As our push for tapping new reserves of oil and gas increase, a new scanning device promises to make the mapping of the Earth’s subsurface more accurate and reliable than ever before and mitigates risk of non-essential hole drilling. Gordon Stove explains.
Time-honoured methodology exploring the potential for new oil and gas fields remains expensive and time consuming with accurate pinpointing of a mineral rich reserve still not widely available. There is, however, a general consensus that a need for a less disruptive method of exploration would minimise risk and increasethe likelihood of successful exploration. For oil and gas, and other minerals, this means a suitable technology whereby sites can be dismissed without the need for expensive and time-consuming techniques and only places with a higher probability of successful recovery can be focused on.
Today’s society is heavily reliant on energy and natural resources that drive the technological innovation of our planet.
Whilst there is an urgent need to develop reliable, affordable and effective energy sources, we still have an ever-increasing demand for the discovery and efficient use of current known resources, such as oil and gas, in a more environmentally-friendly and cost-effective manner, by using remote sensing technology.
We are becoming more reliant on remote sensing techniques, ranging through various spectrums, to assist in the discovery and delineation of such resources. The field of remote sensing is broad and has a variety of applications, from environmental monitoring to military imaging and use by civilian businesses.
- Acoustic: Seismic to explore deep into the subsurface to help map rock layers
- Electromagnetic: low frequency measurements of dispersion of electrical current into the ground
- Infrared: remote monitoring of temperature change
- Visible: imaging of earth’s surface
- y-ray: down hole mapping of uranium depletion used to map sand and shale formations
- Gravity: measurement of subtle changes in the Earth’s gravitational field.
With respect to mapping oil and gas, and in terms of our ability to coarsely map vast volumes of the Earth’s subsurface, seismic and electromagnetic techniques aretypically used. The data acquired can be used to find anomalous regions that, combined with other sensor outputs, can be used to predict, say, the potential for an oil reservoir. Adrok has based its technology – Atomic Dielectric Resonance (ADR) on being able to provide more accurate mapping of the subsurface.
However, although these technologies are widely accepted across the industry, they do suffer from certain downsides, such as poor depth resolution, difficulty in interpretation,large costs and environmental issues with regard to acquisition of data.
A very wide part of the electro-magnetic spectrum is available to remote sensing scientists, giving access to information on scales from the ‘cosmic’ down to the ‘micro’. However, the study of the earth’s sub-surface has generally been left to low technology techniques such as seismic or physical coring of areas of interest.
The ADR scanner works by sending a narrow beam of energy into the ground using microwaves and radio waves. As it travels downward, the energy character of the beam is altered by the various rock layers it encounters. The beam is continually reflected back by these same rock layers and is recorded at surface.
The recorded data quantify how rocks and minerals, including hydrocarbons, interact with the beam as it passes through them and pinpoints their composition. The technology measures the dielectric permittivity of the subsurface as well as characterising the nature of the rock types based on analysis of both the spectroscopic and resonant energy responses.
A key driver in pursuing development of ADR technology is to reduce the number of drill holes required to delineate a subsurface mineral or hydrocarbon reserve. To do this, laboratory analyses of rock specimens and data from training holes are used to guide the interpretation and analyses of the ADR results. As more samples are entered into Adrok’s proprietary library, the confidence in the results will increase.
Another benefit to this approach is that ADR requires no land-use permitting as use of the technology offers a non-destructive, environmentally friendly way of remotely deducing subsurface geology. Since 2007, this ADR methodology has been successfully deployed as a geophysical service by Adrok in the exploration and appraisal of subsurface geological structures and targets (platinum group metals, zinc, nickel, copper, massive sulphides, uranium, and hydrocarbon deposits).
Commercially, Adrok’s survey service could help reduce exploration budgets by assisting in the decision-making process of drill locations. Adrok’s technology has great potential in helping oil energy service companies mitigate risks of drilling ‘non-essential’ holes.
Both seismic and borehole cutting are potentially environmentally disruptive, requiring the use of percussive forces for seismic and road infrastructure for bringing drilling rigs onto a site of interest for cutting cores. And for delicate sites in need of preservation, such as perhaps, areas of archaeologically importance, or as part of the built environment, physically damaging technologies are less than ideal for investigating such areas.
Adrok’s scanning device has been fully designed with a strong ‘passion for innovation’, which has grown from the founding inventor Dr Colin Stove’s vast experience in a variety of remote sensing techniques (from seismic, photogrammetry, through to both microwave and visible satellite imagery). Through many years’ use of these methods, Dr Stove saw a need to design and develop a new technique that could provide both penetration through and identification of materials.
Although the ideas behind ADR have been developing over the past 40 years, Adrok has been working on commercialisation of the technology during the past 15 years, the company being set up on the back of a patent application.
The first few years of Adrok’s life were spent further researching, consulting and developing the best application for the technology and it was soon realised that the best route to market was mapping of the earth’s subsurface – ie, geophysics.
Identifying the need to produce better, more detailed maps/logs of the earth’s sub-surface, Adrok combined this need with its technology design to produce an entirely new concept – the ‘Virtual Borehole’ – to provide nondestructively from the surface, a classification of the rock layers and fluid content of the subsurface.
A Virtual Borehole is generated by acquiring data over a localised area of the Earth’s surface. The data captured is then analysed, and the energy, frequency and permittivity calculated.
In order to compare the gathered sensor response to what is found in the ground, Adrok utilises one or both of the following methods:
- Correlation of gathered signal against known borehole
- And/or by taking rock cores from the ground and placing them in its laboratory chamber and interrogating them with an ADR beam.
- A database of these rock types is generated, and can then be compared and correlated against the field acquired data. The output is a set of logs that can be used by the client to reduce the amount of physical drilling, thus reducing the client’s energy and monetary expenditure.
Complex theoretical modelling has also been developed in-house to model the ADR beam’s properties and to predict how it penetrates the subsurface and interacts with different materials. Combined with physical prototyping, technology improvements are generated and rigorously tested prior to becoming part of the ADR system.
In terms of geothermal energy sources, Adrok is currently conducting a collaborative research project with scientists at the University of Glasgow’s department of engineering, funded through the UK Technology Strategy Board. The project aims to develop a methodology and tool for mapping possible sources of geothermal energy, typically from finding temperature gradients in granites at great depth.
Gordon Stove is MD of Adrok Ltd. Adrok was founded by Dr. Colin Stove, the inventor of the technology. Since then, in addition to government funding, Adrok has invested over £3 million to advance and commercialise the technology. Adrok launched its first commercial services offering, called “Predrilling Virtual Logging”, in the summer of 2007. Adrok’s Atomic Dielectric Resonance (ADR) Scanner uses radio waves and microwaves to locate, identify and map subsurface natural resources including oil and gas, metallic ore deposits and industrial minerals. Unlike other 3D seismic technologies, ADR uses spectroscopy to measure the wavelengths and identify minerals and rock types in the subsurface.
For further information please visit: adrokgroup.com
Issue 122 July 2015