High adventure

Assessment Methods 

for Well Integrity 

during the Hydraulic 

Fracturing Cycle

Washington, D.C.

March 11, 2011

James Bolander

Vice President – HS&E

Southwestern Energy
1

Protecting Drinking Water Resources

Well Integrity

Is the Key!
2

Well Integrity

Well Construction Standards 2Evaluating Stratigraphic Confinement 1

Evaluating Mechanical Integrity of Well 3Monitoring Frac Job & Producing Well 4
3

Well Integrity Hydraulic Fracturing Life Cycle

• Assessment Methods 

for Well Integrity during 

the frac life cycle

• Pre-frac Evaluation

• Understanding casing 

and cement integrity

• Frac Monitoring

• Monitor & record your 

pressures!!

• Post-frac Evaluation

• Maintaining well 

integrity through 

production

Subsurface

Considerations
Cross sectional view

FRESH WATER AQUIFER ZONE

SHALLOW PRODUCING ZONE

INTERMEDIATE PRODUCING ZONE

CONDUCTOR PIPE

SURFACE CASING

PRODUCTION CASING

WELL CONSTRUCTION STANDARDS

TARGET PRODUCING ZONE

CEMENT

CEMENT

CEMENT
Pre-Frac Mechanical Integrity of Well

• Internal Mechanical Integrity

– Verify appropriateness of 

proposed casing program 

(e.g., size, grade, minimum 

internal yield pressure, etc.)

– Test casing string to ensure 

it can withstand maximum 

stimulation pressure

• External Mechanical Integrity

– Verify quality of cement (field blend samples & slurry density)

– Monitor cement job (rates, pressures & returns)

– Identify top of cement

– Test cement job (FIT, CBL, etc.) when operations indicate inadequate 

coverage

5
External Mechanical Evaluation Methods

• Confirming top of cement (TOC) 

and quality are keys to 

protecting drinking water 

sources

– Monitoring rate and fluid 

volumes are the first step in 

evaluating the effectiveness of a 

cement job

– Mechanical test methods include 

the following:

• Temperature surveys which 

can determine the top of cement 

• Cement evaluation tools, such 

as the Segmented Bond Tool 

(SBT) which can determine 

TOC and quality of cement job 

to confirm zonal isolation
FRESH WATER AQUIFER ZONE

SHALLOW PRODUCING ZONE

INTERMEDIATE PRODUCING ZONE

CONDUCTOR PIPE

SURFACE CASING

PRODUCTION CASING

GOOD MECHANICAL INTEGRITY

TARGET PRODUCING ZONE
CEMENT CHANNELING

PRESSURE 

BUILDS UP

CONDUCTOR PIPE

SURFACE CASING

PRODUCTION CASING

FRESH WATER AQUIFER ZONE

SHALLOW PRODUCING ZONE

INTERMEDIATE PRODUCING ZONE

TARGET PRODUCING ZONE

CASING

CEMENT

FORMATION
Monitoring Frac Job 

• Monitor surface injection 

pressure and rate during frac 

job

• Monitor annular pressures 

during and after frac job

• Additional assessment methods 

include microseismic and use of 

tracer technology.

• Terminate operations and take 

corrective action if abnormal 

pressure responses indicate 

mechanical integrity failure or 

fracture growth out of target zone

9
10 0

2000

4000

6000

8000

10000

7:40:48 8:09:36 8:38:24 9:07:12 9:36:00 10:04:48 10:33:36 psi

0

20

40

60

80

100

120 bbl/min or PPAx10

Treating Pressure (psi)

Slurry Rate (bpm)

Prop Conc (ppa x 10)

Top Morrow Shale

Top Fayetteville Shale

Top Hindsville Limestone

~200’

1000’

Cross 

sectional view

Microseismic Evaluation of Stimulation Treatment
Maintaining Well Integrity

11

• Monitor Flowing and Annular pressures for 

changes

• Monitor gas and fluid rates which could indicate 

influx from an external sources

• Monitor gas and fluid composition which could 

indicate influx from external source and aid in 

determining scaling and corrosion tendencies

• Perform diagnostic tests to ensure integrity 

throughout the life of the well:

• Use of radioactive tracers and logging

• Use of Chemical tracers

• Casing Inspection and Production Logging

• Take corrective action to remediate well 

integrity concerns
Fracture Stimulation Results Tracer Survey

Confirms All Zones 

Effectively Stimulated 

Near Wellbore
• During the life 

cycle of the well, 

regular 

maintenance 

may be required.

– Confirmation of 

casing integrity 

by running 

Casing 

Inspection Log to 

determine current 

condition

13

Casing Inspection
LEAK THROUGH CASING

CONDUCTOR PIPE

SURFACE CASING

PRODUCTION CASING

FORMATION

CASING

FRESH WATER AQUIFER ZONE

SHALLOW PRODUCING ZONE

INTERMEDIATE PRODUCING ZONE

TARGET PRODUCING ZONE

PRESSURE 

BUILDS UP
15

Protecting Drinking Water Resources

Well Integrity

Is the Key!

Proper Planning, 

Documentation and 

Assessment are important 

keys to maintaining well 

integrity and 

environmental protection