September 19, 2022

High temperature aging in non-aggressive fluids

This is the second in a series of articles that will discuss key factors to be considered when testing and evaluating durability of materials for zonal […]
November 14, 2021
Example of the test sample geometry used by Duguid.  The flat surfaces were sealed.

Long-term durability of materials for zonal isolation

With the increased interest in underground storage of carbon dioxide and high temperature geothermal wells, along with the development of new materials for zonal isolation, there […]
June 7, 2021
Test setup

The membrane test – experimental considerations

Introduction The procedure to measure the bulk volume changes of well cements under impermeable conditions (The membrane test) is described in API RP10B-5, first edition April […]
April 10, 2021

Micro-annulus – importance for hydraulic isolation

In a previous article I discussed the expected volumes, pressures, and injection rates during repairs of a micro-annulus ranging from 10 to 100 μm in thickness.  […]
April 1, 2021
By-passed drilling fluid

What is expected from the cement in cementing for the life of the well?

I gave a presentation  at a virtual event “Cement Sheath Integrity in Oil and Gas Wells: Current Challenges and Future Solutions” organised by the Ecole des […]
February 18, 2021
Cross section with micro-annulus

Micro-annulus repair

Before initiating a squeeze treatment to plug a micro-annulus between the cement sheath and either the casing or formation, it is worth considering what volumes, rates […]
December 23, 2020

Compressive strength measurements – the effect of slurry stability

Compressive strength measurements on cement systems only provide useful results for slurries that are stable, i.e. slurries that have little or no sedimentation or free fluid […]
December 19, 2020

Anti-settling additives based on biopolymers

Anti-settling agents are important, yet often over-looked, additives for the design of stable cement slurries. Two of the biopolymers the most frequently used as anti-settling agents […]
December 10, 2020
UCA Chart

Compressive strength development at high temperature

Have you wondered why, at temperatures above around 110°C, the compressive strength development of cement systems shows a decrease and then an increase, even if the […]
July 3, 2020
Bingham Fit

Rheological measurements

I have come across a couple of instances recently where rheological measurements on cement slurries did not appear to follow the correct procedure.  Surprisingly, one of […]
June 8, 2020
Slurry density

API sedimentation tests

Have you wondered why the density of the set cement may be lower than designed in high temperature sedimentation tests? Have you ever noticed that slurry […]
January 10, 2020
Gas migration

Latex additives for gas migration control

Introduction For annular gas migration to occur (red zone) three conditions must be met as shown in the diagram above.  The hydrostatic pressure (PH) in the […]
May 4, 2019

Thermoset resins: the importance of thermal properties for zonal isolation

It is important to consider the thermal properties of thermoset resins when applying them to zonal isolation applications.  The key resin properties are the heat of […]
April 10, 2019
Cycloaliphatic epoxy structire

Volume changes during setting of thermoset resins

Thermoset resins, such as polyester, vinyl ester and epoxy resins, are being used for specialised sealing applications in oil and gas wells.  Two advantages of these […]