Interpreting MulticomponentSeismic Data

Robert StewartCREWES Project

University of Calgary

19th Annual CREWES Sponsors MeetingBanff Alberta Nov. 30th, 2007

The place of applied research

• “If we knew what we were doing, it wouldn’t be called research” Albert Einstein– Curiosity, patience, and nurturing

• Beyond inventing though, we want to innovate and apply – our full CREWES mandate– Focus, structure, results, and assessment

Interpreting PP and PS data

• Overview of general procedure• Multicomponent software including

Kingdom, Landmark, ProMAX, ProMC, Transform, VISTA/OMNI, WesternGeco, CREWES

• Examples (events & their arrival time)• Summary

Interpretation work flowP-wave interpretation

• Use logs, synthetics, VSP, sections, volumes to identify horizons & faults, extract amplitudes &

thicknesses, find anomalies

S-wave model• From geology, logs, VSP, empirical, processing, or

gross correlations determine Vs and Tpp to Tps

PS interpretation• Use logs, synthetics, VSP, sections, volumes to pick horizons & faults, amplitudes & thicknesses,

evaluate anisotropy, find anomalies

Joint analysis• Update registration & event matching to extract

Vp/Vs, evaluate differences, undertake joint inversions, highlight interests

Brown, 1998

Workflow (Dumitrescu, 2007)

1. Correlate P and PS data to wells

2. Pick corresponding horizons on both datasets

3. Registration: use horizon-based matching for PS data to PP time

4. Jointly invert PP and PS data; derive lamba-rho & mu-rho

Registration: PP and PS data

PP Migration

PS Migration (in PP time)

H 2

H 1

H 2

H 1

Well 1

Well 1

Registration Workflow (Roth, 2007)PP Seismic PS Seismic

PP Synthetic

PS Synthetic

Co-Visualization

Amplitude EnvelopeBandpass Filter

PP Seismic PS Seismic

Spectral EnhancementFilteringColoured InversionSimilarity

Initial Gamma

ConditionSeismic

Phase Matching

Refined Gamma

ConditionSeismic

Average Vp/Vs used to stretch PS volume to PP time1.85

2400ms

Courtesy of Sinopec and ION

Full Wave Shear Impedance Co-rendered with Similarity

Xu2 | Xu3 boundaryF (gas) Sand

T8 horizon with minimum curvature overlay

Xu2 WellsWaterGas F SandGas I Sand

Coals

4C Interpretation Workflow(Gaiser, 2007 – WesternGeco; GX Technology)

Model expected 4C

signature

Create subsurface model based on

existing data

Design P-wave,S-wave surveys

Provide geologic input into processing

Interpret P-wave,S-wave surveys

Revise, updatevelocity models

Invert datasetsInterpret fluid,

Lithology changes

CGG-V-HR ProMC

Two exploration areas of India (with Geofizyka Torun, ONGC

and Oil India)

Assam

(From Niko, 2006)

The South Kadi 3C seismic project

Logs, VSP, and section – S. Kadi, India

Vp Density Synth VSP P Section

P-wave section with Vp/Vs overlain

PS synthetics & correlation

Sand indicator: Vp/Vs over the OCS-E sand interval

Interpreted sand fairway (yellow) from low Vp/Vs

Villa Hermosa

Cd del CarmenCantarell

Located 80 kilometers northwest of Ciudad del Carmen, Campeche, Mexico, the Sihil field is the latest discovery (1999) of the five blocks bounded by faults, which make up the super giant Cantarell complex.

Cantarell-Sihil Complex Location

CANTARELL BLOCKS

OILGAS

WATER

KUTZ

AKAL

CHACNOHOCH

0 1 2 KM

N

SIHIL

(Chernikoff, Stewart, & Xu, 2007)

Cantarell, Mexico Line N-S

0 2.5 5

km

S N

Top Cretaceous

Top Jurassic

Sihil fault

Sub-Sihil fault

TopCretaceous

Top Jurassic

0 2.5 5

km

PP and PS sections in raw times

2.0s

PS

PP

1.0s 0.5s + 0.5s = 1.0s

0.5s + 1.5s↑= 2.0s

Summary – Multicomponentseismic interpretation

• Four step process (PP, Vs, PS, happyishcouple)

• Numerous useful applications of PP and PS analysis and interpretation

• Thank you for your attention and support of our research and development work!