Advances in Geophysics - IPLOCA · Advances in Geophysics Prof. George Tuckwell ... Geophysical Surveying to establish constraints ... e.g. Detection of buried mine shafts

Copyright of RSK 10 April 2017 1

Advances in Geophysics

Prof. George Tuckwell

Divisional Director, Geosciences and Engineering

Copyright of RSK 10 January 2014 2

Outline

▪ Geophysics in context

▪ Advances in acquisition and processing

▪ New instruments

▪ New physics

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Risk and information maps

•Conceptualisation of risk/need for information

3

top

side

3D view

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Risk and information maps (cont.)

•Tools at our disposal to gather information

4

x-section geophysicse.g. resistivity, seismic

boreholes

surface geophysicse.g. EM conductivity,

magnetics, GPR

trial pits

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•Following a detailed intrusive SI

5

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•Following a detailed intrusive SI – where do you have information?

6

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•Following a detailed intrusive SI – where does risk remain?

7

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•Using geophysics as a site investigation tool

•Find out something about everything in the near-surface

8

Surface geophysics

indicates some

buried structures

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Mine shafts (and archaeology, and UXO)


Advances in acquisition and processing

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Project Example

Brownfield Site

Carrington Power CCGT

860MW gas fired combined cycle power plant on location

of former Carrington Power Station.

3km pipeline corridor from adjacent National Grid Site to CCGT.


Case Study - Location

NG Site

Proposed

power

station

Pipeline

route


Case Study - Project Details

▪Geophysical Surveying to establish constraints

along pipeline route -

▪ Buried Services

▪ Underground obstructions

▪ Geophysics to compliment boreholes

Power cables (lots!) Gas pipe tracing Radar EM mapping


Case Study - Final Interpreted Results Plan

CAD Plan

▪ Pipeline Route



CAD Plan

▪ Pipeline Route

▪ Topographic



CAD Plan

▪ Pipeline Route

▪ Topographic

▪ Statutory service records



CAD Plan

▪ Pipeline Route

▪ Topographic


▪ Drainage tracing



CAD Plan

▪ Pipeline Route

▪ Topographic



▪ Power & radio electrolocation



CAD Plan

▪ Pipeline Route

▪ Topographic




▪ Radar data



CAD Plan

▪ Pipeline Route

▪ Topographic




▪ Radar data

▪ EM data



CAD Plan

▪ Pipeline Route

▪ Topographic




▪ Radar data

▪ EM data

▪ Combined Drawing

Multiple techniques

= More information

= Less risk


Case Study - Intrusive Investigation

Pipes found at location and depth

shown by geophysics;

subsequently exposed;

found to be cut at end; proven to be disused


Case Study – Depth to bedrock & Faults

Borehole data

?


Case Study – Depth to bedrock & Faults

P-wave refraction seismics


Electrical resistivity and seismic data with targeted boreholes to develop a detailed ground model

Case Study – Depth to bedrock & Landfill


Case Study – Depth to bedrock & Landfill


New instruments

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Research into new capabilities

Finding Infrastructure with Non-

Destructive Imaging Technologies

(FINDIT)


Evaluate the full potential of new instruments

BT’s business challenge is

to deliver fibre connections

inc allowing access to

competitors

•Locating existing

infrastructure and ducting

•Detecting non-metallic

connections

•Detecting blockages and

voids


Evaluate the full potential of new instruments

Benefits of new

instruments:

•Much greater data density

•Fully 3D imaging

•Ability to look at the

characteristics of reflections

in the data, not just their

presence

•New processing

approaches possible similar

to exploration seismic work

flows


BT infrastructure – detection and condition tests

•Locating existing infrastructure and ducting

•Detecting non-metallic connections

•Detecting blockages and voids


New physics

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Next generation of gravity meters

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Isolating the signal of interest

instrument reading

+drift

correction+

Free Air anomaly

+Bouguer anomaly

=Simple Bouguer

Anomaly

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What we might measure with what limitations

Forward modelling for the Scintrex, the QT gravity sensor and the QT gravity

gradiometer

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QT Gravity Sensor potential

e.g. Detection of buried mine shafts

which currently are not detectable

from the surface

Density o

f m

ine e

ntr

ies in

an u

rban s

ett

ing,

West M

idla

nds.

(To

pogra

phy b

ased o

n O

rdnance S

urv

ey

mappin

g ©

Cro

wn C

opyrig

ht

and D

ata

base R

ight

2011).

Ref:

Geoscie

ntist

April 2016.

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Market interest

Engagement with the industry

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Direct feed into current commercial work

Increased ability to model out the effects of strong

topography to isolate the gravity signal of interest


Modelling out the terrain effect


UoB test site – Laser scanning


UoB test site


Visibility

“Clocks are not the only means to get a handle on gravity. At the microscopic scales where quantum mechanics rules, streams of matter particles can behave like waves. Like those on a pond’s surface, those waves can interfere, adding to and subtracting from one another—in the quantum description, altering the probability of finding a particle here or there. In a device called an atom interferometer, two particle streams are sent at differing heights and then brought back together to interfere with each other. The degree to which the two paths are different, indicating the relative strength of the gravitational tug from below, measurably alters the degree of addition and subtraction.

Such devices have a multitude of uses. In Britain, for example, 4m holes are dug every year in the course of roadworks and construction, but two-thirds of the time the diggers have no idea what they will find beneath the surface. Test boreholes cover only a small area, and ground-penetrating radar does not reach deep enough. A gravity sensor that could tell pipework from pebbles would save a lot of trouble.

RSK, an environmental consultancy involved in cleaning up brownfield sites and the like, reckons that a third of construction projects overrun by up to a month, and another third by two months or more, and that half of these delays arise because of underground surprises. The company is collaborating with the University of Birmingham in Britain on fieldworthy quantum gravity sensors, in the hope of deploying them in big infrastructure projects. Other efforts to develop cheap sensors have drawn interest from companies such as Schlumberger, an oilfield-services giant, and Bridgeporth, a surveying firm.”


Summary

✓ Geophysics in context

✓ Advances in acquisition and processing

✓ New instruments

✓ New physics


Advances in Geophysics - IPLOCA · Advances in Geophysics Prof. George Tuckwell ... Geophysical Surveying to establish constraints ... e.g. Detection of buried mine shafts

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