• Skip to main content
  • Skip to primary sidebar
  • Skip to footer
  • Primary Cementing
  • Remedial Cementing
  • Plug Cementing
  • Job Execution
  • Post-job results interpretation
  • Equipment
  • Laboratory
  • Mission
  • About
  • Contact and Questions?
  • My Cementing Challenges

Better Well Cementing for ALL

The Leading Online Support Hub for Better Oil Well Cementing.

Max Out Your Cement Coverage

February 12, 2022 By Lenin Diaz 4 Comments

Max Out Your Cement Coverage

If we consider the main variables to ensure proper mud in hole replacement with cement: stand-off, fluids rheology (friction pressure hierarchy) and placement regime (as related to pumping rate); the amount of cement left in the hole (cement coverage), if no losses, quickly reduces (leading to increase cement returns, either to surface or above the LH) when these are not properly optimised. The volume of mud that is left undisplaced in the hole in the areas of lower annular velocity or requiring higher friction pressures is basically reducing the volume of fluids in motion, like the hole is effectively smaller, which can be defined as effective capacity.

Additionally, cement contamination with fluids inside the casing (on the way down, like lack of bottom plug) and in the annulus derived from fluids intermixing will impact the quality of the cement (lower its density) leading to delayed and reduced compressive strength. Normally, UCA are run on the pure slurry, but if cement is contaminated this testing condition doesn’t exist (no pure cement in the hole) resulting in a wrong reference for WOC. Taking the contamination profile from software simulation, the CS test is better run including the contaminating fluid (typically a mixture of mud and spacer) across the area where want to see the best cement.

The difference between reduced effective capacity and contamination is that effective capacity is caused by unmovable fluid (mud) while contamination is the intermixing between moving fluids. The absence of bottom plug, depending on casing size and depth, will lead to fluids intermixing before exiting the shoe (basically all we do to maximize cement coverage in the annulus in terms of fluids rheology – fluids going up – will act against us inside the casing – fluids flowing down) causing longer cement presence (contaminated) in the annulus with lower quality.

Longer cement lenght can cause higher ECD and losses

Our objective in well cementing is ultimately zonal isolation, this is achieved by maximizing not only cement presence but also as good cement quality as possible.

Let me know any question or comments

Cheers

L. Diaz

Related posts:

  1. Cement, Spacer, all there. But where’s the wiper plug?
  2. Workover Cementing Techniques 2: Squeeze Cementing
  3. Liner Cementing Challenges and Solutions
  4. Gas migration and surface casing vent flow (SCVF) issues and prevention

Filed Under: General, Primary Cementing Tagged With: best practices, cementing, primary cementing

Article Posted By:

Lenin Diaz is an oil industry specialist with 26 years of technical and operational expertise in fluids, cementing, water control and shut-off. A distinguished track record spanning BP, Schlumberger, and NAPESCO. Lenin lives in Tenerife, Spain and is the creator of this website. Read More…

Reader Interactions

Comments

  1. Eliseo Garza says

    May 3, 2022 at 6:34 pm

    Hello sir. I would like the cement plug mixing calculator please. Eliseogarza00@gmail.com

    Reply
    • Lenin Diaz says

      June 1, 2022 at 1:18 pm

      Hi Eliseo
      Please send me an email to dlenin@hotmail.com
      And I will explain

      Reply
  2. Hou Linwei says

    June 14, 2022 at 12:21 am

    Hello, sir I wonder if we keep high pressure after bump the plug, will the displacement fluid tempeture rise? If the temperature rise to some level and transmit to slurry, the thicking time will become shorter. Since the slurry will become hard in very short time, there will be no gas/oil invasion into slurry which will make cementing quaility better. Is this plan feasiable?

    Reply
    • Lenin Diaz says

      July 31, 2022 at 6:37 am

      Hi Hou,
      The temperature will increase from circulating temperature to formation’s temperature (as per geothermal gradient), this the main derived increase.
      Now, pressure indeed is an “accelerator” to cement hydration, not as effective as temperature itself, but what it does while favouring the hydration process, which is an exothermal reaction can indeed increase temperature, but not higher than the surrounding temperature, and not necessarily increasing the heating rate
      Cheers
      L. Diaz

      Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar

Trango DEPM is a team of Oil&Gas professionals with broad experience in the O&G industry. Working on onshore and offshore projects around the world, including most vivid and challenging areas as Saudi Arabia, US Marcellus shale and North Sea, but also small on small projects, requiring individual approach, we are well equipped to help you plan, budget, implement and execute your drilling project successfully. We also cooperate with number of other professionals with experience in such areas as drilling, geology, geophysics, procurement or logistics. This allows us to fully run your project or just support you in desired areas of expertise, depends on you needs.

How I survived the 2016 Downturn and the current difficult times?

Find the content you need

Archives

24 Page Free Primary Cementing Guide

Click this image to take a look. It is comprehensive and easy to follow too!

In 2016, I launched Better Cementing for All. Now, I want to keep it alive.

For more than 26 years, I have worked in oil well cementing, offering my services to some of the largest oil corporations in the world and committing myself to excellence. I have mastered my role, and in doing so, I have accrued a skill set that is extremely valuable to my fellow professionals. Eager to do whatever I can to help them, I have owned and operated Better Cementing for All since 2016.
Let me tell you what Better Cementing for All does and what it means. A resource for all oil industry professionals and for cementers both established and prospective, this is a non-profit resource that I established in order to do nothing but serve and make an impact on people who are looking to build careers for themselves in cementing.
From primary cementing to remedial cementing to plug cementing to post-job results, I do it all, and I am comfortable answering in-depth questions about each and every one of these topics. I also offer tools and tips for jobseekers, general self-development advice, and guidance for equipment choices. TO put it simply, this is the go-to spot for anyone who wants to know anything about oil well cementing.
The problem, however, is that covid-19 has made the structure of the website seem untenable. I am trying to juggle the work that I do and my non-profit initiatives and finding it all unhealthy and unsustainable. I want to keep Better Cementing for All up and running, but to do that, I need your help.


My NEW introductory VIDEO

Recent Posts

Cementing Flowchart

In recent weeks, I received some reader requests to include cement job processes or procedures as … [Read More...] about Cementing Flowchart

Cementing. Challenges across permeable zones

This article will provide you with some actionable suggestions for cementing across permeable zones. … [Read More...] about Cementing. Challenges across permeable zones

Forensic Cementing

Forensic is a term usually associated with crimes. Criminal forensics is the use of science to … [Read More...] about Forensic Cementing

Cement Slurry design Basics

First, here is a handy table to simplify the process of cement slurry design: Additive … [Read More...] about Cement Slurry design Basics

well cementing pre-job cement challenge question

Remedial Cementing with Coiled Tubing (animation)

Though I am far from being an animation expert, during my training courses I have always wanted to … [Read More...] about Remedial Cementing with Coiled Tubing (animation)

Illustration: cement substitutes to provide zonal isolation

Plug and Abandonment Webinar (Español)

I am very happy to present here a webinar on plug and abandonment on well cementing for my … [Read More...] about Plug and Abandonment Webinar (Español)

Need urgent help?

WhatsApp me at this number: +34 657 07 01 78

Footer

Recent activity

Visit our latest posts and help others by adding a comment.

Make your contribution and help keep Better Cementing for All alive!

Now more than ever, we are facing a loss of expertise in our industry, and Better Cementing for All is a unifying force, featuring interactions among industry professionals, knowledge sharing through posts, and other valuable pieces of content that we need to preserve.

Recent Comments

  • Merit on Cementing Equipment from Serva SJS Limited
  • Lenin Diaz on Cementing Equipment from Serva SJS Limited
  • Lenin Diaz on All you need to know about Bentonite in Cement Slurries
  • Lenin Diaz on Cementing Equipment from Serva SJS Limited
  • Lenin Diaz on Cementing Equipment from Serva SJS Limited
  • Lenin Diaz on Suicide Squeeze Cementing: risky but valid
  • Samuel Bekele Bedjiga on All you need to know about Bentonite in Cement Slurries

Recent Posts

  • Max Out Your Cement Coverage
  • Cementing Flowchart
  • Cementing. Challenges across permeable zones
  • Forensic Cementing
  • Cement Slurry design Basics
  • Remedial Cementing with Coiled Tubing (animation)
  • Plug and Abandonment Webinar (Español)
  • Webinar series (II). Quality Assurance in Cementing Operations (Spanish)
  • Webinar series (I). Log interpretation (Spanish)

Submit your email

&middot Better Well Cementing For All is owned by L. Diaz © 2023 &middot TOS & Privacy Policy &middot Web Design &middot