Technique and apparatus for use in well testing

A method usable with a well, comprising:

• communicating fluid from the well into a downhole chamber in connection with a well test;
• monitoring a downhole parameter responsive to the communication of the fluid to determine when to close the chamber;
• and
• closing the chamber in response to the monitoring, comprising isolating the chamber from a bottom hole pressure in the well wherein the parameter comprises an indication of at least one of the following:
• whether a mechanical object moved by the flow has reached a predetermined height in the chamber;
• whether a time signature of the movement of a mechanical object substantially matches a predetermined pattern;
• whether a frequency signature of the movement of a mechanical object substantially matches a predetermined pattern;
• whether a velocity of the mechanical object has reached a predetermined value;
• whether a time signature of a velocity of a mechanical object substantially matches a predetermined pattern;
• whether a frequency signature of a velocity of a mechanical object substantially matches a predetermined pattern;
• whether a time rate of change of the velocity of a mechanical object has reached a predetermined value;
• whether a time signature of a time rate of change of the velocity of the mechanical object substantially matches a predetermined pattern;
• and whether a frequency signature of a time rate of change of the velocity of the mechanical object substantially matches a predetermined pattern.

A system usable with a well, comprising:

• a tubular member including a chamber;
• a valve disposed in the tubular member to control fluid flow from the well into the chamber in connection with a well testing operation;
• and
• a circuit to receive an indication of a measurement of a downhole pressure parameter responsive to the fluid flow and to control the valve to selectively close the valve in response to the measurement to isolate the chamber from a bottom hole pressure in the well.

A system usable with a well, comprising:

• a tubular member including a chamber;
• a valve disposed in the tubular member to control fluid flow from the well into the chamber in connection with a well testing operation;
• and
• a circuit to receive an indication of a measurement of a downhole parameter responsive to the fluid flow and control the valve to selectively close the valve in response to the measurement to isolate the chamber from a bottom hole pressure in the well wherein the valve is located near a lower end of the chamber and the system further comprises:
• another valve located near an upper end of the chamber.