Advanced Seismic Processing Methods for Imaging the Subsurface

Henning Trappe 2

Presentation Outline:

Company Profile Research Activities Introduction to CRS Processing Synthetic Acquisition Geometries & Azimuthal Processing Depth Processing: RTM against PSDM Common Diffraction Imaging CDS CRS in Nigeria Summary 3

Company Profile 4 TEEC‘s office in Hanover, Germany 5 Service Portfolio

• Seismic Processing - 2D/3D/time lapse processing - land/marine - Refraction/tomo statics - SRME/SWME demultiple - Prestack database merge

• Special Seismic Processing - CRS processing - Prestack data interpolation - Azimuth processing - High-res attributes

• Seismic Time/Depth Imaging - Velocity model building - Ray tracing - Acquisition design - Prestack depth migration - RTM

• Reservoir Characterisation - AVO processing - Acoustic/elastic seismic inversion - Coherency processing - Facies classification - Fault detection 6 TEEC’s office in , Texas

TEECsolutions LLC 3100 Wilcrest Drive Suite 325 Houston, TX 7 Areas of Expertise

Headquarters Hannover/Isernhagen, Germany Branch Offices: Houston, USA Villahermosa, Mexico Buenos Aires, Argentina (Geoprocesados) Agencies: UK, China, Indonesia, Russia, Nigeria, India, Egypt 8 Areas of Expertise

TEEC is a technical partner of Mease Energy Nig. Ltd

Eke Azuka Stanley MD/CEO Mease Energy Nig. Ltd. 72 Egbelu RoadOff Rumudara, Port Harcourt, Rivers State, Nigeria. Headquarters Hannover/Isernhagen, Germany Branch Offices: Houston, USA Villahermosa, Mexico Buenos Aires, Argentina (Geoprocesados) Agencies: UK, China, Indonesia, Russia, Nigeria, India, Egypt 9 Client List ADDAX (Switzerland) Hansa Hydrocarbons (UK) Petrotrin (Trinidad) AERA Energy (USA) Heritage Oil Ltd. (UK) Pioneer Natural Resources (USA) Anadarko () Hess Corp. (USA) Pozagas (Slovakia) BEB Erdgas und Erdöl GmbH (Germany) Hess Ltd. (UK) (UK) BGP (China) Horizon Resources (USA) Premier Kufpec Pakistan B.V. (Pakistan) BGR Federal Institute for Geosciences and JAPEX (Japan) Natural Resources (Germany) KBB GmbH (Germany) RAG Rohöl-Aufsuchungs AG (Austria) BG Group (UK) Layline Petroleum (USA) Ramboll (Denmark) BHP Billiton (USA) Linde Gas (Germany) Reeder Energy (USA) BP (UK) Maersk Olie og Gas (Denmark) (Spain) BP North American Gas (USA) Max Petroleum (Kazakhstan) Repsol YPF(Argentina) Cabot Oil & Gas (USA) Medusa Oil & Gas SP. z o.o (Poland) RWE Dea AG (Germany) Cabre Maroc (United Kingdom) Medco Energi (USA) RWE Dea Polska SP. z o.o (Poland) PLC (UK) MND (Czech Republic) Samek International (Kazakhstan) Comstock Resources (USA) Mobil Erdgas-Erdöl GmbH (Germany) Sasol (South Africa) CGGVeritas Nadel & Gussman Rockies (USA) Shell (UK) Energy (UK) Nafta a.s. (Slovakia) Sipetrol (UK) Chevron North American Upstream (USA) NAM B.V. (The Netherlands) Shengli (China) Chevron (UK) Network E&P Nigeria (Nigeria) Southwestern Energy (USA) COWI A/S (Denmark) NewAge Petroleum (UK) SPP a.s. Bratislava (Slovakia) Dansk Naturgas A/S (Denmark) NIS Naftagas (Serbia) Statoil (Norway) DBX Geophysical (USA) Noble Energy (USA) Sterling (UK) DMT (Germany) Oando Qua Ibo Limited (Nigeria) Sydkraft AB (Sweden) DONG A/S (Denmark) Occidental Oil and Gas Corp. (USA) TEIKOKU (Japan) EEG GmbH (Germany) OIL India Ltd. Trinity (Trinidad) El Paso (USA) OMV AG (Austria) (Ireland) EnCana (Canada) PDO (Petroleum Development Oman) VITO, Flemish institute for technological E.ON Ruhrgas AG (Germany) PDOC Petrodar Operating Co. (Sudan) research (Belgium) ExxonMobil (USA) PEMEX (Mexico) VNG Verbundnetz Gas AG (Germany) Faroe Petroleum (UK) (UK) WesternGeco GdF Suez E&P Nederland (The Netherlands) PetroCanada (UK) Wintershall (Germany, The Netherlands, Libya, Gedco (Canada) Petroceltic (Ireland) Norway) Geoenergie Bayern GmbH (Germany) Petrochina Xinjiang (China) Woodside Petroleum Ltd. (Australia) Geoenpro Oil Ltd. (India) Petrochina Sichuan (China) WPX Energy (USA) Geonafta (Lithuania) (UK) Zhibek Resources PLC (Kyrgyzstan) ( Malaysia ) 10 Research Projects

• Member of the WIT consortium (developers of CRS)

• Member of the DELPHI consortium (SRME, FWM)

• Research project PROTECT for fault detection for CO2 storage

• Research project SUGAR3: p-cable streamer, high res seismics

• SUGAR3: Advanced CRS techniques & use of multiples for imaging

• WAVE: HPC High Performance Computing

• DIFFTOMO: Benefit of Diffractions for seismic imaging 11 Fault Imaging: Standard Coherency 12 TEEC Operator (cohTEEC) 13 Advanced Software from TEECware Formats: Marine pre- processed Data Land pre- processed Data openCPS, PROMAX, Epos, su, SEGY

SRME Demultiple CRS utilities CRS basic processing - Velocity Update - Structual CRS - Gap Filling Regularised CRS gather / Geometry optimization CRS Shotgather

CRS Tomography

PrestackTime Mig. (PSTM) Prestack Depth Mig. (PSDM) Reservoir Utilities - Straight ray -Kirchhoff - cohTEEC - curved ray -RTM - neuroTEEC - anisotrophic -FWM - Modelling 14

Introduction to CRS Processing 15 CRS Time Domain Imaging 3rd party PreSTM result

2D Kurdistan 16 CRS Time Domain Imaging TEEC CRS PreSTM result

2D Kurdistan 17 Gas Storage 3D Germany onshore Standard CMP gather Shallow gas sands 18 Gas Storage 3D Germany onshore Standard CMP gather

AVO effect •Shallow gas sands

Amplitude preservation 19 Gas Storage 3D Germany onshore conv. AVO Processing

Map View after CRS-AVO 20 CRS Theory

•CRSbasic R RNIP N

NIP R = = Normal Reflector Incidence Point segment

(Mann et al., 1999) Point source at NIP: Exploding reflector R: - Emergence angle a - Emergence angle a - Wavefront curvature R - Wavefront curvature RN NIP 2 2 2 2 2 4h 2  2sin  2t cos   x h  2 2 t  t  x  0    t h  t0  2  0     v0  v0  RN RNIP  vNMO 21 NMO Stack 22 CRS Stack 23 3D Northern Calcareous Alps

Austria

Munich Molasse Linz Foreland Basin Flysch Imbricated Molasse Northern Calcareous Alps 24 3D Northern Calcareous Alps CDP Gather 25 3D Northern Calcareous Alps CRS Gather, offset regularised 26 3D Northern Calcareous Alps Client PreSTM with conventional processing 27 3D Northern Calcareous Alps TEEC PreSTM with CRS processing Offshore Example: CMP Processing Offshore Example: CRS Processing 30 Norway 3D offshore Prestack data merge using CRS gathers Common processing grid 12.5 x 25.0 m bin size Acquisition E-W, 2 streamer 37.5 x 6.25 m bin size

Acquisition N-S, 8 streamer 6.25 x 25.0 m bin size 31 Norway 3D offshore CDP gathers (overlap area)

CDP gathers (overlap area) 32 Norway 3D offshore CRS gathers (overlap area) •

Xlines 950-1350: CRS gathers (overlap area) 33

Synthetic Acquisition Geometries & Azimuthal Processing 34 Irregularities in seismic acquisition 35 Data filled in by CRS gather calculation 36 Regularization onto a common grid 37 Low fold 3D dataset, onshore Germany

Original acquisition geometry 25 m bin grid

Receivers: Red Shots: Blue 38 Low fold 3D dataset, onshore Germany

CRS shot/receiver regularisation and extrapolation to 25 m bin grid

Receivers: Red Shots: Blue 39 Low fold 3D dataset, onshore Germany

CRS shot/receiver regularisation and extrapolation to 12.5 m bin grid

Receivers: Red Shots: Blue 40 Low fold 3D dataset, onshore Germany Migration without CRS, bin size 25 m x 25 m 41 Low fold 3D dataset, onshore Germany Migration of CRS gather, bin size 25 m x 25 m 42 Low fold 3D dataset, onshore Germany Migration of CRS gather, bin size 12.5 m x 12.5 m 43 Azimuthal Processing Theory

Traces of irregular CMP gather

Offset azimuth sectors : - direct azimuth decomposition - not adapted to irregular gathers 44 Azimuthal Processing Theory

Traces of regularized CRS gather

CRS offset-azimuth regularisation - using shot-receiver reciprocity 45

Data example: Raw input fold

CMP location 46

Data example: Azimuthal CRS processed data fold

CMP location 47 Pennsylvania 3D PSTM all azimuths

AGC 150 ms for display 48 Pennsyvania 3D PSTM – Azimuth changing (animation)

AGC 150 ms for display 49 A

Azimuth ALL 0-30 30-60 60-90 90-120 120-150 150-180

PreSTM cigs showing HTI anisotropy effect 50 A

Azimuth ALL 0-30 30-60 60-90 90-120 120-150 150-180 PreSTM cigs with HTI anisotropy correction Anisotropy as indication of stress and fractures

Anisotropy: indication of stress and fracture density

Direction of v_fast: indication of stress and fracture orientation Anisotropy indication of stress and fracture density v_fast – v_slow is given as percentage of the isotropic velocity

0 %: no anisotropy 1 %: “strong” anisotropy

v_fast

v_slow Direction of v_fast indication of stress and fracture orientation

In the ideal case: v_fast is directed along fractures v_slow is directed perpendicular to fractures

0 deg: north – south oriented fractures 90 deg: east – west oriented fractures N phi

v_fast

W E

v_slow

S 54

Depth Processing: RTM against PSDM Reverse Time Migration - RTM

EAGE education tour 56 North Germany 3D onshore Shot sorted input data 57 North Germany 3D onshore Acquisition geometry reconstructed CRS data 58 Depth Imaging and RTM 3D dataset, onshore India

Kirchhoff PreSDM using CRS gathers 59 Depth Imaging and RTM 3D dataset, onshore India

RTM using CRS gathers 60 Kirchhoff PreSDM with CRS gather 61 RTM with CRS gather 62 : TEEC-RTM on CMP gather

RTM CMP 63 Gulf of Mexico: TEEC-RTM on CRS gather

RTM CRS 64

Common Diffraction Imaging CDS 65 Concept of CRS Tomography Subsurface Models (2D case) NMO Model CRS Model  location  location, dip, curvature

 1 Parameter :  3 Parameters: , R , R vNMO NIP N 2 4h 2  2sin  2t cos2   x 2 h2  t 2 h  t 2  t 2  t  x  0      0 2  0    vNMO  v0  v0  RN RNIP 

with: Δx = midpoint distance ; h = half offset

Concept of model-independent imaging / Gelchinski (1988), Hubral (1999) 66 CDS Common Diffraction Surface

Diffractions might be useful to identify subtle

features below seismic resolution

Diffractions are characterised in CRS theory

Rn == Rnip => Rcds

TEEC established a unique approach:

Highlighting Diffractions in the seismic volume Collapse improved Diffraction through migration 67 CMP Stack 68 CDS Stack 69 CMP PSTM 70 CDS Migration 71

CRS in Nigeria 72 Location of Qua Ibo 3D

Map of Survey Area in blue rectangle Red lines show 2D seismic surveys

Source: Google Maps 73 Source and receiver map Sources: Explosives in black Airguns in red

Receiver: Receiver in brown CMP Gather 74 CRS Gather 75 Standard PreSTM IL 1100 (without CRS) 76 CRS PreSTM IL 1100 77 Standard PreSTM IL 1229 (without CRS) 78 CRS PreSTM IL 1229 79 CMP stack Timeslice 1032ms 80 CRS stack Timeslice 1032ms 81 CMP stack Timeslice 1152ms 82 CRS stack Timeslice 1152ms 83 84

Summary:

Company Profile Research Activities Introduction to CRS Processing Synthetic Acquisition Geometries & Azimuthal Processing Depth Processing: RTM against PSDM Common Diffraction Imaging CDS CRS in Nigeria 85

The End… Thank you for your attention ! 86 Concept of CRS Tomography Subsurface Models (2D case) NMO Model CRS Model  location  location, dip, curvature

 1 Parameter :  3 Parameters: , R , R vNMO NIP N 2 4h 2  2sin  2t cos2   x 2 h2  t 2 h  t 2  t 2  t  x  0      0 2  0    vNMO  v0  v0  RN RNIP 

with: Δx = midpoint distance ; h = half offset

Concept of model-independent imaging / Gelchinski (1988), Hubral (1999) 87 Concept of CRS Tomography

RN Measurement Surface

α “relates” to reflector’s dip α RNIP “relates” to reflector’s depth

RN RN “relates” to reflector’s shape (radius of curvature) α NIP 88 Concept of CRS Tomography

Original velocity model used for calculation of synthetics

Reconstructed velocity model after CRS processing on synthetics and CRS tomography

Reconstructed velocity model with ray tracing overlay 89 Concept of CRS Tomography

Reconstructed velocity model with overlay of horizon migrated reflector elements (top). Original velocity model with overlay of same migrated reflector elements (bottom). 90

CRS versus 5D 91 Why should I use CRS processing?

I have …

… low fold data, … a low signal-to-noise ratio, … data gaps.

I need …

… a smart reconstruction of the subsurface from little data. Inline CMP stack 92 Why should I use CRS processing?

Inline CMP stack Inline 5-D stack 93 Why should I use CRS processing?

Inline CMP stack Inline 5-D stack Inline CRS stack 94 Why should I use CRS processing?

Time slice CMP stack Time slice 5-D stack Time slice CRS stack 95 Velocity model building / depth migration workflow

Time processing CRS processing Boost of signal/noise ratio Refraction Tomography CRS Nip Tomography Data driven model building (OpenCPS) (proprietary software)

shallow deep model model

FWI Start model

Multistage acoustic FWI processing QC: RTM offset gathers + depth sections (proprietary software)

Final model

Final RTM (proprietary software) 96 Acoustic FWI result

•BP 2004 model

True model

Start model

FWI model 97 Mirror migration Sea surface 98 Mirror migration Sea surface

Mirror Migration 99 Mirror migration

Mirror RTM Mirror RTM Mirror RTM Single OBS Single OBS Five OBS primary ghost ghost wavefield wavefield wavefield