DEVELOPMENT OF METHODS TO PROHIBIT AND REMEDIATE LOSS OF ANNULAR ISOLATION IN SHALE GAS WELLS Prevention and Remediation of Sustained Casing Pressure and other Isolation Breaches

Involved Parties

Funded by RPSEA (Project Number 11122-42)

Primary Researchers: CSI Technologies

Partner: Southwestern Energy

Subcontractors:

– The Measurement Group

– The University of Houston

Two Phase project spanning two years time

Issue

Sustained Casing Pressure (SCP)

– When gas gathers by some form or another in any annular region of an oilfield well

– Most cases involve the gas migrating through the production cement sheath

Objectives

Devise a method to detect, diagnose, and stop unwanted gas flow the result in sustained casing pressure (SCP)

Devise a protocol to asses gas flow potential and apply appropriate preventative methods

Focus Areas

Primary focus will be in Fayetteville Shale

Secondary Focus will be in Marcellus Shale

Image from www.searcychamber.com Image from march.rutgers.edu

Phase 1 – Technology Status Assessment

Extensive literature review covering

– Gas flow remediation

Current and Experimental Operation

– Current cementing procedures in shale plays

– Gas flow prevention in primary cementing

– Gas flow detection methods

Phase 1 – Analyze Current Problems

Comprehensive Data Mining Campaign

– Data supplied by Southwestern Energy

SCP fundamentals will be discovered

Data gathered will include:

– Well architecture

– Cement Slurry design and placement

– Timing and magnitude of SCP experienced

– Any remediation methods that were attempted

Field personnel will observe current ops

Phase 1 – Develop Acoustic Detection Tool

A downhole acoustic tool will be developed

– Developed in conjunction with The Measurement Group

– Capable of locating Gas Flow behind Casing

– Important because the closer the remediation can be done to the source the better

Will be tested

– Using large scale models

– Actual field trials

Phase 1 – Develop Analytical Prevention Methods

Using the data provided by Southwestern, analytical models will be developed

– In conjunction with the University of Houston

– Capable of predicting potential for gas flow based upon well characteristics

Phase 1 – Evaluate Potential Sealants: Remediation

Lab and Large scale testing will be performed on:

– Portland Cement

– Swellable Polymers and Resins

– Nano-particles

– Etc.

Placement techniques will be studied and developed

Phase 1 – Evaluate Potential Sealants: Prevention

Test current cement systems to obtain baseline

Potential design changes to currently used cement systems

New additives which could aid in gas migration prevention

Phase 1 – Remediation Protocols

Protocols will be developed to:

– Identify location of gas

– Location to place sealant

– The type of sealant

– Placement method

Phase 1 – Prevention Protocols

Protocols will be developed to:

– Specify completion methods and tools

– Better cementing operations

Based upon:

– Well and formation characteristics

– Analytical gas flow prediction model

Phase 2 – Candidate Well Selection

Wells will be chosen based upon a specific set of criteria for field trials of both the remediation and preventative methods

Very controlled so that there are as few variables as possible.

Image from rigzone.com

Phase 2 – Field Trials

Using protocols and sealants developed, field trials will be conducted on the candidate wells previously chosen

Operations will be closely monitored by CSI field personnel

Data will be gathered and analyzed:

– During operation

– Short Term

– Long Term

Phase 2 – Data Evaluation

The field trial data will be used to:

– Determine technical success

– Identify and implement needed improvements

– Perform economic analysis

Benefits

Better zonal isolation

Reduced sustained casing pressure

Reduce expensive remediation operations

Overall well integrity

Image from www.swn.com

Phase 2 – Further Information

www.rpsea.org

Article in the Oilfield Technology Magazine (September 2013)

“The Devil is in the Details”

In future:

– Technical papers

– Seminars (Private and Public)

– Conference presentations

– Journal articles

THANK YOU www.CSI-tech.net