Abstract: Method and apparatus for testing wells where extremely high temperatures and pressures are to be encountered in the zone under test. The apparatus provides means for testing and trapping samples of well fluid from the formation in the zone under test for removal from the well bore with substantial reduction in sample pressure at the ground surface. The method permits confining the well fluid under test within the well bore near the zone under test to minimize the possibility of hazardous well fluids reaching the ground surface other than as trapped samples in expandable sampler chambers or otherwise safely controlled.

Abstract: Method and apparatus for testing wells where extremely high temperatures and pressures are to be encountered in the zone under test. The apparatus provides means for testing and trapping samples of well fluid from the formation in the zone under test for removal from the well bore with substantial reduction in sample pressure at the ground surface. The method permits confining the well fluid under test within the well bore near the zone under test to minimize the possibility of hazardous well fluids reaching the ground surface other than as trapped samples in expandable sampler chambers or otherwise safely controlled.