Colorado s Underground Injection Control Program: Prevention and Mitigation of Induced Seismicity

Transcription

1 Colorado s Underground Injection Control Program: Prevention and Mitigation of Induced Seismicity Energy & Environment Symposium April 2015 Robert P. Koehler, PhD. UIC Lead

2 OVERVIEW What is a UIC well? General Review Criteria for UIC Wells UIC Review Criteria Specifically for Induced Seismicity Regulatory Procedures for Induced Seismicity Risk Management Greeley Example

3 Drill Surface Hole NOT TO SCALE

4 Case Surface Hole NOT TO SCALE

5 Drill And Case 1 st Casing String NOT TO SCALE

6 Completed For Injection NOT TO SCALE Post Drilling Permit Evaluation: Water Samples Fracture Gradient Determination Cement Bond Log

7 OVERVIEW What is a UIC well? General Review Criteria for UIC Wells UIC Review Criteria Specifically for Induced Seismicity Regulatory Procedures for Induced Seismicity Risk Management Greeley Example

8 UIC REGULATIONS RULE OBJECTIVES Aquifer Protection Production Zone Isolation Mineral and Surface Owner Rights

9 UIC REGULATIONS RULE EVALUATION Mineral and Surface Owners Within ¼ Mile Notified Legal Notice Published In Local Newspaper

10 UIC REGULATIONS RULE EVALUATION Wellbore Construction Integrity: Casing Design Cement Design/ Cement Bond Log Offset Wells Geology / Stratigraphy / Well Logs

11 UIC REGULATIONS RULE 325 EVALUATION Injection Zone Water Analyses Total Dissolved Solids (TDS): Seawater 35,000, Freshwater 1,000 mg/l If TDS < 10,000 mg/l; EPA and CDPHE Notified, Aquifer Exemption Requested by Operator Aquifer Protection Form 2 Drilling Permit Water Well Analyses Colorado Division of Water Resources Review

12 OVERVIEW What is a UIC well? General Review Criteria for UIC Wells UIC Review Criteria Specifically for Induced Seismicity Regulatory Procedures for Induced Seismicity Risk Management Greeley Example

13 INDUCED SEISMICITY EVALUATION Review Criteria Seismicity Look For History Of Seismic Activity In Area Geology Look For Faults At The Well And In The Area Check Proximity To Crystalline Basement Look For Lost Circulation & At Drilling Rate Mudlogs Drilling Reports

14 Colorado Geology Survey Review COGCC participating with IOGCC and GWPS discussions and with CGS group- USGS, CSU, CU, CSM, Mesa State

15 USGS Seismic Events > M2.5 Orange dots: Pre-2011 USGS Seismic Event > M2.5 Blue Square: Injection Wells

16 OVERVIEW What is a UIC well? General Review Criteria for UIC Wells UIC Review Criteria Specifically for Induced Seismicity Regulatory Procedures for Induced Seismicity Risk Management Greeley Example

17 UIC Injection Permit Limitations: Maximum Injection Volume Maximum Surface Injection Pressure Maximum Daily Injection Rate

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19 Greeley Example 2014 Seismic Events-SWD-C4A Well May 31 st at ~9:35PM M 3.2 Event 6 miles NE of Greeley Colorado

20 NGL s SWD-C4A Well Commercial disposal well drilled in Weld County located in the Denver Basin (flowback associated with Niobrara shale play) Total depth: 10,818 Injection volume (Aug 2013 May 2014): ~ k bbls per month Permitted max pressure: 1,512 psi Perforated formations: Permian Lyons through Pennsylvanian Fountain Formation Fountain Formation sits on top of basement, zones of injection were initially <500 from basement Area is known to have a complex network of antithetic-synthetic faults originating in basement

21 Greeley May 31 st quake as detected on closest seismograph station (USGS ISCO) ~70 miles away at Idaho Springs. Anne Sheehan et al. University of Colorado

22 NGL C4A Schematic NGL C4A INJECTION INTO CRYSTALLINE BASEMENT Spinner survey: 30%-50% of injected fluid exiting bottom of the wellbore Fractures identified based on lost circulation, increased drilling rates, 3D-seismic Well plugged back from ft to ft Since that time no significant seismic activity even though well has returned to injection at rate equivalent to that at time of May 31, 2013 earthquake. NOT TO SCALE

23 C4A Authorized To Re-Inject Traffic Light criteria will apply. Injection resumes at 5,000 barrels of water per day (bpd) with a maximum injection pressure of 1,512 psi for 20 days. If no M 2.5 seismic events may increase to 7,500 BWPD at 1,512 psi for 20 days. If no M 2.5 seismic events for 20 days NGL may request an increased injection rate. NGL will install a permanent seismometer station near the Well.

24 Summary of Critical Points: Do not inject into crystalline basement Induced Seismicity Being Managed By: Permit Limits on Maximum Injection Volume Maximum Surface Injection Pressure Maximum Daily Injection Rate Stoplight Program Seismic Event >M2.5, halt injection & evaluate

25 Questions?

26 C4A Well Time Table 1. Drilled & completed: December 15, Injection Permit approved: March 22, Injection began: April Seismic Events: a. First USGS reported, M3.2: May 31, 2014 b. Second USGS reported, M2.6: June 23, C4A Shut-in for 20-DAYS: June 23, Reinjection 5,000 bpd: July 19, Injection Rate Increase to <7,500 bpd: August 7, <9,500 bpd: October 3, <12,500 bpd: December 10, <15,000 bpd: March 26, 2015 Bpd = Barrels per day, 42 gallons per barrel

27 UIC Inspection and Enforcement FOR BOTH DISPOSAL AND SECONDARY RECOVERY All UIC wells are inspected annually o INJECTION PRESSURE IS CHECKED o ANNULAR PRESSURE IS CHECKED All UIC wells are pressure tested for casing integrity every 5-years. All UIC wells are equipped with a packer and tubing annulus are inspected for leaks through by opening the tubing annulus value. Any well showing abnormal pressure on the tubing annulus is required to cease injection, be repaired of abandoned.

28 2) Standard Condition of Approval: < Maximum Allowable Injection Volume MIV = f h p (1/4 mile) 2 f = Porosity f = Porosity h = Reservoir height h = Reservoir height p = PI 1/4 mile 1/4 mile

29 1) Standard Condition of Approval: < Maximum Allowable Injection Rate & Pressure Step Rate Test for Fracture Gradient Fracture Initiation Zone of Allowed Injection Rate & Pressure

30 STANDARD CONDITIONS OF APPROVAL ALL APPROVED INJECTION PERMITS HAVE: Maximum Allowable Injection Pressure that is below the injection zone fracture pressure. Maximum Allowable Injection Volume: this is calculated to hold the radius of influence of injected fluid to ¼ Mile. The volume may be increased at a later date with additional review and approval by COGCC. There may be special data, test or log required periodically. o Bradenhead test o Temperature, radioactive or noise logs o Cased hole integrity logs o Transit Analysis. o Seismic Monitors

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32 Colorado Regional Context Colorado Earthquake and Fault Map

33 Wellbore Integrity MECHANICAL INTEGRITY TEST Applied pressure monitoring of internal casing pressure BRADENHEAD MONITORING TEST Monitoring for internal annulus pressure GROUND SURFACE AQUIFER(S) CEMENTED CONDUCTOR WELLHEAD Bradenhead valve CEMENT SURFACE CASING PRESSURIZED FLUID TUBING STEEL CASING PERFORATIONS BRIDGE PLUG INJECTION ZONE Per COGCC Rule 326 Per COGCC Rules 207.b. and 608.e

34 Historical Examples of Induced Seismicity in Colorado Rangely Large injection volumes High injection rate Rocky Mountain Arsenal Large injection volumes High injection rate Low porosity reservoir Low permeability reservoir Paradox Valley Large injection volumes High injection rate

35 Anne Sheehan et al. University of Colorado USGS: Did you feel it?

36 Pre-plug back bottom of hole accepting about 30% to 50% of the injection fluid in a highly fractured zone Plugged back TD to 10,360 feet above a highly fractured zone. Post plug back bottom of hole accepting about 10% of the injection fluid.

37 Take-Away Thoughts 1. Although there is strong temporal and spatial data to suggest seismic events were induced by the SWD-C4A well, the link is not definitive. 2. In Colorado, these low magnitude earthquakes have a high public perception, due to the location and possible linkage to wastewater disposal. 3. The COGCC, by regulating location, volume, pressure, rate, and monitoring seismic activity, views the risk of induced seismicity as manageable.

38 I. Colorado Regional Context II. Colorado s UIC Program III. The 2014 Greely Seismic Events and SWD-C4A Well Low damage risk, yet significant public perception Manageable risk... with regulatory focus on location, volume, rate, pressure, and monitoring.

39 UIC Data Review 1. REVIEW THE DRILLING RECORDS FOR: a) DAILY DRILLING LOGS b) DRILLING BREAKS c) LOST CIRCULATION ZONES d) RATE OF PENETRATION CURVES (ROP) 2. REQUEST A TRANSIENT TEST TO DETERMINE INJECTION RATES AND PERMEABILITY 3. STATIC WATER LEVEL MEASUREMENT