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Seismic Data Acquisition & Analysis –

Technology & Innovation Denis Sweeney - ASA Sales Manager - WesternGeco

Chief Geophysicist

Chief Geologist

Chief

Executive Office

Petroleum Director

Business Development

Manager

Environment

Manager

Company

Director

Technical

Advisor

Drilling

Engineer

Geologist

Product Manager Geoscientist Sales Manager Country Manager

Petrophysicist Geomechanical Engineer Seismic Interpreter Company Director

Geologist

Geophysicist Inversion Specialist

Chemical Engineer Mechanical Engineer

Surface seismic surveys reduce drilling risk

Seismic technology and the decision making process

Geophysical Model

Decision Model

Acquisition

Technique

Seismic

Amplitude

Response

Porosity

Thickness

NPV Drilling Program

Well

Budget

Recoverable

Hydrocarbons

Geologic

Complexity

Recovery

Factor Per BOE

Value

Water

Saturation

Summary

J. I. Denham, L. R. Denham The History of Seismic Resolution

How are we doing?

Measuring resolution Data used

Results

Discussion Summary

In the eighty years of reflection seismology, resolution of our data

has deteriorated rather than improved

But this is because we have improved signal-to-noise ratio in

many ways

And we’ve cut costs

You can have resolution, low noise or low cost

Pick any two

We usually pick the last two

Land seismic channel count evolution

Ian Jack, ‘Progress in land seismic technology’, Finding Petroleum, OilVoice Forum, London, 7th March 2013

Sampling: Signal vs. Noise Bouska, SEG DISC, 2009

An Integrated Project Design for a 3D Seismic Exploration survey in the Burgos Basin, Mexico

M. Benabentos, F. Ortigosa and C.C. Li

Focus on the Signal -or- focus on the Noise

The earth is complex in all directions

Example: Sichuan Basin, China

Wide-angle, full-azimuth acquisition

4x spatial sampling

65x trace density

3000+ shots/day

Integrated workflow, software and expertise

The solution: UniQ integrated point-receiver land system

Conventional Systems vs. Point Receiver

Conventional recording system

Sum

Acquisition System

In-field

Processing

Field

Tape

Single digital output

Receiver Signals

Point-receiver recording system

Receiver Signals

Field Tape

Acquisition System

Point Receiver Processing

Array impact on stack trace at reservoir target

The value of seismic imaging Data

No value

Information

Limited value

Knowledge

Ultimate value

Processing

Inversion to seismic

attributes,

interpretation,

calibration with well

data etc.

Acquisition data - large number

of amplitude / time pairs

Manipulate these amplitude coefficients to

generate an image of the sub-surface

This highlights interesting structures and

potentially bed thicknesses but will not

provide true knowledge of the reservoir

Only when we gain an understanding

of the rock and fluid properties we

truly gain knowledge of the reservoir

What’s wrong with this picture ?

Another version…

Surface seismic surveys reduce drilling risk

Full-azimuth Spatial Sampling and bandwidth are key

2D Seismic Imaging - good

3D Seismic Imaging - better

Broadband Seismic Imaging in 3D – best

Onshore Myanmar

de

pth

[m

]

7.97 7.975 7.98 7.985 7.99 7.995 8 8.005 8.01 8.015

-150

-100

-50

0

50

100

150

200

Image structural

configuration of

targets

Oligocene-Miocene

Pegu Group

X

Offset shot

Y

X Z

Θ

Field conditions to address

Temples and other structures

Complex surface geology and small villages

Significant populations

Significant small agricultural plots

Field conditions to address

Volcanic plugs

Significant topography / infrastructure

Complex drainage patterns

Difficult access

UniQ technology – case study

Ordos Basin

Full-azimuth, high density, 3D point-source / point-

receiver survey in central China acquired during 2013

Study objective: identify “sweet spots” in a

heterogeneous gas shale reservoir beneath thick

deposits of loess

Variations in topography, thickness, and seismic velocity of the loess were key factors that had

led to inadequate imaging results from previous 2D exploration surveys in the area

Project recorded for Shaanxi Yanchang Petroleum Corp by CNPC Sichuan Geophysical

Company utilizing UniQ acquisition system and SLB Geosolutions data processing (Beijing)

Proven solution – Ordos Basin

Proven irregular geometry & source technique

High trace density with irregular geometry and shallow explosives shots work in complex

operating environments

Proven reliability in complex terrain

Over 90% uptime

Up to 1800 shallow dynamite shots recorded per day in area shown

Daily production – Shot points per day

Proven solution – Ordos Basin

Near surface conditions and noises

Unconsolidated loess with severe variations in thickness

Rapid variations in topography

Heavily forested areas, hills and gulches

500 oil wells pumping with some active drilling rigs

Proven solution – Ordos Basin

Elevation map of Yanchang Liuping 177 survey area

2D crooked line 07YC111 is shown as the white line

Proven solution – Ordos Basin

2D crooked line 07YC111

Section of 2D crooked line 07YC111 from southwest (left) to northeast (right) with green box representing boundary

of the 3D pilot survey i.e. 3D to be recorded over the poorest data area

Yanchang Formation

Benxi Formation

Proven solution – Ordos Basin

Example raw shot records showing statics challenges and noise

Source location of the left shot gather is in gulch, while on the right one it is in loess

Proven solution – Ordos Basin

Noise attenuation

CMP gathers before noise attenuation (left), after noise attenuation (middle) and after Kirchhoff time migration (right)

Proven solution – Ordos Basin

High effort 2D 3D UniQ

Part of legacy 2D crooked line 07YC111 (left) with Yanchang Liuping 177 3D survey PSTM data (right)

Yanchang Formation

Benxi Formation

Mark

et

Matu

rity

Technological Leadership – IsoMetrix

Source: Schlumberger

Conventional Imag

ing

Cap

abili

ty

Highly commoditized with no differentiation

and limited value proposition

Increased industry uptake and service providers

attempting to develop solutions to bridge

technology gaps

WesternGeco Offering: Q-Marine*, ObliQ*, Coil Shooting*, DISCover**

Step change in the

seismic acquisition

arena

Marine Technology

Broadband Streamer

Acquisition

Conventional Streamer

Acquisition

IsoMetrix*

Technology

Channels

7680

Channels

522,240 P

Z

Y

P

Z

P

IsoMetrix

Broadband

1 point-receiver recording

62.5cm

accelerometer spacing

522,240 sensors per 12x8km spread

IsoMetrix – multi-measurement seismic streamer

Conventional

IsoMetrix

Complex wavefield reconstruction – 100m streamer separation

IsoMetrix technology – case study

The Identification and Implication of Injectites in the Shwe Gas Field,

Offshore Northwestern Myanmar – May 2013

1 Cossey and Associates Inc., 2 Daewoo International Corporation

Introduction Injectite Definition: Unconsolidated sand remobilized and forced upwards through overlying layers due to overpressure

Extrusion type

Dike type

Sill type

Parent sand body

Before Injectite Interpretation After Injectite Interpretation

How can we interpret ratty sands as injectites?

Geophysicist

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ophysicist

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