A method for controlling corrosion is described. The method includes determining a concentration of a first gas in a first formation, determining a concentration of a second gas different than the first gas in a second formation, determining a ratio between the first gas and the second gas, comparing the determined ratio to a threshold ratio of the first gas to the second gas for the wellbore which reduces a corrosion rate within the wellbore, and based on a result of comparing the determined ratio to the threshold ratio, modifying a quantity of the first formation fluid or the second formation fluid flowed into the wellbore. The first gas and the second gas mix within the wellbore.

A 4D quantitative and intelligent diagnosis method for spatio-temporal evolution of oil-gas reservoir damage types and extent includes: determining a characteristic parameter characterizing reservoir damage by each of a plurality of factors based on a spatio-temporal evolution simulation equation of reservoir damage by each of the plurality of factors; and determining an effective characteristic parameter characterizing the damage extent of the reservoir based on the characteristic parameter characterizing reservoir damage by each of the plurality of factors. The method quantitatively simulate the characteristic parameters of reservoir damage caused by the various factors and a total characteristic parameter of the reservoir damage.

Various downhole logging tools and methods of using and making the same are disclosed. In one aspect, a downhole logging tool for inspecting a well casing is provided that includes a housing adapted to be supported in the well casing by a support cable. A transmitter is positioned in the housing and operable to generate a magnetic field. Plural receivers are positioned in the housing in circumferentially-spaced apart relation and are operable to sense the magnetic field with azimuthal sensitivity. Electronic circuitry is operatively coupled to the receivers to determine a parameter of the sensed magnetic field and determine a characteristic of the well casing based on the parameter.

An apparatus is for detecting corrosion in an internal pipe bore in a pipeline. A tracer chamber containing a first tracer is formed in a portion of the pipeline and is bounded towards the internal pipe bore by a chamber wall having a first corrosion resistance and including at least one wall portion with a second corrosion resistance, the second corrosion resistance being smaller than the first corrosion resistance. A method is for detecting corrosion in an internal pipe bore in a pipeline.

Methods for detecting a corrosion in downhole equipment are described. The methods include incorporating a tracer layer including tracer particles in a piece of downhole equipment; deploying the piece of downhole equipment including the tracer layer into a wellbore; releasing the tracer particles from the tracer layer into the formation upon interaction of metal ions with the tracer layer; and analyzing levels of tracer particles in formation fluids produced to ground surface.

A system includes an electromagnetic inspection device, a processing device, and a memory device. The electromagnetic inspection device includes at least one transmitter that can transmit an electromagnetic signal toward a wall of a flexible pipe. The electromagnetic inspection device also includes at least one receiver that can receive at least one scattered electromagnetic signal from the wall of the flexible pipe. The memory device includes instructions executable by the processing device to cause the processing device to transmit an electromagnetic signal using the transmitter, to receive the scattered electromagnetic signal using the receiver, and to identify at least one anomaly in the wall of the flexible pipe using the scattered electromagnetic signal.

A method for evaluating a chemical treatment at a subsurface for improved well performance may include obtaining information about a post-reaction fluid that results from a fluid flowing through a testing vessel for a period of time, where the testing vessel comprises a plurality of materials, where the plurality of materials is designed to be representative of the subsurface, and where the plurality of materials comprises rock and proppant. The method may also include performing, using the information, a compatibility test on the post-reaction fluid and the plurality of materials after the period of time. The method may further include evaluating, after performing the compatibility test, an effect of the post-reaction fluid on the plurality of materials.

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.

Sensing systems include a tube defining a Fabry-Perot cavity and an optical fiber including a distal end disposed within the Fabry-Perot cavity and a proximal end. A corrodible material caps the Fabry-Perot cavity. Devices for sensing corrosion of downhole equipment include an optical fiber with a corrodible material disposed over a distal end of the optical fiber. Systems for sensing a condition in equipment include an optical fiber with a fiber Bragg grating proximate a distal end thereof and a mass of sensor material coupled to the distal end of the optical fiber. The mass of sensor material is suspended from above the fiber Bragg grating. Other systems for sensing a condition in a wellbore include an optical fiber and a plurality of fiber Bragg gratings along a length thereof. A plurality of sensor materials are coupled to the optical fiber and surround respective fiber Bragg gratings.

A system and method for detecting defects in a tubular structure installed in a wellbore extending into a subterranean formation. An input image of the tubular structure contains input data indicative of a characteristic of the tubular structure. A background image is determined based on the input image. The background image contains background data indicative of the characteristic of the tubular structure associated with manufacturing of the tubular structure. A defect image is determined based on a difference between the input image and the background image. The defect image contains defect data indicative of the characteristic of the tubular structure associated with defects in the tubular structure.