--> High Precision Determination of Trace Elements in Crude Oils by Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry

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High Precision Determination of Trace Elements in Crude Oils by Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry

Abstract

A new geophysical exploration tool sourced by billions of naturally occurring electrical discharges from cloud to earth has been developed. Analysis of sixteen years of recorded North American lightning data have revealed non-random patterns of lightning strikes. When these data are cleaned, lightning strike density and newly-defined lightning attribute maps show interesting correlations to surface and subsurface geology.

To date, applications of this new and naturally sourced electromagnetic (NSEM) analysis technique include the exploration for groundwater, minerals and hydrocarbons, the identification of geohazards, as well as the optimal location of pipe and power lines and where additional insulation and grounding are required. Although lightning is a worldwide phenomenon guided by meteorological conditions, the precise location of strikes and their individual attributes are guided by shallow earth or terralevis electromagnetic currents. These currents are in turn highly influenced by lateral geological inhomogeneity caused by faults, fractures, mineralization, pore-fluids, and salinity variations. Lightning strikes and their attributes cluster around geologic features. Since surface and subsurface geology is a function of geologic time, geology is constant relative to the short time spans associated with lightning databases. This enables lightning data to be stacked similar to the way multi-fold seismic data is stacked and processed.

When processed in this manner, lightning strike density and attribute maps show clusters and lineations which appear to correlate to fresh water, some surface projections of faults, near surface fluvial depositional patterns, and possibly to hydrocarbon seeps, salt domes, hydrocarbons, and mineralization. A case study from the Texas Gulf Coast shows a “Rise Time” lightning attribute map that identified twenty-eight anomalies, each correlating back to a Tertiary aged oil or gas field.

Ongoing research utilizing patent pending algorithms show the electrical information contained in the lightning databases enables the calculation of resistivity and permittivity volumes. From these volumes, slices and cross-sections can be displayed, analyzed, and interpreted similar to the way 3D seismic data are evaluated. These volumes can be calculated and displayed at the same bin spacing as any available 3D data volume where the right lightning databases are available, thus allowing the data to be easily integrated with available seismic and subsurface data.

Although NSEM is a derivative of potential field data having lower frequency and resolution, it has tremendous value for building regional geological frameworks. It can help identify trapping faults in the search for hydrocarbons, prospective mineral acreage, and hydrocarbon migration pathways. NSEM is a useful new reconnaissance mapping tool that can be used to determine where to acquire geophysical or geochemical data for detailed follow-up evaluations.

In addition, NSEM has potential to assist in a wide range of non-exploration applications such as the identification of subsurface contaminant plumes, the placement of power lines and pipelines, the identification of surface and subsurface geohazards, and the mitigation of risk associated with lightning strikes. A disaster investigation report is referenced to illustrate how an awareness of lightning strike density could have helped avoid a deadly coal bed methane explosion.

NSEM is a new geophysical data type with wide application to society. This data is significantly less expensive to acquire, process, and interpret than most, if not all, geophysical techniques on the market today. Its cost is about 1/100th of what it would cost to acquire typical 3-D seismic data and an entire project can be completed within two months. Three-dimensional resistivity and permittivity data can be viewed in cross-section and as horizontal slices. It can also be scaled to the same display parameters as any 2-D or 3-D geophysical data, which facilitates its calibration to other geophysical and geological data.