Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Petroleum and Natural Gas Engineering, Turkey
Approval Date: 2012
Student: BARIŞ ALP
Co-Supervisor: İSMAİL ÖZGÜR YAMAN, SERHAT AKIN
Abstract:In well cementing, the cement slurry is exposed to the conditions far different than those of ordinary Portland cement (PC) used in construction. After placement, hardened cement paste should preserve integrity and provide zonal isolation through the life of the well. American Petroleum Institute (API) Class G cement is the most common cement type used in various well conditions. Class G cement has a high degree of sulfate resistance which makes it more stable than PC when subjected to the compulsive well conditions. Ground granulated blast furnace slag (GGBFS) blended cement has a long history of use in the construction industry, but is not extensively used in well cementing applications. This study presents an experimental program to investigate the applicability of CEM I and GGBFS blended cement pastes in the well cementing industry. Class G cement and blends of CEM I and GGBFS with the proportions (80:20), (60:40), (40:60) and (20:80) are prepared with same water/cement ratio (0.44) as restricted for Class G cement in API Specification 10A to be tested. The cement pastes are cured for ages of 1 day, 7 days and 28 days at 80 ˚C which represents the condition of medium-depth oil wells. The presence of an adequate amount of GGBFS in the blend improves properties of the cement paste especially in the long term and at elevated temperatures. They are comparable to and under some conditions more preferable to the neat Class G cement paste. However, the physical properties of cement pastes prepared with neat Class G cement develop within the first day and negligible change is observed later. In order to get better hydration for the blended cement paste, the amount of CEM I must be kept more than GGBFS in the blend to provide sufficient alkalinity for the hydration of GGBFS. The conclusions obtained from this study indicate that GGBFS blended CEM I produces high quality well cementing material when compared to Class G cement.