Lafarge Oil & Gas Global Well Cement Standards

Russian GOST 1581-96

by Larisa Markina, Bill Carruthers, Gregory BernsteinAPI Meeting

June 2012

CEMENT

API GOST

American Petroleum Institute (API) is an American National Standards

Institute (ANSI) accredited standards organization. API partners with the

International Organization for Standardization (ISO) in

development of well cement standards and other matters

GOST standards are administered by the Euro-Asian Council for

Standardization, Metrology and Certification (EASC). The national standards of Russia are GOST R

managed by The Federal Agency on Technical Regulating and Metrology

(Rosstandard)

Used worldwide GOST 1581-96 was adopted by the relevant ministries and state agencies

in Armenia, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Russia and

Uzbekistan

Main standard for well cementsANSI/API 10A (ISO 10426)

Main standard for well cements:GOST 1581-96

Test methods for I-G and I-H GOST 26798.2-96

GOST 1581-96 history

3

Well cements in Russia were first produced in the 1920s (Novorossijsk Cement Plants). Until 1940s well cements met specific customer needs (set time, strength etc) without any common standard

The first common standard for well cement was drafted and approved in 1942. GOST 1581-42 lasted without significant changes until 1963 and:

Specified 2 neat well cements for low and high temperature wells Based on the properties of Novorossijsk cement (standard at that time)

Well cement standards were developed jointly by the cement industry and the oil-gas industry in the relevant academic, technical and standard institutes

By the 1950-60s the industry realized that just 2 neat cements did not provide sufficient flexibility to deal with the varied well conditions. At this time GOST deviated from API methodology by introducing composite cements

GOST1581-63 introduced cements with additives – up to 15% of the “active” additives and 10% “inert” additive

In the 1970s industry advanced further and in addition to neat and blended cements introduced lightweight, heavy weight and other special cements. Most of these cements were added to the 1996 standard edition

The last modification is GOST 1581-96 introduced on October 1, 1998 as a state standard of the Russian Federation by Decision of Gosstroy of Russia dated April 10, 1998 № 18-31

ANSI/API 10A GOST 1581-96Only neat cements allowed (clinker

and gypsum)Allows a wide range of cements – neat, blended, lightweight and other

5 classes of neat cement with no additives of any kind (A, B, C, G, H).

The set-modifying agents can be interground or blended during

manufacture of Class D cement

Class I with no additives

Class IG no additives. Tests at 0.44 water to cement ratio

Class IH no additives. Tests at 0.38 water to cement ratio

Class II cement with mineral additives

Class III with the additives regulating cement slurry density

Class IIIA is the lightweight cement (allows weight control additives)

Class IIIB is the heavyweight cement

GOST Class 1G and 1H cements are close to API10A Class G and H. However, GOST Class 2 and Class 3 cements allow additives. GOST specifies lightweight and heavyweight cement systems - such cements are not specified by API

GOST 1581-96 Classification of standard well cements

Section 4. Classification

4.1 As to material composition the cements are subdivided into types as follows:I — well Portland cement without additives;I-G — well Portland cement without additives with normalized requirements with water/cement ratio equal to 0.44 [1];I-H — well Portland cement without additives with normalized requirements with water/cement ratio equal to 0.38 [1];II — well Portland cement with mineral additives;III — well Portland cement with special additives, regulating cement mortar density.

4.2 As to cement mortar density the cements type III are subdivided as follows: -lightened (Об); -weighted (Ут).4.3 As to application temperature the cements types I, II and III are subdivided into

cements, intended for:- low and normal temperatures (15—50) °С;- moderate temperatures (51—100) °С;- higher temperatures (101—150) °С.

4.4 As to sulfate resistance the cements are subdivided into:а) types I, II, III

- normal (there are no requirements for sulfate resistance);- sulfate resistant (СС);

b) types I-G and I-H- high sulfate resistance (СС-1);- moderate sulfate resistance (СС-2).

GOST 1581-96 Additive Requirements

5.1.3 Requirements for cement chemical parameters are given in table 5. Table 1

In percent

Additive content

Cement type

Clinker content Mineral additive Special additive — lightening (including natural pozzolanic) or

weighting I

I-G 100 Not permitted I-H II 80-94 6-20* — III 30-89 — 11-70

__________ *Additives of sedimentary origin shall not be in amount more than 10 % of cement mass

Note — Material composition is characterized by contents of Portland cement clinker and additives disregarding gypsum stone, added over 100 % of cement mass

GOST 1581-96 Physical Characteristics

Table 2 Index description Value for cement at applications temperatures

low and normal moderate and higher

type I, II

type III-0б

type I, II type III-06 type III-Ут

1 Bending strength, MPa, no less than, in age: 1 day — — 3.5 — — 2 days 2.7 0.7 — 1.0 2.0 2 Fineness of grinding *- - remains in sieve with mesh № 008 in accordance with GOST 6613,

%, no more than 12.0 10.0 15.0 12,0 12.0 - specific surface area, m2/kg, no less than 270 — 250 — 230 3 Bleeding, ml, no more than 8.7 7.5 8.7 7.5 10.0 4 Cement mortar flow, mm, no less than for cement: - non-plasticized 200 — 200 — — - plasticized 220 — 220 — — 5 Time of thickening to consistency 30 Bс**, min, no less than 90 * It is allowed to determine fineness of grinding for cement type I only in accordance with specific surface area, and for cement types I and III- Ут — only according to remains in sieve **Bearden units of consistency

GOST 1581-96 Chemical and Physical Characteristics of Class 1G and 1H (two GOST cement types directly equivalent to API Class G and Class H)

Index description Value for cement types I-G and I-H

no less than no more than

Compressive strength, MPa, after 8 hours of hardening at temperature:

38° С 2.1 -60° С 10.3 -

Bleeding, ml - 3.5Cement mortar consistency after 15 —30 min

of test mode, Вс- 30

Time of thickening to consistency 100 Вс, min

90 120

Table 4

Index description Value for cement type

I II III I-G and I-H

Loss of ignition, no more than 5.0 - 3.0

Mass concentration of insoluble residue, no more than

5.00 - 0.75

Mass concentration of sulphur oxide(VI) SO3

no less than 1.5 —

no more than 3.5 3.0

Mass concentration of chlorine- ion С1-, no more

than

0,10

Mass concentration of alkaline oxides’ sum in conversion to Na2O, no more than

— 0.75

GOST 1581-96 Requirements for materials - clinkerTable 4

5.2 Requirements for materials

5.2.1 As to chemical composition Portland cement clinker shall correspond to technological regulations. Mass concentration of magnesium oxide MgO in the clinker shall not be more than 5.0 %.

Mineralogical composition of the clinker for sulphate-resistant well cements shall correspond to the values, given in table 6.

Table 6

In percent Value for clinker cement type and

sulphate resistance Index description I, II, III I-G and I –Н

СС CC-I СС-2

Content of tricalcium silicate C3S: no less than — 48 48 no more than — 65 58 Content of tricalcium aluminate С3А, no more than 5 3 8 Sum of tricalcium aluminate С3А and tetracalcium alumoferrite C4AF, no more than

22 24 —

* Sum of tetracalcium alumoferrite and double content of tricalcium aluminate

GOST 1581-96 Requirements for materials – gypsum and additivesTable 4

5.2.2 Gypsum stone – in accordance with GOST 4013. It is allowed to use other materials, containing calcium sulphate, in accordance with corresponding normative documents.

5.2.3 Mineral additives — in accordance with corresponding normative documents.

5.2.4 Special additives (lightening and weighting), regulating cement mortar density, — in accordance with corresponding normative documents. Lightening and weighting additives shall provide production of the cement with density, indicated in table 3, and shall not cause destruction and corrosion of cement stone.

5.2.5 Technological additives, regulating main well-technical properties of the cement, and technological additives, used for grinding intensification, — in accordance with corresponding normative documents.

Content of the additives added to cement during grinding shall not exceed the values, mentioned in table 7

Table 7 In percent of cement mass

Value for additives (in conversion to additive dry substance) Cement early- retarding plasticizing hydrophobic water Grinding

type strength agent agent agent retaining intensifier, accelerator including organic

I, II, III 0.5 0.3 0.5 0.5 1.5 1.00

*Organic additives shall not be more than 0.15 %

Value of cement mortar density for cement type III, g/cm3

lightened weighted

designation of density designation of density

average density ±0.04 average density ±0.04

064 1.40 Ут0 2.00

065 1.50 Ут1 2.10

066 1.60 Ут2 2.20

УтЗ 2.30

Table 3

Table 3

GOST 26798.2-96 1G and 1H Well cements test methods

3.8.2 Procedure of cement mortar preparation Cement sample shall be prepared in accordance with GOST 26798.1.

Mass of cement and water sample, used for cement mortar preparation, shall correspond to the values, indicated in table 2.

Table 2 Cement type Water/cement ratio

W/C Water mass

mв, g

Cement sample mass, g, for one mixing in determining the time of

thickening, dehydration and strength

I-G 0.44 349 792 I-H 0.38 327 860

Water is poured into container, which shall be placed on mixer base. It is required to set rotation speed equal to (4000±200) rpm. Evenly within 15 sec it is required to pour cement sample into container, to cover container with lid and to switch to rotation speed (12000 ± 500) rpm, mixing shall continue within (35±1) sec.

GOST 26798.2-96 1G and 1H Well cements test methods

4 Determination of consistency and time of thickening

4.1 Control equipment

Consistency meter, working under higher pressure. Consistency meter is a hermetic chamber, which includes cylindrical container for cement mortar with blade mixing device. Space between container and chamber walls shall be filled with oil of viscosity from 5 up to 100 Bс (oil bath). Rotation speed of container with cement mortar is (150±15) rpm.

Consistency meter shall be equipped with heater, providing an oil bath temperature rise at a rate of 2.8 °С/min, equipment for an oil bath temperature and cement motor measuring and regulation with error no more than ± 1.7 °С, timer with error no more than ± 30 s/hr , as well as potentiometric device for determining value of cement mortar consistency.

4.2 Test preparation and testing

4.2.1 Cement mortar, prepared in accordance with 3.8.2, shall be poured into cylindrical container. During filling a container the cement mortar shall be slightly mixed in order to prevent its disintegration.

4.2.2 Container with cement mortar shall be placed in hermetic chamber and in accordance with the instruction, enclosed to consistency meter, it is required to perform further operations.

4.2.3 Time from completion of cement mortar mixing in accordance with 3.8.2 till start of test mode shall be equal to 5 min ± 15 sec

4.2.4 Testing shall be performed in mode in accordance with tables 3 and 4.

4.2.5 After 15—30 min of test mode in indications of device it is required to determine cement mortar consistency, which value shall correspond to the requirements of GOST 1581.

4.2.6 Time of cement mortar thickening is considered a time from start of test mode till moment when cement mortar reaches consistency 100 Bс.

GOST 26798.2-96 Consistometer schedule (compares with API schedule 5)

Table 3 Preliminary warming up Test mode Pressure, Temperature Conditions of Time of Operation parameters

MPa °С, reaching reaching Pressure, Temperature a test mode operation MPa °С,

parameters, min

6.9 ± 0.7 27±1 Table 4 28±1 35.б±0.7 52±1

Table 4 Time, min Pressure, MPa, Temperature, °С,

±0.7 ± 1

0 6.9 27

2 9.0 28

4 11.1 30

6 13.1 32

8 15.2 34

10 17.3 36

12 19.3 37

14 21.4 39

16 23.4 41

18 25.5 43

20 27.6 44

22 29.6 46

24 31.7 48

26 33.8 50

28 35.6 52

Summary

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Two methodologies exist in standardization of the well cements: Neat cement approach which does not allow any additives (API) Combination of neat and blended cement standards (GOST)

The neat cement (API) methodology restricts innovation and flexibility to meet various customer needs at a cement plant since it allows no additives – while technologies of blending, inter-grinding and selection of advanced ingredients to control properties of the clinker-cement systems represent perhaps the core modern expertise of Lafarge

On the other hand, a standard with too much ambiguity in cement chemical composition and properties would cause challenges to the well service companies in slurry designs

We recommend for the future API approach to combine the advantages of both methodologies. For example a standard may – as GOST – allow considerable range of the blended cement products, as long as the quality targets are well defined. GOST may consider extending the neat cements range as API

Authors:

Larisa MarkinaSenior Project Manager – Lafarge Oil & Gas –Russia

larisa.markina@ru.lafarge.comTel: +7(495) 926 71 31 Ext. 6584

Bill CarruthersLafarge Technical Director – Lafarge Oil & Gas

Bill.Carruthers@Lafarge-NA.comTel: 936-447-4959

Gregory BernsteinBusiness Development Director – Lafarge Oil & Gas

Gregory.Bernstein@Lafarge-NA.comTel: 703-338-2671