Subsurface formation testing apparatus

Apparatus for measuring characteristics of connate fluid samples from subsurface earth formations traversed by a borehole, comprising:

• a body member adapted for placement within the borehole;
• a fluid sample probe cooperatively arranged on and extensible from said body member into the subsurface earth formations;
• sample collection means cooperatively arranged on said body member for receiving and retaining a sample of the connate fluid from the subsurface formations;
• a fluid passage coupled between said fluid sample probe and said sample collection means;
• pressure measuring means coupled to said fluid passage for measuring the pressure of said connate fluid sample, said pressure measuring means including a first pressure sensor comprising a strain gauge pressure transducer for generating a first electrical output signal representative of a first pressure measurement and a second pressure sensor for generating a second electrical output signal representative of a second pressure measurement;
• temperature measuring means coupled to said fluid passage for measuring the temperature of said connate fluid sample, said temperature measuring means generating an electrical output signal representative of said connate fluid temperature;
• and
• means for correcting said first and second pressure measurement signals of said connate fluid sample as a function of said connate fluid sample temperature to provide a temperature-corrected pressure signal of the connate fluid.

Apparatus for measuring temperature corrected pressure characteristics of fluid samples from subsurface earth formations traversed by a borehole, comprising:

• a body member for placement within a borehole;
• a fluid sample probe cooperatively arranged on and extensible from said body member;
• sample collection means cooperatively arranged on said body member for receiving a sample of fluids;
• a fluid passage coupled between said fluid sample probe and said sample collection means;
• first strain gauge pressure measuring means coupled to said fluid passage for measuring the pressure of said fluid sample and generating first electrical signals representative thereof;
• second quartz gauge pressure measuring means coupled to said fluid passage for measuring the pressure of said fluid sample and generating second electrical signals representative thereof;
• temperature measuring means coupled to said fluid passage for measuring the temperature of said fluid sample and generating a third electrical signal representative thereof;
• means for transmitting said first and second pressure measurement signals and said third temperature measurement signals, said transmitting means including a narrow-band frequency modulation transmission system;
• and
• means coupled to said transmission means for correcting said first and second pressure signals as a function of said third temperature signals to provide a temperature corrected pressure signal.