Abstract: An apparatus and method may operate to mount an electrode assembly with the exterior of a casing string to be placed in a borehole in a subterranean formation. The electrode assembly may include electrodes in spaced relation to one another. After the casing string and associated electrode assembly are in the borehole, the method may include providing a series of excitation signals at a plurality of frequencies to at least one electrode to inject a series of injection signals into fluid in the annulus. The method can further include receiving signals in response to the series of injection signals through at least one other electrode. The received signals can be representative of an impedance spectrum including impedance values representative of the fluid in the borehole annulus. The method can further include identifying the fluid in reference to the impedance spectrum. Additional apparatus, systems, and methods are disclosed.

Abstract: A method of cementing a subterranean formation includes providing a cement composition comprising cementitious material, aqueous base fluid, nanoparticles, synthetic clay, and a thixotropic modifier, where the solid materials are about 0 wt % to about 40 wt % of the total weight of the cement composition; introducing the cement composition into a subterranean formation; and allowing the cement composition to set in the subterranean formation. Cement compositions include cementitious material, aqueous base fluid, nanoparticles, synthetic clay, and a thixotropic modifier.

Abstract: A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae is described. The interrogation circuitry comprises at least one inductor comprising at least two sensing coils for reception of signals from the MEMS data sensors.

Abstract: A system that is positionable in a wellbore can include a transceiver that is positionable external to a casing string and programmable to vary a number of data packets that are wirelessly transmitted by the transceiver. The number of data packets can correspond to an amount of data wirelessly transmitted by the transceiver about an environment in the wellbore.

Abstract: Micro-Electro-Mechanical System (“MEMS”) tags having high and low resonant frequencies are used to detect the cured or uncured state of wellbore cement. The MEMS tags may be added to wellbore cement, and pumped downhole. An interrogation tool emits a signal at one or both of the resonant frequencies which, in turn, interacts with the MEMS tags to produce a response signal. Since uncured cement has a high attenuation, only the lower resonant frequency response signal is sensed by an interrogation device, thus indicating the cement remains uncured. When the cement cures, its conductivity drops and the attenuation of the higher resonant frequency response signal drops also, thus allowing that signal to be detected by the interrogation device and indicating the cement has cured.

Abstract: A system can include a cementing tool positionable within a casing string of a wellbore. A receiver that is positionable at the surface of the wellbore can receive an optical signal. A locator coupled to the cementing tool can generate an electrical signal in response to detecting a change in a surrounding magnetic field. A light source can generate an optical signal. A fiber optic cable can transmit the optical signal generated by the light source. A fiber reel can dispense the fiber optic cable from an end of the fiber optic cable.

Abstract: Methods including experimentally determining a salt creep profile for a single salt or intercalated salts in a subterranean formation, designing a proposed cement slurry based on the salt creep profile, experimentally determining whether the proposed cement slurry is capable of forming a wellbore load resistant cement sheath based on actual thermal and thermo-mechanical properties of the proposed cement slurry, theoretically determining whether the proposed cement slurry is capable of forming the wellbore load resistant cement sheath by designing an electronic, cross-section geometric model of the subterranean salt formation and simulating a condition of the wellbore loads on the cured proposed cement slurry using the geometric model, establishing a final cement slurry capable of forming the wellbore load resistant cement sheath, and performing a final cementing operation with the final cement slurry in the subterranean salt formation.

Abstract: Sensor assemblies are deployed in a borehole for a well, such as an oil well or other hydrocarbon recovery well. The sensor assemblies may be coupled to a casing string (e.g., the exterior of the casing), and detect RFID tags or other properties of material (e.g., fluids) in an annulus surrounding the casing string. During cementing or other operations, RFID tags may be used to track fluids. RFID detection circuits may be used to scan at different frequencies, and corresponding results may be compared by various means and processes to determine the presence of RFID tags.

Abstract: A method of treating lost circulation issues stemming from loss zones during the drilling and cementing process through the utilization of a thixotropic cement. The method comprises the steps of encountering a loss zone in a bore hole during drilling or running casing and pumping a treatment fluid into the loss zone, wherein the treatment fluid is a gel capable of gelling, breaking when sheared, and building back shear strength after shearing is removed.

Abstract: An apparatus and method may operate to position an electrode assembly within a fluid. The electrode assembly may include an injection electrode and a receiving electrode in spaced relation to one another. The method may include providing a series of excitation signals at a plurality of frequencies to the injection electrode to inject a series of injection signals into the fluid. The method can further include receiving signals in response to the series of injection signals through the receiving electrode. The received signals can be representative of an impedance spectrum including impedance values representative of the fluid. The method can further include generating a phase angle fingerprint based on the impedance spectrum to characterize the fluid according to the phase angle fingerprint. Additional apparatus, systems, and methods are disclosed.

Abstract: A variety of systems, methods and compositions are disclosed, including, in one method, a method of cementing may comprise providing a cement composition comprising a hydraulic cement, water, and a microcellulose additive, wherein the microcellose additive may comprise microcellulose with a metal deposited on a surface of the microcellose, wherein the metal may be selected from the group consisting of an alkali metal, an alkaline earth metal, and combinations thereof; placing the cement composition in a selected location; and allowing the cement composition to set.

Abstract: Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof, introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.

Abstract: The invention provides a method and system for treating a subterranean formation by detecting the displacement and position of a downhole fluid having a pH through the fluids reaction with a pH-sensitive material, mobilizing a plug assembly comprising the material to contact one or more constrictions in a wellbore casing.

Abstract: Systems and methods for performing positive and/or negative pressure testing in managed pressure operations in subterranean well bores are provided. In some embodiments, the methods comprise: performing a positive or negative pressure test in a well bore in a subterranean formation, wherein the well bore is maintained in a closed pressure loop, and at least one choke valve is provided in communication with the well bore, the choke valve being coupled to a controller, and during the test in the well bore, monitoring an actual bottomhole pressure in the well bore using data from at least one downhole sensor in the well bore, and if the actual bottomhole pressure in the well bore increases or decreases, manipulating the choke valve using the controller to increase or decrease the bottomhole pressure in the well bore.

Abstract: Micro-Electro-Mechanical System (“MEMS”) tags having high and low resonant frequencies are used to detect the cured or uncured state of wellbore cement. The MEMS tags may be added to wellbore cement, and pumped downhole. An interrogation tool emits a signal at one or both of the resonant frequencies which, in turn, interacts with the MEMS tags to produce a response signal. Since uncured cement has a high attenuation, only the lower resonant frequency response signal is sensed by an interrogation device, thus indicating the cement remains uncured. When the cement cures, its conductivity drops and the attenuation of the higher resonant frequency response signal drops also, thus allowing that signal to be detected by the interrogation device and indicating the cement has cured.

Abstract: Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof, introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.

Abstract: A system can include a cementing tool positionable within a casing string of a wellbore. A receiver that is positionable at the surface of the wellbore can receive an optical signal. A locator coupled to the cementing tool can generate an electrical signal in response to detecting a change in a surrounding magnetic field. A light source can generate an optical signal. A fiber optic cable can transmit the optical signal generated by the light source. A fiber reel can dispense the fiber optic cable from an end of the fiber optic cable.

Abstract: A method of detecting the presence of a downhole fluid at a particular location in a wellbore including pumping an activating fluid into a wellbore; contacting a flow controlling device in a pipe string casing with the activating fluid, the flow controlling device comprising at least one swellable element; activating the at least one swellable element in the flow controlling device; blocking fluids or controlling the flow of fluids entering or leaving the casing with the activated flow controlling device; allowing the pressure to change; and detecting the pressure change. An apparatus includes a pipe string in a wellbore and a flow controlling device in the pipe string casing, wherein the flow controlling device includes at least one swellable element, wherein upon activation, the at least one swellable element swells and fully or partially seals off the flow area of the flow controlling device.

Abstract: Methods of formulating a cement slurry for use in a subterranean salt formation, including methods for formulating a cement slurry capable of providing long-term zonal isolation within a subterranean salt formation. The methods also take into account the effects of treatment fluids on the cement slurry, such as drilling fluids, spacer fluids, flush fluids, or other relevant fluids used to perform a subterranean formation operation.

Abstract: Determining a type of annular material in a wellbore comprises measuring an acoustic noise of one or more reference materials and thereby generating a corresponding one or more acoustic profiles, monitoring the annular material with an acoustic sensor positioned in the wellbore and thereby obtaining an acoustic response of the annular material, comparing the acoustic response with the one or more acoustic profiles using a processor communicably coupled to the acoustic sensor, and characterizing the annular material based on the comparison of the acoustic response and the one or more acoustic profiles.