IBDP Pre-Injection Microseismicity

Transcription

1 VW1 CCS1 Z feet (msl) IBDP Pre-Injection Microseismicity Valerie Smith, Senior Reservoir Geophysicist October 8, 2013 Processing by: Paul Jaques, Systems Engineer, Schlumberger Cambridge Research

2 Any interpretation, research, analysis, data, results, estimates, or recommendation furnished with the services or otherwise communicated by Schlumberger to customer at any time in connection with the services are opinions based on inferences from measurements, empirical relationships and/or assumptions, which inferences, empirical relationships and/or assumptions are not infallible, and with respect to which professionals in the industry may differ. Accordingly, Schlumberger cannot and does not warrant the accuracy, correctness or completeness of any such interpretation, research, analysis, data, results, estimates or recommendation. Customer acknowledges that it is accepting the services "as is", that Schlumberger makes no representation or warranty, express or implied, of any kind or description in respect thereto. Specifically, customer acknowledges that Schlumberger does not warrant that any interpretation, research, analysis, data, results, estimates, or recommendation is fit for a particular purpose, including but not limited to compliance with any government request or regulatory requirement. Customer further acknowledges that such services are delivered with the explicit understanding and agreement that any action taken based on the services received shall be at its own risk and responsibility and no claim shall be made against Schlumberger as a consequence thereof Schlumberger. All rights reserved. An asterisk is used throughout this presentation to denote a mark of Schlumberger. Other company, product, and service names are the properties of their respective owners. 2

3 Introduction Introduction well locations and geophone configurations Pre-Injection Microseismicity Regional Seismicity Conclusion 3

4 Illinois Basin Decatur Project (IBDP) Why are we interested in Pre-Injection Microseismicity? How stable is the detection system? Can we use it for calibration? Can we establish a natural baseline? How does it compare to data since CO 2 injection? 4

5 Introduction: Map View of IBDP wells 5

6 Introduction: IBDP Well Configuration and Geophones Oblique View looking north. Permanent Seismic Sensing System (PS 3 ) Geophone Array Vertical Exaggeration: 0.5X OYO Geophone Array Eau Claire Mt. Simon Injection Zone feet GM CCS Ground Level VW1 St. Peter Sandstone ~ msl feet VW1 Westbay Zones (perfs) -6,000 TD= 7,236 feet MD 6

7 Introduction: Pre-Injection Microseismic Data Pre-Injection coverage period: May 1, 2010 to November 15, 2011 Data examined: 10 Tbyte of microseismic data 68,575 total triggers were reduced down to 7,894 detected events (by filtering out noise and surface activity) 500 samples every second per channel (during pre-injection period). 7

8 Introduction: Pre-Injection Microseismic Data Discrimination of event sources: P and S Wave arrival times Waveform magnitudes (x, y, z- components) Frequency content Correlation in time with known events Example microseismic event PS 3 Geophone Level 2 P-Wave S-Wave Geophone Level 1 time 8

9 Pre-Injection Microseismicity Detection filters optimized to select microseismic events.

10 Microseismic Data Types The pre-injection data consisted of 7 unique groups: 1) Microseismicity associated with drilling activity (Located) 2) VW1 Perforation Shots (Located) 3) Microseismicity likely related to well activity (Located) 4) Local events unrelated to well activity (Located) 5) Distant events (distance approximated in miles, but unknown (x,y,z) 6) Surface noise (filtered out, i.e. eliminated) 7) Unknown noise (eliminated these events which contribute to false triggers, i.e. those which don t have distinct P & S arrivals.) 68,575 total triggers - (Surface & Unknown noise) = 7,894 Detected events 10

11 Pre-Injection Microseismic Detection 7,894 Detected Events 7,787 non-located events 107 Located Events VW1 perforation shots potentially locatable 107 located Near VW1, possible well activity Local microseismic events VW1 drilling activity Of these 7,787 non-located events associated with the drilling of VW1, ~2,000 events can potentially be locatable. 74 of the these events have been selected for locating and typify the P to S wave signature associated with the drilling of VW1. Distant Events (approximated in miles) 11

12 Pre-Injection Microseismicity in Depth versus Time Microseismicity appears to fall into certain groups. 12

13 Pre-Injection Microseismicity in Depth versus Time VW1 drilling Oct. 4 to Nov VW1 Perforations May 2, 2011 Next to Perf Zone 7 May 15, 2011 Distant Events : time marker only, depth unknown. 13

14 Pre-Injection Microseismicity in Magnitude versus Time 14

15 Pre-injection Microseismic Events Locations Overview Drilling Related VW1 Perforation Well Related Local Activity VW2 GM2 N MSL View to the East VW1 CCS1 Gamma Ray S CCS2 VW1 feet GM1 CCS ft N 1000 ft Vertical Exaggeration: 0.5X 15

16 Microseismic Events Attributed to Drilling of VW1 (Oct. 4, 2010 to Nov. 17, 2010) VW1 Drilling Events N VW1 CCS1 S Moment magnitude: Max: Avg: Min: Count: 74 VW1 MSL Gamma Ray feet GM1 CCS ft N 1000 ft Vertical Exaggeration: 0.5X 16

17 Microseismic Events Attributed to Drilling of VW1 (Oct. 4, 2010 to Nov. 17, 2010) VW1 Drilling Activity Moment magnitude: Max: Avg: Min: Count: 74 Time N View to the East VW1 CCS1 St. Peter Knox Gamma Ray S VW1 z-axis Feet (MSL) Eau Claire Eau Claire Shale Mt. Simon 1000 ft GM1 CCS1 N Injection Zone Pre. Mt. Simon 1000 ft Vertical Exaggeration: 0.5X 17

18 VW1 Perforation Shots (May 2, 2011) VW1 Perforations (detected) Actual Perforations Moment magnitude: Max: Avg: Min: Count: 11 N VW1 View to the East Eau Claire Eau Claire Shale Mt. Simon CCS1 Gamma Ray S VW1 Feet (MSL) GM1 CCS1 Pre. Mt. Simon Injection Zone 1000 ft N 1000 ft Vertical Exaggeration: 0.5X 18

19 Microseismic Events Located Close to VW1 (May 15, 2011, Possibly Well Activity Related) 19

20 Local Microseismic Events (Sept 6, 2010 Oct. 21, 2011) Local Microseismic Events Max: Avg: Min: Count: 8 VW2 GM2 CCS2 N MSL VW1 CCS1 Gamma Ray S feet VW1 GM1 CCS ft N 1000 ft Vertical Exaggeration: 0.5X 20

21 Pre-injection Microseismic Moment Magnitude Histogram Near VW1, well activity VW1 drilling activity Local events Does not include VW1 Perforation shots or the distant events. Count =

22 Regional Seismicity Detection of low frequency, long-offset events.

23 Introduction: Regional Seismicity Detection of regional seismicity Although the sensors in CCS1 and GM1 are primarily intended for detecting microseismic events, they also detect the low frequency signatures from distant earthquakes. To perform this analysis, the data was processed using a different trigger configuration to search for any low frequency and distant events, i.e. long-offset. 23

24 Example of regional earthquake recorded on PS 3 tools: 3.9 magnitude event in east Missouri. P to S time difference = 30 seconds. 3.9 magnitude event in east Missouri 24

25 21 regional earthquakes have been detected (pre-injection) 12 of which correspond to the USGS Earthquake Database. Searching for these low frequency and distant events required a different trigger configuration than that used for detecting the local, higher frequency microseismic events. From USGS database Locations on next slide. 25

26 12 Earthquakes from USGS Database IBDP 150 miles 240 km miles 26

27 Histogram of Long Offset, Low Frequency Events (direction is to the SE) ~1,100 of these type of events were detected. Events are not natural phenomena but somehow linked to the working day from 8 am to 5 pm. (using local time adjusted for daylight savings ) 27

28 ~1,100 long-offsets were detected. Typical event has 20-second P to S-time. This event is typical of those occurring at ~ 17:00 local time to the SE of Decatur. Event distance ~ 105 miles P to S-time difference = 20 seconds. 28

29 P to S-time Differences for Long-offset Events SE of CCS1. Illinois Indiana 105 miles 169 km Knox 50 miles 29

30 Conclusions for Microseismic Events 5 types of events were distinguished from the 18-month dataset. (distant events, drilling activity, local events, perforation shots, well-related) Of the 7,894 detected events, only 8 were interpreted as being representative of background activity. Background activity magnitude is no greater than VW1 drilling or perforations. Of the 7,894 detected events, 7,861 appear to be directly associated with the drilling of VW1. Potentially 2,000 of these are locatable. The system detected and recorded the 11 perforation shots in VW1. Pre-injection microseismicity is significantly lower than during injection. 30

31 Pre-Injection Microseismic Detection Conclusions With a few exceptions, local events plot near VW1. VW2 VW1 CCS1 PS3 Oblique View looking northeast. Pre-Mt. Simon N 31

32 Conclusion for Regional Events The regional seismic analysis detected 21 events that had the characteristics of a long-offset, low frequency event. Such characteristics are associated with earthquake events. 12 of the 21 regional seismic events match events documented by the USGS. Approximately 1,100 long-offset, low frequency events were detected. These events are believed to be associated with quarry or mine activities. Most of these events occur between 8 am and 5 pm local time 32

33 Final Conclusion The IBDP microseismic detection system is robust and through the 18-month pre-injection period the system recorded: local microseismicity well drilling operations regional seismicity.

34 Microseismic Cluster Activity: Cluster Locations with Relation to Surface Moment Magnitude Jan 18, 2012 July 31, GM2 CCS GM1 15 VW1 10 CCS Microseismic cluster reference numbers in order of appearance ft 0 6 N 34

35 Microseismic Cluster Activity: Relationship to Basement Structure from Schlumberger Carbon Services