American Association of Petroleum Geologists Distinguished Lecturer Sponsored by AAPG Foundation

Transcription

1 American Association of Petroleum Geologists Distinguished Lecturer Sponsored by AAPG Foundation AAPG Distinguished Lecture Tour.DStoneburner Slide 0

2 The Exploration, Appraisal and Development of Unconventional Reservoirs: A New Approach to Petroleum Geology Dick Stoneburner Winter 2013 Formerly: President North America Shale Production Division BHP Billiton Petroleum President/COO Petrohawk Energy Corp. Currently Temporarily Retired/Unemployed AAPG Distinguished Lecture Tour.DStoneburner Slide 1

3 Brief History of Shale Exploration George Mitchell and Mitchell Energy pioneered shale exploration in the Barnett in the early 1980 s By the late 1990 s they had proven that vertical Barnett wells were commercially viable In the early 2000 s a move was made to drill horizontally in the Barnett, but completion technology was lagging and results were marginal In 2006 the use of isolated multi-stage completions was proven to be successful which was the true game changer for horizontal drilling in shale reservoirs AAPG Distinguished Lecture Tour.DStoneburner Slide 2

4 BCFE/D Growth of North America Shale Production The development of isolated multi-stage hydraulic fracturing in 2006 caused a dramatic increase in shale production By 2011 the Haynesville Shale surpassed the Barnett as nation s leading shale play 7 Development of isolated multi-stage hydraulic fracturing 6 5 Barnett Haynesville Fayetteville Marcellus Woodford Eagle Ford AAPG Distinguished Lecture Tour.DStoneburner Slide 3

5 Unconventional Exploration Process AAPG Distinguished Lecture Tour.DStoneburner Slide 4

6 Contrasting the Methodologies of Exploration Conventional Prospect identification focuses outside in Seismic control works outside in Stratigraphic support eventually focuses on facies analysis local to the prospect Reservoir quality issues are relegated to the area of the prospect Unconventional Project identification focuses inside out Seismic control works inside out Stratigraphic support focuses on analysis of the entire basin Reservoir quality analysis is required over a very broad area of the basin AAPG Distinguished Lecture Tour.DStoneburner Slide 5

7 Prospect Identification: Conventional Analogy K2 Shenzi Prospect Neptune Mad Dog Atlantis Discoveries 0 US feet Deep Water Gulf of Mexico Prospect Structurally controlled and supported by local analogs At time of Prospect Identification, there were three significant analogs in the area of the prospect The area of the prospect was on the order of 10K acres with Resource Potential in excess of several hundred MMBOE AAPG Distinguished Lecture Tour.DStoneburner Slide 6

8 Prospect Identification: Unconventional Analogy GUADALUPE BEXAR GONZALES LAVACA WILSON DEWITT FRIO VICTORIA MAVERICK DIMMIT ZAVALA ATASCOSA CHOKE CANYON RESERVOIR LIVE BEE GOLIAD COLETO CREEK RESERVOIR OAK LAKE CORPUS CHRISTI WEBB DUVAL Eagle Ford Shale Prospect Known regional source rock across large petroliferous basin Reservoir quality and geochemical attributes poorly understood The area of the prospect was >10 MM acres with high side Resource Potential of >10 BBOE AAPG Distinguished Lecture Tour.DStoneburner Slide 7

9 Case Study for Unconventional Exploration: Hawkville Field In early 2008 the CEO of Petrohawk charged the Exploration team to find another Haynesville-like play We targeted the Eagle Ford Shale based on its significance as a regional source rock Q1: Mapped the Eagle Ford across the entire Gulf Coast Basin and identified an anomalously thick, porous and highly resistive Eagle Ford section in La Salle and McMullen Counties Q2: Acquired Eagle Ford cuttings on a key well and had them analyzed for TOC, VRo and other key parameters Q3: Acquired ~160,000 acres and spud the initial test well Q4: Completed it in October 2008 for 7.6 Mmcf/d and 251 Bc/d AAPG Distinguished Lecture Tour.DStoneburner Slide 8

10 Hawkville Field in Early 2008 Very limited well control in prospective area Prospect was located in a regional setting between two divergent shelf margins which suggested the presence of a mini-basin While the geochemical properties were unknown, the depth range (10,000-11,500 ) suggested a relatively mature source rock AAPG Distinguished Lecture Tour.DStoneburner Slide 9 DE WITT FRIO BEE ZAVALA WILSON KARNES GOLIAD MCMULLEN DIMMIT LA SALLE MAVERICK VICTORIA LIVE OAK ATASCOSA X/Y: Feet Swift Pielop #1 Phillips LaSalle #1 Sligo Shelf Margin Edwards Shelf Margin

11 Key Finding #1: World Class Petrophysical Characteristics Atascosa_bee_dewitt_gonzales_liveoak_lasalle_maverick_webb_wilson Swift Pielop 1 Primarily oil Significant portions derisked GR Resistivity AT90 Early entry, 0low avg. 100 cost Eagle Ford Scalable Shale Longer-term leases Low near-term capital requirements Log PHIDEDIT Density Log Depth(ft) Depth(ft) Buda Swift Pielop #1 Top Eagle Ford Base Eagle Ford AAPG Distinguished Lecture Tour.DStoneburner Slide 10

12 Key Finding #2: Positive Geochemical Characteristics Phillips LaSalle #1 D&A in 1952 Eagle Ford Shale Gas Risk Assessment Diagram AC TOC (0-5) EFS Tr (50 100) Ro ( ) BUDA Minimum Threshold Phillips LaSalle #1 Tmax ( ) Dryness (0 100) AAPG Distinguished Lecture Tour.DStoneburner Slide 11

13 Key Finding #3: Seismic Definition of the Reservoir SP: MT 3D CookWest MIG TVF, 401, 1130 MT GT LR-37, MT 3D LAKEWOOD - BURKS MT RANCH, GT 77-16, 1482, MT GT MIG TVF MT GT 927 MIG TVF, The anomalously thick Eagle Ford at Hawkville could be identified with 2D seismic data Dora Martin 2H Dora Martin 4H Dora Martin 1H Dora Martin PH 1 Isochron Thick in Center of Hawkville Field EFS Res EFS Res EFRT EFS Res Buda A grid of 2D data was acquired that allowed the mapping of the entire extent of the thick Eagle Ford reservoir Eagle Ford Shale Data Courtesy of Seitel, Inc. AAPG Distinguished Lecture Tour.DStoneburner Slide 12

14 Hawkville Field in Late 2008 Petrohawk Energy STS #1H Spud Date:08/ st Prod: 10/2008 Petrohawk Energy Dora Martin #1H Spud Date:09/ st Prod: 01/2009 Fall 2008 Petrohawk Acreage Position ~160,000 net acres AAPG Distinguished Lecture Tour.DStoneburner Slide 13

15 The Eagle Ford Shale in 2012 Eagle Ford Shale Competitor Map AAPG Distinguished Lecture Tour.DStoneburner Slide 14

16 Night View of Texas by Satellite AAPG Distinguished Lecture Tour.DStoneburner Slide 15

17 Unconventional Appraisal Process AAPG Distinguished Lecture Tour.DStoneburner Slide 16

18 Critical Data for Effective Appraisal Program: Core Data and Core to Log Data There is nothing more critical to the evaluation of a shale resource than the extensive data gathered from whole core analysis: Measurement of conventional reservoir attributes such as Porosity, Sw, Permeability, etc. Identify and measure the mineralogy, specifically clay minerals versus coarse grained constituents Measurement of key geochemical (TOC, Thermal Maturity, etc.) and geomechanical attributes (Young s Modulus and Poisson s Ratio) Most importantly, calibrate core measurements to conventional open hole log suites, therefore expanding knowledge regarding reservoir characterization, formation evaluation (OGIP, Recovery and EUR) and optimization of the hydraulic fracture stimulation AAPG Distinguished Lecture Tour.DStoneburner Slide 17

19 Pilot Wells During Appraisal Process Essential to acquire acceptable grid of open hole data subsequent to discovery Percentage of wells with pilot holes with complete data suite (core plus full complement of open hole logs) is low, but it is critical to have adequate baseline of core data Collective data set will enhance: o o Reservoir characterization Identify optimum stratigraphic target for lateral o Help determine the optimum stimulation recipe (fluid compatibility, geomechanics, stress regime, fracture density, etc.) o Provide basis for creating algorithms that translate core data to log data AAPG Distinguished Lecture Tour.DStoneburner Slide 18

20 Analytical Process from Core Complete Cored Interval o Spectral Core Gamma o Fracture & Sedimentological Description o Core Photography Basic Rock Properties o Porosity characterization (GRI method) o Steady-state nano-permeability (CT-Scan plugs) Reservoir Geology & Geochemistry o Geochemistry (TOC, Pyrolysis, Vitrinite Reflectance) o Thin Section Petrography & FIB SEM o X-Ray Diffraction AAPG Distinguished Lecture Tour.DStoneburner Slide 19

21 Analytical Process from Core (continued) Adsorption & Desorption o Desorbed gas content & composition o Adsorption isotherm o Isotope Analysis Completion & Stimulation o Geomechanical Properties (Single-State & Multi-Stage) o Proppant Embedment and Fracture Conductivity o Capillary Suction (CST) and Roller-Oven Testing AAPG Distinguished Lecture Tour.DStoneburner Slide 20

22 Basic Petrophysical Workflow Core Data Xplots lnterpreted LOG CURVES cluster analysis TOC Porosity Permeability Saturation Lithology Geomechanics ALGORITHMS facies classification AAPG Distinguished Lecture Tour.DStoneburner Slide 21

23 Max Perm Ø-Total TOC Core to Log Calibration: TOC-Porosity- Permeability-Saturation TOC Fair correlation coefficient r 2 ~ 0.65 Triple Combo RHOB Hydrocarbon-filled Porosity Highest correlation coefficient r 2 ~ 0.93 Ø-HC Total porosity HC-filled porosity 4 Sw based on default Rw ~ Permeability Least dependable of the algorithms (use qualitatively and in localized zones) Ø-HC AAPG Distinguished Lecture Tour.DStoneburner Slide 22

24 Core to Log Calibration: Lithology Dolomite 1.1% Pyrite 3.1% Plagioclase 3.2% Calcite 60.9% Quartz 15.4% Clay 15.2% * Key Element to Mineral Conversions QFM ~ * Si Calcite ~ Ca Calcite + Dolomite ~ (Ca Mg) Pyrite = S Kerogen ~ 0.83 /TOC Clay ~ (1- sum of above) Carbonate (chalk) (Source : Herron and Herron, 1998) element data from ECS-type logs composite lithofacies display element to mineral conversion * PEF check 1 3 marl calcareous mudstone clay-rich mudstone argillaceous mudstone siliceous mudstone AAPG Distinguished Lecture Tour.DStoneburner Slide 23

25 Static YM Core to Log Calibration: Geomechanics Use as a proxy for estimating Vs DTS when dipole or sonic scanner data is unavailable r 2 ~ 0.94 Track 14 Softer Young s Modulus Static ~ 0.65 * Dynamic R2 ~ 59% 1. Use industry standard algorithms to calculate dynamic elastic modulii (Vp, Vs, RhoB) Lambda Mu Bulk Modulus P-wave Modulus Poisson s Ratio Young s Modulus Harder Uniaxial Compressive Strength (UCS *) from DTC or Vp Dynamic YM 2. Convert from dynamic to static modulii for fracture propagation modeling Dynamic-static relationships are derived from multi-stage Triaxial testing where both static and dynamic measurements are collected simultaneously Softer AAPG Distinguished Lecture Tour.DStoneburner Slide 24

26 Core to Log: QC and Interpretation GR-TOC RES PORO-PERM SATURATION 1 0 LITHOLOGY FRACTURE PROPAGATION 1 6 Top Shale Base Shale TOC distribution Sweetspot screening Rock properties from ECS-type tool should dovetail with geomechanical descriptions Frac properties from DTC-DTS AAPG Distinguished Lecture Tour.DStoneburner Slide 25

27 YOUNG S MODULUS Facies Extraction Using Geomechanical Data F Facies extracted from Crossplot B E A-1 A-2 C D A-3 A-4 Cluster Analysis Poisson s Ratio vs. Young s Modulus Lambda*Rho vs. Mu*Rho (or any other attribute combination) POISSON S RATIO AAPG Distinguished Lecture Tour.DStoneburner Slide 26

28 The Whole Core Itself: Macro Observations From the Eagle Ford Marl Foraminifer Marl Foram-Rich Marl Limestone Calcareous Shale Ash Beds/Bentonite Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 27

29 The Relationship of Eagle Ford Core to Gamma Ray Showing Significant Vertical Heterogeneity GR COREGR_ 0 api 200 K 72 SB DEPTH FT Courtesy of Core Laboratories K 69 SB K 65 MFS K 64 SB BUDA K63 SB Buda AAPG Distinguished Lecture Tour.DStoneburner Slide 28

30 Mineralogical Analysis: Relationship of Texture and Composition to Shale Reservoir Quality Epi-fluorescence Petrography o Lithology o Rock Type o Mineralogy o Micro Fractures Silica-Filled Algal Cyst X-ray Diffraction Analysis o Mineralogy o V Clay SEM Analysis 0.1 mm Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 29

31 Micro Textural Relationships: The Importance of Scale to Proper Reservoir Identification 0.5 mm Standard 30 micron thick slide: No apparent grain support which would suggest poor reservoir quality Ultra Thin (20 micron) slide: Significant grain support which leads to better reservoir quality Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 30

32 Depth, feet The Importance of Coarse Grained Constituents : Haynesville Shale MINERALOGY by XRD (Elm Grove Plantation #63 Well) Bossier Haynesville Volume Percent Qtz Ksp Plg Cal Dol Pyr I/S I/M Chl Ker Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 31

33 The Importance of Coarse Grained Constituents : Marcellus Shale Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 32

34 Depth, feet The Importance of Coarse Grained Constituents : Eagle Ford Shale MINERALOGY by XRD (PC-Q #1H) Austin Chalk Eagle Ford Buda Volume Percent Qtz Plg Cal Dol Pyr Mar I/S I/M Chl Kao Ker Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 33

35 Eagle Ford: Mineralogical Variation Across the Trend Maverick Basin Area Hawkville Area San Marcos Area East Texas Area Clay content increases from west to east Kerogen content remains relatively constant Increase in clay resultant from clastic influence of the East Texas Basin QTZ % CARBONATE % 20% 40% 60% CLAY % 80% XRD Data from Core Lab KEROGEN % 100% AAPG Distinguished Lecture Tour.DStoneburner Slide 34

36 Effective Gas Permeability, md The Relationship of Porosity and Permeability to Mineralogy: Can t Have One Without the Other 1.00E E E E E E E E E E E E E E-14 1 md 1 md BASIC ROCK PROPERTIES 3 MMCFGPD V 8 MMCFGPD H 250 MCFGPD V 1.5 MMCFGPD V Gas-Filled Porosity, percent Raam Unit #3 (Barnett) (Haynesville) Mr Bill 1-30 (Caney) Mr Bill 1-30 (Woodford) Barnett (Avg) Haynesville (Avg) Caney (Avg) Woodford (Avg) 16 MMCFGPD H Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 35

37 Dry Gas Wet-Gas Oil Window Source Rock Reservoirs: Observed Maturity Effects Burial Depth Maturity (Ro) Oil Gravity (API) 0.5 GOR Organo Porosity Water Saturation Pore Pressure Gradient Recovery Factor Maximum Liquids Recovery Zone? Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 36

38 The Importance of Stress Isotropic Tempered Glass Anisotropic Natural Glass Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 37

39 Measuring Stress: Essential to Understand Geomechanics of the Reservoir Laboratory Measurement ostatic and Dynamic Measurements on Core Samples (Young s Modulus) Log Data ofull-waveform Acoustic Logs (Dipole Sonic) obulk density olithology AAPG Distinguished Lecture Tour.DStoneburner Slide 38

40 Definition of Fracture Geometry Fracture Width Height Growth Fracture Closure Stress Production Zone Embedment Zone Courtesy of Core Laboratories AAPG Distinguished Lecture Tour.DStoneburner Slide 39

41 Unconventional Development Process AAPG Distinguished Lecture Tour.DStoneburner Slide 40

42 3D Seismic Data: Critical to a Successful Development Program The cost of 3D seismic data is minimal in the total field development cost 3D seismic data is critical in identifying faults and dip changes that could compromise the stratigraphic targeting of a horizontal wellbore Merged ~650 square miles of acquired proprietary data and licensed data in Hawkville Field AAPG Distinguished Lecture Tour.DStoneburner Slide 41

43 Geo-Steering: An Important New Geoscience Skill Set Horizontal drilling creates significant geological challenges Unforeseen dip changes and/or faults can cause a well to be out of zone for a large portion of a lateral The combination of utilizing 3D seismic data and Measured Depth (MD) to True Vertical Depth (TVD) Gamma Ray correlation allows the geologist to direct the drilling operation to allow the well to stay within the target window The post-drill geologic interpretation of the wellbore also provides insight into the completion design and can cause the completion engineer to vary certain stages of the hydraulic fracture stimulation depending on the inferred reservoir quality within each stage AAPG Distinguished Lecture Tour.DStoneburner Slide 42

44 Pre-Drill Well Plan Prior to 3D Seismic Data Acquisition 11,000 Well plan is designed using subsurface mapping from well control and regional 2D seismic data Degree of confidence in the interpretation is fairly low Target Line: Zero Vertical Section Assuming Average 2 degree dip AAPG Distinguished Lecture Tour.DStoneburner Slide 43

45 Pre-Seismic Geosteering Interpretation at TD Pilot Hole Gamma Ray Vertical Section Montage Horizontal Hole TVD Gamma Ray Horizontal Hole MD Gamma Ray AAPG Distinguished Lecture Tour.DStoneburner Slide 44

46 3D Seismic Acquired After Completion Faulting AAPG Distinguished Lecture Tour.DStoneburner Slide 45

47 Geosteering Interpretation Using 3D Seismic Data Faults were conduit for frac hit by pressure and fluid transmission from offset well completion AAPG Distinguished Lecture Tour.DStoneburner Slide 46

48 Stage by Stage Fracture Stimulation Montage Lost lateral section from frac hit from offset well AAPG Distinguished Lecture Tour.DStoneburner Slide 47

49 Microseismic Data: Down Hole View of Fracture Geometry Monitor Well Fault plane conduit for frac hit induced by offset well Lost Lateral Section Down hole geophones AAPG Distinguished Lecture Tour.DStoneburner Slide 48

50 Conclusions The geologic aspects of the Exploration process in shale reservoirs requires an inverted thought process as compared to conventional exploration and usually is done with insufficient knowledge of reservoir quality The geologic aspects of the Appraisal process in shale reservoirs is highly dependent on an understanding of the nano elements of the reservoir and requires a tremendous amount of data gathering and analysis over an extremely large area The geologic aspects of the Development process in shale reservoirs has generated a new set of skills, the most prominent being geo-steering, that is exciting, challenging and cross functional with several engineering disciplines AAPG Distinguished Lecture Tour.DStoneburner Slide 49

51 Acknowledgments BHP Billiton Petroleum colleagues, specifically Vanon Sun Chee Fore, Terry Gebhardt, John Goss, Alan Frink, Andy Pepper, Melissa Florian and Kelley O Brien Core Laboratories, specifically Randy Miller Seitel, Inc. AAPG Distinguished Lecture Tour.DStoneburner Slide 50