re Oil Well Cement

Dear Stephenb,

Thanks for sharing the information on Oil Well Cement.Could you please also inform critical moduli values of Raw Meal or Kiln Feed for making G type Oil Well Cement both for MSR & HSR?

Regards,

Raj Sahu

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re Oil Well Cement

You need to look at the calculated C3S and C3A values for your raw meal which will give you an indication of what your clinker will look like.

For MSR:

C3A:  3-5%

C3S: 35-37%

For HSR:

C3A: 0%-1.25%

C3S: 38-41%

Thanks.

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re Oil Well Cement

Dear Mr.Raju Sahu,

This is further to the query for requirements for the moduli values in clinker for OWC Class G production. The API 10 A, 24^th Edition which is the latest specification classifies the OWC cement into six types of Cements called as Class A, Class B,Class C, Class D, Class G & Class H. The Class A is the ordinary Portland cement type used for general purpose similar to ASTM Type 1 cement and the other cement which is widely used is the Class G well cement a basic well cement which comes in two classes namely Moderate Sulfate Resistant Grade (MSR) &
High Sulfate Resistant Grade(HSR).

The API 10A requirements for OWC Cement Class ‘G’ MSR is

C₃S = 48 % Min to 58% Maximum

C₃A = 8 % Maximum

The API 10A requirements for OWC Cement Class ‘G’HSR is

C₃S = 48 % Min to 65 % Maximum

C₃A = 3 % Maximum

From the above it is clear that we require higher C₃S for which we require high grade limestone and high grade Iron Ore so as to meet low C₃A requirements. The Clinker thus produced should have low free lime with maximum of 0.5 %  as higher free lime content will lead to shorter thickening time and it also should not be over burnt as it could have adverse effect on the rheological properties of the OWC cement produced. There is a separate chapter on Oilwell cements in Lea's book of Cement Chemistry ( Chapter 14 - Special Cements by John Bensted) which throws more light in the manufacture and rheological properties of OWC cement.

So normally we maintain the  Kiln Feed LSF in the range of 95-97, SM in the range of 2.3-2.5 and AM in the range of 0.65-0.70 for HSR variety of OWC Class G cement. If the burnability
is good then you can increase the C₃S content accordingly.

Hope it is clear,

Regards,

Arvind

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re Oil Well Cement

Dear Arvind,

Many thanks for appropriate reply.Could you please share your experience on the following points of OWC?

1.Factors on whih thickening time depend

2.Is there any data on  optimum Alite & Belite crystal grain size  of a typical Class G-HSR OWC?

3.What type of set regulator -Gypsum used ?

Regards,

Raj Sahu

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