Abstract: Compositions and methods of using same are described for negating asphaltene deposition in a formation, wellbore, near wellbore region, and production tubing. Compositions of the invention comprise an asphaltene solvent and a viscosity reducing agent, the asphaltene solvent and viscosity reducing agent present in a ratio so as to substantially reduce viscosity of an asphaltene-containing material while substantially negating deposition of asphaltenes either in a reservoir, in production tubing, or both when mixed or otherwise contacting the asphaltene-containing material.

Abstract: A method for determining a wax appearance temperature of a fluid includes obtaining nuclear magnetic resonance (NMR) measurements of the fluid at a plurality of temperatures; deriving a NMR parameter from each of the NMR measurements; and determining the wax appearance temperature by analyzing the NMR parameter as a function of temperature. An apparatus for detecting wax appearance in a fluid includes a sample cell for holding a fluid for nuclear magnetic resonance (NMR) measurements at a plurality of temperatures; a temperature measuring device disposed proximate the sample cell; a magnet for polarizing molecules in the fluid in the sample cell; at least one radiofrequency (RF) coil for generating pulses of magnetic field and for detecting NMR signals; and circuitry for controlling and measuring the temperature of the fluid in the sample cell and for obtaining NMR measurements.

Abstract: The viscosity of a heavy oil is estimated according to a power law equation which relates the heavy oil viscosity to a function of the assumed, measured, or estimated glass transition temperature of the heavy oil and the measured temperature of the heavy oil.

Abstract: The viscosity ? (in centipoise) of a heavy oil sample is determined according to an equation of the form ln ? ? g = - C ? ? 1 * ( T - c ? ? 246 ) c ? ? 47.10 + ( T - c ? ? 246 ) , where T is the temperature of the heavy oil, T2LM is the logarithmic mean of the T2 distribution of the sample obtainable from nuclear magnetic resonance (NMR) measurements, c?=1.0±0.05, c?=1.0±0.04, ?g is the glass transition temperature viscosity of the heavy oil and a function of T2LM, and C1 is a variable which is a constant for the heavy oil and is a function of T2LM. Both C1 and ?g are considered functions of certain NMR values associated with the heavy oil sample, with ?g and C1 preferably estimated by empirically fitting data to the equations lnT2LM=a?+b?ln?g and lnT2LM=a?+b?C1, where a?, b?, a? and b? are constants.

Abstract: Viscosity of heavy oil is determined in situ in a formation by making nuclear magnetic resonance (NMR) measurements in the formation, and then calculating viscosity according to an equation of the form T 2 ? LM = a + b ? ( ? T ) c , where T is the temperature of the heavy oil sample, ? is the viscosity, T2LM is the logarithmic mean of the T2 distribution spectrum of the sample, and a, b, and c are non-zero constants. Typically, constant b has a value between 5 and 7 and constant c has a value between ?0.7 and ?0.5.

Abstract: A method and system for characterizing asphaltene gradients of a reservoir of interest and analyzing properties of the reservoir of interest based upon such asphaltene gradients. The analysis employs a correlation that relates insoluble asphaltene concentration to spectrophotometry measurement data measured at depth.

Abstract: A method for determining a wax appearance temperature of a fluid includes obtaining nuclear magnetic resonance (NMR) measurements of the fluid at a plurality of temperatures; deriving a NMR parameter from each of the NMR measurements; and determining the wax appearance temperature by analyzing the NMR parameter as a function of temperature. An apparatus for detecting wax appearance in a fluid includes a sample cell for holding a fluid for nuclear magnetic resonance (NMR) measurements at a plurality of temperatures; a temperature measuring device disposed proximate the sample cell; a magnet for polarizing molecules in the fluid in the sample cell; at least one radiofrequency (RF) coil for generating pulses of magnetic field and for detecting NMR signals; and circuitry for controlling and measuring the temperature of the fluid in the sample cell and for obtaining NMR measurements.

Abstract: deposition in a formation, wellbore, near wellbore region, and production tubing. Compositions of the invention comprise an asphaltene solvent and a viscosity reducing agent, the asphaltene solvent and viscosity reducing agent present in a ratio so as to substantially reduce viscosity of an asphaltene-containing material while substantially negating deposition of asphaltenes either in a reservoir, in production tubing, or both when mixed or otherwise contacting the asphaltene-containing material Methods of the invention comprise forcing a composition comprising an asphaltene solvent and a viscosity reducing agent to contact an asphaltene-containing hydrocarbon in an underground geologic formation, and producing from the formation a production composition comprising at least some of the treatment composition and at least some of the asphaltene-containing hydrocarbon under conditions sufficient to substantially negate deposition of asphaltenes in the formation.

Abstract: A method for estimating a concentration of a substance in a test sample of formation fluid, comprising measuring an NMR parameter of a first sample of formation fluid to obtain a first measurement, adding a known quantity of the substance to the first sample to produce a modified sample, measuring the NMR parameter of the modified sample to obtain a second measurement; and determining a relation between the concentration of the substance and a function of the NMR parameter using the first and second measurements and the NMR parameter of the substance.

Abstract: A technique includes providing a deposition measuring device having a deposition from a fluid sample on an interior surface of the device. The technique also includes operating the device with a solvent to produce a solvent solution that contains the deposition. The solvent solution is used to quantify at least one chemical compound that is present in the deposition.