Additive is introduced into a tubular that carries produced fluid from a wellhead; the additive addition prophylactically guards against damage to the tubular, such as from corrosion or oxidation. Gas from the wellhead is utilized as a pressure source for driving the additive into the tubular. The rate of additive injection is varied based on characteristics of the tubular or fluid in the tubular. Characteristics of the fluid in the tubular include iron content, residual additive, moisture content, and flowrate; characteristics of the tubular include its corrosion rate of the tubular. The characteristics are measured real time, measured historically, or predicted from a model.

Hybrid 3D geocellular grids are generated to represent a subset of a natural fracture network (“NFN”) directly in the simulation, while the remainder of the NFN is approximated by a multi-continuum formulation. The resulting output is a 3D geocellular grid that possesses a higher level of mesh resolution in those areas surrounding the first fracture subsets, and lower mesh resolution in the areas of the second fracture subset.

A method and system for estimating a pipe property for a plurality of nested pipes. The method may comprise disposing an electromagnetic logging tool in a wellbore. The electromagnetic logging tool may comprise a transmitter disposed on the electromagnetic logging tool and a receiver disposed on the electromagnetic logging tool. The method may further comprise transmitting an electromagnetic field from the transmitter into a pipe string to energize the pipe string with the electromagnetic field thereby producing an eddy current that emanates from the pipe string, measuring the eddy current in the pipe string with the receiver on at least one channel to obtain a plurality of measurements, forming a log from the plurality of measurements, zoning the log into a plurality of zones based at least in part on a well plan, and extracting a representative signal for each zone of the plurality of zones.

Impedance is used to determine the performance of paraffin inhibitors in oil containing paraffin. The method and system can use a specially designed impedance cell having a cell constant of less than 1 cm.sup.−1. Further, the method can include obtaining at least impedance measurements above the wax appearance temperature (WAT) for an oil sample treated with a paraffin inhibitor and an oil sample not treated, and impedance measurements below the WAT for the treated oil sample and the untreated oil sample. Thereafter, the impedance measurements are correlated to determine paraffin inhibitor performance.

Layered coating applications for sensing telemetry are provided. An example method can include depositing an optical waveguide on an inner surface of a wellbore tool, the optical waveguide including a first layer of low refractive-index material, a second layer of high refractive-index material applied to a first surface of the first layer, and a third layer of low refractive-index material applied to a second surface of the second layer; configuring non-uniformities at one or more locations of the optical waveguide, the non-uniformities configured to reflect or scatter light at angles relative to a site of interaction between the light and the non-uniformities; determining a reflection and/or transmission pattern of light propagated through the optical waveguide and reflected or scattered by the non-uniformities; and based on the reflection and/or transmission pattern of the light, determining one or more conditions associated with of the wellbore tool.

A system for locating a casing collar includes a drill pipe sub-assembly with a drill pipe segment and detection apparatus. The detection apparatus includes a bypass port disposed in a wall of the drill pipe segment; an annular sleeve which directs fluid through the bypass port and into a drill pipe segment interior portion; an actuator which opens and closes the bypass port; and two magnetized coils which generate an electromagnetic field. The actuator closes the bypass port in response to a predetermined voltage generated by the magnetized coils when they displace past a casing collar. Also included are a weight loss detection device which detects a loss of weight in the drill pipe segment, and a depth determination device which determines a depth of the casing collar, based on detected loss of weight. Also disclosed and described are a related method and drill pipe sub-assembly.

A drill bit for drilling a subterranean formation. The drill bit includes a drill bit body, at least one cutting element disposed on the drill bit body, and an optical sensor disposed on the drill bit body and configured to generate an environmental parameter measurement while drilling the subterranean formation. The optical sensor includes a fiber bragg grating embedded in an optical fiber that passes through a first channel in the drill bit body and a second channel in the drill string to couple to a surface logging station for analyzing the environmental parameter measurement, where the environmental parameter measurement represents at least a downhole chemical composition measured by the fiber bragg grating, and an analysis result of the surface logging station is presented to a user to facilitate a drilling operation.

A method for performing a maintenance operation of a well in an oil/gas field is disclosed. The method includes identifying an extent of corrosion deposit of the well, predicting, using a descaling model of the oil/gas field and based on the extent of corrosion deposit, expected descaling metal loss in a tubular of the well, calculating, based on the expected descaling metal loss, a tubular burst/collapse pressure for a predicted thickness of the tubular, comparing the tubular burst/collapse pressure against a well operating pressure to generate a comparison result, and performing the maintenance operation of the well based on the comparison result.

Methods and systems pertaining to a processing system and a downhole logging tool for investigating nested tubulars in a borehole. The downhole logging tool includes a transmitter coil for emitting a broadband excitation signal including one or more step excitations. The downhole logging tool also includes receiver coils including at least two receiver coils spaced apart from the transmitter coil at respective first and second distances from the transmitter, the first and second distances being distinct from each other, and each receiver coil being able to receive a response signal resulting from the excitation signal. The downhole logging tool also includes an acquisition system for recording the excitation signal and the response signal of each receiver coil over time. The processing system derives information indicative of variations in individual thicknesses of the nested casing tubulars based on variations of the response signals over time.

Embodiments include a core plug holding apparatus including a tubular member configured to be inserted into a side pocket of a mandrel, the tubular member having an uphole end, a downhole end, and a core plug section located between the uphole end and the downhole end, wherein the core plug section is used for housing of one or more core plug samples and wherein tubular member includes one or more orifices formed in the core plug section. Embodiments include a method of sampling a well including deploying one or more core plug holding apparatuses into one or more side pocket mandrels of a completion; holding the one or more core plug holding apparatuses in the one or more side pocket mandrels for an incubation period; and retrieving the one or more core plug holding apparatuses from the one or more side pocket mandrels after the passage of the incubation period.