Single phase sampling apparatus and method

A formation fluid sample bottle comprising:na cylindrical tube with an enclosed top end and an open bottom end;a sample piston slidingly inserted into said cylindrical tube to form a sample chamber inside said cylindrical tube between said enclosed top end and said sample piston;a charging piston slidingly inserted into said cylindrical tube between said sample piston and said open bottom end to form a pressurized gas chamber inside said cylindrical tube between said sample piston and said charging piston; andan end cap fixed to said open bottom end;wherein:said charging piston includes a valve to allow the introduction of a pressurizing gas into said pressurized gas chamber.

A single phase formation evaluation tool comprising:nat least one formation fluid sample bottle with an enclosed top end, an open bottom end and an axial bore extending through said formation fluid sample bottle;a sample piston slidingly inserted into said axial bore of said formation fluid sample bottle to form a collection chamber within said axial bore, between said enclosed top end and said sample piston;a charging piston slidingly inserted into said axial bore of said formation fluid sample bottle below said sample piston, to form a pressurized gas chamber within said axial bore, between said sample piston and said charging piston; andan end cap fixed to said open bottom end of said formation fluid sample bottle.

A pressurizing piston for use in collecting formation fluid samples downhole and maintaining the pressure of the sample above the bubble point of the sample, comprising:na cylindrical main body with a distal end, a proximal end and a threaded axial bore;a check valve inserted into said axial bore at said distal end of said main body;a plunger with a narrowed diameter distal section, an open proximal end, an axial bore, an outer circumference with at least one O-ring located at said outer circumference, and threads located on said outer circumference engaged to said cylindrical main body threaded axial bore; anda release plug inserted into said plunger open proximal end to seal off said plunger axial bore.

A method for downhole fluid sample collection comprising the steps of:nproviding a tube with a first end and a second end, and a first piston and a second piston located within said tube;inserting pressurized gas in the space between said first and second piston;lowering the tube downhole;collecting a formation fluid sample in the space between the first end of the tube and said first piston;raising said tube with said formation fluid sample.

A method for extracting a single phase fluid sample from a wellbore formation and maintaining the sample in a single phase, comprising the steps of:nforcing a sample piston and a charging piston together within a formation fluid sample bottle to purge any existing gas from a pressurized gas chamber;attaching a pressurized gas source to said charging piston;forcing pressurized gas through said charging piston into said pressurized gas chamber;removing said pressurized gas source from said charging piston. inserting said formation fluid sample bottle into a formation evaluation tool;lowering said formation evaluation tool into a wellbore to a desired formation depth;allowing hydrostatic pressure from said wellbore to force said charging piston toward said sample piston to further pressurize said pressurized gas;pumping formation fluid into said single phase collection apparatus;raising said formation evaluation tool; andremoving said single phase collection apparatus from said formation evaluation tool.