Changing method of CPMG test value increased by short waiting time test value

A measurement group, zero-space technology, applied in the direction of electric/magnetic detection, measurement device, magnetic resonance measurement, etc. for logging records, can solve the problem of inaccurate transformation output and so on

Inactive Publication Date: 2003-11-26
SCHLUMBERGER OVERSEAS SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, combining (or splicing) these two distributions into a common T2 distribution can lead to a less accurate transformed output

Method used

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  • Changing method of CPMG test value increased by short waiting time test value
  • Changing method of CPMG test value increased by short waiting time test value
  • Changing method of CPMG test value increased by short waiting time test value

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Embodiment Construction

[0030]FIG. 1 shows a schematic diagram of a nuclear magnetic resonance (NMR) logging tool 30 used to survey a formation 31 traversed by a borehole 32 . The NMR logging tool 30 is suspended in the borehole 32 by an armored cable 33 , the length of which substantially determines the relative depth of the logging tool 30 . The cable length is controlled by suitable means on the ground, such as the cable reel and winch mechanism 7A. The surface unit 7 may include a processor subsystem for communicating with downhole equipment including the NMR logging tool 30 .

[0031] NMR logging tool 30 may be any suitable nuclear magnetic resonance device. It may be a suitable wireline device as shown in Figure 1, or a device capable of logging while drilling (LWD). The NMR logging tool 30 generally includes equipment for generating a static magnetic field in the structure, at least one radio frequency (RF) antenna, and for generating pulses of RF energy in the formation to induce a RF magne...

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Abstract

A method for determining an earth formation property from nuclear magnetic resonance measurements includes applying suppression functions to spin echoes in at least one burst measurement set to produce a modified burst data set, the suppression functions to suppress contribution of spin echoes having non-negligible polarization correction; inverting the modified burst data set and at least one standard spin echo measurement set to produce a nuclear magnetic resonance parameter distribution, the at least one standard spin echo measurement set and the at least one burst measurement set being acquired on an earth formation sample; and computing the earth formation property from the nuclear magnetic resonance parameter distribution. The nuclear magnetic resonance parameter includes at least one selected from longitudinal relaxation time, transverse relaxation time, a ratio of longitudinal relaxation time to transverse relaxation time, and diffusion constant.

Description

technical field [0001] The present invention generally relates to the field of well logging, and in particular relates to a well logging technology using nuclear magnetic resonance tools and a method for transforming and processing nuclear magnetic resonance data. Background technique [0002] Oil well logging tools include nuclear magnetic resonance (NMR) tools. NMR instruments can be used to determine properties of the formation, such as the volume of the pore portion, the volume of the pore portion filled by flowing fluid, and the total porosity of the formation. The general background of NMR logging is described in US Patent Application US6140817, which has been assigned to the assignee of this patent. [0003] Typically, the signals measured by NMR logging tools arise from selected nuclei present in the probed volume. Since hydrogen nuclei are most numerous and easy to detect, most NMR logging tools are tuned to detect hydrogen resonance signals (from water or hydroca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R33/44G01V3/32
CPCG01N24/081G01V3/32
Inventor R·海德勒
Owner SCHLUMBERGER OVERSEAS SA
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