In some embodiments, a method for locally lumped equation of state fluid characterization can include determining a set of components for the material balance calculations for a plurality of grid blocks of a reservoir. The plurality of grid blocks can experience different recovery methods between them. Lumping schemes can be determined for the plurality of grid blocks. Phase behavior calculations can be performed on the plurality of grid blocks, wherein different lumping schemes can be used across the plurality of grid blocks.

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 whilst 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.

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.

A method for determining validity of an arrangement of a plurality of contiguous depositional environment polygons that depict a geological region includes obtaining a plurality of polygons stored in a dataset of polygons, each polygon of the plurality of polygons assigned a different depositional environment characteristic, and the plurality of polygons representing the geological region, arranging the plurality of polygons adjacent each other using geographical coordinates of the polygons, and thereby obtain an arrangement of the plurality of polygons, determining whether the arrangement of the plurality of polygons is valid using a rule-base that includes pairs of compatible depositional environment characteristics arranged adjacent each other, and generating a map of geological polygons for a region that facilitates exploration of a natural resource

According to aspects of the present disclosure, systems and methods for a closed-loop speed/position control mechanism. An example system may include a housing and a planetary gearbox disposed within the housing, wherein a ring gear of the planetary gearbox is coupled to the housing, a sun gear of the planetary gearbox is coupled to a drive shaft, and a planetary carrier of the planetary gearbox is coupled to an output shaft. A controller may receive measurements from sensors proximate to the output shaft and use those measurements to transmit control signals to change the rotation of the drive shaft. In this way, the output shaft may be rotated independently of the housing by controlling the rotation of the drive shaft. In example systems, the output shaft may be a sonde or an offset mandrel coupled to a drill bit. The rive shaft may be coupled to a fluid-controlled controlled drive mechanism and rotation may be controlled by adjusting flow control valve. The closed-loop system may be used to set a target rotation speed of said output shaft or may be used to maintain the output shaft in a constant position or orientation despite housing rotation.

A tool and a method for determining material quality of a hydrocarbon wellbore cross section, having one or more tubular elements having filling materials in between, is described. A tool includes a body and moveable assemblies, having multiple arms configured to be in contact with an inner wall of a downhole tubular element, that that are configured to move between a retracted position where the multiple arms of the moveable assemblies are within a housing located in the body of the tool and an extended position where the multiple arms of the moveable assemblies are protruding from the housing and are in contact with the inner wall of the downhole tubular element. The moveable assemblies comprise both an acoustic broad band source array that operates in the frequency range of 0-100 kHz and an acoustic broad band receiver array having a radially spaced acoustic broad band receiver.

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 downhole tool, comprising: a tool mandrel; a pad comprising a transmitter operable to transmit an electric current into a formation and a receiver operable to receive at least a portion of the electric current from transmitter; an extension from the tool mandrel that couples pad to tool mandrel; and a signal filter positioned in the downhole tool to suppress passage of mandrel leakage current that passes through tool mandrel to pad. A method of resistivity imaging, comprising: disposing a downhole tool into borehole; transmitting a current into formation surrounding the borehole with a transmitter that is extended from tool mandrel of the downhole tool towards borehole wall; and recording at least a portion of the current that returns to receiver of downhole tool, wherein a signal filter suppress passages of mandrel leakage current that passes through the tool mandrel to a pad on which the transmitter is disposed.

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 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.