GeoSpectrum Intro

Seismic Exploration for Fractured Lower Dakota Alluvial Seismic Exploration for Fractured Lower Dakota Alluvial Gas Sands, San Juan Basin, New MexicoGas Sands, San Juan Basin, New Mexico

U.S. Department of Energy Contract No. DE-AC-00NT40697U.S. Department of Energy Contract No. DE-AC-00NT40697

Contractor:Contractor: GeoSpectrum, Inc., Midland, Texas GeoSpectrum, Inc., Midland, Texas

Industry Partner: Industry Partner: Burlington Resources, Farmington, New MexicoBurlington Resources, Farmington, New Mexico

Principal Investigator: Principal Investigator: Dr. James J. Reeves, Ph.D., P.G., P.E.Dr. James J. Reeves, Ph.D., P.G., P.E.Project Manager: Project Manager: W. Hoxie Smith, M.S.W. Hoxie Smith, M.S.

Regional Map of 4 Corners AreaRegional Map of 4 Corners Area

After James A. Peterson, et al (1965) Figure 1

MCFGMCFG

Cumulative GasCumulative Gas

Base Map / Dakota Gas Production

Figure 2

Greenhorn-Burro Canyon Type Log

(After Whitehead, 1993) Figure 3

Prospect Development MethodologyProspect Development Methodology

Table 1

Bubble size is best 12-months production

Hydrocarbon Pore Volume vs. Porosity-Thickness

55

27

31

28

55E

47

15 30

41

Figure 5

Number of Dakota Fractures vs. Best 12 Month Production Indicator

Number of Dakota Fractures

Bes

t 12

Mo

nth

s P

rod

uct

ion

In

dic

ato

r

Figure 6

Seismic Line Sample

DKOT

MRSN

ENSS

Figure 7

Lineaments in Seismic SectionCoherency Slice @ 1350 ms

Figure 8a

Lineaments in Seismic SectionCoherency Slice @1350 ms (3D View)

Figure 8b

Lineaments in Seismic SectionAll Azimuth Frequency @ Timeslice 1308 ms

Figure 9a

Lineaments in Seismic SectionAll Azimuth Frequency @ Timeslice 1308 ms (3D View)

Figure 9b

Dinosaur Ridge Dakota

Photo credit John M. Ghist

Dinosaur Ridge Near Morrison, Colorado

Figure 10

Lower Dakota Seismic Lineamentswith Borehole Breakout Rose Diagrams

Figure 11

Lower Dakota Seismic Lineament DensityLower Dakota Seismic Lineament Density

Lineaments Per Grid

900 x 900 ft Grid

Fractured Reservoir Leads

I H G F

E

D

CB

A

Lower Dakota Rose Diagrams

Figure 12

Lower Dakota Seismic StructureLower Dakota Seismic Structure

Subsea Depth ftSubsea Depth ft

Showing Lower Dakota Rose Diagrams and Seismic Lineaments

Figure 14

Multiple Scales of Observation

Dakota Production Trend

Regional Scale

Seismic Lineaments

Field Level Scale

Borehole Image Data

Localized Scale

Dakota Production Mapping (after C. F. Head, June 2001)Seismic Lineaments w/ Lower

Dakota Rose Diagrams Figure 13

55e (48)

31 (503)

27 (105) 48 (107)

28 (1710)

55 (711)

47 (73)

15 (45)

41 (33)

30 (66)

Co-located Co-kriged Dakota Fractures

Dakota FracturesDakota Fractures

With Upper Dakota Rose Diagrams

SITE 3

SITE 4

SITE 1

SITE 2

Azimuth Dependent Dix Interval Velocity DifferenceFigure 28

Wellbore Fracture Data vs. Seismic Velocity Data

Wellbore Fracture Data vs. Velocity AnisotropyIn

terv

al

Vel

oci

ty (

az 1

45-

55)

ft/s

ec(S

EIS

MIC

or

Mac

ro-S

cale

Mea

sure

men

t)

Dakota Fractures(WELLBORE or Micro-Scale Measurement)

Figure 29

Thickness ftThickness ft

Lower Dakota Seismic Isopach

Figure 16

Lower Dakota Seismic Coherency / Channel Stratigraphy

CoherencyCoherency

Figure 17

y = 128459x + 4314.6

r2 = 0.6580

r = 0.8111

Sei

smic

Am

pli

tud

e

Lower Dakota Clay Volume

Lower Dakota Clay Volume vs. Seismic Amplitude Data(w/ Sg Bubbles)

Figure 18

Co-located Co-kriged Clay Volume

Percent Clay

Near Trace Seismic Amplitude

98%

79%87%

40%

56%75%

61%

90%

59%

(With Average Water Saturation Bubbles)

Figure 19a

Co-located Co-kriged Clay Volume

Percent Clay

Near Trace Seismic Amplitude

Showing Lower Dakota Rose Diagrams and Seismic Lineaments

Figure 19b

Lower Dakota Acoustic Impedance

AC IMPAC IMP

ft/ms-g/ccft/ms-g/cc

Lower Dakota Rose Diagrams Figure 20

Amplitude vs. Angle of Incidence

Class 1, 2, & 3 AVO anomalies

From Rutherford and Williams (1989) Figure 23

AVO Modeling for Lower Clay Volume WellsAVO Modeling for Lower Clay Volume Wells

#55

60% Sg

3% clay

710 mcfd

#28

44% Sg

8% clay

1710 mcfd

#31

39% Sg

13% clay

502 mcfd

These 3 wells wells have the best production indicators in the study area

Figure 22a

AVO Modeling for Higher Clay Volume WellsAVO Modeling for Higher Clay Volume Wells

#47

21% Sg

18% clay

73 mcfd

#15

13% Sg

14% clay

45 mcfd

#30

10% Sg

17% clay

66 mcfd

Figure 22b

y = 278.59x - 188.43

r2 = 0.7946

r = 0.8914

Ph

ase

Dif

fere

nce

(D

egre

es)

Gas Saturation (%)

Lower Dakota Gas Saturation vs. Phase Difference(w/ Clay Volume Bubbles)

Figure 24

Near-Far Phase(No Clay Editing)

Range:

–15 to –85 degrees

No clay editing

Figure 25a

Near-Far Phase(w/ Clay Editing)

Range:

–15 to –85 degrees

With clay editing

Figure 25b

Lower Dakota Seismic Phase Difference

Percent Percent

Gas SaturationGas Saturation

Co-located Co-Kriged Lower Dakota Gas Saturation

Shown with Lower Dakota Rose Diagrams Figure 26

AVO Modeling/Gather Well #28 & Site 4AVO Modeling/Gather Well #28 & Site 4

Site #4Well #28

Figure 27

Composite Map Composite Map Lower Dakota Reservoir AttributesLower Dakota Reservoir Attributes

AREAS

Gas, low clay, velocity anisotropyGas, low clay, velocity anisotropy

Gas, low velocity anisotropyGas, low velocity anisotropy

Gas, high clayGas, high clay

Gas, high clay, low velocity Gas, high clay, low velocity anisotropyanisotropy

No gasNo gas

No gas, low velocity anisotropyNo gas, low velocity anisotropy

No gas, high clayNo gas, high clay

LINES

Black LinesBlack Lines…lineaments…lineaments Thick Black Clouds… outline of Thick Black Clouds… outline of higher lineament densityhigher lineament density

4 ATTRIBUTESClay Content Lineament Density Velocity AnisotropyPhase Difference/Gas Saturation

Figure 30

Conclusions / Prospect Drilling ResultsConclusions / Prospect Drilling Results

Well No.

Date Completed

Clay Volume

Gas Saturation

Velocity Anisotropy

Initial Production (MCFGPD)

52 01/2004 Good Good Excellent 4000

28E 05/2004 Good Good Good 2000

31E 06/2004 Good Good Good 850–2000

53 04/2004 Poor No AVO Attribute

Excellent Declined to 250

AcknowledgementsAcknowledgementsGeoSpectrum, Inc. would like to thank the following people for

their contributions to this study:

U.S. Department of Energy for the majority of the funding of this study.

The industry operator and their employees and associates who provided data and interpretations which greatly benefited this project.

Dr. James J. Reeves, for his conscientious work as Principal Investigator.

Mr. W. Hoxie Smith, who diligently served as Project Manager for this study.

Mr. W. Roger Smith, who abstracted the Play Geology section of this paper from the operator’s well files.

Mr. Don Zimbeck, for his professional seismic data processing.

Mr. Jim Oden, who provided his expert seismic interpretation.

Mr. Jeff Kane, who’s petrophysical analysis was invaluable.

Ms. Sylvia Chamberlain, who was responsible for exploratory data analysis and AVO analysis / modeling.

Mark E. Semmelbeck, Ph.D., for his proficient production data analysis.

Mr. Mark M. Gygax, for his engineering review of data and results and efforts in putting this slide show together.

DOE technical contract managers, who’s timeliness and assistance has been greatly appreciated.

President and Technical ManagerJames J. Reeves, Ph.D., P.G., P.E.

Dr. Reeves has his degrees from the Colorado School of Mines. He is a registered Professional Engineer in the State of Texas. Dr. Reeves' industry experience includes work with Gulf Oil Corporation and Pecten International Company as an Exploration Geophysicist. As an Assistant Professor of Geology at the University of Texas of the Permian Basin, he taught several courses on finite difference and finite element numerical modeling. He also conducted research in seismic data processing and interpretation of seismic data at UTPB, and as an Associate Research Professor for Texas Tech University. Dr. Reeves has served as a Principal Investigator and Project Geophysicist in two Department of Energy studies focusing on the integration of geological, geophysical, and reservoir engineering data to optimize oil and gas production.

Mr. Smith has over 20 years of industry experience, including 9 years with Atlantic Richfield Company (ARCO) and 4-years with Dawson Geophysical Company before co-founding GeoSpectrum Inc. He has managed several large industry reservoir projects and served as the Project Manager for an integrated reservoir characterization study conducted through the U.S. Department of Energy's Oil & Gas Program. Mr. Smith has been the featured speaker at numerous professional society meetings including national meetings of the Society of Exploration Geophysicists, American Association of Petroleum Geologists, and the Society of Petroleum Engineers. He received his B.S. degree in Geology from Colorado State University and his M.S. degree in Geology from the University of Texas of the Permian Basin.

Vice President and Project Coordinator W. Hoxie Smith, M.S.