摘要:
When NMR spin echo measurements are obtained with one or more of (i) different echo intervals, (ii) different static field gradients, (iii) different polarization times, or (iv) noise levels, due to fluid diffusivity, the spin echo measurements cannot be simply combined. However, by applying a correction factor, such a combination is possible, giving an improved interpretation of the formation properties.
摘要:
NMR data are acquired using a phase-alternation of the tipping pulse. Differences between consecutive samples acquired with same or different frequencies are determined and an average value of the differences is determined over a sample window and over a range of echoes. This average value, determined separately for the in-phase and quadrature component data is a measure of the systematic noise and may be applied to the in-phase and quadrature component data to give corrected data with a higher resolution than prior art methods of processing phase alternated pulse sequence data. The method may also be used to improve the resolution of multifrequency NMR data acquired with a gradient logging tool.
摘要:
Various embodiments include apparatus and methods to determine properties of a structure using data measurements on the structure. These measurements can be subjected to an inversion process that uses an optimization procedure conducted in a continuous function space. Additional apparatus, systems, and methods are disclosed.
摘要:
A method of calculating a porosity of a geological formation includes determining a bulk pore volume and a movable fluid pore volume in the geological formation in which drilling mud including a mud filtrate is introduced, calculating a porosity of the formation based on a bulk pore volume, and correcting the porosity based on the movable fluid volume in the geological formation.
摘要:
A method for performing a downhole operation includes marking at least one location in a wellbore using a magnetized material. The magnetized material may generate a magnetic field stronger than a magnetic field generated in the wellbore by a surrounding formation.
摘要:
A method and apparatus for estimating a flow rate of a phase of a multiphase fluid is disclosed. A first velocity distribution is obtained for a first set of nuclei in the fluid from a Nuclear Magnetic Resonance (NMR) signal received for the fluid in response to a first NMR excitation signal. A second velocity distribution is obtained for a second set of nuclei in the fluid from an NMR signal received for the fluid in response to a second NMR excitation signal. A velocity of the phase is estimated from the first velocity distribution and the second velocity distribution. The flow rate of the phase is estimated using the estimated velocity of the phase and an estimated volume fraction of the phase.
摘要:
A method for determining a proportion of a hydrocarbon constituent in a mixture including at least one hydrocarbon, includes determining at least one nuclear magnetic resonance (NMR) property for at least one hydrocarbon constituent in the mixture; correlating an NMR response for the property for each hydrocarbon constituent in the mixture; and from the correlating, calculating the proportion of at least the constituent. A computer program product is also provided.
摘要:
Data from a string of multiple formation evaluation data sensor are evaluated by an expert system. Based on the analysis, the logging speed is increased if all the sensors justify it, and is reduced if any of the sensors require a reduced logging speed. Alternatively, the sensitive volume of a NMR sensor is altered based on a determination of a fraction of the sensitive volume that includes a borehole fluid. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
摘要:
The grain size of a pore-scale geometric model of a clastic earth formation are adjusted so that the NMR relaxation time distribution output of the model matches a measured NMR distribution. Fluid drainage and imbibing can be simulated. Additional properties of the earth formation are predicted using the pore-scale model. The additional properties may be based on additional measurements of properties of a fluid in the formation.
摘要:
Data from a string of multiple formation evaluation data sensor are evaluated by an expert system. Based on the analysis, the logging speed is increased if all the sensors justify it, and is reduced if any of the sensors require a reduced logging speed. Alternatively, the sensitive volume of a NMR sensor is altered based on a determination of a fraction of the sensitive volume that includes a borehole fluid. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.