WO2007116317A2 - Blindage électromagnétique et magnétostatique permettant d'effectuer des mesures en avant du trépan - Google Patents

Blindage électromagnétique et magnétostatique permettant d'effectuer des mesures en avant du trépan Download PDF

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Publication number
WO2007116317A2
WO2007116317A2 PCT/IB2007/001241 IB2007001241W WO2007116317A2 WO 2007116317 A2 WO2007116317 A2 WO 2007116317A2 IB 2007001241 W IB2007001241 W IB 2007001241W WO 2007116317 A2 WO2007116317 A2 WO 2007116317A2
Authority
WO
WIPO (PCT)
Prior art keywords
downhole assembly
earth formation
receiver
transmitter
transient electromagnetic
Prior art date
Application number
PCT/IB2007/001241
Other languages
English (en)
Other versions
WO2007116317A3 (fr
Inventor
Gregory B. Itskovich
Original Assignee
Baker Hughes Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/682,381 external-priority patent/US20070216416A1/en
Application filed by Baker Hughes Incorporated filed Critical Baker Hughes Incorporated
Priority to BRPI0710580-0A2A priority Critical patent/BRPI0710580A2/pt
Publication of WO2007116317A2 publication Critical patent/WO2007116317A2/fr
Publication of WO2007116317A3 publication Critical patent/WO2007116317A3/fr

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Classifications

    • 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
    • G01V3/26—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device
    • G01V3/28—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device using induction coils

Definitions

  • the invention relates to the field of electromagnetic induction well logging. More specifically, the present invention is a method of reducing effects of conductive drill pipes on signals in transient electromagnetic measurements for evaluation of earth formations ahead of the drillbit.
  • Magnetostatically shielding the receiver may further include providing a ferrite coating and/or a cut on a drilling tubular. Electromagnetically shielding the receiver may further include using a highly conductive material.
  • the method may further include obtaining a reference signal with the downhole assembly suspended in air, and using the reference signal in estimating the distance. The estimated distance may be further use to control a direction of drilling of a bottomhole assembly. The estimated distance may be used in further operations.
  • 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 preferably 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 S 1 -S 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 preferably 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 preferably adapted to activate alarms 44 when certain unsafe or undesirable operating conditions occur. Not shown in Fig. 1 are details about the logging tool of the present invention, discussed below.
  • Transmitter coil 201 is capable of inducing a magnetic moment.
  • the transmitter coil 201 is oriented to induce a magnetic moment along the Z-direction.
  • the receiver coil assembly 204, 205 comprises an array of the Z-oriented coils 204 and the X-oriented coils 205 having magnetic moments oriented so as to be capable of detecting induced magnetic moments along orthogonal directions (i.e., M 2 , and M x , respectively).
  • M 2 , and M x orthogonal directions
  • the eddy currents produced from a Z-transmitter can exist for a long time and typically have the longest possible rate of decay of all transient electromagnetic signals.
  • Longitudinal cuts disposed in the damping portion 202 force the eddy currents to follow one or more high resistivity paths instead of circumferential circuits, thereby inducing a quicker rate of decay of the eddy currents.
  • Inducing a fast decay of the eddy currents in the drill pipe 202a enables improved measurements of the transient electromagnetic signal components. Such improvements enable improved determination of information, for instance, about positions of oil/water boundaries and/or resistivity of the surrounding earth formation.
  • Fig. 2 illustrates one configuration of the transmitter 201 and receiver(s) 204, 205
  • the Z-oriented transmitter coil 201 can be positioned along the damping portion 202
  • a receiver coil pair 205-204 comprising an X-oriented coil 205 and a Z-oriented receiver coil 204 may be axially displaced from the Z-oriented transmitter coil 201.
  • the receiver pair 205-204 may typically be placed at a distance of from about 0 m to about 10 m from the transmitter coil 201, also along the damping portion 202.
  • Itskovich discloses the use of damping for interrupting the flow of eddy currents induced in a member of the BHA, such as a tubular like the drill pipe 202a.
  • the damping portion 202 of the drill pipe 202a of the present illustrative embodiment has longitudinal cuts of sufficient length to interrupt the flow of eddy currents, in this case, about 10 m in length.
  • the transmitter-receiver pair 201-205-204 may be placed centrally in the damping portion 202 of the drill pipe 202a.
  • a ferrite coating may be provided on the member of the BHA, such as the tubular like the drill pipe 202a.
  • the use of cuts or a non-conducting ferrite coating may be referred to as magnetostatic shielding. Itskovich also teaches the use of a ferrite coating to provide magnetostatic shielding.
  • an MWD apparatus that includes a perfectly conducting mandrel acts in much the same way as a perfectly non-conducting logging tool body used in wireline applications. Methods developed over the years for wireline applications could then be used with little modification to MWD applications.
  • One point of novelty in Tabarovsky may lie in the recognition of a problem caused by an imperfectly conducting mandrel and the development of a processing method to deal with the effects of an imperfectly conducting mandrel.
  • Modeling results may be used to illustrate the effectiveness of the approach described in various illustrative embodiments of the present invention.
  • a two-layered formation as shown in Fig. 3 may be used.
  • the MWD tool 300 may be placed in a resistive upper half-space 315 with a resistivity R 01 of 50 ⁇ -m.
  • Ahead of a drillbit 311 , on the other side of a boundary 313 is a medium 320 with a resistivity R 02 of 1 ⁇ -m.
  • the boundary may be at a distance (0-5 m) below the drillbit 311.
  • the boundary 313 may be a bed boundary or may, for example, be a fluid interface between a hydrocarbon-saturated formation and a water-saturated formation.
  • the parameters of the model used in the modeling are the following:
  • the pipe radius 6 cm
  • Resistivity of the pipe 0.714x 10 '6 ⁇ -m
  • Resistivity of the copper shield 1.7 xlO " ⁇ -m
  • Resistivity R 02 of the conductive half-space 320 R 02 1 ⁇ -m.
  • Fig. 4 shows an inability of a tool without shielding, but otherwise similar to the MWD tool 300 of Fig. 3, to resolve the distance to the boundary 313 in the absence of shielding.
  • Fig. 4 shows transient electromagnetic signals 341, measured in volts (V) plotted against time (sec), corresponding to different distances of the interface 313 (Im, 2m, and 5m) from the drillbit 311 with no electromagnetic shielding 303 and no magnetostatic shielding 305.
  • V volts
  • sec time
  • the transient electromagnetic signals 361 corresponding to the different distances of the interface 313 (Im, 2m, and 5m) from the drillbit 311 are again not distinguishable in the case of a tool with the electromagnetic shielding 303, but with no magnetostatic shielding 305.
  • the transient electromagnetic signals 361 for the difference distances are indistinguishable from each other.
  • a reference calibration signal 363 obtained when the tool with the electromagnetic shielding 303, but with no magnetostatic shielding 305, is suspended in air.
  • Comparison of Fig. 5 with Fig. 4 shows the electromagnetic shielding 303 made of copper by itself does not improve the resolution, but it does reduce the transient electromagnetic signal intensity from both the earth formation and the metal pipe.
  • the reference calibration signal such as the reference calibration signal 421, for example, was discussed in Itskovich.
  • the reference calibration signal 421 may be subtracted from the transient electromagnetic signals represented by the curves 401, 403, and 405 measured under downhole conditions.
  • curves 441, 443, and 445 corresponding to the different distances of the interface 313 (Im, 2m, and 5m) from the drillbit 311, as shown in Fig. 8, are obtained.
  • Fig. 8 shows an ability of the MWD tool of Fig. 3 to resolve the distance to the boundary 313 using both the electromagnetic shielding 303 and the magnetostatic shielding 305 and the reference calibration signal 421.
  • the MWD tool 300 of Fig 3 may thus be used to determine distances to an interface such as the boundary 313 ahead of the drill bit 311.
  • Fig. 9 is a flow chart illustrating some of the steps of various illustrative embodiments of a method according to the present invention. In various illustrative embodiments, the steps that may be used to determine distances to an interface such as the boundary 313 ahead of the drill bit 311 may be illustrated in Fig. 9.
  • a calibration signal is obtained 501 with the MWD tool 300 suspended in air.
  • a resistivity model of the earth formation ahead of the drillbit 311 is defined 503. The initial resistivity model may come from knowledge of the local geology or it may be based on data from previously drilled wells.
  • Figs. 4-8 were for signals at a Z-oriented receiver coil, such as the Z-oriented receiver coil 204, corresponding to a Z- oriented transmitter coil, such as the Z-oriented transmitter coil 201.
  • the method of the present invention may also be used with other transmitter-receiver configurations and/or combinations and, in particular, with an X-oriented receiver coil, such as the X-oriented receiver coil 205, with a Z- oriented transmitter coil, such as the Z-oriented transmitter coil 201, for example.
  • the processing of the data may be accomplished by a downhole processor or a surface processor. Implicit in the control and processing of the data is the use of a computer program implemented 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/or optical disks.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Electromagnetism (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

Selon l'invention, un émetteur situé sur un ensemble fond de trou émet un signal électromagnétique transitoire dans une formation terrestre. Un récepteur situé sur l'ensemble fond de trou reçoit des signaux qui indiquent la résistivité de la formation et les distances séparant cette dernière des limites du lit. Une combinaison de blindage électromagnétique et de blindage électrostatique permet de déterminer la distance par rapport à une interface située en avant du trépan.
PCT/IB2007/001241 2006-03-15 2007-05-14 Blindage électromagnétique et magnétostatique permettant d'effectuer des mesures en avant du trépan WO2007116317A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
BRPI0710580-0A2A BRPI0710580A2 (pt) 2006-03-15 2007-05-14 Blindagem eletromagnética e magnetostática para realizar medidas adiante da broca

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US78244706P 2006-03-15 2006-03-15
US60/782,447 2006-03-15
US11/682,381 2007-03-06
US11/682,381 US20070216416A1 (en) 2006-03-15 2007-03-06 Electromagnetic and Magnetostatic Shield To Perform Measurements Ahead of the Drill Bit

Publications (2)

Publication Number Publication Date
WO2007116317A2 true WO2007116317A2 (fr) 2007-10-18
WO2007116317A3 WO2007116317A3 (fr) 2008-01-17

Family

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BR (1) BRPI0710580A2 (fr)
WO (1) WO2007116317A2 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3715655A (en) * 1970-12-30 1973-02-06 Texaco Inc Induction logging apparatus having a common series element for nulling
GB2100544A (en) * 1981-06-16 1982-12-22 Ensco Inc Radar drill guidance system
US4514693A (en) * 1977-12-27 1985-04-30 Texaco Inc. Dielectric well logging system with electrostatically shielded coils
EP0434439A2 (fr) * 1989-12-21 1991-06-26 Halliburton Company Procédé et dispositif pour faire des mesures à induction à travers un tubage
US20050167100A1 (en) * 2004-02-04 2005-08-04 Baker Hughes Incorporated Method of eliminating conductive drill parasitic influence on the measurements of transient electromagnetic components in MWD tools

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3715655A (en) * 1970-12-30 1973-02-06 Texaco Inc Induction logging apparatus having a common series element for nulling
US4514693A (en) * 1977-12-27 1985-04-30 Texaco Inc. Dielectric well logging system with electrostatically shielded coils
GB2100544A (en) * 1981-06-16 1982-12-22 Ensco Inc Radar drill guidance system
EP0434439A2 (fr) * 1989-12-21 1991-06-26 Halliburton Company Procédé et dispositif pour faire des mesures à induction à travers un tubage
US20050167100A1 (en) * 2004-02-04 2005-08-04 Baker Hughes Incorporated Method of eliminating conductive drill parasitic influence on the measurements of transient electromagnetic components in MWD tools

Also Published As

Publication number Publication date
BRPI0710580A2 (pt) 2014-06-24
WO2007116317A3 (fr) 2008-01-17

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