The present invention relates to a ground subsidence detection apparatus, which is capable of continuous detection of ground subsidence, predicts the occurrence of sinkholes and thus can preemptively prevent a sinkhole from forming, and due to having a simple structure, can increase durability and reduce cost. Provided is a ground subsidence detection apparatus exhibiting an alarm color using reflection of a light source and a detection weight, which, without using a separate power source, falls due to gravity in the event of cavity formation in the ground, or falls due to ground movement when ground movement occurs.

A system for drilling a well may be adapted to process signals received from a fiber optic cable located in the casing of a previously drilled well or wells. The fiber optic cable may act as a distributed sensor receiving acoustic signals generated during the drilling of the well, and the system may be programmed to process the signals from the fiber optic cable to locate the borehole of the well being drilled, including its location relative to the previously drilled well or well. The system may be used to automatically update a well plan for the well being drilled responsive to information about the location of the borehole and also may be used to automatically adjust one or more drilling parameters or drilling operations responsive to the location of the second well borehole.

A system for drilling a well may be adapted to process signals received from a fiber optic cable located in the casing of a previously drilled well or wells. The fiber optic cable may act as a distributed sensor receiving acoustic signals generated during the drilling of the well, and the system may be programmed to process the signals from the fiber optic cable to locate the borehole of the well being drilled, including its location relative to the previously drilled well or well. The system may be used to automatically update a well plan for the well being drilled responsive to information about the location of the borehole and also may be used to automatically adjust one or more drilling parameters or drilling operations responsive to the location of the second well borehole.

A method for configuring a logging module for logging sensors deployment based on a sensing data acquisition objective includes selecting a tool body, selecting at least one type of sensor, and selecting at least one type of roller. The method also includes incorporating the at least one selected type of sensor onto the at least one selected type of roller to provide at least one sensor roller, and mounting the at least one sensor roller into a compressible mounting assembly provided in the tool body to provide the logging module.

A system includes a cable and a toolstring. The toolstring may couple to the cable to enable the toolstring to be placed in a wellbore. The toolstring includes a sensor that can collect measurements relating to the wellbore. An electromagnetic or anchoring device may selectively hold the toolstring or the cable against a surface of the wellbore.

Carbonate samples are received from a wellbore formed in a geologic formation. An oxygen isotope ratio and carbon isotope ratio present within each of the carbonate samples are determined. A mineral composition of each of the carbonate samples is determined. A plot showing the determined oxygen isotope ratios versus a depth from where within the wellbore each of the carbonate samples was obtained is created. One or more negative oxygen isotope shifts are identified based on the plot. Natural carbonate cement levels within one or more of the plurality of carbonate samples that correspond to the one or more negative oxygen isotope shifts identified in the plot are determined. One or more production sweet spots are determined based on the identified negative oxygen isotope shifts and the determined natural carbonate cement levels.

A downhole tool and method of utilizing the downhole tool to make measurements in a wellbore formed in a formation and having different wellbore diameters. The downhole tool generally includes a tool body defined along a longitudinal central axis and having an internal passage extending longitudinally therethrough and an external pocket extending therealong; a sensor module having a sensor and being deployed within the external pocket; a spacer deployed in the external pocket, the spacer positioned between the sensor module and the tool body; and a clamp attached to the tool body, the clamp overlaying both the sensor module and the spacer to confine the sensor module within the external pocket. The spacer may have an inner concave surface engaging the sensor module and an outer convex surface seating in the external pocket.

A tool and method for determining material quality of hydrocarbon wellbore cross sections comprising tubular elements and filling materials, the tool comprising: a body; moveable assemblies having arms configured to be in contact with an inner wall of a downhole tubular element, wherein the plurality of the moveable assemblies are configured to move between a retracted position where the arms are within a housing located in the body of the tool and an extended position where the arms protrude from the housing and are in contact with the inner wall of the downhole tubular element, wherein at least one of the plurality of moveable assemblies comprises an acoustic broad band source array operating in the frequency range of 0-100 kHz and at least one of the plurality of moveable assemblies comprises an acoustic broad band receiver array comprising one or more radially spaced acoustic broad band receivers.

A method and systems for performing a borehole operation with a borehole fluid that includes applying an amplitude oscillation deformation force to a sample of the borehole fluid over a period of time, measuring the deformation force from the sample, determining a storage modulus of the borehole fluid over the period of time based on the measured deformation force, determining a gel strength of the borehole fluid by correlation with the storage modulus, comparing the gel strength with a desired gel strength and if the gel strength is outside of an acceptable range of the desired gel strength, adjusting a drilling parameter, a composition of the borehole fluid, or a combination thereof, and using the borehole fluid in the borehole operation. Determining the storage modulus and the gel strength may be done using a processor and the force may be applied using a piezoelectric device.

A measurement-while-drilling method and device assesses outburst risk and evaluates gas drainage performance of a coal seam. The device includes a compartment, a pressure sensor, a temperature sensor, a flow sensor, an electromagnetic sensor, an acoustic sensor, a wave velocity measurement module, a monitoring and control module, a power supply and a communication interface. These are installed between a drill bit and an inclinometer or a first drill pipe. Measurements are performed while drilling to obtain a real time gas parameter, lithologic and coal seam information, for on-site assessment of outburst risk. During drill bit replacement, gas pressure, temperature, flow velocity, wave velocity, electromagnetic radiation, and an acoustic signal are recorded in real time, to calculate stress of the coal seam and coal seam outburst risk. On-site measurement is done while drilling without sampling and can use multiple parameters to perform synchronous measurement to obtain a comprehensive evaluation.