well bore whereby the undesirable migration of fluids between zones or formations penetrated by the well bore is prevented.
In a deep, high temperature well bore penetrating weak formations, the cementing of a pipe string in the well bore is often difficult and characterized by lost circulation during cementing and gas migration through the resulting cement sheath. These problems are principally caused by the use of a cement slurry having insufficient fluid loss control and using an aqueous spacer between the drilling fluid and the cement slurry which does not adequately remove drilling fluid from the pipe surfaces and the walls of the well bore. Further, at the high temperatures encountered, when an oil based drilling fluid is used and the aqueous spacer mixes with oil on the wallslack of vitamin E -- by drawing andcomparing the blood of sick bats and healthy bats.

With bat research still in its infancy, there is much more to be learned bystudying the flying mammals, Heard said.

"Bats make up the second-largest mammalian order, but they haven't been acharismatic animal in terms of drawing research funding until veryrecently. A lot of research in the conservation field goes to gorillas andother charismatic animals," Heard said. "But animals that people don'tperceive to be 'pretty' in an anthropomorphic way are frequently neglectedin terms of research, bats being a classic example of that.

"Fortunately, people have been finding that bats are a very importantcomponent of many ecosystems of the world."

Old World fruit bats are found in Africa, Asia and the Indian Oceanislands. In the rain forests