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 probe is provided that contacts the inner surface of the casing or other production tubing and imparts energy to the surface at the contact point, for example as heat energy or mechanical energy. Energy is imparted around the circumference of the casing, and a fiber optic distributed sensor located on the outer surface of the casing is used to measure and record the energy that it receives while the probe is moved to impart energy around the circumference. A record of energy versus position of the probe around the circumference can be obtained, from which maxima in the detected energy measurements can then be found. The position around the circumference which gave the maximum measurement should be the position at which the optical fiber of the fiber optic distributed sensor is located. In addition, an ultrasonic arrangement is also described, that relies on ultrasonic sound to provide detection.

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 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 drill string can include an electromagnetic transmitter oriented at an actual effective tilt angle with respect to the drill string and an electromagnetic receiver oriented at an actual effective tilt angle with respect to the drill string. The transmitter and received can be used to investigate geologic formations surrounding the drill string, and measurements of the geologic formations can be based on the actual effective tilt angles of the transmitter and the receiver. Forward modelling software can use the actual effective tilt angles of the transmitter and the receiver to predict measurements of the geologic formations

According to aspects of the present disclosure, an example downhole tool may include tool body, a first pad radially extendable from the tool body, and a radial array of conformable sensors coupled to the first pad. At least one conformable sensor of the radial array of conformable sensors may include a first flexible material. A transmitter may be coupled to one of the tool body and the first flexible material, and a receiver may be coupled to one of the tool body and the first flexible material. At least one of the transmitter and the receiver may be coupled to the first flexible material.

Systems and methods for directional drilling are described. The system includes one or more controllers and is configured to receive data from a plurality of downhole sensors, provide operational control signals, determine a relationship between different parameters, receive current data including at least one of current differential pressure (DP), weight-on-bit (WOB), or rotations per minute (RPM) of a drill bit, and estimate at least one of current toolface orientation or current shock and vibration of the drill bit using the current data and the determined relationship. The system is further configured to provide operational control signals that may adjust the current toolface orientation to a desired toolface orientation. Current WOB and/or current RPM are adjusted to minimize current shock and vibration of a portion of a bottom hole assembly (BHA).

An installation apparatus for a measurement tool in an underground mine with overhead drill holes, the installation apparatus comprising: a support that can be removably secured to the ceiling, wall and/or ground of the mine, and an installation conduit that can be removably coupled to the support and aligned with the drill hole to deploy a survey and/or geophysical tool into the open drill hole.

A device for centering a sensor assembly in a bore comprises a plurality of arm assemblies connected first and second support members. Each arm assembly comprises a first arm pivotally connected to the first support member, a second arm pivotally connected to the second support member, and a third arm pivotally connected between the first and second arms. The third arm is pivotally connected to a third support member positioned axially between the first and second support members. The third arm extends across the longitudinal axis of the device so that in use each arm assembly contacts opposite sides of the bore to centralise the sensor assembly in the bore.

A sensor assembly includes a position measurement sensor, a slickline, and a processor. The position measurement system measures angular velocity of the sensor assembly inside a wellbore that extends in an axial direction. The slickline raises and lowers the position measurement sensor in the wellbore. The processor executes a series of measurement units including: an inclination measurement unit, a coordinate measurement unit, a depth measurement unit, and a data storage unit. The inclination measurement unit determines an inclination of the position measurement sensor. The coordinate measurement unit determines radial coordinates of the position measurement sensor. The depth measurement unit determines a real-time depth level of the position measurement sensor. Each of the inclination, the radial coordinates, and the real-time depth level are determined from the angular velocity. The data storage unit stores the measured values, including the angular velocity, inclination, radial coordinates, and real-time depth level.