Lafarge Oil & Gas Global Well Cement Standards Russian GOST 1581-96 by Larisa Markina, Bill Carruthers, Gregory Bernstein API 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 cements ANSI/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 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

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

GOST 1581-96 Physical Characteristics

Table 4 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 3.5 Cement mortar consistency after 15 —30 min of test mode, Вс 30 Time of thickening to consistency 100 Вс, min 90 120 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 Mass concentration of chlorine- ion С1-, no more than 0,10 Mass concentration of alkaline oxides’ sum in conversion to Na2O, no more than

GOST 1581-96 Requirements for materials - clinker Table 4 GOST 1581-96 Requirements for materials - clinker

Value of cement mortar density for cement type III, g/cm3 Table 3 Table 4 GOST 1581-96 Requirements for materials – gypsum and additives Table 3 Value of cement mortar density for cement type III, g/cm3 lightened weighted designation of density 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

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

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

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

Summary 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

Lafarge Technical Director – Lafarge Oil & Gas Authors: Larisa Markina Senior Project Manager – Lafarge Oil & Gas –Russia larisa.markina@ru.lafarge.com Tel: +7(495) 926 71 31 Ext. 6584 Bill Carruthers Lafarge Technical Director – Lafarge Oil & Gas Bill.Carruthers@Lafarge-NA.com Tel: 936-447-4959 Gregory Bernstein Business Development Director – Lafarge Oil & Gas Gregory.Bernstein@Lafarge-NA.com Tel: 703-338-2671