Method and system for distributed well monitoring

A method for simultaneously monitoring multiple zones in a borehole, said method comprising:

• running a distributed pressure monitoring system with a casing within a borehole, comprising:
• strapping a multi-wire cable to the casing as it is made up and lowered into the borehole;
• mounting protectolizers onto the casing at selected intervals corresponding with the zones to be monitored;
• assembling pressure sensors within sensor housings;
• connecting the pressure sensors to the cable and mounting the sensor housings within the protectolizers;
• installing open pressure tentacles having a wire mesh hose packed with gravel onto the sensor housing while providing fluid pressure transmission to the pressure sensor through a frit and a silicone grease packed conduit;
• and
• cementing the casing and attached distributed pressure monitoring system within the borehole with a cement selected to provide less hydraulic diffusivity than that of the formation.

A method for simultaneously monitoring the formation pressure in multiple zones of a borehole, comprising:

• substantially separating formation pressure from overburden pressure by connecting the input of pressure transducers at selected zones to a pressure tentacle in the form of a gravel packed wire mesh hose;
• substantially isolating zones of a formation intersected by the borehole and adjacent pressure sensors, comprising:
• filling the borehole with a cement selected to provide less hydraulic diffusivity than that of the formation;
• arranging the pressure tentacles such that, when cemented, they will come into close proximity with the borehole wall at least somewhere along the length of the pressure tentacle;
• separating the pressure sensors axially along the borehole such that the distance between pressure sensors makes the sensors relatively insensitive to axial pressure transmission through the cement when compared to radial pressure transmission from the borehole to the pressure tentacle.

A method for simultaneously monitoring the formation conditions in multiple selected zones of a borehole, comprising:

• placing a plurality of sensory input elements adjacent selected zones in the borehole;
• substantially isolating the selected zones of a formation intersected by the borehole and adjacent sensory input elements, comprising:
• filling the borehole with a cement selected to provide less diffusivity as to the condition monitored than that of the formation;
• arranging the sensory input elements such that, when cemented, they will come into relatively rapid communication with conditions at the borehole wall;
• and
• separating the sensory input elements axially along the borehole such that the axial distance between sensory input elements makes the measurement of the monitored condition relatively insensitive to axial transmission through the cement when compared to radial transmission from the borehole to the sensory input element.

A distributed pressure monitoring system for monitoring formation pressure along a substantial lengths of a casing in a borehole, said monitoring system comprising:

• a communications line connected to surface facilities on one end and leading down the casing;
• a plurality of pressure sensors spaced along the casing, each connected in communication with the communications line;
• a sensor housing enclosing each sensor;
• and
• a plurality of open pressure tentacles, each attached to the sensor housing and in communication with one of the pressure sensors and open pressure tentacle comprising:
• a frit connected to the pressure sensor;
• a wire mesh hose closed on one end and connected to the pressure sensor upstream of the frit;
• and
• a gravel pack within the wire mesh hose.

A method for simultaneously monitoring the formation conditions in multiple selected zones of a borehole, comprising:

• placing a plurality of sensory input elements adjacent selected zones in the borehole, comprising;
• attaching a multiple wire cable to a casing set in an interval of the borehole intersecting the selected zones;
• providing a plurality pigtail connections to the multiple wire cable;
• attaching a plurality of sensor onto the casing in communication with the multiwire cable through the pigtails, the sensors being located on the casing so as to correspond with selected zones when the casing is set;
• substantially isolating the selected zones of a formation intersected by the borehole and adjacent sensory input elements, comprising:
• filling the borehole with a cement selected to provide less diffusivity as to the condition monitored than that of the formation;
• arranging the sensory input elements such that, when cemented, they will come into relatively rapid communication with conditions at the borehole wall, comprising:
• providing the sensory input elements as sensor tentacles in the form of gravel packed permeable wire mesh hoses in pressure transmitting communication with pressure transducers;
• and
• arranging the sensor tentacles such that, when cemented, they will come into close proximity with the borehole wall at least somewhere along the lengths of the sensor tentacle;
• and
• separating the sensory input elements axially along the borehole such that the axial distance between sensory input elements makes the measurement of the monitored condition relatively insensitive to axial transmission through the cement when compared to radial transmission from the borehole to the sensory input element.

A system for monitoring a characteristic which transfers through an earth formation, the system comprising:

• a borehole formed into the earth formation;
• a casing set within the borehole;
• a layer of cement securing the casing within the borehole, the characteristic being transferable through at least part of the thickness of the cement layer or bore hole skin as a function of diffusivity;
• at least one sensor for measuring said characteristic, each sensor being attached to the casing and including sensing means extending into the layer of cement;
• and
• a signal communication means for transferring signals representing said characteristic from the sensor to a selected surface facility.

A method of monitoring a characteristic which transfers through an earth formation, the method comprising:

• a) attaching at least one sensor for measuring said characteristic to a casing which is to be installed in a borehole formed in the earth formation, the sensing means being arranged such as to extend between the casing and the borehole wall when the casing is installed in the borehole;
• b) providing means for transferring signals representing said characteristic from the sensor to a selected surface facility;
• c) lowering the casing into the borehole;
• d) selecting a cement for cementing the casing in the borehole so that said characteristic is transferable through at least part of the thickness of the cement layer formed when the casing is cemented in the borehole;
• e) cementing the casing in the borehole whereby the sensor becomes located in the cement layer between the casing and the borehole wall.

A system for monitoring a characteristic which transfers through an earth formation, the system comprising:

• a borehole formed into the earth formation;
• a casing set within the borehole;
• a layer of cement securing the casing within the borehole, the cement being selected to provide much less axial diffusion for the monitored condition than that of the earth formation;
• at least one sensor for measuring said characteristic, each sensor being attached to the casing and
• a signal communication means for transferring signals representing said characteristic from the sensor to a selected surface facility.

A method for simultaneously monitoring the formation conditions in multiple selected zones of a borehole, comprising:

• placing a plurality of temperature sensors adjacent selected zones in the borehole;
• substantially isolating the selected zones of a formation intersected by the borehole and adjacent temperature sensors, comprising:
• filling the borehole with a cement selected to provide less diffusivity as to the condition monitored than that of the formation;
• arranging the temperature sensors such that, when cemented, they will come into relatively rapid communication with conditions at the borehole wall;
• and
• separating the temperature sensors axially along the borehole such that the axial distance between temperature sensors makes the measurement of the monitored condition relatively insensitive to axial transmission through the cement when compared to radial transmission from the borehole to the sensory input element.

A method for simultaneously monitoring the formation pressure conditions in multiple selected zones of a borehole, comprising:

• placing a plurality of pressure sensors adjacent selected zones in the borehole;
• substantially isolating the selected zones of a formation intersected by the borehole and adjacent pressure sensors, comprising:
• filling the borehole with a cement selected to provide less axial diffusivity as to pressure than that of the formation;
• arranging the pressure sensors such that, when cemented, they will come into relatively rapid communication with conditions at the borehole wall;
• and
• separating the pressure sensors axially along the borehole such that the axial distance between pressure sensors makes the measurement of the monitored condition relatively insensitive to axial transmission through the cement when compared to radial transmission from the borehole to the pressure sensor.