A threaded connection includes a pin and a box. The pin includes, in the order from a free end side of the pin toward a tubular body side thereof, an inner sealing surface, an inner male threaded portion, a shoulder portion, an outer male threaded portion, and an outer sealing surface. The box includes, in the order from a tubular body side of the box toward a free end side thereof, an inner sealing surface, an inner female threaded portion, a shoulder portion, an outer female threaded portion, and an outer sealing surface. Between the inner sealing surface and the inner female threaded portion of the box, an inner groove along a circumferential direction is provided, and some threads of the inner male threaded portion of the pin are contained in the inner groove.

A device for measuring a flow velocity and a flow direction and geological parameters of groundwater through cross holes of deep wells includes detectors and a device for throwing the tracer source. A method includes measuring a correspondence between a conductivity and a concentration of a tracer solution at different temperatures in a laboratory; selecting at least two boreholes; selecting a target aquifer section; placing the detectors in the target aquifer section in the hole to test a conductivity background value and a temperature value; using the device for throwing the tracer source to place the tracer solution in the hole for throwing the tracer source, and using the detectors to measure a water conductivity and temperature in a detection hole, to obtain a distribution curve of a tracer solution solubility with time; performing cross-test, and calculating the seepage flow velocity and flow direction of groundwater in the hole.

An apparatus for detecting a location of an optical fiber having an acoustic sensor disposed subsurface to the earth includes an acoustic emitter configured to emit a first signal having a first frequency and a second signal having a second frequency that is higher than the first frequency, the first and second emitted acoustic signals being azimuthally rotated around the borehole and an optical interrogator configured to interrogate the optical fiber to receive an acoustic measurement that provides a corresponding first received signal and a corresponding second received signal. The apparatus also includes a processor configured to (i) frequency-multiply the first received signal to provide a third signal having a third frequency within a selected range of the second frequency, (ii) estimate a phase difference between the second received signal and the third signal, and (iii) correlate the phase difference to the location of the optical fiber.

A method of determining fluid inflow rates within a wellbore comprises determining a plurality of temperature features from a distributed temperature sensing signal originating in a wellbore, determining one or more frequency domain features from an acoustic signal originating the wellbore, and using at least one temperature feature of the plurality of temperature features and at least one frequency domain feature of the one or more frequency domain features to determine a fluid inflow rate at one or more locations along the wellbore.

Raw signal measurements can be received by sensors in a wellbore. Borehole effects can affect the raw signal measurements. The raw signal measurements can be converted into ratio signals having attenuation and phase shift. An apparent resistivity can be determined from the ratio signals. Mud resistivity can be determined based on apparent resistivity, at least part of the raw signal measurements, and the borehole size. A true resistivity can be determined based on the mud resistivity and at least part of the ratio signals. The raw signal measurements and the ratio signals can be updated based on the true resistivity. Steps can be repeated to determine a corrected true resistivity. Based on the true resistivity value and updated raw signal measurements and ratio signals, an operating characteristic of a well tool can be caused to be adjusted.

In an example method a system obtains first data regarding a first oil well, including one or more first thermal images of the oil well generated by one or more first thermal cameras. The system determines, using computerized neural network, a presence of a gas leak at one or more locations on the first oil well based on the first data. The one or more locations include at least one of a first location along a pipeline configured to convey gas to a flare area of the first oil well, or a second location at a rig floor of the first oil well. In response to determining the presence of the gas leak at the one or more locations, the system generates a notification indicating the presence of the gas leak at the one or more locations.

In an example method a system obtains first data regarding a first oil well, including one or more first thermal images of the oil well generated by one or more first thermal cameras. The system determines, using computerized neural network, a presence of a gas leak at one or more locations on the first oil well based on the first data. The one or more locations include at least one of a first location along a pipeline configured to convey gas to a flare area of the first oil well, or a second location at a rig floor of the first oil well. In response to determining the presence of the gas leak at the one or more locations, the system generates a notification indicating the presence of the gas leak at the one or more locations.

A downhole fluid analysis system includes an optical sensor comprising, which includes a light source configured to emit light comprising a plurality of wavelengths, a light detector, and an optical tip through which at least a portion of the light travels and returns to the detector, wherein the incident angle of the light causes total internal reflection within the optical tip. The system further includes a piezoelectric helm resonator that generates a resonance response in response to an applied current, and an electromagnetic spectroscopy sensor positioned symmetrically with respect to the piezoelectric helm resonator in at least one direction. The light may be reflected in the optical tip at one or more reflection points, and each reflection point may generate an evanescent wave in a medium surrounding the optical tip. The light may be internally reflected in the optical tip at a plurality of reflection points.

The present disclosure describes methods and systems for downhole well integrity reconstruction in a hydrocarbon reservoir. One method for downhole well integrity reconstruction in a hydrocarbon reservoir includes: positioning, a laser head at a first subterranean location, wherein the laser head is attached to a tubular inside of a wellbore; directing, by the laser head, a laser beam towards a leak on the wellbore; and sealing the leak using the laser beam.

The present disclosure describes methods and systems for downhole well integrity reconstruction in a hydrocarbon reservoir. One method for downhole well integrity reconstruction in a hydrocarbon reservoir includes: positioning, a laser head at a first subterranean location, wherein the laser head is attached to a tubular inside of a wellbore; directing, by the laser head, a laser beam towards a leak on the wellbore; and sealing the leak using the laser beam.