281 results about "Oil-based mud" patented technology

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.

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.

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 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.

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.

An induction logging tool having transmitter and receiver antennas is used to make measurements of earth formations. The antennas may be mounted on the mandrel of a bottomhole assembly for MWD applications, or may be pad mounted for wireline applications. The induction measurements are inverted using a linearized model. The model parameters are determined in part from caliper measurements.