Control of air entrainment in the cement slurry blending process is critical to cement slurry density, mixing adequacy, gas permeability and pump cavitation avoidance. These factors have a direct impact on cement job quality. This paper documents the development and field trials of an antifoamer, which significantly improves cement quality and performance. Cement quality and performance are important to ensure proper well integrity and prevent contamination of fresh water aquifers. Field case studies are included to support laboratory test results using various antifoamers.
Previous research on cement antifoamers is reviewed in detail. This paper analyzes laboratory tests that were conducted to evaluate the performance of various commonly used cement antifoamers. Laboratory tests included air entrainment tests, compressive strength tests, cement density tests, and storage stability tests. A vital part of the paper reviews field trials performed in wells utilizing Advanced Cement Antifoamer (ACA). Cement quality and performance results using ACA were compared to conventional cement antifoamers.
Laboratory cement foaming tests showed over 50% less air entrainment in cement systems compared to conventional antifoamers. Less air entrainment improves cement compressive strength and reduces the risk of remedial treatments for the life of the well. The field case studies prove that ACA provided over 50% less air entrainment and improved cement density control compared to conventional antifoamers used at twice the concentration. This allows operators to reduce well completion costs by using half the concentration. Liquid defoamer does not need to be added during the cement treatment. The use of ACA resulted in reduced risk and liability of low quality cement from improper cement density control using conventional antifoamers.
This paper provides detailed information on this innovative cement antifoamer. ACA was designed with a unique chemistry that significantly reduces air entrainment, while using a smaller dosage compared to commonly used alternative products. This performance was validated in various cement systems and a wide range of surface and downhole well conditions.