WG on Composite Cements: Motion to API SC10 for adding a new composite basic cement (Class F?) to API Spec 10A New Orleans, January 2013, Heiko Plack

Page 2 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012  Amendment of Clause „Classes and grades“ –new Subclause + wording for „Class F“  Amendment of a new Clause „Constituents (alternatively: „Additives“, or „Secondary Materials“, or else) –Specification and characterization of those „constituents“ which can be used for oil well cements  Amendment of Clause „Chemical requirements“ –for Class F  Amendment of Clause „Physical and performance requirements“ –for Class F Content

Page 3 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May xClass F This product is obtained by intergrinding Portland cement clinker and one or more forms of calcium sulfate with silica as specified in Clause xy, or by subsequent blending of separately produced Portland cement with separately ground silica flour as specified in Clause xy. To the manufacturers discretion another constituent (additive) as specified in Clause xy can be interground or interblended. This product is intended for use as a basic well cement and is available in O, MSR and HSR grades, depending on the C3A content of the Portland cement clinker being interground or Portland cement being interblended to the product. In case the CaO to SiO2 mole ratio of the Portland cement and silica component of the product is less than 1,05 the product is considered as being more stable against a strength retrogression at temperatures higher than 105°C (220°F). Clause Classes and grades

Page 4 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Intentionally and based on the experience from the construction industry both options for production are mentioned respectively permitted: -joint grinding of components in a finish mill (i.e. Italcimenti „Geoterm“), and -separate production / processing of components and subsequent high precision blending (i.e. „Dyckerhoff HT Basic Blend“) A second non-Portland constituent may help to improve performance properties of the finished cement, i.e. an extender for improving free fluid respectively slurry stability. At this stage and following SC10‘s guidelines only pozzolanic materials are permitted (see proposal on following slides for a new clause „Constituents“). There are already O&G operators using a blend of API cement and silica for all well sections from the top to the bottom. Thus such a composite cement has proven already the potential of being a real basic cement. Preventing strength retrogression effects at > 110 °C static temperatures has traditionally been the main reason for adding silica and should therefore also be mentioned here. Likewise this extents the “application window” of such a basic cement beyond what is currently provided by Classes G and H. Clause Classes and grades - comments

Page 5 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May x.yConstituents 4.x.y.1Silica Silica is synonymous with silicon dioxide (SiO2). Silicon and oxygen are the two most abundant elements in the earth’s crust. Silica is commonly found in nature as sand. Silica exists in many different forms that can be crystalline as well as non-crystalline (amorphous). The term silica in the context of this specification refers to crystalline silica only with a silicon dioxide content of minimum 90%. Silica flour or processed silica refer to crystalline sand being ground to a certain fineness. In well cementing at static temperatures beyond 105°C (220°F) finely ground crystalline silica flour, when blended to Portland cement, chemically reacts with the cement during hydration. This helps preventing compressive strength retrogression and stabilizes permeability of hardened cement. Clause 4.x.y Constituents (1/5)

Page 6 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May x.y.2Pozzolanic materials 4.x.y.2.1General Pozzolanic materials are natural substances of siliceous or silico-aluminous compositions or a combination therof. Although fly ash has pozzolanic properties, it is specified in a separate clause (see 4.x.y.3). Pozzolanic materials do not harden themselves when mixed with water, but when finely ground and in presence of water, they react with dissolved calcium hydroxide (Ca(OH)2) to form strength-developing calcium silicate and calcium aluminate compounds. These components are similar to those which are formed in the hardening of hydraulic materials. Pozzolanas essentially consist of reactive silicon dioxide (SiO2) and aluminium oxide (Al2O3). The remainder contains iron oxide (Fe2O3) and other oxides. The proportion of reactive calcium oxide for hardening is neglegible. The reactive silicon dioxide content shall be not less than 25% by mass. Pozzonlanic materials shall be correctly pepared, i.e. selected, homogenised, dried, or heat treated and comminuted, depending on their state of production or delivery. Clause 4.x.y Constituents (2/5) Source: EN : 2000 Cement, Part 1 : Composition, specification and conformity criteria for common cements

Page 7 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May x.y.2.2Natural pozzolana Natural pozzolanas are usually materials of volcanic origin or sedimentary rocks with suitable chemical and mineralogical composition and shall conform to 4.x.x x.y.2.3Natural calcined pozzolanas Natural calcined pozzolanas are materials of volcanic origin, clays, shales or sedimentary rocks, activated by therma treatment and shall conform to 4.x.y.2.1. Clause 4.x.y Constituents (3/5) Source: EN : 2000 Cement, Part 1 : Composition, specification and conformity criteria for common cements

Page 8 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May x.y.3Fly ashes Here the stipulations of either ASTM C 618 "Fly Ash and Raw or Calcined Natural Pozzalan for Use as a Mineral Admixture in Portland Cement Concrete“ or EN : 2000 Cement, Part 1 : Composition, specification and conformity criteria for common cements, Clause could be included, preferably somehow adjusted in wording to match the specifics of well cementing Part of Lafarge proposal? Clause 4.x.y Constituents (4/5)

Page 9 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 When adding composite cements to API Spec 10A is deems necessary to specify also the used secondary materials („constituents, or „non- Portland cement additions), at least to the extent being important for the use in well cements (applications). SC 10 during past meetings made decision to limit for the time being standardization efforts on “composite cement” on silica and pozzolana materials as non-Portland cement additions. These materials are already widely used for well cementing. A new clause for “constituents” at this stage therefore only refers to silica, natural pozzolanas and fly ash. However, when further developing API Spec 10A, new sub-clauses for other secondary constituents could easily be amended at a later stage (i.e. for blast furnace slag, burnt shale, silica fume, limestone, etc.). Clause 4.x.y Constituents - Comments(5/5)

Page 10 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Considered as a „basic cement“ Constituents: Portland cement (or clinker) + silica flour + (not mandatory) natural pozzolan or fly ash Mix water, % mass fraction of cement:42% –Free fluid: < 5,9% –API Schedule 5 thickening time: 90‘ < TT < 120‘ –Max. consistency 15‘ – 30‘:< 30 Bc –Compressive strength 700 psi No chemical requirements to be specified, but: –Classification as MSR or HSR grade possible if Portland clinker or cement used complies with MSR or HSR requirements as specified for Classes G/H –Calculation of CaO/SiO2 mole ratio ( 110 °C BHST) Clause „Chemical requirements“ and „Physical and performance requirements“ – Class F General: Physical & performance requirements: Chemical Requirements:

Page 11 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Clause „Chemical requirements“ and „Physical and performance requirements“ – Class F – comments (1/3)  Physical requirements were derived from comprehensive laboratory testing of numerous blends consisting of (see presentation H. Plack on API Conference in Denver, Summer 2012): –different Portland cement types (Classes) of different fineness and reactivity, –silica flours with differing fineness and –different water-to-blend ratios  Standardization efforts target on specifying another „basic“ cement, and not a „special cement“, e.g. lightweight cement (covered by Lafarge NA proposal)  Specified w/c ratio = 0,42 = slurry density for performance testing (application) is > g/cm3

Page 12 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Clause „Chemical requirements“ and „Physical and performance requirements“ – Class F – comments (2/3)  Secondary materials / constituents do slightly affect the slurry density because their absolute density is less than Portland cement (Class G 3,18 g/cm3, silica 2,65 g/cm3, nat. pozzolan 2,57 g/cm3)  Most important performance requirements identified as –Free fluid (slurry stability) –Max. consistency 15 – 30‘ („rheology“) –Thickening time Schedule 5 („pumping time“), range of 90‘ to 120‘ (consistency“) –Compressive strength („later“ strength)

Page 13 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Clause „Chemical requirements“ and „Physical and performance requirements“ – Class F – comments (3/3)  For discussion: Specifying –content of Portland cement? Minimum content actually set by minimum strength –content of silica? Actually not needed when stating CaO/SiO2 mole ratio. However, could be done as %BWOC, e.g. API Class F(35) –type of other non-Portland constituent? Maybe applying the EN abbreviations, e.g. API Class F(35)-P (or –Q, or –V)? P = natural pozzolana; Q = natural calcined pozzolana; V = siliceous fly ash

Page 14 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 API Winter Meeting 2013 in New Orleans: Discuss this as a proposal. Get approval to circulate this to SC10 members right after the Winter Meeting for final comments (deadline for comments end of May 2013). Summer Conference 2013: Summarize, assess and consider received comments (if persuasive) on the SC10 meetings. API ballot for an addendum to API Spec 10A (Class F?) right after the summer meeting? Possible Road Map

Page 15 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Test Results

Page 16 API SC 10 Denver, June 2012 – Composite Cement Testing | H. Plack | May 2012 Components Involved (Characterization)