Downhole signaling system

A method of logging a well being drilled by using a drilling fluid in a tubular member suspended in the wellbore, which comprises:

• a. stopping the circulation of drilling fluid including closing the upper and lower ends of said tubular member, the step of closing the lower end of said tubular member includes preventing flow of fluid through the main flow path in either direction through said lower end;
• b. measuring a downhole parameter;
• c. generating pressure variations at the bottom of said tubular member in said drilling fluid in response to the parameters measured;
• and
• d. detecting the pressure variations at the surface.

A method of logging a well drilled using a drilling fluid circulated in a tubular member suspended in the well, which comprises:

• a. stopping the circulation of drilling fluid;
• b. obtaining a downhole measurement;
• c. generating pressure variations in said drilling fluid at the bottom of said tubular member indicative of said measurement, said generating being while said circulation of said drilling fluid is stopped;
• d. detecting the pressure variations in said drilling fluid at the surface.

A system of logging a well being drilled in the earth, which comprises:

• a. a drill string suspended in the borehole;
• b. a mud pump connected to the upper end of said drill string;
• c. a fluid pressure source;
• d. means to selectively connect said mud pump or said pressure source to said drill string;
• e. a closable circulating valve at the lower end of said drill string operable to open from its closed position when the .DELTA.P across it exceeds a selected value, and will remain open at a .DELTA.P, lower than said selected value;
• f. measuring means to measure downhole parameter;
• g. pressure-variation generating means in the lower end of said drill string to generate pressure changes in response to said measuring means;
• h. detecting means at the surface to detect pressure changes of the fluid within said drill string.

A method of transmitting data from the bottom of a fluid-filled drill string in a borehole drilled in the earth, which comprises:

• a. closing said drill string to fluid passage at the lower end of said drill string and at the surface of the earth, the step of closing the lower end of the tubular member includes a step of connecting into said drill string a circulating valve that requires relatively high differential pressure to open, but will remain open with relatively low differential pressure;
• b. applying fluid pressure at the top of the closed string;
• c. generating data by measurements in said borehole;
• d. relieving said pressure in said closed string in response to said data;
• e. monitoring said pressure at the surface of the earth.

A method of logging the well being drilled by using a drilling fluid in a tubular member suspended in the wellbore which comprises:

• a. stopping the circulation of drilling fluid and closing the upper and lower ends of said tubular member, the step of closing the lower end of the tubular member including the step of connecting into said tubular member a circulating valve that requires relatively high differential pressure to open, but will remain open with relatively low differential pressure;
• b. measuring a downhole parameter;
• c. generating pressure variations at the bottom of said tubular member in said drilling fluid in response to the parameter measured;
• and
• d. detecting the pressure variations at the surface.