A method for monitoring microbial levels in a wellbore fluid is provided. The method includes collecting a wellbore fluid sample, recovering ATP from the wellbore fluid sample, using the recovered ATP in an ATP-mediated oxidation of luciferin to oxyluciferin to yield photons, quantifying the photons, correlating the quantified photons to an ATP concentration, comparing the ATP concentration to predetermined action levels, and taking countermeasures when the ATP concentration exceeds the predetermined action levels.

A composition includes a functionalized fluorescent dye. The functionalized fluorescent dye includes an isothiocyanate-containing dye functionalized with a functional group. The functional group includes an aromatic compound with a primary amine. The functionalized fluorescent dye can be mixed with a fluid to form a tracer fluid for tracing fluid flow in a subterranean formation.

Provided in some embodiments are systems and methods for preparing oriented samples of a laminated rock having different lamination orientations, for each of different stress-levels, transmitting an acoustic pulse through each oriented sample while tri-axially compressing the oriented sample at the stress-level to generate test data indicative of acoustic velocities through the laminated rock at different combinations of lamination orientations and stress levels, determining acoustic velocities through the laminated rock at the different combinations of lamination orientations and stress levels based on the test data, generating a rock model for the laminated rock based on the acoustic velocities, and determining a property of a second laminated rock (e.g., total organic carbon (TOC) content) based on the rock model for the laminated rock.

A method can include flowing fluid from a formation from an inlet of a tool to an annulus; flowing spacer fluid from a conduit to the annulus; flowing the fluid and the spacer fluid in the annulus to a station; and collecting the fluid.

The disclosure describes a method to indirectly measure the amount of elemental sulfur or amorphous dithiazine in a reservoir sample by converting them to H.sub.2S gas. The H.sub.2S is captured via caustic cyanide solution and quantified by analytical methods and correspond to the concentration of elemental sulfur or amorphous dithiazine. The method has particular applicability to determine where best to drill and avoid locations of high sulfur.

A method of mud logging is disclosed which the chemical constituents and concentrations of formation fluid are calculated based on pulse power plasma parameters and the constituent species and concentrations of drilling mud, including reaction products, upon which the pulse power plasma has acted. Based on correlation between pulse power plasma parameters, including drilling parameters, drilling can be optimized for identified formation and formation fluid species. An offset between the chemical makeup of the drilling mud exposed to pules power plasma and the chemical makeup of formation fluid is calculated. Based on the calculated offset, pulse power plasma drilling can be controlled as a function of drilling mud concentration including in other wellbores in the formation or field.

A method for operating a kerogen-rich unconventional gas reservoir characterized by there being multiple hydraulically-fractured wells drilled thereinto comprises: recovering a methane-containing gas from a first hydraulically-fractured well drilled into the gas reservoir, steam-methane reforming the recovered methane-containing gas to yield a hydrogen gas and an inorganic carbon-containing gas, injecting at least a portion of the hydrogen gas into a second hydraulically-fractured well drilled into the gas reservoir, and injecting at least a portion of the inorganic carbon-containing gas into a third hydraulically-fractured well drilled into the gas reservoir.

The effect of drilling fluids on particular subterranean environments can be analyzed to improve the formation of drilling fluids and additives such as lost circulation materials. A plug can be generated by a particle plugging apparatus by injecting lost circulation material into the particle plugging apparatus. A set of tests to be performed on the plug can be identified. The set of tests can include at least one physical test and at least one electronic test. A test schedule indicating the order in which each test of the set of tests is to be performed can be defined. The set of tests can be executed to generate a testing output. The testing output can be used to generate a three-dimensional network model of the plug.

Systems, devices, and techniques for determining downhole fluid contamination are disclosed. In one or more embodiments, phase-related properties are measured for a reservoir fluid having a determined composition. An equation-of-state (EOS) is selected and/or tuned based, at least in part, on the measured phase-related properties and the tuned EOS is applied to estimate fluid property values for a reference fluid over specified ranges of at least two thermodynamic properties. Contaminant reference data are generated that correlate the estimated fluid property values for the reference fluid with respective contaminant levels. Within a wellbore, a fluid sample is analyzed to determining a fluid property values. A contaminant level is identified that corresponds within the contaminant reference data to the determined fluid property value of the fluid sample.

A device for testing the three-phase saturation of oil, gas and water in a high-temperature and high-pressure planar model includes a displacement pump, a confining pressure pump, a back pressure pump, containers, a planar model system, a data acquisition system, a back pressure valve and an oil-gas separator. The planar model system includes a planar model, an autoclave body, a heating temperature-controlling system, a Y-axis direction stepping motor, a X-axis direction stepping motor and an acoustoelectric detector. A method for testing the three-phase saturation of oil, gas and water by using the device includes calibrating three-phase saturation of oil, gas and water to a rock core, preparing a formation water sample and a crude sample, regaining the original formation conditions of the planar model, simulating the depletion or displacement process of oil reservoirs, performing linear ultrasonic-and-resistivity-scanning test on planar model, determining the three-phase saturation distribution of oil, gas and water.