oil

April 10, 2021
Micro-annulus

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
Cube

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
Welan

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 […]
September 17, 2019

Geopolymer Patent Publications

Discussion The graph above shows the number of published geopolymer related patent applications and granted patents per year for the last 30 years.   The methodology I […]
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 […]
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 […]
July 17, 2018
Hydration Reactions

Cement chemistry and hydration reactions

Shrinkage and expansion of Portland cement systems The chemical shrinkage of hydrating Portland cement systems, the resulting bulk volume changes and the potential consequences for hydraulic […]