WO2006058005A1 - Fast t1 measurement of an earth formation by using driven equilibrium - Google Patents
Fast t1 measurement of an earth formation by using driven equilibrium Download PDFInfo
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- WO2006058005A1 WO2006058005A1 PCT/US2005/042328 US2005042328W WO2006058005A1 WO 2006058005 A1 WO2006058005 A1 WO 2006058005A1 US 2005042328 W US2005042328 W US 2005042328W WO 2006058005 A1 WO2006058005 A1 WO 2006058005A1
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- pulse
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/18—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
- G01V3/32—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with electron or nuclear magnetic resonance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N24/00—Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects
- G01N24/08—Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects by using nuclear magnetic resonance
- G01N24/081—Making measurements of geologic samples, e.g. measurements of moisture, pH, porosity, permeability, tortuosity or viscosity
Definitions
- the present invention is related to methods of geological exploration in wellbores.
- the present invention is a method of improving nuclear magnetic resonance pulse techniques.
- a variety of techniques are currently utilized in determining the presence and estimation of quantities of hydrocarbons (oil and gas) in earth formations. These methods are designed to determine formation parameters, including among other things, the resistivity, porosity and permeability of the rock
- the tools designed to provide the desired information are used to log the wellbore. Much of the logging is done after the wellbores have been drilled. More recently, wellbores have been logged while drilling, which is referred to as measurement- while-drilling (MWD) or logging- while-drilling (LWD).
- MWD measurement- while-drilling
- LWD logging- while-drilling
- NMR Nuclear Magnetic Resonance
- the NMR tools generate a static magnetic field in a region of interest surrounding the wellbore. NMR is based on the fact that the nuclei of many elements have angular momentum (spin) and a magnetic moment. The nuclei have a characteristic Larmor resonant frequency related to the magnitude of the magnetic field in their locality. Over time the nuclear spins align themselves along an externally applied magnetic field.
- the spins return to the equilibrium direction (i.e., aligned with the static field) according to an exponential decay time known as the spin-lattice relaxation time or Ti.
- ⁇ /2 ⁇ 4258 Hz/Gauss, so that a static field of 235 Gauss would produce a precession frequency of 1 MHz.
- the Tj of fluid in pores is controlled totally by the molecular environment and is typically ten to several thousand milliseconds in rocks.
- the spins continue to precess, but now their phases converge until they momentarily align a further time tcp after application of the 180° pulse.
- the realigned spins induce a voltage in a nearby receiving coil, indicating a spin echo.
- Another 180° pulse is applied after a further time tcp, and the process is repeated many times, thereby forming a series of spin echoes with spacing 2 t C p between them.
- Optimized Rephasing Pulse Sequence which optimizes the timings for inhomogeneous Bo and B] fields to obtain maximum NMR signal or, alternatively, to save radio frequency power.
- a pulsed RF field is applied which tips the spins on resonance by the desired tip angle for maximum signal, typically 90° tipping pulse.
- a refocusing pulse having a spin tip angle substantially less than 180° is applied with carrier phase shifted by typically ⁇ /2 radians with respect to the 90° tipping pulse. Although the refocusing pulses result in spin tip angles less than 180° through the sensitive volume, their RF bandwidth is closer to that of the original 90° pulse.
- ORPS is not a CPMG sequence, since the timing and duration of RF pulses are altered from conventional CPMG to maximize signal and minimize RF power consumption. Nevertheless ORPS also possesses the characteristic that the tipping pulse is phase shifted by ⁇ /2 with respect to the refocusing pulses.
- An additional forced recovery pulse at the end of an echo train may be used to speed up the acquisition and/or provide a signal for canceling the ringing artifact. The forced recovery pulse occurs at the same time as the formation of an echo and acts about the same axis as the original 90° tipping pulse.
- the final pulse rotates the nuclear spins (that are in the process of forming the echo) away from the transverse (XY) plane and back into substantial alignment with the magnetic field. Since the final magnetization is in equilibrium with the static magnetic field, such a pulse sequence is often referred to as a Driven Equilibrium pulse sequence. It is shown by Edzes ("An analysis of the Use of Pulse Multiplets in the Single Scan Determination of Spin-Lattice Relaxation Rates", J. Mag. Res., 17, 301-313 (1975)) that errors arising from inhomogeneities in the static and RF magnetic fields, from improper RF phases or from resonance offset, can largely be compensated by using a proper pulse multiplet, i.e. a driven equilibrium pulse sequence. Edzes also discusses a method of obtaining a spin-lattice relaxation constant using pulse multiplets evenly spaced in time after an inversion pulse.
- a driven equilibrium pulse sequence is discussed, for example, in U.S. Patent No. 6,597,171, to Hurlimann et al.
- a sequence of magnetic pulses is applied to a fluid in a rock, the sequence including a first part that is designed to prepare a system of nuclear spins in the fluid in a driven equilibrium followed by a second part that is designed to generate a series of magnetic resonance signals.
- the first part can be a driven equilibrium pulse sequence.
- Repeated use of a driven equilibrium block results in an equilibrium magnetization that is dependent on Tj and Tj. Combining such driven equilibrium blocks with the usual CPMG sequence gives the Ti and Tj of the sample.
- Hurlimann ' 171 uses driven equilibrium pulses for preparation of a sample for Ti or Tj measurements, there is no discussion of using echo signals within the driven equilibrium sequence for directly determining fo ⁇ nation and/or fluid properties.
- At least one radio frequency pulse is generated covering a relatively wide range of frequencies to saturate the nuclear magnetization in a cylindrical volume around the tool; transmitting a readout pulse at a frequency near the center of the range of covered frequencies, the readout pulse following a predetermined wait time; applying at least one refocusing pulse following the readout pulse; receiving at least one NMR echo corresponding to the readout pulse; repeating the above steps for a different wait time to produce a plurality of data points on a T / relaxation curve; and processing the produced Ti relaxation curve to derive petrophysical properties of the formation.
- One embodiment of the present invention is a method of evaluating an earth formation.
- a driven-equilibrium (DE) pulse group is applied to the earth formation to generate at least one echo signal.
- a longitudinal relaxation time Ti of the earth formation is estimated using an amplitude of the at least one echo signal.
- the at least one echo signal may be a plurality of echo signals.
- a plurality of DE groups may be applied after a saturation sequence to get a Ti distribution.
- a Ti distribution may also be obtained by applying a plurality of DE groups after an inversion sequence.
- a CPMG or ORPS sequence may follow to gather Ti relaxation decay data from which a T 2 distribution can be estimated.
- the signals may be further processed to determine, porosity, clay bound water, bound water irreducible, bound water moveable, diffusivity and/or permeability.
- the apparatus includes a nuclear magnetic resonance (NMR) tool which applies at least one driven-equilibrium (DE) pulse group to the earth formation to generate at least one echo signal.
- a processor estimates a longitudinal relaxation time Ti of the earth formation using an amplitude of the at least one echo signal.
- the at least one echo signal may comprises a plurality of echo signals.
- the at least one DE pulse group may have a plurality of DE pulse groups, and when the plurality of DE groups are applied subsequent to a saturation sequence a Ti distribution may be estimated.
- a Ti distribution may be obtained also be estimated by applying a plurality of DE groups following an inversion sequence.
- the processor may further estimate porosity, clay bound water, bound water irreducible, bound water moveable, diffusivity, and/or permeability.
- the NMR tool may be a zero gradient tool or one in which a static field gradient is present in a region of examination.
- the NMR tool may be on a bottomhole assembly (BHA) for drilling operations, or may be part of a downhole logging assembly conveyed on a wireline
- Another embodiment of the invention is a machine readable medium having instructions of evaluation of an earth formation
- the medium includes instructions for estimating a longitudinal relaxation time Tj of the earth formation using an amplitude of at least one echo signal produced by applying at least one driven-equilibrium (DE) pulse group to the earth formation.
- the medium further includes instructions for estimating a distribution of values of T/.
- the medium may further include instructions for estimating porosity, clay bound water, bound water irreducible, bound water moveable, diffusivity and/or permeability.
- the medium may also include instructions for applying one or more DE pulse groups to the earth formation.
- the medium may also include instructions for applying pulse sequences including a plurality of DE groups, and processing the resulting signals to determine a T 2 distribution.
- FIG. 1 shows a measurement- while-drilling tool suitable for use with the present invention
- FIG. IA shows the antenna and magnet configuration of an exemplary NMR device suitable for use with the present invention
- FIG. 2 shows a typical driven equilibrium (DE) group
- Figs. 3A-B show spin echo responses to a series of DE pulse groups
- Figs. 4A-B show spin echo responses to a series of DE pulse groups, each designed to give rise to three spin echoes
- Fig. 5A shows a pulse sequence usable for a conventional saturation recovery Tj method
- FIG. 5B shows a pulse sequence for a conventional inversion recovery Ti method
- Fig. 6A shows a pulse sequence for a fast saturation recovery Ti method
- Fig. 6B shows a pulse sequence usable for a fast inversion recovery Ti method
- Fig. 7A shows a pulse sequence that combines a fast saturation recovery Ti method with a CPMG or ORPS sequence to also measure T 2 or a T 2 distribution
- Fig. 7B shows a pulse sequence that combines a fast inversion recovery Ti method with a CPMG or ORPS sequence to also measure Ti or a T 2 distribution.
- FIG. 1 shows a schematic diagram of a drilling system 10 with a drillstring 20 carrying a drilling assembly 90 (also referred to as the bottom hole assembly, or "BHA") conveyed in a "wellbore" or “borehole” 26 for drilling the wellbore.
- the drilling system 10 includes a conventional derrick 11 erected on a floor 12 which supports a rotary table 14 that is rotated by a prime mover such as an electric motor (not shown) at a desired rotational speed.
- the drillstring 20 includes a tubing such as a drill pipe 22 or a coiled-tubing extending downward from the surface into the borehole 26. The drillstring 20 is pushed into the wellbore 26 when a drill pipe 22 is used as the tubing.
- a tubing injector such as an injector (not shown), however, is used to move the tubing from a source thereof, such as a reel (not shown), to the wellbore 26.
- the drill bit 50 attached to the end of the drillstring breaks up the geological formations when it is rotated to drill the borehole 26.
- the drillstring 20 is coupled to a drawworks 30 via a Kelly joint 21, swivel 28, and line 29 through a pulley 23.
- the drawworks 30 is operated to control the weight on bit, which is an important parameter that affects the rate of penetration.
- the operation of the drawworks is well known in the art and is thus not described in detail herein.
- the drilling fluid (source) 32 is circulated under pressure through a channel in the drillstring 20 by a mud pump 34.
- the drilling fluid passes from the mud pump 34 into the drillstring 20 via a desurger (not shown), fluid line 38 and Kelly joint 21.
- the drilling fluid 31 is discharged at the borehole bottom 51 through an opening in the drill bit 50.
- the drilling fluid 31 circulates uphole through the annular space 27 between the drillstring 20 and the borehole 26 and returns to the mud pit 32 via a return line 35.
- the drilling fluid acts to lubricate the drill bit 50 and to carry borehole cutting or chips away from the drill bit 50.
- a sensor S 1 typically placed in the line 38 provides information about the fluid flow rate.
- a surface torque sensor S 2 and a sensor S 3 associated with the drillstring 20 respectively provide information about the torque and rotational speed of the drillstring. Additionally, a sensor (not shown) associated with line 29 is used to provide the hook load of the drillstring 20.
- the drill bit 50 is rotated by only rotating the drill pipe 22.
- a downhole motor 55 (mud motor) is disposed in the drilling assembly 90 to rotate the drill bit 50 and the drill pipe 22 is rotated usually to supplement the rotational power, if required, and to effect changes in the drilling direction.
- the mud motor 55 is coupled to the drill bit 50 via a drive shaft (not shown) disposed in a bearing assembly 57.
- the mud motor rotates the drill bit 50 when the drilling fluid 31 passes through the mud motor 55 under pressure.
- the bearing assembly 57 supports the radial and axial forces of the drill bit.
- a stabilizer 58 coupled to the bearing assembly 57 acts as a centralizer for the lowermost portion of the mud motor assembly.
- a drilling sensor module 59 is placed near the drill bit 50.
- the drilling sensor module contains sensors, circuitry and processing software and algorithms relating to the dynamic drilling parameters. Such parameters typically include bit bounce, stick-slip of the drilling assembly, backward rotation, torque, shocks, borehole and annulus pressure, acceleration measurements and other measurements of the drill bit condition.
- a suitable telemetry or communication sub 72 using, for example, two-way telemetry, is also provided as illustrated in the drilling assembly 90.
- the drilling sensor module processes the sensor information and transmits it to the surface control unit 40 via the telemetry system 72.
- the communication sub 72, a power unit 78 and an MWD tool 79 are all connected in tandem with the drillstring 20. Flex subs, for example, are used in connecting the MWD tool 79 in the drilling assembly 90. Such subs and tools form the bottom hole drilling assembly 90 between the drillstring 20 and the drill bit 50.
- the drilling assembly 90 makes various measurements including the pulsed nuclear magnetic resonance measurements while the borehole 26 is being drilled.
- the communication sub 72 obtains the signals and measurements and transfers the signals, using two-way telemetry, for example, to be processed on the surface. Alternatively, the signals can be processed using a downhole processor in the drilling assembly 90.
- the surface control unit or processor 40 also receives signals from other downhole sensors and devices and signals from sensors SpS 3 and other sensors used in the system 10 and processes such signals according to programmed instructions provided to the surface control unit 40.
- the surface control unit 40 displays desired drilling parameters and other information on a display/monitor 42 utilized by an operator to control the drilling operations.
- the surface control unit 40 typically includes a computer or a microprocessor-based processing system, memory for storing programs or models and data, a recorder for recording data, and other peripherals.
- the control unit 40 is typically adapted to activate alarms 44 when certain unsafe or undesirable operating conditions occur.
- Magnets 132 and 134 are permanently magnetized, for example, in the axial direction and, in one embodiment, are positioned in opposing directions. Like magnetic poles, for example, the north magnetic poles of the two magnets 132 and 134 face one another for producing a toroidal region of substantially homogeneous radial magnetic field 140 perpendicular to the pair of axially aligned magnets 132 and 134.
- a radio frequency (RF) transmitting antenna or coil 136 is located, for example, between the two spaced-apart magnets 132 and 134.
- the RF coil 136 is connected to a suitable RF pulse transmitter for providing power at selected frequencies and a processor which determines a pulse sequence timing.
- the RF coil 136 is pulsed and creates a high frequency RF field orthogonal to the static magnetic field.
- the pulsed RF coil 136 creates the pulsed RF field 142 illustrated by dashed lines.
- the distance of the toroidal region 140 of homogeneous radial magnetic field from the axis of the magnets 132 and 134 is dependent upon the distance between like poles of the magnets 132 and 134.
- Rock pores (not shown) in the earth formations are filled with fluid, typically water or hydrocarbon.
- the hydrogen nuclei in the fluid are aligned in the region of homogeneous magnetic field 140, generated by the magnets 132 and 134.
- the hydrogen nuclei are then "flipped" away from the homogeneous magnetic field 140 by the pulsed RF field 142 that must fulfill the resonance condition (2) and is produced by RF coil 136.
- the hydrogen nuclei revolve or precess at high frequency around the magnetic field 140 inducing an NMR signal in the RF coil 136.
- the induced NMR signals are sent to the surface for processing or can be processed by a downhole processor (not shown).
- a downhole processor not shown.
- Other variations for conducting NMR experiments would be known to those versed in the art, and any of these could be used in the application of the present invention.
- This basic structure is used, for example, in U.S. Patent 6,215,304 to Slade, the contents of which are fully incorporated herein by reference.
- the tool of Slade is what is called a "zero gradient" tool in which the static magnetic field gradient in the region of examination is close to zero.
- the method of the present invention may also be used with NMR tools that have field gradients.
- An example of such a device is shown in U.S Patent 6,348,792 to Beard et al., having the same assignee as the present invention and the contents of which are fully incorporated herein by reference.
- Equilibrium in an NMR system is the state in which the affected nuclear spins are in equilibrium with the surrounding magnetic field and temperature, (i.e., parallel to the static external field, generally referred to as the z-axis).
- the actual magnetization can be manipulated by RF pulses to point along the z-axis using a method of "Driven Equilibrium".
- FIG. 2 One example of a driven equilibrium (DE) group used in accordance with the present invention is shown in Fig. 2.
- a group of driven equilibrium RF pulses can be used to probe the z-magnetization by tipping it into the xy plane, generating an echo and tipping it back into the z direction.
- the DE group of Fig. 2 comprises the sequence: 90 x - ⁇ - l 80 y - ⁇ (echo) ⁇ - 180 y - ⁇ - 9O. X . (3)
- a combination of 9O x tipping pulse 201 and 180 y refocusing pulse 203 (applied at a time ⁇ after the tipping pulse) trigger a spin echo 220 in the acquisition window between 203 and 205.
- the dephasing spins are refocused using a second 180 y refocusing pulse 205.
- a time ⁇ after the latter refocus pulse 205 the spins refocus again and at this time a 90 -x recovery pulse 207 performs the opposite function of the initial 9O x tipping pulse 201 by flipping the magnetization back along the z direction.
- Approximately 80%-90% of the initial magnetization can be recovered in practice.
- pulse sequences can be used in practice, such as replacing a signal acquisition window with a 90 -x pulse following the second or subsequent echoes. It will be apparent to a person of skill in the art that different timing can be used in various practical applications as well.
- the DE group like the CPMG pulse sequence, corrects for cumulative pulse errors.
- cumulative pulse errors are compensated from the second echo of the primary echo train onward.
- the error from the 9O x pulse is also compensated. Consequently, the echoes of successive DE groups have the same amplitude. Minor differences in the amplitudes of echoes from successive DE groups are generally attributable to the presence of stimulated echoes.
- Figs. 3-4 show simulations using a series of DE pulse groups obtained using an NMR simulation program.
- pulse lengths corresponding to 180° are not used. Instead, shorter pulse lengths, such as those used in an ORPS sequence, are implemented.
- Figs. 3A-B show spin echo responses to a series of DE pulse groups.
- Each DE pulse group is designed to give rise to one spin echo (e.g. the DE group of Eq. (3)).
- Fig. 3 A shows an echo sequence with 10 such DE pulse groups 300.
- time is shown along the abscissa in seconds, and amplitude is shown along the ordinate in arbitrary units.
- the resultant spin echo magnetization values along the x- axis 305 are also shown.
- Fig. 3B shows echo amplitudes corresponding to each of the 10 DE pulse groups of Fig. 3A. As can be seen from Fig. 3B, the echo amplitudes, after an initial transition period, hardly vary at all.
- DE pulse groups which give rise to more than one spin echo.
- the first spin echo does not achieve the full amplitude whereas the second spin echo is generally more representative of the maximum possible echo amplitude.
- Figs. 4A-B show spin echo responses to a series of DE pulse groups, each designed to give rise to three spin echoes. At the time when the 4' echo would appear, a 90 -x pulse aligns the magnetization back along the z-axis. As expected, the second echo of each pulse sequence achieves a greater amplitude. It can be useful to obtain more than one echo by increasing the length of the driven equilibrium block.
- Fig. 4A shows an echo sequence with 10 DE pulse groups 400 comprising 3 spin echoes each.
- time is shown along the abscissa in seconds and amplitude along the ordinate in arbitrary units as in Fig. 3A.
- Spin echo magnetization values along the x-axis 405 are shown.
- Fig. 4B shows echo amplitudes obtained with the DE pulse groups of Fig. 4A.
- the DE group index is shown along the abscissa.
- Letters a to c denote the first to third echoes of each DE group.
- the continuity of echo amplitudes can be seen.
- the arbitrary amplitude units of all the four figs. 3A/B and 4A/B are the same for the echo amplitudes. Comparing Fig. 4B with Fig. 3B we see that for the DE groups with 3 echoes all the echo amplitudes are greater than the average echo amplitude of Fig. 3B that produced one echo per DE group.
- Figs. 5-6 illustrate how the driven equilibrium sequence can be used to speed up Tj measurements.
- Fig. 5A shows a pulse sequence usable for a conventional saturation recovery Tj method.
- Blocks marked S (501) indicate a saturation sequence, e.g. aperiodic sequence (APS), and blocks marked D (503) denote a detection sequence, e.g. short CPMG or ORPS.
- ⁇ i, ⁇ 2 , ⁇ 3 etc. are delay times.
- Blocks marked 7 indicate an inversion sequence (e.g. 180° pulse or fast adiabatic sweep), and blocks marked D (509) denote a detection sequence, e.g. short CPMG or ORPS.
- ⁇ j, % 2 , etc. are delay times, and T ⁇ is a wait time of sufficient length to achieve equilibrium magnetization.
- two ⁇ ; are shown in Fig. 5 A but less or more are possible.
- Tw is about 3 to 5 times the longest expected Tj.
- the inversion recovery method for obtaining T) gives higher quality data than the saturation sequence (Fig. 5A) because the detected magnetizations span a range of two Mo while the magnetizations using the saturation recovery span only one Mo, where Mo is the equilibrium magnetization in the applied static magnetic field.
- the incorporation of wait times Tw in the inversion recovery method cause it to take much longer than the saturation recovery method.
- FIG. 6A shows a pulse sequence usable for a fast saturation recovery T ⁇ method.
- the block marked S (601) indicates a saturation sequence, e.g. aperiodic sequence (APS).
- Blocks marked DE (603) denote a driven equilibrium block.
- Each DE block detects one or more echoes and ends with magnetization in z direction.
- ⁇ ⁇ , ⁇ 2 , ⁇ 3 etc. are the times at which the recovering magnetization is sampled.
- Fig. 6B shows a pulse sequence usable for a "fast" inversion recovery
- T w indicates the wait time to reach equilibrium magnetization.
- the block marked / (607) indicates an inversion sequence (e.g. 180° pulse or fast adiabatic sweep), and blocks marked DE (609) denote a driven equilibrium block, detecting one or more echoes and ending with magnetization in z direction.
- X 1 , X 2 , ⁇ 3 etc. are times at which the recovering magnetization is sampled.
- Fig. 7a shows the fast saturation recovery sequence of Fig. 6a followed by a CPMG or ORPS sequence.
- 710 is an excitation pulse (typically 90°)
- 711 are the refocusing pulses (180° for CPMG, less than 180° for ORPS)
- 712 are spin echoes.
- Fig. 7b shows the inversion recovery sequence of Fig. 6b followed by CPMG or ORPS sequence.
- 710' is an excitation pulse (typically 90°)
- 711' are the refocusing pulses (180° for CPMG, less than 180° for ORPS)
- 712' are spin echoes.
- the number of DE groups in figures 7A and 7B may be more or less than those shown.
- Tj and Ti distributions can be processed using prior art methods to determine parameters of interest of the earth formation and fluids in the earth formation. These parameters include porosity, clay bound water, bound water irreducible, bound water moveable, diffusivity and permeability
- the wait time with the DE blocks before the CPMG needs to be at least 3 to 5 times the longest expected Tl time. It is worth mentioning that the recovery sampled by the DE groups is strictly not governed by Tl relaxation alone but contains some contribution of T2 relaxation within each DE block In the same way the T2 measurement in the following CPMG is governed by a contribution of Tl relaxation too due to the inhomogeneous magnetic field and hence a stimulated echo contribution.
- Tl editing M.D. H ⁇ rlimann and L. Venkataramanan, J. Magn. Reson. 157, 31-42 (2002).
- NMR data sampled in this way can be graphed three-dimensionally to show a T1-T2 distribution of the earth formation.
- the NMR signals obtained from the echoes within the DE groups may be affected by motion of the NMR tool. Where the motion is known the signals may be corrected very similar to the method disclosed in US patent application Ser. No. 10/918,965 filed on August 16, 2004
- the processing of the data may be accomplished by a downhole processor.
- measurements may be stored on a suitable memory device and processed upon retrieval of the memory device.
- Implicit in the control and processing of the data is the use of a computer program on a suitable machine readable medium that enables the processor to perform the control and processing.
- the machine readable medium may include ROMs, EPROMs, EAROMs, Flash Memories and Optical disks.
- the method is equally applicable to wireline applications in which the NMR tool is conveyed on a wireline.
- all or part of the processing may be done at the surface or at a remote location.
- the NMR tool is typically part of a downhole string of logging instruments.
Abstract
Description
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Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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CA002587896A CA2587896A1 (en) | 2004-11-22 | 2005-11-19 | Fast t1 measurement of an earth formation by using driven equilibrium |
NO20072657A NO20072657L (en) | 2004-11-22 | 2007-05-24 | Rapid T1 painting of a soil formation using driven equilibrium |
GB0711757A GB2436037A (en) | 2004-11-22 | 2007-06-18 | Fast T1 measurement of an earth formation by using driven equilibrium |
Applications Claiming Priority (2)
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US62996704P | 2004-11-22 | 2004-11-22 | |
US60/629,967 | 2004-11-22 |
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WO2006058005A1 true WO2006058005A1 (en) | 2006-06-01 |
WO2006058005B1 WO2006058005B1 (en) | 2006-08-03 |
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PCT/US2005/042328 WO2006058005A1 (en) | 2004-11-22 | 2005-11-19 | Fast t1 measurement of an earth formation by using driven equilibrium |
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CA (1) | CA2587896A1 (en) |
GB (1) | GB2436037A (en) |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN102330548A (en) * | 2011-08-08 | 2012-01-25 | 中国石油大学(北京) | Method for obtaining NMR (nuclear magnetic resonance) echo strings for ringing elimination |
CN112710688A (en) * | 2019-10-24 | 2021-04-27 | 中国石油天然气股份有限公司 | Nuclear magnetic resonance longitudinal relaxation acquisition method and system |
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WO2002008795A2 (en) * | 2000-07-21 | 2002-01-31 | Services Petroliers Schlumberger | Nuclear magnetic resonance measurements and methods of analyzing nuclear magnetic resonance data |
US6392409B1 (en) * | 2000-01-14 | 2002-05-21 | Baker Hughes Incorporated | Determination of T1 relaxation time from multiple wait time NMR logs acquired in the same or different logging passes |
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WO2002099462A2 (en) * | 2001-06-05 | 2002-12-12 | Halliburton Energy Services, Inc. | System and methods for formation evaluation while drilling |
-
2005
- 2005-11-19 CA CA002587896A patent/CA2587896A1/en not_active Abandoned
- 2005-11-19 WO PCT/US2005/042328 patent/WO2006058005A1/en active Application Filing
-
2007
- 2007-05-24 NO NO20072657A patent/NO20072657L/en not_active Application Discontinuation
- 2007-06-18 GB GB0711757A patent/GB2436037A/en not_active Withdrawn
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US5023551A (en) * | 1986-08-27 | 1991-06-11 | Schlumberger-Doll Research | Nuclear magnetic resonance pulse sequences for use with borehole logging tools |
US6466013B1 (en) * | 1999-04-19 | 2002-10-15 | Baker Hughes Incorporated | Nuclear magnetic resonance measurements in well logging using an optimized rephasing pulse sequence |
US6392409B1 (en) * | 2000-01-14 | 2002-05-21 | Baker Hughes Incorporated | Determination of T1 relaxation time from multiple wait time NMR logs acquired in the same or different logging passes |
WO2002008795A2 (en) * | 2000-07-21 | 2002-01-31 | Services Petroliers Schlumberger | Nuclear magnetic resonance measurements and methods of analyzing nuclear magnetic resonance data |
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Title |
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HÜRLIMANN M D ET AL: "Quantitative Measurement of Two-Dimensional Distribution Functions of Diffusion and Relaxation in Grossly Inhomogeneous Fields", JOURNAL OF MAGNETIC RESONANCE, ACADEMIC PRESS, ORLANDO, FL, US, vol. 157, no. 1, July 2002 (2002-07-01), pages 31 - 42, XP004408045, ISSN: 1090-7807 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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CN102330548A (en) * | 2011-08-08 | 2012-01-25 | 中国石油大学(北京) | Method for obtaining NMR (nuclear magnetic resonance) echo strings for ringing elimination |
CN112710688A (en) * | 2019-10-24 | 2021-04-27 | 中国石油天然气股份有限公司 | Nuclear magnetic resonance longitudinal relaxation acquisition method and system |
CN112710688B (en) * | 2019-10-24 | 2023-08-22 | 中国石油天然气股份有限公司 | Nuclear magnetic resonance longitudinal relaxation acquisition method and system |
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GB0711757D0 (en) | 2007-07-25 |
GB2436037A (en) | 2007-09-12 |
NO20072657L (en) | 2007-08-20 |
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