Disclosed herein is a method for viscosity measurement of non-Newtonian fluid for in-line measurement and process control. The process involves mixing additives to a base fluid to form the non-Newtonian fluid. The non-Newtonian fluid is fed to an in-line viscosity measurement device to obtain a rheological measurement. The addition of the additives to the base fluid is then adjusted based on the rheological measurement. A system for accomplishing the same is also disclosed.

Disclosed herein is a method for viscosity measurement of non-Newtonian fluid for in-line measurement and process control. The process involves mixing additives to a base fluid to form the non-Newtonian fluid. The non-Newtonian fluid is fed to an in-line viscosity measurement device to obtain a rheological measurement. The addition of the additives to the base fluid is then adjusted based on the rheological measurement. A system for accomplishing the same is also disclosed.

A wellbore treatment fluid comprising: a base fluid; and a water-soluble salt, the salt comprising: a cation; and an anion, wherein the anion is selected from phosphotungstate, silicotungstate, phosphomolybdate, and silicomolybdate. The treatment fluid can have a density greater than or equal to 13 pounds per gallon. A method of treating a portion of a subterranean formation penetrated by a well comprising: introducing the treatment fluid into the well.

A wellbore treatment fluid comprising: a base fluid; and a water-soluble salt, the salt comprising: a cation; and an anion, wherein the anion is selected from phosphotungstate, silicotungstate, phosphomolybdate, and silicomolybdate. The treatment fluid can have a density greater than or equal to 13 pounds per gallon. A method of treating a portion of a subterranean formation penetrated by a well comprising: introducing the treatment fluid into the well.

An organic lubricant composition comprising a vegetable oil; an organic acid; and an organic alcohol, where the organic lubricant composition is substantially free of inorganic compounds.

An organic lubricant composition comprising a vegetable oil; an organic acid; and an organic alcohol, where the organic lubricant composition is substantially free of inorganic compounds.

At least one nucleic acid from a sulfate-reducing bacteria (SRB) may be extracted from an oilfield fluid and may be amplified by a PCR amplification method in the presence of at least one primer to form an amplification product. The primer(s) may be or include a sequence including, but not necessarily limited to, SEQ ID NO: 20, SEQ ID NO: 21, and mixtures thereof. The amplification product may be hybridized with a probe specific for a fragment of an alpha subunit of an APS gene, and a presence of hybridization and a degree of hybridization may be detected.

At least one nucleic acid from a sulfate-reducing bacteria (SRB) may be extracted from an oilfield fluid and may be amplified by a PCR amplification method in the presence of at least one primer to form an amplification product. The primer(s) may be or include a sequence including, but not necessarily limited to, SEQ ID NO: 20, SEQ ID NO: 21, and mixtures thereof. The amplification product may be hybridized with a probe specific for a fragment of an alpha subunit of an APS gene, and a presence of hybridization and a degree of hybridization may be detected.

Embodiments described herein provide enhanced low-density hollow glass bead (HGB) fluids, as well as methods for utilizing such HGB fluids for wellbore drilling operations, completion operations, and workover operations. Such low-density HGB fluids include the following combination of constituents: a base oil, an oil viscosifying agent, HGBs at a concentration in a range between 20 vol % and 60 vol %, an organophilic clay, a clay activator, a surfactant, and (optionally) an H.sub.2S scavenger. Moreover, the low-density HGB fluids are suitable for use as lower-density cap fluids for pressurized mudcap drilling (PMCD) operations, alternative drilling fluids for managed pressure drilling (MPD) operations, alternative drilling fluids for conventional drilling operations corresponding to very-low-pressure or highly-depleted reservoirs, and/or lightweight fluids for wellbore workover operations.

Provided here are various invert emulsion drilling fluid compositions. One such invert emulsion drilling fluid is a water in oil emulsion, which can include an invert emulsifier to stabilize the water in oil emulsion, a fatty acid, a 36 carbon fatty dimer diamine, a filtration control agent; and an inorganic mineral including one or more of lime, calcium chloride, and barite. The invert emulsion drilling fluids can be formulated to be substantially free of clay.