Monitoring of In-Situ Chemical Oxidation (ISCO) with Time Series Geophysical Surveys

Transcription

1 Monitoring of In-Situ Chemical Oxidation (ISCO) with Time Series Geophysical Surveys Philip T. Harte, P.G. U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey

2 Review of Time Series Geophysical Surveys for ISCO NEWMOA-In-Situ Chemical Oxidation Workshop Repeated geophysical surveys to identify temporal change in bulk (formation and fluid) electrical properties at discrete depths - Includes background or pre-injection survey Effective with electrically conductive injectate, i.e. permanganate Allows for a more complete picture of treatment Provides enhanced mapping capability when coupled with conventional monitoring

3 NEWMOA-In-Situ Chemical Oxidation Workshop Application of Time Series Geophysical Surveys for ISCO Signal to noise ratio and signal strength -Electrical signal > Measurement resolution Site infrastructure considerations -Interferences Well construction (tool specific) Selection of the correct method/tool

4 NEWMOA-In-Situ Chemical Oxidation Workshop Geophysical Survey Methods Surface (e.g. Electromagnetic (EM), Direct Current (DC) resistivity) Borehole Logging (e.g. EM, **Gamma, **Neutron, **ATV) Cross hole (e.g. Radar, Radio frequency, Electrical (ERT)) Surface to Borehole (e.g. Electrical, Heat, Radar, etc.) **Geologic characterization

5 NEWMOA-In-Situ Chemical Oxidation Workshop Method 1: Borehole Electromagnetic (EM) Log Works in open holes, pvc wells, 2 inches or greater Induces current and measures formation bulk electrical properties (including water conductivity) beyond solid wall pvc casing or screen -Does not require direct fluid or formation contact

6 Method 1: Borehole EM Log Injection well A. No detection in water sample NEWMOA-IN-Situ Chemical Oxidation Workshop Monitoring well Well screen UNIT B UNIT A Sample zone of monitoring well screen Well screen B. Detection with Borehole EM Borehole EM Log UNIT B USGS UNIT A Survey zone of Borehole EM Log

7 Animation of injection/em logging -Placeholder- NEWMOA-In-Situ Chemical Oxidation Workshop

8 Method 2: Surface Direct Current (DC) Resistivity NEWMOA-In-Situ Chemical Oxidation Workshop Ground Aquifer

9 Method 2: Surface Direct Current (DC) Resistivity NEWMOA-In-Situ Chemical Oxidation Workshop Resistive unsaturated washed cobbles Ground Conductive groundwater near water table Sand and Gravel Bedrock Conductive groundwater on bedrock

10 NEWMOA-In-Situ Chemical Oxidation Workshop Permanganate Injection, OU1, Savage Superfund Site, Milford, NH - PCE contaminant plume in a sand and gravel aquifer - OU1 treatment system contains Barrier barrier wall, and pump-n-treat system (since 1999) - Outside barrier, PCE declines to Barrier below 10 ppb in many areas - Inside barrier, declines slow Barrier - ISCO Treatment initiated several times with permanganate

11 Permanganate-DC NEWMOA-In-Situ Chemical Oxidation Workshop Resistivity/Conductivity Lab Testing Calibrate field results to geology Measure differences in bulk electrical conductivity with the addition of permanganate (and changes to pore fluid conductivity)

12 NEWMOA-IN-Situ Chemical Oxidation Workshop DC Resistivity Lab Testing Results Coarse sand (6) Medium sand (5) Gravel with silt (4) Fine sand (3) Silty sand and f. gravel (2) Silty sand (1) Permanganate (3%) Dilute permanganate (.3%) Ambient Groundwater Unsaturated sand Increasing coarseness Electrical conductivity, ms/m Bulk measurement of formation and pore fluid

13 NEWMOA-IN-Situ Chemical Oxidation Workshop Location of injection wells, 2008 Barrier Wall (low permeability) Area of detail in next slide

14 Stratigraphy NEWMOA-IN-Situ Chemical Oxidation Workshop Soil PW-6R EM time series Cobble 1 Background Injections ( from Nov , 08) Injections ( from Nov 10-17, 08) Injections ( from Nov. 5-12, 08) Permanganate flow Groundwater flow Injections ( from Oct. 31 to Nov. 03, 08) Upper sand Cobble 2 Middle sand 1 Int. sand Middle sand 2 Cobble 3 Lower sand Basal sand Nov 3, 08 Nov 5, 08 Nov 7, 08 Nov 12, 08 Nov 19, 08 Dec 3, 08 Apr 16, 09 Borehole EM detects permanganate Bedrock U.S. Department of the Interior U.S. Geological Survey Logged well: PW6R EM conductivity, ms/m

15 Temporal PCE NEWMOA-In-Situ Chemical Oxidation Workshop Transport

16 NEWMOA-IN-Situ Chemical Oxidation Workshop Location of injection wells, 2008 Barrier Wall (low permeability) Area of detail in next slide

17 Stratigraphy Soil NEWMOA-In-Situ Chemical Oxidation Workshop PW-15D EM time series Cobble 1 PW15D-EMAPR2009 PW15D-EMJAN0609 PW15D-EMNOV2108 Upper sand Cobble 2 PW15D-EMNOV1908 PW15D-emdec1008 EI-EM(2006) Background Middle sand 1 Interbedded sand Middle sand 2 PW15M screen Basal sand Till Likely metal from bit during drilling PW15D screen EM conductivity, ms/m

18 NEWMOA-In-Situ Chemical Oxidation Workshop Location of DC Resistivity Survey A Area affected by injection Area affected by injection A

19 A Background DC Resistivity Survey Barrier IP-5 PW-6D IP-2 IP-9-11 NEWMOA-In-Situ Chemical Oxidation Workshop A Barrier ,000 High Conductivity Resistivity, ohm-m

20 Temporal Surveys NEWMOA-In-Situ Chemical Oxidation Workshop A A PRE-INJECTION, SEPT.08 POST-INJECTION, Nov. 19, 08 Permanganate POST-INJECTION, SEPT.09 Permanganate decrease Permanganate increase

21 Summary- Time series geophysical surveys NEWMOA-In-Situ Chemical Oxidation Workshop Provided enhanced mapping capabilities Effectively tracked spread of permanganate Established framework to interpret post-pce trends Identified data gaps Identified density induced transport control Aided in formulation of alternate injection strategies

22 Acknowledgments NEWMOA-In-Situ Chemical Oxidation Workshop U.S. EPA, REGION 1 Mike Jasinski Richard Hull Steve Mangion Weston, Inc. Bette Nowack N.H. DES Robin Mongeon U.S. Geological Survey Thor Smith James Degnan John Williams