Halliburton Energy Services, Inc.

Numar Corporation

Daniel Lee Miller

James Elmer Galford

John C Bouton

Manfred G Prammer

Ridvan Akkurt

Peter Ian Day

Richard F Sigal

Ron Cherry

Songhua Chen

Rebecca Corina Jachmann

Jie Yang

Wei Shao

George R Coates

George Richard Coates

Duncan Mardon

Lei Bob Hou

Ronnel Charles Balliet

Prabhakar R Aadireddy

MingJen Wang

Prabhakar Aadireddy

An NMR logging system is disclosed which continues logging without interruption despite switching activation sets to adapt to changes in formation properties. Based on detection of an approaching or encountered geological boundary, an appropriate activation set is transmitted to the downhole NMR tool while the NMR tool continues logging. This system optimizes NMR data collection for each formation and associated formation fluid properties while reducing the need to stop the tool string movement while switching the activation set, and reduces incomplete collection of NMR and non-NMR logging tool data.

NMR data acquisition while switching NMR activation sets

Nuclear magnetic resonance apparatuses and systems are described. In an example, the apparatus comprises a tool housing and a magnet assembly disposed within the tool housing to produce a magnetic field in a volume in a geological formation. An external housing containing an antenna assembly is coupled to the tool housing.

External housing for signal to noise improvement

An method and system are disclosed for NMR echo-train data acquisition and processing for enhanced vertical resolution for a given signal to noise ratio. In one aspect, the method is based on providing an estimate of non-formation signal components and removing the estimate from the NMR signals. Computation of the estimate is done from the data itself or using a direct measurement of non-formation signals. In another aspect, the functions of reducing coherent noise components is separated from the function of reducing the random noise components, to enhance the resolution of the NMR pulse echo data for a given signal to noise ratio (SNR) of the data. Combination processing is disclosed, which enables efficient filtering of the input NMR data for both relatively high and relatively low SNR of the formation data.

Method and apparatus for improving the vertical resolution of NMR logs

Borehole NMR logging apparatus and methods. A multifrequency method using triple-wait-time is disclosed for determining gas- and light-oil-filled porosity over a broad range of reservoir conditions. The method improves the signal-to-noise ratio and the determination of T values for the hydrocarbons, especially when the reservoir contains different fluid types. A set of conditions is derived for the selection of optimum acquisition parameters for logging applications. The data acquisition and processing method enables accurate determination of the pore volumes occupied by each hydrocarbon phase as well as the pore volume occupied by water, as well as accurate T . A set of conditions is developed to aid in the selection of wait-time combinations appropriate for logging conditions.

NMR apparatus and methods for measuring volumes of hydrocarbon gas and oil

A simple, pore-level model for diffusion and NMR relaxation of oil-water mixtures in water wet pores has been developed. In addition to lending physical insight into the relaxation time behavior of mixed pore fluids, the model can be used to generate a practical tool for interpreting diffusion log data, i.e., a T2 vs. D cross plot. Locating points on the cross plot simultaneously yields the near wellbore water saturation and the rock pore size. For light oils, T2 is shown to be mainly a pore size indicator whereas D is controlled mainly by Sw. The pore size 'resolution' decreases as oil viscosity and/or Sw decreases. A preliminary verification of the model has been made with limited core data and the results of applying the model to interpreting NMR log data are encouraging. The capability to separate the effects of pore size from fluid saturation on NMR response of pore fluids indicates an important potential advantage of the T2 and D measurement combination over standard T2 logging for characterizing formation pore size and related reservoir flow properties.

NMR system and method for formation evaluation using diffusion and

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Kingwood, TX, United States of America

Daniel Lee Miller