Formation fluid sampling and hydraulic testing tool

A method of drilling and sampling with a drilling apparatus that includes a drilling string comprised of a drilling pipe and a drilling bit, said method including the steps of:

• providing a formation fluid sampling and hydraulic testing tool that includes:
• an outer tube disposed between said drilling pipe and said drilling bit, wherein said outer tube is provided with a plurality of through holes for receiving formation fluid into said outer tube for the purpose of collecting a sample of the fluid and imposing a hydraulic stress on a formation, and wherein opposite ends of said outer tube are open;
• an inner tube disposed within, and spaced from, said outer tube to form an annular space between them, wherein said inner tube is provided with a plurality of through holes disposed at one end of said inner tube and adapted to communicate with said annular space;
• means for closing off or releasing said through holes of said inner tube;
• means for sealing said annular space from said open ends of said outer tube;
• and first and second valve means for establishing or closing off communication between an interior of said inner tube and said open ends of said outer tube;
• for a drilling operation, conveying drilling fluid through said inner tube to said drilling bit for lubricating the latter and removing formation cuttings from a borehole while drilling and for conditioning said borehole, wherein said drilling fluid causes said means for closing off or releasing said through holes of said inner tube to close off such through holes, and further causes said first and second valve means to open;
• and
• for a sampling operation, terminating said drilling operation, wherein said first and second valve means close, whereupon drilling fluid is pumped out of said drilling string via said pumping mechanism to create an underpressure and cause said means for closing off or releasing said through holes of said inner tube to release such through holes, thereby allowing formation fluid to be drawn through said through holes of said outer tube into said annular space, through said through holes of said inner tube and into the interior of said inner tube, and from there into said drilling pipe and to a fluid sampling collection site.