevated downhole temperatures. This phenomenon is known as barite sag, and it is encountered in vertical and directional wells under static or dynamic conditions leading to serious well control issues. This study aims to evaluate the use of barite-ilmenite mixture as a weighting agent to prevent solids sag in oil-based muds at elevated temperatures. Sag test was conducted under static conditions (vertical and inclined) at 350 °F and under dynamic conditions at 120 °F to determine the optimum ilmenite concentration. Afterward, a complete evaluation of the drilling fluid was performed by monitoring density, electrical stability, rheological and viscoelastic properties, and filtration performance to study the impact of adding ilmenite on drilling fluid performance. The results of this study showed that adding ilmenite reduces sag tendency, and only 40 wt.% ilmenite (from the total weighting material) was adequate to eliminate barite sag under both static and dynamic conditions with a sag factor of around 0.51. Adding ilmenite enhanced the rheological and viscoelastic properties and the suspension of solid particles in the drilling fluid, which confirmed sag test results. Adding ilmenite slightly increased the density of the drilling fluid, with a slight decrease in the electrical stability within the acceptable range of field applications. Moreover, a minor improvement in the filtration performance of the drilling fluid and filter cake sealing properties was observed with the combined weighting agent. The findings of this study provide a practical solution to the barite sag issue in oil-based fluids using a combination of barite and ilmenite powder as a weighting agent to drill HPHT oil and gas wells safely and efficiently with such type of fluids.