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Earth Explorer is an online source of news, expertise and applied knowledge for resource explorers and earth scientists. Sponsored by Geosoft.


News & Views

News Archive

December 7, 2016

Geosoft introduces IP and resistivity inversion in VOXI Earth Modelling

Geosoft has added induced polarization and resistivity data inversion to its VOXI Earth Modelling 3D inversion software service. Geoscientists are now able to create detailed 3D models of conductivity and chargeability from IP and resistivity survey data with VOXI. The resulting models can assist in interpreting and targeting regions for mineral and environmental applications...

December 5, 2016

Mexico's Deepwater Round Exceeds Expectations

Some of the world's biggest oil companies showed up Dec. 5 and agreed to invest on the Mexican side of the Gulf of Mexico, proving that deepwater exploration still has a pulse despite challenging market conditions...

November 30, 2016

Magnetic inversion results for Ngamiland available for download

A regional-scale geophysical inversion of magnetic field data in the Ngamiland region of northwestern Botswana is now available for download from the Botswana Geoscience Portal, a partnership initiative of the Botswana Geoscience Institute, industry sponsors and Geosoft...

November 30, 2016

LIGO Resumes Search for Gravitational Waves

After a series of upgrades, the twin detectors of LIGO, the Laser Interferometer Gravitational-wave Observatory, have turned back on and resumed their search for ripples in the fabric of space and time known as gravitational waves. LIGO transitioned from their engineering test runs to full science observations at 8 a.m. Pacific Standard Time on November 30...

November 9, 2016

International Volcano Scientists Unite

For the first time, the United States will host the international Volcano Observatory Best Practices workshop, previously held only in Italy. The workshop will take place this month in Vancouver, Washington. It is designed specifically for volcano observatories around the world and their staff to exchange ideas and best practices with each other...

October 4, 2016

USGS Assesses Mineral Potential for Sagebrush Habitats in Six Western States

USGS has completed a comprehensive assessment and inventory of potential mineral resources covering approximately 10 million acres of Federal and adjacent lands in Idaho, Montana, Nevada, Oregon, Utah and Wyoming...

October 3, 2016

Uganda Targets Up to U.S.$100 Million for Mineral Exploration

Uganda is well endowed with mineral resources and, like many naturally-gifted African countries, is becoming keen on ensuring that these resources play a transformative role in its long-term structural transformation dream - the Vision 2040...

September 9, 2016

Small-Scale Fishers Get A Big Boost With First-Of-Its Kind Impact Investment Fund

Conservation organization Rare announces the Meloy Fund for Small-Scale Fisheries at Our Ocean Conference. The Global Environment Facility, one of the largest funders of conservation worldwide, will be investing $6 million into the fund...

September 1, 2016

Scientists take to the skies to track West African pollution

Scientists operating research aircraft over West Africa have detected organic materials in the atmosphere over a number of urban areas, contributing to concerns of the rise in pollution across the region...

August 17, 2016

New IGS Xplore prospectivity maps for Botswana

International Geoscience Services have released a series of base metal prospectivity maps for the Ngamiland District of northwestern Botswana using free geodata available on the recently-launched Botswana Geoscience Portal, hosted by Geosoft. The maps identify favorable areas for copper, zinc and lead mineralization using geological, geochemical and geophysical datasets downloaded directly from the portal.

August 11, 2016

NexGen Makes New High Grade Discovery

NexGen Energy reported the discovery of a new high grade zone of mineralization 4.7 km northeast of the Arrow Deposit as part of an on-going summer drilling program on its 100% owned, Rook I property, Athabasca Basin, Saskatchewan...

August 10, 2016

Rampion UXO Disposal to Take Place This Week

E.ON has confirmed that the two unexploded devices, detected along the Rampion offshore cable route will be safely disposed this week following the consultation with the Marine Management Organisation...

August 9, 2016

Diamonds In The Rough: E&Ps Find New Reserves In Mature Basins

The oil industry’s history demonstrates clearly that new plays and prospects have long been found in mature basins that were thought to be well on the way to being squeezed dry. Through the acquisition of new data, developing new concepts and coming up with fresh interpretations, long-producing basins around the world from the North Sea to Malaysia have continued to reveal new riches...

August 8, 2016

Northern Shield Identifies High Quality VTEM Targets at Séquoi

Northern Shield Resources announced the results of the interpretation and modelling of the VTEM survey from the Séquoi Property in the Labrador Trough of Quebec . Séquoi is owned 100% by Northern Shield and is being explored for Noril'sk style Ni-Cu-PGE massive sulphides. After geophysical modelling and interpretation of the VTEM data from Séquoi, six VTEM anomalies of significant interest have been identified...

August 3, 2016

Rio Tinto tailors big data drive to copper

Rio Tinto will put the weight of an exploration big data push and its newly-formed Growth and Innovation group behind its desire to identify a "tier 1" copper asset. Speaking at the annual Diggers & Dealers conference in Kalgoorlie, Growth and Innovation group executive Stephen McIntosh said Australia was "overdue for a tier 1" mineral discovery of any type...

August 1, 2016

Tetra Tech Awarded $200 Million Navy CLEAN Contract

Tetra Tech announced that it has been awarded a $200 million, single-award contract by Naval Facilities Engineering Command (NAVFAC) Atlantic. Through the Comprehensive Long-term Environmental Action Navy (CLEAN) contract, Tetra Tech will provide environmental engineering support services to installations within the NAVFAC Atlantic Area of Responsibility...

May 3, 2016

NATO Science for Peace and Security (SPS), MODUM Partners announce "Young Scientist Summer School on Sea Dumped Chemical Weapons"

This international project cooperates closely with CHEMSEA (Search and Assessment of Chemical Weapons) Project for and sharing and knowledge transfer...

April 12, 2016

Monday mad rush for gold stocks

Renewed optimism about the outlook for gold saw investors pile back into gold stocks, pushing many stock to 52-week highs in heavy volumes...

April 11, 2016

Medgold Resources: Continues to Expand the Boticas Gold Project, Portugal; Proposes $200,000 Private Placement

Medgold Resources is pleased to announce new assay results from contiguous rock-chip sampling from the Limarinho South zone at its Boticas gold project in Portugal, which include a highlight of 6.0m @ 5.7 g/t Au...

April 8, 2016

De-carbonizing our energy sector

Nuclear energy currently provides around 11 percent of the world's electricity. China, the European Union, the United States, India, Russia, South Korea, and other nations’ have major existing fleets...

April 1, 2016

Follow-Up Drilling Results Indicate Wide Gold Zones at Hendricks Gold Discovery

Gascoyne Resources Limited announced that it has received the final assay results from the 10,000 metre aircore exploration drilling programme...

March 26, 2016

The Oil Market Is Finally Hitting Its Breaking Point

After a significant reduction in investments over the past two years, oil companies can no longer overcome the production declines from legacy wells...

March 15, 2016

N-Sea Expands into the French Offshore Wind Industry

Subsea IMR provider, N-Sea, has signed a letter of intent with CERES Recherches & Expertise Sous-Marine and TechSub Industrie Environement, to provide subsea survey, installation and remediation services to the French offshore wind industry...

March 9, 2016

PDAC 2016 Convention Exceeds 22,000 Attendees

Optimism and opportunity abounded at the PDAC 2016 Convention of The Prospectors & Developers Association of Canada in spite of recent industry challenges...

March 3, 2016

6 Alpha Launches EOD Contracting Division

6 Alpha Associates, a specialist risk consultancy practice, with expertise in the assessment and management of unexploded ordnance, has launched a dedicated explosive ordnance disposal division...

Enhancing geological interpretations with gravity and magnetics across all petroleum plays

by Graham Chandler on August 05, 2014 expertise

As the utility of gravity and magnetic methods for oil exploration expands, so does the need for more awareness on how these methods can be used to enhance geological interpretations, according to Calgary-based consultant Henry Lyatsky.

Lyatsky advises oil and gas explorers and occasionally teaches industry short courses and lectures at the University of Calgary on the optimal use of geophysical techniques. He is both a geophysicist and a geologist, and considers that there is not enough direct communication between the two disciplines. As a result, the usefulness of gravity and magnetics in oil and gas exploration is still too often overlooked, he says. But it’s not for lack of technological advances or effectiveness in the field.

Ready role for gravity and magnetics

With both gradiometry and conventional potential-field data, even in mature basins with hundreds of thousands of wells, such as the Alberta Basin, there is a ready role for gravity and magnetics to assist with exploration and delineation. “You still need your basement faults, you still want your fault network,” says Lyatsky, “and that’s where the value comes in.”

Gravity and magnetics methods are also proving useful in British Columbia. A number of basins in the central part of the province have been conventionally explored to various degrees and with limited success, but with the shale gas revolution growing exponentially, they’re now being looked at afresh for unconventional oil and gas deposits.

When revisiting previously explored basins, the use of more accurate tools such as gradiometry, and gravity and magnetic methods in general, can open up new opportunity. “The more basins you look at, the more you need tools like gravity and magnetics,” Lyatsky says. “In central British Columbia there are several basins in the Intermontane Belt that can still be considered semi frontier environments, and this is where gravity and magnetics would be most useful.”

On the west coast of British Columbia, Lyatsky has also made extensive use of conventional gravity and magnetic data, in conjunction with seismic data and geological information, to help understand the geology of that region’s offshore basins and evaluate their hydrocarbon potential.  His well-publicized study of those basins concluded that the best petroleum prospects probably exist in the southwestern part of the Queen Charlotte Basin.

Gravity gradiometry

“One recent trend has been the expansion of gravity gradiometry,” Lyatsky notes, adding that “there are multiple providers of all types of gradiometers.” An advantage of this trend is better accuracy. “This is an excellent advance and I am delighted to see it happen,” he says. “Gravity gradiometry is a high-precision delineation tool which has its uses in mining and exploration as well as in the delineation of oil and gas.”

Improved gradiometry products can also be helpful farther afield, such as in the delineation of offshore subsalt deposits. When used together with traditional gravity and seismic methods, these tools can sometimes assist in assessing the geometry, structure and gravitational effect of a salt dome and what’s around it. “Again, gradiometry is an essential tool,” he notes, “not by itself but as an additional, complementary technique.” “It’s hard to carry out seismic surveys in offshore subsalt environments, especially in deep-water conditions,” says Lyatsky, who has used seismic and conventional gravity techniques on subsalt projects in the North Sea. “Salt targets are difficult at every level as they are irregular, high-velocity and low-density. The more techniques you can use to help visualize them, the better.”

Gravity and magnetic inversion

Inversion is now being more broadly applied in the oil and gas sector. It has been used for depth determination with some success, especially where adequate geological constraints are present.

Lyatsky cautions that there usually aren’t enough geological constraints to invert uniquely. “For example, if you want to know the depth to source, it really helps to know the shape of the source. If you want to know the shape, it really helps to know the depth. If you don’t know either, it becomes tricky to come up with an inversion that is unique.” And yet even when there are not enough constraints, cautiously executed inversion can be a useful tool for reconnaissance and exploration, particularly when gravity and magnetics are used together. 

New tools bring new value, however they don’t replace what’s tried and true. “Just because you have a scalpel doesn’t mean you no longer need an axe,” Lyatsky quips. “The more tools in the tool box, the better, and we should not forget the value of the old ones. Everything has its use in different circumstances.”

Enhancing geological interpretations

Determining which tools to consider, in any exploration project, begins with a good understanding of your geological objective. “You need to start by thinking like a geologist,” says Lyatsky. “Be sure of what it is you are trying to find, that is to say, what geological information you are trying to extract. Know your target. And don’t go looking for the silver bullet, because it doesn’t exist.”

If you have a good sense of the geological exploration model you are trying to test, says Lyatsky, you can then ask yourself: How can seismic data help refine this model? How can magnetics and gravity help me refine this model?

“Ultimately any exploration project is a geological project, and the geologist must be convinced his tools are useful. The mistake we make as geophysicists is that we don’t talk enough with geologists. If I were to make a recommendation, it would be to reverse that situation.”

At the university and around the oilpatch, Lyatsky does his best to ensure young professionals don’t overlook gravity and magnetics applications. “Where we fall short in educating students is that we don’t teach them to think comprehensively about their geological model, and we don’t teach them about applying geophysical tools for a particular set of circumstances or a particular model,” he states. “Half the time you get geophysicists and geologists talking at cross-purposes. Seismic and gravity experts talk past each other because they are too narrowly specialized.”

“It’s important to know the traditional methods, and investigate new developments such as gradiometry and inversion” recommends Lyatsky.  “Understand what they can do and what their limitations are. But above all, remember that everything relates to the geology.”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



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