Dual-string barrier evaluation

Assess A- and B-annulus with Epilogue evaluation without removing the inner pipe during well decommissioning

Overview

Simultaneously evaluate the A- and B-annulus to reduce P&A costs

During the plug and abandonment (P&A) well decommissioning, conventional barrier evaluation operations require removal of inner pipe (casing or tubing) to evaluate the B-annulus and assess well integrity. This traditional approach to barrier or cement evaluation may take several days per well, depending on the operational complexity—increasing rig time and costs.

With Epilogue™ dual-string barrier evaluation, you no longer have to remove the inner pipe, enabling evaluation of both the A- and B-annulus in a single run. This approach completely revolutionizes conventional operations to reduce P&A rig days, costs, and overall carbon footprint. By using rigless well integrity evaluation logging, you can use the evaluation insights in the P&A job design stage to optimize future opex and minimize contingencies.

Epilogue dual-string barrier evaluation enables A- and B-annulus barrier logging without removing the inner pipe. It provides crucial information, such as pipe-to-pipe standoff and A-annulus liquid type.

Epilogue dual-string barrier evaluation enables A- and B-annulus cement barrier logging without removing the inner pipe.

Evaluating Well Integrity

There’s a more efficient way to assess well integrity, no matter your project.

Applications

Plug and abandonment (P&A) well decommissioning
- Well integrity evaluation
- Cement evaluation
Additional applications
- Sidetrack well candidate selection
- Time optimization for drilling new wells
- Carbon sequestration time-lapse monitoring
- Production well time-lapse monitoring

Benefits

Well integrity evaluation without removing inner pipe (casing or tubing), saving time and cost

Continuous measurement of well liquid properties in A-annulus and pipe-to-pipe standoff

Industry's only simultaneous A- and B-annulus evaluation with environmental corrections: corrected bond index, segmented bond log, and 360° azimuthal maps

Features

Combines deep-array multimode sonic and multimodality ultrasonic measurements
Evaluates both A- and B-annulus in a single run—without having to remove inner pipe
Delivers multiple levels of B-annulus assessment
Applies environmental corrections for accurate data interpretation

How It Works

Obtain reliable in-place B-annulus data using deep-array multimode sonic and multimodality ultrasonic measurements

Building on years of innovative well integrity evaluation technology, Epilogue dual-string barrier evaluation is the most advanced and accurate method for imaging the annular profile in the B-annulus, overcoming crucial well conditions that may affect B-annulus interpretation.

Epilogue dual-string barrier evaluation leverages a unique combination of wireline-conveyed, deep-array multimode sonic (0.5–20 kHz) and multimodality ultrasonic (100–500 kHz) measurements. The low-frequency sonic measurement provides the B-annulus evaluation. Unlike conventional tools that generate only monopole sonic measurement, multimodality ultrasonic measurement from Epilogue dual-string barrier evaluation provides crucial information such as pipe-to-pipe standoff and A-annulus liquid type. The combination of multimode sonic and multimodality ultrasonic measurements provides more reliable B-annulus evaluation with radial coverage and azimuthal mapping that applies environmental corrections.

: Epilogue evaluation accurately represents same well with inner pipe (right) and without (left).

Logs derived from the same well, with (right) and without (left) the inner pipe removed, showing high data quality using Epilogue dual-string barrier evaluation.

Unique B-annulus deliverables for advanced well integrity evaluation

With the richness of deep-array multimode sonic and multimodality ultrasonic measurements, Epilogue dual-string barrier evaluation can deliver outputs at four different levels to suit your well objectives and operational requirements. The Level 1 B-annulus bond index flagging enables you to definitively evaluate the top of cement (TOC) or solids and entire intervals of poorly or moderately bonded sections. To better determine barrier quality, we recommend Level 2 for its use of ultrasonic measurement to apply environmental corrections. The Level 3 segmented bond log derived independently from the eight azimuthal receivers and monopole transmitter provides the bond quality around the casing. Our most advanced Level 4 deliverable provides 360° high-resolution images to evaluate the B-annulus.

Table of the four levels of Epilogue dual-string barrier evaluation for B-annulus deliverables.

Deliverables from deep-array multimode sonic and multimodality ultrasonic corrected measurements.

Epilogue dual-string barrier evaluation deliverables from both deep-array multimode sonic and multimodality ultrasonic measurements, corrected for wellbore environment effects of pipe-to-pipe standoff and varying liquid density in the A-annulus.