Evaluating Suitability of Appalachian Basin Reservoirs for NGLs Storage Jessica Moore, West Virginia Geological & Economic Survey

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1 1 THE APPALACHIAN STORAGE HUB STUDY: Evaluating Suitability of Appalachian Basin Reservoirs for NGLs Storage Jessica Moore, West Virginia Geological & Economic Survey

2 2 ASH STUDY OUR GOAL Complete a geologic study of all potential options for subsurface storage of NGLs Required a stratigraphic correlation of key units Mapping thickness and structure of key units Studies of reservoir character Developing ranking criteria

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4 4 THREE MAIN PRODUCTS Regional subsurface study with correlations, cross sections, thickness and structure maps Criteria with which to rate and eventually rank candidate formations and reservoirs as safe and secure storage containers A project database and website in which all of the data and research findings ae located and can be accessed by the public and potential storage companies

5 5 WHAT WE DID NOT CONSIDER Who owns or operates a depleted gas field or gas storage field that was rated highly Or if this operator would be interested in NGL storage Who owns the rights to the Greenbrier Limestone or Salina Salt And again, if the owner might be interested in NGL storage If a candidate is in an area of future Marcellus or Utica drilling Surficial activities, other than towns or cities Cost implications for storage and pipelines Focus was entirely on subsurface geology

6 6 GEOLOGIC INTERVALS OF INTEREST System/Age Interval Description Storage Type Mississippian Greenbrier Limestone Limestone comprised of multiple carbonate facies Mined-rock cavern Multiple sandstones of Lower Mississippian- Keener to Berea variable location, thickness Devonian and extent Depleted gas reservoirs Upper Devonian Multiple sandstones of Venango, Bradford and variable location, thickness Elk groups and extent Depleted gas reservoirs Lower Devonian Oriskany Sandstone Regionally persistent sandstone Depleted gas reservoir Upper Silurian Salina Group Bedded salt formations Salt cavern Upper Silurian Newburg sandstone Localized sandstone equivalent to Salina C Depleted gas reservoir interval Lower Silurian Clinton/Medina Group Multiple sandstones of variable location, thickness and extent Depleted gas reservoirs Lower Ordovician - Rose Run-Gatesburg Regionally persistent Upper Cambrian sandstones sandstone Depleted gas reservoirs

7 RESERVOIR CHARACTERIZATION Identify stratigraphic units or reservoirs with the best geologic and geomechanical properties to ensure long-term, secure storage of ethane and other NGLs Legacy data compilation Mapping Petrophysical calculations Qualitative thin section analyses 7

8 8 RESERVOIR CHARACTERIZATION EFFORTS Unique characterization efforts for each type of storage container Depth structure maps Thickness isopach maps Extent facies evaluation (Greenbrier) and clean vs. dirty salt intervals (Salina F4) Preliminary assessment screened field-level data for 2,700+ depleted gas reservoirs

9 9 GREENBRIER LIMESTONE (MINED-ROCK CAVERNS) Increase data density by interpreting geophysical logs Bulk density, density porosity and photoelectric factor give indication of lithology

10 10 GREENBRIER LIMESTONE (MINED-ROCK CAVERNS) Characterize facies using geophysical logs (digital and raster) and drillers descriptions Carbonate ramp environment of deposition Schematic illustration of Mississippian facies distribution of the Appalachian basin (Wynn, 2003). The main facies types within the AOI were deposited in inner- to mid-ramp settings.

11 11 GREENBRIER LIMESTONE THREE FACIES Appalachian Storage Hub (ASH) Study Appalachian Storage Hub (ASH) Study Appalachian Storage Hub (ASH) Study Figure 7. Net thickness map of the Greenbrier lime mudstone facies package.

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14 14 SALINA F4 SALT (SALT CAVERNS) Regional correlation and mapping efforts determined that the F4 Salt was the only Salina member likely to occur in thicknesses 100 ft Appalachian Storage Hub (ASH) Study Four areas (numbered sequentially from north to south) with net thicknesses 100 ft

15 SALINA F4 SALT: DEPTH Appalachian Storage Hub (ASH) Study Below deepest occurrence of fresh drinking water Not penetrated by many gas wells that could provide vertical migration routes Increase in salt plasticity limits lower cavern depths to <7,000 ft Area Average Depth (ft) 5,300 6,200 6,650 6,600 15

16 SALINA F4 SALT: AREAS 1 AND

17 SALINA F4 SALT: AREAS 3 AND

18 SALINA F4 SALT (SALT CAVERNS) GEOPHYSICAL LOGS SALT CORE SAMPLES. 18

19 19 SALINA F4 SALT: NET THICKNESS Upper F4 Salt vs. lower salt Interbedded dolomite and anhydrite within larger salt package

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22 PRELIMINARY ASSESSMENT OF DEPLETED GAS RESERVOIRS 2,700+ fields with sandstone reservoir data Of these, ~1,500 fields were 2,000 ft deep Preliminary rating efforts were used to pare down this dataset for more focused work 22 22

23 23 PRELIMINARY ASSESSMENT OF DEPLETED GAS RESERVOIRS Preliminary rating criteria Distance to infrastructure Acreage Average depth Average porosity Net thickness Permeability Pressure Distance to infrastructure >30 mi >20 mi but <=30 mi >5 mi but <=20 mi <=5 mi Acreage <=500 ac >500 ac but <=1,000 ac >1,000 ac but <=5,000 ac >5,000 ac Stacked opportunity Mode CO 2 storage Criterion Description Range of Values Proximity of field to any of the existing or proposed pipeline infrastructure, as illustrated in Figure 4-26 Measured size (or footprint ) of a field (ac) Average depth <=2,000 ft >5,000 ft >2,000 ft but <=3,500 ft >3,500 ft but <=5,000 ft Average depth (ft) at which a field stores/stored natural gas, based on multiple wells completed in that field

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25 RESULTS OF PRELIMINARY ASSESSMENT 113 depleted gas fields 12 natural gas storage fields 5 limestone areas 4 salt areas 25 25

26 26 DETAILED RATING CRITERIA Mined-Rock Caverns Salt Caverns Depleted Gas Reservoirs Gas Storage Fields Distance to Infrastructure Distance to Infrastructure Distance to Infrastructure Distance to Infrastructure Acreage Acreage Acreage Acreage Average depth Average depth Average depth Average depth Net Thickness Net Thickness Net Thickness Net Thickness Trap integrity Trap integrity Trap integrity Trap integrity Legacy well penetrations Legacy well penetrations Legacy well penetrations Legacy well penetrations Stacked opportunity Stacked opportunity Stacked opportunity Stacked opportunity Pressure Pressure Pressure Average Porosity Average Porosity Permeability Permeability Mode CO 2 storage Estimated cumulative gas production Mode CO 2 storage Working gas capacity

27 27 DETAILED RATING CRITERIA Distance to Infrastructure (mi): Average depth (ft) (gas fields): (salt caverns): <2,000 >3,500-5,000 >2,000-3,500 >5,000 0 <2,000 >2,000-3,000 >3,000-5,000 >5,000-7, Acreage (ac) (gas fields): (salt caverns): (mined-rock caverns): ,000 5, ,000 50, , ,000 75, , Net thickness (ft)(gas fields): (salt caverns):

28 DISTANCE TO INFRASTRUCTURE 28

29 29 DETAILED RATING CRITERIA Legacy well penetrations (no. wells per 1,000 acres): Stacked opportunity: Pressure (psi): Gas fields , NO DATA Salt Caverns Average porosity (%): Gas fields

30 STACKED OPPORTUNITY RATINGS 30

31 TRAP INTEGRITY RATING CRITERIA No data 0 Limited data on trap characteristics 1 Inferred lithologic and/or structural closure 2 Documented lithologic and/or structural closure 3 Trap integrity - 0 Trap integrity

32 32 TRAP INTEGRITY RATINGS Good trap No top Trap Good trap No bottom trap Okay trap No trap

33 DETAILED RATING CRITERIA Permeability (md): NO DATA , Mode CO 2 storage (tons): 0 10, ,000 1,000, Estimated cumulative gas production (BCF) (gas fields): NO DATA Working gas capacity (MMCF) (storage fields): 0 1,000 5,000 10,

34 DETAILED RATING RESULTS 30 opportunities 22 depleted gas fields 3 salt areas 3 mined-rock areas 2 natural gas storage fields 34 34

35 DETAILED RATING RESULTS TABULAR FORMAT Container Type Field/Location Geologic Interval Rating Result 5 Greenbrier 19 Mined-Rock Cavern 4 Greenbrier 16 2 Greenbrier 15 Salt Cavern 1 Salina F4 Salt 15 2 Salina F4 Salt 15 4 Salina F4 Salt 15 RIPLEY Oriskany 24 Natural Gas Storage Field RACKET-NEWBERNE (SINKING CREEK) Venango 22 MAPLE-WADESTOWN Keener to Berea 23 BURDETT-ST. ALBANS Keener to Berea 22 CONDIT-RAGTOWN Keener to Berea 22 ABBOTT-FRENCH CREEK Venango 25 WESTON-JANE LEW Elk 24 CAMPBELL CREEK Oriskany 25 ELK-POCA (SISSONVILLE) Oriskany 24 NORTH RIPLEY Newburg 27 ROCKY FORK Newburg 27 KANAWHA FOREST Newburg 27 COOPER CREEK Newburg 25 CANTON CONSOLIDATED Clinton/Medina 25 CANTON CONSOLIDATED Clinton/Medina 24 CANTON CONSOLIDATED Clinton/Medina 24 Depleted Gas Reservoirs RAVENNA-BEST Clinton/Medina 24 CONSOLIDATED DUMM RIDGE Rose Run- 18 Gatesburg DUMM RIDGE Rose Run- 18 Gatesburg FRAZEYBURG Rose Run- 18 Gatesburg RANDOLPH Rose Run- 18 Gatesburg KIRKERSVILLE Rose Run- 17 Gatesburg DUMM RIDGE Rose Run- 17 Gatesburg ROCKBRIDGE Rose Run- Gatesburg 17 35

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37 37 DATA SHARING All data from the project is available via the web. Visit

38 38 NEXT STEPS Site- or field-specific studies Drill tests; coring Mechanical testing of core samples Collection of petrophysical data (porosity, permeability, etc) Evaluation of well penetrations and wellbore integrity and that s just the geology!