278 results about "Oil-based mud" patented technology

A method and apparatus for obtaining a resistivity measurement of an earth formation surrounding a borehole in an MWD device uses an electrode for injecting current into the earth formation and an electrode for obtaining a responsive signal from the borehole. The electrodes are located on the drill bit arm or blade. Measured resistivity values are obtained at the location of the drill bit. Measurements can be taken in both oil-based mud and water-based mud environments. Maximum or minimum resistivity can be used to best represent the resistivity of the surrounding formation.

Methods and systems are provided for downhole analysis of formation fluids by deriving fluid properties and associated uncertainty in the predicted fluid properties based on downhole data, and generating answer products of interest based on differences in the fluid properties. Measured data are used to compute levels of contamination in downhole fluids using an oil-base mud contamination monitoring (OCM) algorithm. Fluid properties are predicted for the fluids and uncertainties in predicted fluid properties are derived. A statistical framework is provided for comparing the fluids to generate, in real-time, robust answer products relating to the formation fluids and reservoirs thereof. Systematic errors in measured data are reduced or eliminated by preferred sampling procedures.

The present invention provides a downhole method and apparatus to determine the percentage of oil based mud or water based mud filtrate contamination in a formation fluid sample. The present invention determines the percentage of filtrate contamination in a sample comprised of a mixture of crude oil and an oil based mud filtrate or of formation brine and a water based mud filtrate. The filtrate contamination percentage is determined from a relationship between the densities of uncontaminated formation fluid and filtrate. Filtrate may oil based or water based mud. The density of formation fluid is determined from a series of high precision pressure measurements of formation fluid at a plurality of depths in a hydrocarbon producing well. The density of filtrate is provided by downhole measurements with a flexural mechanical resonator or by measurements made downhole or at the surface.

The invention relates to the formulation and application of water based predominantly pH neutral microemulsions and microemulsion forming surfactant systems essentially comprising a surfactant or surfactant˜end, lactates)—esters) of lactic acid—and water/brine and optionally solvent. Uniquely the formulations are acid and caustic free and also do not make use of alcohol, glycol and glycol ether components in the systems as co surfactant, co-solvent or mutual solvent. In particular the invention relates to the methods and the application of this microemulsion technology for use in industrial hard surface cleaning applications especially the inks and printing industries and the oil and gas industry. In addition the formulations can be used in the production of microemulsion based drilling muds (which may or may not be Oil Based Muds—OBMs) and they may be used to enhance the drill cuttings slurrification processes for re-injection purposes or for facilitated cuttings transport.

Single phase microemulsions improve the removal of filter cakes formed during drilling with oil-based muds (OBMs). The single phase microemulsion removes oil and solids from the deposited filter cake. Optionally, an acid capable of solubilizing the filter cake bridging particles may also be used with the microemulsion. In one non-limiting embodiment the acid may be a polyamino carboxylic acid. Skin damage removal from internal and external filter cake deposition can be reduced. In another optional embodiment, the single phase microemulsion may contain a filtration control additive for delaying the filter cake removal, destruction or conversion.

The present disclosure relates to a method to estimate a subsurface formation property. A downhole logging tool is provided and disposed in a wellbore. Multiple measurements of various measurement types are obtained at various depths of investigation using the downhole logging tool. The multiple measurements may include natural gamma ray measurements, density measurements, resistivity measurements, nuclear measurements, and nuclear magnetic resonance measurements. The signal-to-noise ratio of the measured signals is increased using, for example, lateral stacking and multi-shell inversion. The subsurface formation property is estimated using the increased signal-to-noise ratio signals. The subsurface formation property may include porosity, adsorbed gas volume, free gas volume, bound water volume, free water volume, oil volume, and kerogen volume. A fluid analysis may be performed using a multi-dimensional nuclear magnetic resonance technique. Fluids such as water, oil, gas, and oil-based mud in the wellbore may be identified and/or evaluated.

Methods and systems are provided for downhole analysis of formation fluids by deriving differential fluid properties and associated uncertainty in the predicted fluid properties based on downhole data less sensitive to systematic errors in measurements, and generating answer products of interest based on the differences in the fluid properties. Measured data are used to compute levels of contamination in downhole fluids using, for example, an oil-base mud contamination monitoring (OCM) algorithm. Fluid properties are predicted for the fluids and uncertainties in predicted fluid properties are derived. A statistical framework is provided for comparing the fluids to generate robust, real-time answer products relating to the formation fluids and reservoirs thereof. Systematic errors in measured data are reduced or eliminated by preferred sampling procedures.

A multi-mode oil base mud imager for use in non-conductive drilling fluid includes at least one current source—a current return pair, and one or more monitor electrodes not located between the current source and the current return of the current source—current return pair. Where more than one current source—current return pair is included, the tool is capable of multiple depths of investigation into surrounding formation. This data can be used as a gauge to establish the reliability of the data and to determine the resistance of the invaded zone around the borehole, as well as standoff distance of the tool from the borehole wall.

A composition for reducing lost circulation in a well, while drilling the well with a drilling mud, which is composed of a base fluid, a mixture of particles, and a blend of fibers. The composition is used by stopping drilling with the mud, injecting a spacer, injecting the water-based composition, injecting a spacer, and resuming drilling with the oil-based mud.

A method and apparatus for treating for disposal oil contaminated substrates, such as drill cuttings from drilling with an oil-based mud, by steam distillation. If necessary, the contaminated substrate 10 can be pretreated with an emulsion breaker 14. The contaminated substrate 10 can be treated with steam 16 in a first mixing still 12. The substrate can be optionally treated with a second steam source 20 in a second mixing still 18. The steam provides heat to vaporize the oil, moisture to treat the substrate and water to the reaction mixture. Recoverable constituents in the vapor can be condensed in a vapor collection system 24. The treated substrate 22 is essentially free of oil and can have a controlled water content. The process exhibits low energy consumption, rapid treatment, compact equipment and a high degree of process control.

The invention relates to a preparation method of a while-drilling plugging fluid for oil-based drilling fluid, belonging to the technical field of drilling fluid treatment in petroleum drilling projects. The preparation method of the while-drilling plugging fluid for oil-based drilling fluid comprises the following steps: dropwise adding an aqueous phase which contains a propylene water-soluble organic monomer A, a water-soluble crosslinking agent B and a powder-like organic material C into oil D which contains a dispersing agent E; and after emulsification, initiating by using an oxidation-reduction initiating system to obtain a stable suspension plugging agent. According to the while-drilling plugging fluid, a deformation function is realized, the fluid has good compatibility with the oil-based drilling fluid, and can resist the temperature which reaches 150 DEG C, the particle size is 1 micron-100 microns, and the permeable loss of the nano-micron-grade cracks and pores in oil-based sludge drilling can be rapidly and effectively blocked, so that the drilling operation cost is reduced; and according to the oil-based while-drilling plugging agent prepared through the method, drying and granulation are not needed, and the agent can be directly used for while-drilling plugging in the oil-based drilling fluid, and is convenient to use and easy to popularize.

A method and system for estimating native hydrocarbons from oil-based drilling muds with the aid of NMR data. Adaptive echo stacking may be used to balance between precision and sensitivity to changes in the fluid composition. Apparent T₂ decay time and effective diffusion constants derived from the NMR data may be transformed into an indication of native hydrocarbon type, using known diffusion constants, fuzzy logic, and neural networks.

The present invention provides a downhole method and apparatus using molecularly imprinted polymers to analyze a downhole fluid sample or determine the percentage of oil based mud filtrate contamination in a formation fluid sample.

A method is disclosed for using aqueous VES-based gravel carrier fluids in gravel packing operations using screens and shunt tubes that have been run into a well completed with an oil-based mud. With this method, the previously necessary but undesirable steps of first running in a perforated liner and then displacing the oil-based mud with an aqueous-based fluid in the region to be gravel packed are both avoided while the advantages of gravel packing with an aqueous-based fluid are retained.

The present invention provides a simple, robust, and versatile high-resolution spectrometer that is suitable for downhole use. The present invention provides a method and apparatus incorporating a spinning, oscillating or stepping optical interference filter to change the angle at which light passes through the filters after passing through a sample under analysis downhole. As each filter is tilted, the color or wavelength of light passed by the filter changes. Black plates are placed between the filters to isolate each filter's photodiode. The spectrometer of the present invention is suitable for use with a wire line formation tester, such as the Baker Atlas Reservation Characterization Instrument to provide supplemental analysis and monitoring of sample clean up. The present invention is also suitable for deployment in a monitoring while drilling environment. The present invention provides a high resolution spectometer which enables quantification of a crude oil's percentage of aromatics, olefins, and saturates to estimate a sample's gas oil ratio (GOR). Gases such as CO₂ are also detectable. The percentage of oil-based mud filtrate contamination in a crude oil sample can be estimated with the present invention by using a suitable training set and chemometrics, a neural network, or other type of correlation method.