摘要:
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.
摘要:
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.
摘要:
Methods for processing sonic logging data obtained from a logging tool having an array of R receivers, includes selecting a sub-array size of Rsb receivers where Rsb
摘要:
Methods and related systems are described for use for determining orientation of a measurement tool in a cased borehole. The measurement tool is deployed in a cased section of a borehole. The tool includes a volume containing a reference fluid having a first density, and a marker within the fluid having a different density. The position of the marker within volume containing the reference fluid is senses, and orientation information of the measurement tool is determined based at least in part on combining information relating to the position of the marker with prior recorded data representing orientation measurements made while the section of the borehole was not yet cased.
摘要:
An integrated framework is described for automating some or all of mud slowness estimation for both fast and slow formations. An estimation of fluid slowness based on monopole radial profiling is calculated if conditions permit. Alternatively, an estimation of fluid slowness based on Scholte wave slowness is estimated if conditions do not permit calculation based on monopole radial profiling. Tool standoff may also be estimated based on monopole radial profiling.
摘要:
Methods for determining the best value for at least one slowness-related parameter that has been determined in a number of ways is disclosed. Sonic logging data input in the methods are processed to determine multiple values of at least one slowness-related parameter using slowness/time coherence (STC) processing methods. The error of each determined parameter is determined and the determined errors used in selecting a representative parameter value from the multiple determined slowness-related parameter values.
摘要:
Automatic detection and accurate time picking of weak events embedded in strong noise such as microseismicity induced by hydraulic fracturing is accomplished by: a noise reduction step to separate out the noise and estimate its spectrum; an events detection and confidence indicator step, in which a new statistical test is applied to detect which time windows contain coherent arrivals across components and sensors in the multicomponent array and to indicate the confidence in this detection; and a time-picking step to accurately estimate the time of onset of the arrivals detected above and measure the time delay across the array using a hybrid beamforming method incorporating the use of higher order statistics. In the context of hydraulic fracturing, this could enhance the coverage and mapping of the fractures while also enabling monitoring from the treatment well itself where there is usually much higher and spatially correlated noise.
摘要:
Methods and apparatus to filter acoustic waveforms in downhole environments are described. An example method involves receiving acoustic waveform data representing acoustic signals traversing at least a portion of a borehole adjacent a subterranean formation and performing a direct transform operation on the acoustic waveform data to generate wavelet map data. The wavelet map data comprises a time-frequency representation of the acoustic waveform data. The example method also involves identifying a waveform of interest via the wavelet map data, extracting data associated with the waveform of interest from the wavelet map data, generating filtered wavelet map data based on the extracted data, and performing an inverse transform operation on the filtered wavelet map data to generate filtered acoustic waveform data
摘要:
Methods and related systems are described for use for determining orientation of a measurement tool in a cased borehole. The measurement tool is deployed in a cased section of a borehole. The tool includes a volume containing a reference fluid having a first density, and a marker within the fluid having a different density. The position of the marker within volume containing the reference fluid is senses, and orientation information of the measurement tool is determined based at least in part on combining information relating to the position of the marker with prior recorded data representing orientation measurements made while the section of the borehole was not yet cased.
摘要:
Systems, methods, and apparatus to drive reactive loads are disclosed. An example apparatus to drive a reactive load includes a reactive component in circuit with the reactive load, a first switching element in circuit with the reactive load to selectively hold the reactive load in a first energy state and to selectively allow the reactive load to change from the first energy state to a second energy state, a second switching element in circuit with the reactive load to selectively hold the reactive load in the second energy state and to selectively allow the reactive load to change from the second energy state to the first energy state, and a controller to detect a current in the reactive load, and to control the first and second switching elements to hold the reactive load in the first or the second energy state when the current traverses a threshold.