Your SlideShare is downloading. ×
0
Hydraulic Fracturing Panel   Water Considerations           Presented at  Texas Groundwater Summit       August 28-30, 201...
Amount of Water Needed to Hydraulically                          Fracture a WellWater demand to frack a well is substantia...
Water Quality of Concern in FlowbackFlowback contains fracking additives  Precipitated & entrained solids (scaling tendenc...
Stress-            Stress-Field Induced Preferential FlowInjected fluids tend to follow existing fractures consistentwith ...
Regulations Predicated on Isotropic MediaDisposal Well Permit Guidance (Texas)  … the applicant shall review … wells that ...
Inadvertent Contaminant Migration                             Possible Modes of Migration1.   Migration along fault or thr...
Example: Proposed Injection Well±                         A        0   0.5   1   2       3   4                            ...
Abandoned Oil/Gas Wells    RRC Database is not Comprehensive         Proposed         Disposal±           Well            ...
Area of Interest                   Page 9
Stress-Field Ellipse Indicating Potential         Direction of Preferential Flow                              ¼-mile      ...
Actual Threat from Disposal Wells    Failure of wells used for deep-well disposal of waste fluids and migration ofwaste fl...
How Great is the Threat from Abandoned Wells?Oil drilling began in earnest in the early 1900s, some                       ...
Is Waste Disposal by Deep-Well Injection                                   Deep-                            a Problem?Disp...
RecommendationsThere are several actions the State can take to mitigatethe threat of contamination due to “breakout” from ...
Contact InformationRonald T. Green, Ph.D., P.G.Institute ScientistGeosciences and Engineering DivisionSouthwest Research I...
Page 16
SW Segment of the Carrizo-Wilcox Aquifer              Pre-              Pre-Development Potentiometric SurfaceGroundwater ...
1929- Carrizo-                   1929-30 Carrizo-Wilcox Aquifer                       Potentiometric SurfacePumpage was es...
1999 Carrizo-Wilcox Aquifer                          Carrizo-                       Potentiometric SurfacePumpage was esti...
Page 20
Upcoming SlideShare
Loading in...5
×

Water Considerations and Hydraulic Fracturing, Ron Green

617

Published on

Published in: Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
617
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
19
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Transcript of "Water Considerations and Hydraulic Fracturing, Ron Green"

  1. 1. Hydraulic Fracturing Panel Water Considerations Presented at Texas Groundwater Summit August 28-30, 2012 by Ronald T. Green, Ph.D. , P.G.Geosciences and Engineering Division Southwest Research Institute®
  2. 2. Amount of Water Needed to Hydraulically Fracture a WellWater demand to frack a well is substantial: 5-15 acre-ft (1,500,000-5,000,000 gallons) to frack a borehole acre- (1,500,000- gallons) Compared with 100,000 gallons to drill a wellDisposal of Fracking Waste Water Considerable amount of degraded water returns to surface as flowback: flowback: 20% in “dry” formations, 80% in “wet” formations Quality of flowback can be poor: fracking additives plus high-salinity in poor: high- situ groundwater Disposal of flowback in Texas is often by deep-well injection deep- Page 2
  3. 3. Water Quality of Concern in FlowbackFlowback contains fracking additives Precipitated & entrained solids (scaling tendencies) Ca, Mg, Ba, Sr Ba, Mineral scales (calcium carbonate & BaSO4) Iron solids (iron oxide and iron sulfide) Dispersed clay fines, colloids & silts High dissolved solids levels (chlorides, sulfates, calcium, etc.) Bacteria Suspended solids, frack sand (proppant) (proppant) Liquid & gas hydrocarbons Acid gases (CO2 & H2S) Friction reducer residueplus formation (i.e., highly saline) water Page 3
  4. 4. Stress- Stress-Field Induced Preferential FlowInjected fluids tend to follow existing fractures consistentwith pre-existing stress field instead of as a isotropic sphere pre- An injection well has greater influence in the direction of maximum horizontal stress and major faults and fractures Actual Isotropic volume of sphere injection Page 4
  5. 5. Regulations Predicated on Isotropic MediaDisposal Well Permit Guidance (Texas) … the applicant shall review … wells that penetrate the proposed disposal zone within a 1/4 mile radius of the proposed disposal well to determine if all abandoned wells have been plugged in a manner that will prevent the movement of fluids from the disposal zone into freshwater strata.This regulation assumes pure radial flow and does notaccount for heterogeneity that could result from stress- stress-field induced directional flow Page 5
  6. 6. Inadvertent Contaminant Migration Possible Modes of Migration1. Migration along fault or through confining layer – not likely unless vertical separation is minimal2. Migration via an existing borehole (i.e., abandoned open well) – possible, particularly if an abandoned well is not identified, reasonably close to the disposal well, and contaminant is injected into the same horizon as the screened section of the abandoned well Injection of Disposal disposal fluids well Abandoned open wells Usable aquifer Confining layer Zone of injection Page 6
  7. 7. Example: Proposed Injection Well± A 0 0.5 1 2 3 4 Kilometers Page 7
  8. 8. Abandoned Oil/Gas Wells RRC Database is not Comprehensive Proposed Disposal± Well Well Symbol A! Permitted Location D Canceled Location R Dry Hole !( Oil Well Existing Water # * Gas Well Wells ) " Oil/Gas Well !. Plugged Oil Well 0 0.5 1 2 3 4 #0 Plugged Gas Well Kilometers / " Plugged Oil/Gas Well Page 8
  9. 9. Area of Interest Page 9
  10. 10. Stress-Field Ellipse Indicating Potential Direction of Preferential Flow ¼-mile radius Proposed Disposal± Well Well Symbol A! Permitted Location D Canceled Location Abandoned R Dry Hole Wells !( Oil Well Existing Water # * Gas Well Wells ) " Oil/Gas Well !. Plugged Oil Well 0 0.5 1 2 3 4 #0 Plugged Gas Well Kilometers / " Plugged Oil/Gas Well Page 10
  11. 11. Actual Threat from Disposal Wells Failure of wells used for deep-well disposal of waste fluids and migration ofwaste fluids through 1,000s of feet of rock are not the greatest threatAbandoned wells pose the greatest threatin deep-well disposal of waste fluids, and possibly hydraulic fracking Page 11
  12. 12. How Great is the Threat from Abandoned Wells?Oil drilling began in earnest in the early 1900s, some 1900s,wells have been in existence for almost a century.Records of wells, especially older wells, are oftenincomplete or absent. absent.Well casing is estimated effective for 20 yrs, structural yrs,integrity of older abandoned wells may be compromised.How many? Estimates vary from less than 10,000 toover 110,000 (orphan and inactive) wells. wells. Page 12
  13. 13. Is Waste Disposal by Deep-Well Injection Deep- a Problem?Disposal of degraded fluids after fracking (flowback) by flowback)12,610 disposal wells in TexasRRC requires notification of all occurrences of breakout, but breakout,doesn’t maintain a single databaseRRC on retains records on breakout for only two yearsThere are documented cases of breakoutIn absence of a centralized database, risk is unknown, butpossible Page 13
  14. 14. RecommendationsThere are several actions the State can take to mitigatethe threat of contamination due to “breakout” from adisposal well. Limit or prohibit injection of liquid wastes into oil/gas (i.e., productive) formations, particularly formations with a history of formations, oil/gas development. That’s where the abandoned wells are. Increase the ¼-mile radial distance from proposed disposal well ¼- over which abandoned wells are searched. Develop a single database for all occurrences of “breakout”. Risk from breakout can only be assessed if number of occurrences and their severity are known. Page 14
  15. 15. Contact InformationRonald T. Green, Ph.D., P.G.Institute ScientistGeosciences and Engineering DivisionSouthwest Research Institute6220 CulebraSan Antonio, Texas 782381.210.522.5305 (office)1.210.522.5184 (fax)1.210.316.9242 (cell)rgreen@swri.edu Page 15
  16. 16. Page 16
  17. 17. SW Segment of the Carrizo-Wilcox Aquifer Pre- Pre-Development Potentiometric SurfaceGroundwater elevationreconstructed with limiteddata and historicalevidence of spring flowand flowing artesian wells.(modified from Deeds et al., 2003) Page 17
  18. 18. 1929- Carrizo- 1929-30 Carrizo-Wilcox Aquifer Potentiometric SurfacePumpage was estimatedat 27,000 acre-ft/yr in1929-30Zone of depression isabout 150 ft lower thanpre-developmentgroundwater elevation(modified from Deeds et al., 2003) Page 18
  19. 19. 1999 Carrizo-Wilcox Aquifer Carrizo- Potentiometric SurfacePumpage was estimatedat 65,000-80,000acre-ft/yr in 1999Zones of depression areabout 350 ft lower thanpre-developmentgroundwater elevation(modified from Deeds et al., 2003) Page 19
  20. 20. Page 20
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×