Primary Research Organization: Innotech Alberta
Start Date: August 2023
Anticipated End Date: Completed, under review
Project Summary and Scope of Work
Many manufacturers of Portland cement in North America are no longer providing API Class G cement to the energy industry. For several years, users (producers, service companies) have been requesting blends using performance-based specifications rather the API specifications (Kisiloski, 2022). A similar transition has occurred in the construction industry with a move from prescriptive specifications based on chemical and physical properties (ASTM C150) to performance-based specifications (ASTM C1157) More recently, cement suppliers are aiming to reduce the CO2 emissions during cement production by including ground limestone in neat cement (Portland-limestone-cement, PLC). This material has less reactivity than the clinker it replaces so blends are typically ground finer to maintain reaction time. For example, Lafarge’s HSL (High Sulfate Limestone) has 15% ground limestone (Kisiloski, 2022).
While primary cementing regulations are less restrictive, AER Directive 20 for well abandonment currently stipulates the use of Class G cement. Class G cement is also still noted as the most common standard for oilwell cementing world-wide.