Credit: Boston.com
The AP is reporting that there have been numerous problems and failures related to the use of cement in sealing oil wells in the Gulf of Mexico. One current theory is the the Deepwater Horizon spill also may have been caused by problems with cement.
And, apparently federal regulators never set standards about what type of cement(s) should be used:
The drillers are urged to simply follow guidelines of the American Petroleum Institute, an industry trade group.
Far more stringent federal and state standards and controls exist on cement work for roads, bridges and buildings.
[. . . ]
An AP review of federal accident and incident reports on offshore wells shows that the cementing process has been implicated at least 34 times since 1978. Many of the reports, available from the U.S. Minerals Management Service that regulates offshore wells, identify the cause simply as “poor cement job.”
[ . . . ]
Reports by MMS, a branch of the Interior Department, also provide evidence of the role bad cement work has played in accidents. One study named cementing as a factor in 18 of 39 well blowouts at Gulf rigs from 1992 to 2006. Another attributed five of nine out-of-control wells in the year 2000 to cementing problems.
[ . . . ]
Halliburton, which had the Deepwater Horizon job, mixes in nitrogen to make its slurry more elastic. The nitrogen also helps create a lightweight cement that resembles a gray foamy mousse and bonds better to the casing.
But the recipe also depends on the job, because cement must respond to varying pressures and temperatures. Cement contractors work closely with oil and gas companies on the formulas for individual wells. The oil and gas companies have the final say on what is used.
ACerS Cements Division is partnering for an upcoming meeting July 11-13 with the Center for Advanced Cement-Based Materials. As one of the big cements research centers in the U.S., it’s good to see ACBM and other colleagues weigh in on this:
In the wake of the accident, some experts support mandatory uniform cement standards for underwater wells. “When you change the composition, it should meet a certain standard. Such standards exist for the building construction industry,” said Surendra Shah, Northwestern University engineering professor and director of the Center for Advanced Cement-Based Materials at Evanston, Ill.
[ . . . ]
Many construction projects use concrete hardened with sand and gravel aggregate, but cement is the glue that holds it together. On federal projects, “just about everything is regulated, from the thickness of the concrete, to the strength of the concrete, to the type of aggregate that’s used,” said Brian Turmail, spokesman for the Associated General Contractors of America.
I suspect this topic may be hashed over at the ACerS Cements Division/ACBM meeting.