Offshore Industry Gets a Fresh Look at Foamed Cement

Abstract

Foamed Cementing An ongoing research project started nearly 3 years ago by the US Department of Energy’s National Energy Technology Laboratory (NETL) is shedding new light on what really happens to foamed cement as it is pumped deep down offshore wells during completions. The genesis of the research was the 2010 subsea blowout of the Macondo well in the US Gulf of Mexico (GOM) that destroyed the Deepwater Horizon drilling rig and claimed 11 lives. In the aftermath, the industry faced tough questions about the limits of its technology and the US government tapped NETL to improve the safety of offshore development. After 6 months of interviewing experts in the offshore industry, lead researcher and NETL scientist Barbara Kutchko, who served as an objective expert in the federal litigation over the Macondo incident, decided to focus on foamed cement based on the clear need for more information about how the technology performs outside of the laboratory. “I knew there was a big issue with foamed cement,” Kutchko said. “There was not a lot of research behind it. Foamed cements are mixed under atmospheric conditions, yet there was little known about its properties in the wellbore.” Cement specialists who are lending their expertise to the research said initial findings confirm long-held theories about how the 25-year-old technology performs. As the work progresses, they also said it may result in improvements in how foamed cement is made and applied. Among the things that the research has proved thus far is that as the density of the bubbles inside the foamed cement varies, so does its strength. When the bubbles are smaller, the chances of them joining together to form a larger bubble is less likely, resulting in higher quality and stronger cement. Foamed cement was first introduced in the early 1980s as a low-density substitute for conventional cement and can be pumped more easily down deep wells. In the offshore environment, where deck space and weight are always at a premium, lighter-weight foamed cement has also greatly improved the logistics of completing subsea wells.