GIS Masters Project by Rick Gonzalez

1
GIS Masters ProjectbyRick Gonzalez

• A GIS Approach to the Geology, Production, and
  Growth of the Barnett Shale Play in Newark East
  Field

2
Terminology

• Angular Uncomformity a rock unit (horizon) that
  has been previously tilted at an angle,
  subsequently eroded over time, and eventually was
  overlaid by other rocks in a horizontal manner
• Cross Section a transect view of the subsurface
  running from well to well that uses well logs
  with formation tops correlated over the same in
  order to visualize the relative depths and
  thickening and/or thinning of formations.
• Cumulative overall total production.
• Dip the attitude of a rock in space in relation
  to the horizontal plane and its direction (north,
  east, southwest, southeast, etc.) measured in
  degree units.
• Frac term given to the stimulation technique
  performed on a formation at depth in a drilled
  well also, fracturing the formation.
• Isopach contour map of the thickness of a rock

3
Terminology

• Kelly Bushing (KB) the grip on the drilling
  floor of a rig that holds the drilling string in
  place as it is rotating also the point of
  elevation at the top of the Kelly Bushing that is
  used as reference and subtracted from the
  Measured Depth in order to obtain subsea values
  for formation tops.
• Lineament a linear expression on the surface of
  the earth represented by prominent ridges or
  edges on the topography that is usually due to
  rock deformation or movement caused by stresses
  as the earths crust moves.
• Measured Depth (MD) the measurement at a well
  from Kelly Bushing (KB) to the Total Depth (TD)
  of a well.
• Pinch-out the point at which a formation
  eventually terminates due to thinning, or is cut
  off and is no longer present laterally as in an
  angular unconformity.

4
Terminology

• Stratigraphy (stratigraphic) related to the
  layering of the horizons or formations and their
  relationship to other rock units.
• Subcrops subsurface rocks or formations.

5
Introduction History of Barnett Shale Drilling

• In early existence of Newark East (1981)
  technology nonexistent to make economic wells
• Mitchell Energy (now Devon Energy) was Barnett
  play pioneer in area
• Gas shows showed Barnett potential
• Tested and studied Barnett to compile a database
• At same time developed stimulation techniques to
  frac Barnett
• gel fracture treatment
• Key keep the fractures contained within the
  Barnett
• Need Viola Ls below and dense Marble Falls Ls
  above to contain frac
• slick water fracture treatment
• Wells more productive using slick water frac
• Re-stimulation higher rates than initial
  fracturing
• Play expanded rapidly thereafter

6
Introduction Geology

• Barnett 45 quartz, 27 clay, 8 carbonate, 7
  feldspar, 5 organic matter, 5 pyrite, 3
  siderite,
• and trace min.
• Avg. porosity 6, very low permeability
  (nanodarcies)
• Barnett Shale important b/c produces commercial
  volumes of gas (well EUR from 0.5 2 bcf)
• Deposited over regional angular unconformity
• Underlying Viola Ls pinches-out at this
  unconformity
• Wells drilled west of Viola erosional limit
  produce a lot of water, little or no gas
• Wet Ellenburger Limestone lies directly below
  Barnett Shale west of Viola limit

7
Introduction Motivation for Study

• Arose from curiosity about the productive history
  and geology of the Barnett Shale in Newark East
  field.
• Because the play is rapidly expanding, was met
  with reluctance from operators to share
  proprietary data.
• Nevertheless, took it as a challenge to dig
  around for as much data to understand Barnett
  play.

8
Introduction Regional Setting
Muenster Arch
Bend Arch
B
A
A
Newark East Field
Gas Maturation Limit
Ouachita Thrust
Fort Worth Basin
Viola Limit
B
9
Introduction Regional Cross Sections
Cross sections borrowed from Recent Development
of the Barnett Shale Play, Fort Worth Basin
(Bowker, 2003)
Viola pinch-out
Erosional contact (unconformity)
10
Study Contents

• Objectives
• Literature Review
• Data Collection and Manipulation
• Analysis and Methods
• Results and Discussion
• Conclusion
• References Cited
• Acknowledgments

11
Objectives

• Gain insight to the structural geology and its
  relation to production using data
• To map productive Barnett Shale and its adjoining
  subcrops what is the attitude of the structures?
• Analyze surface lineaments vs. known subsurface
  fracture trends to see if relation exists.
• Map field operators to show where present.
• Map field expansion from beginning and show how
  it has encroached on the metroplex.

12
Objectives What is the significance?

• Study is significant because of the lack of
  non-proprietary data available with respect to
  this evolving gas field, its geology, and
  production.
• Most work done is in-house not for public
  consumption.
• Newark East is rapidly becoming largest gas field
  in the U.S. and its NE of the DFW area!

13
Literature Review

• Many studies are proprietary.
• Few Internet sources, but some require big
  for data and studies.
• Found old geologic maps submitted by Mitchell
  Energy to TRC.
• Obtained text of poster presentation at AAPG
  meeting in Dallas (April 2004).
• USGS paper on Barnett Shale Total Petroleum
  System
• Study on core fracture analysis and open hole
  fractures.
• Other miscellaneous papers on thermal maturation,
  organic content and lithology, field development,
  and fracture/stimulation techniques.

14
Data Collection and Formatting

• Data courtesy of DrillingInfo.com
• Well header (well name, operator,
  latitude-longitude, status)
• Production numbers
• 2813 wells
• Provided in comma delimited format
• Downloaded from site
• Opened in Excel, cleaned up, and saved (2384
  wells) as HeaderData spreadsheet
• Lat-long converted to SPCS North Texas

15
Data Collection and Formatting

• Formation (depth) data (IHS/PIs) collected from
  Oil Information Library in Downtown Fort Worth.
• Input to spreadsheet well by well b/c system
  would not allow for batch exporting
• Tops, GL, KB, MD, TD data were collected.
• Due to time constraint, uniform pattern of well
  data were collected.
• Data collected for about four and a half months,
  twice a week, for eight hours at a time
• Another month for verification of depth tops
  using well logs on microfiche (not all wells
  could be verified)
• Some well logs existed where no IHS data were
  available. These were used.
• Most IHS tops were Barnett Shale (upper and
  lower) Marble Falls and Viola not reported as
  often. These obtained from logs if available.
• Tops for total of 884 wells were obtained.
• Only tops for vertical wells were used

16
Data Collection and Formatting

• Data saved asTops spreadsheet.
• Subtract the Measured Depth from a wells KB
  value to obtain subsea for mapping
• Subseas calculated by opening the Tops table in
  ArcMap, creating new fields for each formation,
  then using the calculate function to obtain the
  subsea value.

17
Other Data Used

• Cultural shape files such as roads, lakes,
  municipality outlines, county outlines, and
  freeways obtained from 2002 ESRI Data CDs.
• Viola erosional limit, faults, regional
  structural elements, and lineaments were
  digitized onscreen to new shapes.
• mask.shp created for use in interpolation
• DEM and Hillshade grids downloaded from TNRIS in
  E00 format and converted to grid.

18
Cross Section Data

• Electric well logs obtained for use in creating
  cross sections (transects of the subsurface)
  across Newark East field
• Converted from microfiche to raster TIFF images
• Cropped in Irfran View software, saved, and
  imported to Petra software
• Tiffs were depth registered in Petra
• Structural cross sections made using well
  locations.
• Created three cross sections for use in
  demonstrating dip of subsurface structures and
  thickening or thinning of formations.

19
Methods Geodatabase Setup

• Geodatabase was created in ArcMap.
• HeaderData and the Tops spreadsheet imported as
  separate tables to gdb through Access.
• HeaderData data were added as an X-Y table event
  in ArcMap.
• Tops table joined in ArcMap to the HeaderData
  table by the API. The API is a unique number
  assigned by the state to a well for
  identification purposes.
• Once joined, data queried by attribute for each
  formation
• Selected records exported to a new table in the
  gdb.
• Different number of wells selected for each
  formation b/c not every well had every formation
  top
• Other tables created by query of joined tables
  Practical IP, Cumulative Gas, Cumulative Oil,
  Operator Name, and First Production Date

20
Methods Formation Structure Interpolation

• Preliminary interpolation was done using Inverse
  Distance Weighted (IDW) method in Spatial
  Analyst.
• Used mask to interpolate core drilling area.
• Preliminary maps were analyzed for data busts
  areas of bulls eye contouring.
• Wells with busts were noted and if could not be
  verified and/or corrected they were removed.
• Same IDW method was used to create preliminary
  maps of Practical IP, Cumulative Gas, and
  Cumulative Oil
• 24 hour flow rate during 2nd month of production

21
Methods Formation Structure Interpolation

• Before obtaining the final interpolated
  structures, three cross sections were built.
• Allow verification of the general subsurface
  structures.
• Based on info from cross sections, Practical IP
  map, TRC maps, and well data, faults were
  interpreted and digitized on screen.
• Faults used as barrier in IDW interpolation.
• IDW technique p-value of 2, variable search
  radius with 12 points. Grid size of 500 feet for
  all formations.
• P-values higher than 2 resulted in many bulls eye
  effects on the interpolation. (at high p-values
  only the immediate surrounding points influence
  the interpolation)
• Not having enough control points on both sides of
  a fault caused problem with interpolation no
  interpolation on other side.
• Solved problem by creating some ghost points
  (wells) on other side of fault.

22
Methods Barnett Shale Isopach

• Next, created Barnett thickness map
• From interpolated structures
• Using map calculator
• Subtract Barnett grid from Viola grid
• Results in gross thickness map for Barnett Shale

23
Methods Operators and First Prod Date

• Query of HeaderData table for Operator name
• Saved selected records for each Operator to new
  table in gdb
• Load x-y tables as event themes in ArcMap
• Mapped by Operator name
• Same with First Production Date query for date
  intervals (82-85, 86-90, 91-95, 96-98, 99-00,
  01-04)
• Saved each date interval selection to new table
  in gdb
• Load x-y tables as event themes in ArcMap
• Map by First Prod Date

24
Methods Lineament and Fault Trends

• Pick surface lineaments using DEMs
• 65 surface lineaments digitized on screen to
  shape file.
• Measured lineaments.
• Measurements input to spreadsheet.
• Data were divided trends 0 to 90 and 91 to 180
  deg.
• Mean trend of both sets calculated.

25
GIS Masters ProjectbyRick Gonzalez

• Results and Discussion History and Geology

26
Operators

• Where are companies operating?
• Devon largest operator
• Most production from Devon

27
First Production 1982-1985

• 21 wells
• Mitchell Energy

28
Production In 1986 - 1990

• More wells drilled to establish database
• on Barnett Shale
• Also, develop completion techniques

29
Production In 1991 - 1995

• Decline curve model established
• EUR numbers assessed at that time
• (1 BCF per well)

30
Production In 1996 - 1998

• Infill drilling
• First slick water frac (1997)
• First refrac of Lower Barnett (1998)

31
Production In 1999 - 2000

• Fracturing of Upper Barnett
• Play starts to rapidly expand

32
Production In 2001 - Feb 2004

• Horizontal drilling techniques
• improve

33
Wells and Urban Places Feb 2004

• Wells being drilled almost everywhere!
• Somewhat limited by urban centers and local
  ordinances,
• HOAs, mineral rights issues, noise restrictions,
  etc.
• But Barnett has potential to produce in all
  Tarrant and Dallas county
• Estimated total gas in place is 26.2 TCF (USGS)
• 4 to 10 tcf recoverable

34
Note about Viola

• Viola pinches-out (terminates) in far western
  Tarrant County and NW through the middle of Wise
  County against regional uncomformity.
• West of the erosional limit Ellenburger Limestone
  is present.
• No well logs found in OIL to examine this western
  limit.
• Wells in area are not usually drilled deep enough
  to log Ellenburger.
• No depth tops found from database at OIL except
  for one in middle of NE Field.

35
Top of Marble Falls Limestone
Muenster Arch
Viola Limit
36
Top of Barnett Shale
Muenster Arch
Viola Limit
37
Top of Lower Barnett Shale
Muenster Arch
Viola Limit
38
Top of Viola Limestone
Muenster Arch
Viola Limit
39
Tops of Formations (Looking Northwest)
40
Cross Section A A
A
A
Marble Falls Top
Upper Barnett Top
Forestburg Top
Lower Barnett Top
Viola Top
41
Cross Section B - B
B
B
Marble Falls Top
Upper Barnett Top
Forestburg Top
Lower Barnett Top
U
Viola Top
D
42
Cross Section C C
C
C
Upper Barnett Top
Marble Falls Top
Forestburg Top
Viola Top
Lower Barnett Top
U
D
U
D
43
3D Model of Structures
44
Barnett Thickness Map
45
Lineament Mapping of Surface
46
Lineament Mapping of Surface
47
Lineament Mapping Results

• In this GIS study the NE trending lineaments
  averaged 55 degrees.
• SE trending lineaments averaged 133.
• The subsurface faults mapped averaged 65 degrees.
• Is there a relationship between lineaments on the
  surface and fractures in the subsurface?
• Know from previous work (Hill, 1992) that
  drilling induced fractures have a mean strike of
  54 degrees.
• Natural fractures have a mean strike of 114
  degrees.
• Open-hole fracture tests showed mean of 60
  degrees.
• results apparently document a change in the
  stress field from the time the natural fractures
  formed to the present day. (Hill, 1992)

48
Lineaments and Subsurface Faults
TrendsStatistics
There seems to be a relationship if one
examines the means, but the data are variable.
The relation is not conclusive.
49
GIS Masters ProjectbyRick Gonzalez

• Results and Discussion Production

50
Practical IP (Initial Potential)
51
Practical IP (Initial Potential)

• Highest prod rates typically
• occur in areas away from fault
• zones.
• Fracture zones tend to produce
• more water.

52
Cumulative Gas Produced

• Most production occurs away
• from major faulting.
• Middle part of field is oldest
• thus most prod is from there

53
Cumulative Gas Produced(Close Up and Inset With
Wells)
54
Cumulative Oil Produced

• Most crude prod come from
• northern area
• Near edge of oil generation
• window in Montague, Cook,
• Clay, and Jack Counties

55
Cumulative Oil Produced
56
GIS Masters ProjectbyRick Gonzalez

• Conclusions

57
Assessment

• Objective was to gain an understanding of geology
  and production in Newark East field.
• Interpolation of Barnett Shale and adjoining
  subcrops data demonstrated structures below
  subsurface
• Interpolation of production data demonstrated
  areas of high and low production
• How are two related?
• Demonstrated that faulted areas are not good for
  drilling poor production rates occur in these
  areas
• Communiation with Ellenburger below
• Also, who are the Operators?
• Demonstrated the major operators on map
• Field growth and relationship with urban limits
• Demonstrated growth over time and its
  encroachment on urban centers, present state

58
Assessment

• Is there a relationship between surface
  lineaments and subsurface fracturing/faulting?
• It would seem that there is a relationship
  because the means for both sets of data are
  similar.
• Could not conclusively demonstrate this
  relationship because of the statistical
  variability of the data.

59
Contributions

• Related to GIS approach of mapping not just
  Barnett Shale, but also formations above and
  below it since these have not been mapped in
  non-proprietary works.
• Study helps to understand the geologic structures
  in the most active gas play in the U.S.
• Also, a comparison of area surface lineaments
  versus subsurface fracturing/faulting might be of
  interest to others as such comparison does not
  exist.
• Study helps to understand current drilling rate
  and expansion in DFW area
• Study helps understand who the major companies
  are that operate in the field

60
Future Research

• Incorporate additional wells outside the core
  area and update current well data.
• Should include data for the formations below the
  Viola Limestone group if they exist.
• Would be of interest to know the structural
  interface between the Viola and Ellenburger
• A more thorough analysis of surface lineaments
  compared to subsurface fracturing/faulting might
  be more indicative of whether or not the two are
  related.

61
References Cited

• Adams, G., 2004, Challenges of urban drilling
  abs Barnett Shale Symposium II, Brookhaven
  College, Richardson, Texas.
• Bowker, K., 2002, Recent developments of the
  Barnett Shale play, Fort Worth Basin, in Law, B.
  E. and Wilson, M., eds., Innovative Gas
  Exploration Concepts Symposium Rocky Mountain
  Association of Geologists and Petroleum
  Technology Transfer Council, October, 2002,
  Denver, CO, 16p.
• Henry, J. D., 1982, Stratigraphy of the Barnett
  Shale (Mississippian) and associated reefs in the
  northern Fort Worth basin Dallas Geological
  Society paper, 21 p.
• Hill, R. E., 1992, Analysis of natural and
  induced fractures in the Barnett Shale, Mitchell
  Energy Corporation, T. P. Sims No. 2, Wise
  County, Texas Gas Research Institute Report
  GRI-92/0094, 51 p.
• Jarvie, D. M., B. L. Claxton, F. Henk, and J. T.
  Breyer, 2001, Oil and shale gas from the Barnett
  Shale, Fort Worth Basin, Texas abs AAPG Annual
  Meeting, Program and Abstracts, p. A100.
• Jarvie, D. M. and B. L. Claxton, 2002, Barnett
  Shale oil and gas as an analog for other black
  shales abs AAPG Midcontinent Meeting, New
  Mexico.
• Jarvie, D. M.,2003, The Barnett shale as a model
  for unconventional shale gas exploration,
  presentation for AAPG meeting Accessed June 2004
  at URL http//www.humble-inc.com
• Kuuskraa, V. A., G. Koperna, J. W. Schmoker, and
  J. C Quinn, 1998, Barnett Shale rising star in
  Fort Worth basin Oil Gas Journal, v. 96, no.
  21, p. 67-68, 71-76.
• Lancaster, D. E. et al, 1992, Reservoir
  evaluation, completion techniques, and recent
  results from Barnett Shale development in the
  Fort Worth basin Society of Petroleum Engineers,
  SPE paper 24884, 12 p.

62
References Cited

• Pollastro, R. M. et al, 2003, Assessing
  undiscovered resources of the Barnett-Paleozoic
  total petroleum system, Bend Arch-Fort Worth
  basin province, Texas Search and Discovery
  Article 10034 AAPG Southwest Section Meeting,
  Fort Worth, Texas. 17 p.
• Steward, D. B., 2004, Personal communication
  discussion on the Barnett Shale.
• Thomas, J. D., 2003, Integrating synsedimentary
  tectonics with sequence stratigraphy to
  understand the development of the Fort Worth
  basin abs AAPG Southwest Section Meeting, Fort
  Worth, 9 p.
• Williams, P., 2002, The Barnett Shale Oil and
  Gas Investor, v. 22, no 3, p34-45.
• Zhao, H. and Givens, N., 2004, The Barnett
  Shale not so simple after all poster AAPG
  National Meeting, Dallas.

63
Acknowledgments
I would like to thank the following individuals
and/or companies who made this study possible
either by donation of their digital data or
access to their hard copy files. Their
contributions to this project are very much
appreciated The Oil Information Library in Fort
Worth and Mr. Roy English for his help while
researching at the library DrillingInfo.com and
Charles Hopkins for the production data he
provided Dan B. Steward and Natalie B. Givens
at Republic Energy Inc. in Dallas for taking the
time to discuss the Barnett Shale and providing
material for research Dr. Robert Stern at the
University of Texas at Dallas and Bill Harrison,
Geoff Ice, Yvette Chovanec, Steve Vonfeldt,
Martin Selznick and Debbie Fierros at Rosewood
Resources, Incorporated for their support and
encouragement on this project. Also, my wife
Alicia for putting up with me while engrossed in
this work. Most of all to the Lord for finally
getting me to the end of this degrees work. If
anyone was left out please know it was not
intentional. Thanks to all!