System and method for installation and use of devices in microboreholes

A system for making measurements associated with a rock formation comprising:

• a main borehole;
• a microborehole extending from the main borehole into the rock formation;
• and
• a sensing device at least part of which is positioned in the microborehole away from the main borehole by a distance at least the diameter of the main borehole.

A system for making measurements associated with a rock formation comprising:

• a main borehole;
• a microborehole extending from the main borehole into the rock formation;
• a sampling device positioned and arranged to take a fluid sample at a sampling zone being located in the microborehole away from the main borehole by a distance of at least the diameter of the main borehole;
• and
• a packer installed in the microborehole dimensioned and arranged to hydraulically isolate the sampling zone from conditions present in other parts of the microborehole and/or main borehole.

A system for making measurements associated with a rock formation comprising:

• a main borehole;
• a microborehole extending from the main borehole into the rock formation;
• an injection device positioned and arranged to inject a tracer at an injection zone being located in the microborehole away from the main borehole by a distance of at least the diameter of the main borehole;
• and
• a packer installed in the microborehole dimensioned and arranged to hydraulically isolate the injection zone from conditions present in other parts of the microborehole and/or main borehole.

A method of installing a sensor in a rock formation comprising the steps of:

• drilling a main borehole;
• drilling a microborehole extending from the main borehole into the rock formation;
• positioning a sensing device in the microborehole so as to make a measurement at a measurement zone being located in the microborehole away from the main borehole by a distance of at least the diameter of the main borehole;
• and
• installing a packer in the microborehole to hydraulically isolate the measurement zone from conditions present in other parts of the microborehole and/or main borehole.