What are Lead and Tail Cement?

In some cementing operation, operators will pump 2 cement slurries, normally called “Lead Cement” and “Tail Cement”.  Both lead and tail cement have pro and con as described below.

Lead cement: Lead cement is in the top section of cement, where has lower both pressure and temperature (see figure above). It has lower density and strength than Tail cement; however, it is also cheaper than Tail cement.

Tail cement: Tail is pumped after lead cement because it must be settled at the lower section of well bore, where needs high strength cement (see figure above) . It has higher strength than lead cement, but it is more expensive than lead cement.

Ref books: Cementing Technology Books

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17 Responses to What are Lead and Tail Cement?

  1. jimmy says:

    Do we select volume(height) of Lead and tail cement slurries on the basis of loss zones? or just form the top perforation interval to csg shoe? or are there other factor(s) which are used in the selection of the lead and tail slurry volumes?

    Thanks.

    • There are several factors to select lead and tail height as follows;
      Economic of well cost
      Expected FIT at shoe
      Loss zone
      Production zone
      etc.

      I can not conclude how height of lead and tail should be because there are a lot of information that you must consider for cement design. I normally run about 1000 – 1500 ft of 17 ppg cement as tail cement and lead will be high overlap 300 ft inside previous casing shoe.

      Regards,
      Rachain J

  2. Madan Mohan says:

    Technically lead & tail slurries are designed & pumped to meet the limitations of ECD under particular downhole condition. Apart from this there are few other associated advantages of using lead-tail combinations. Further, you may interact at “cementing service@gmail.com“. Thanks.

  3. Khusan Eyyubov says:

    Could anyone tell us by which criteria the lead and tail cement height should be designed?

    • It depends on your location. Typically, top of lead cement should be 1000 ft inside previous casing shoe or 500 ft above the shallowest hydrocarbon zone. Top of tail cement should be around 1500 ft at least.

  4. deni says:

    1.whether the fragile formations were found in shallow depth only (how deep) or can be found in the deeper formations.?
    2.wether we can use the lead cement only for all depth (in what well conditions)?

    • 1. By the book, formation at shallow depth is weaker than formations at the deeper depth. However, in reality, it can happen any formation in the wellbore because we don’t know where the weakest formation is in the wellbore.
      2. You can use the single cement slurry in many cases. You need to look at the formation strength. If you have weak formation, you may run single weight slurry.

  5. deni says:

    Thanks alot for answers.
    what numbers of range for lead and tail cement in ppg or cc ?

  6. noval says:

    how is the range numbers of lead and tail cement in ppg and gr/cc?
    thanks for sharing and succes to you.

  7. Dokubo K. says:

    Good one all.
    I agree with all.
    Lead comes 1st
    Lead is lighter or less dense
    Lead is cheaper
    Lead is weaker….
    But then it has its own advantage and importance as rightly stated. It meets the formation requirement with regards ECD….

  8. magnus says:

    it true that tail cement must always be outside the internal diameter of the casing i.e. must be in the casing annulus at all times

  9. ramadan sayed says:

    thanks for all this topics but also it depend on the weak formation and the total pressure on casing shoe

  10. Mbala ebuka cyril says:

    Thanks very much for your numerous responses to the questions asked, but please I need an urgent answer,”What are the advantages of LEAD and TAIL slurry regarding to their strenght”

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