Apparatus and methods for making azimuthal resistivity measurements

• US 9,645,276 B2
• Filed: 01/12/2016
• Issued: 05/09/2017
• Est. Priority Date: 06/12/2013
• Status: Expired due to Fees

• Current Assignee: Well Resolutions Technology
• Original Assignee: Well Resolutions Technology
• Inventors: Wang, Tsili
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US14/993,165
• Publication Number:
  US 20160124107A1
• Time in Patent Office: 483 Days
• Field of Search: 324339, 7315202
• CPC Class Codes: E21B 17/1078 Stabilisers or centralisers for casing, tubing or drill pipes devices for off-center positioning E21B17/10; E21B17/1007 - E21B17/1064 take precedence
• CPC Class Codes: E21B 44/005 Below-ground automatic control systems
• CPC Class Codes: E21B 47/024 of devices in the borehole determining slope or direction of the borehole E21B47/022
• CPC Class Codes: E21B 47/09 Locating or determining the position of objects in boreholes or wells , e.g. the position of an extending arm; Identifying the free or blocked portions of pipes
• CPC Class Codes: E21B 49/00 Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
• CPC Class Codes: E21B 7/062 the tool shaft rotating inside a non-rotating guide travelling with the shaft E21B7/067 and E21B7/068 take precedence
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: G01V 3/26 operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device with electromagnetic waves G01V3/30
• CPC Class Codes: G01V 3/28 using induction coils
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves
• CPC Class Codes: G01V 3/34 Transmitting data to recording or processing apparatus; Recording data
• CPC Class Codes: G06F 16/24554 Unary operations; Data partitioning operations
• CPC Class Codes: G06F 16/24578 using ranking

Abstract

A resistivity measuring tool used in a drillstring having a drill bit on a distal end for drilling a wellbore in a formation includes a tool body having a longitudinal axis, a sensor configured to measure the angular position of the tool body relative to the wellbore, at least one axial antenna including a wire winding for generating an axial magnetic moment parallel with the longitudinal axis, and at least one transverse antenna. The transverse antenna includes an antenna body disposed within a pocket extending radially inward from an outer surface of the tool body and one or more turns of wire wound around the antenna body, the wire winding generating a transverse magnetic moment orthogonal to the longitudinal axis.

Claims

1. A method of making resistivity measurements of a formation from a wellbore being drilled, the method comprising:

providing a resistivity measuring tool comprising;

a tool body having a sensor configured to measure the angular position of the tool body relative to the wellbore,

a first axial transmitting antenna including a wire winding symmetric about a longitudinal axis of the tool body for generating an axial magnetic moment,

a second axial transmitting antenna including a wire winding symmetric about a longitudinal axis of the tool body for generating an axial magnetic moment, and

transverse antenna disposed including a wire winding for generating a transverse magnetic moment and located longitudinally between the first and second axial transmitting antennas;

simultaneously transmitting electromagnetic energy into the formation from the first and second axial antennas, thereby inducing a voltage signal related to a formation parameter in the wire winding of the transverse antenna;

combining and processing the signals generated due to the first and second axial transmitting antennas to (i) reduce or remove a formation resistivity anisotropy effect and thereby enhance a bed boundary effect, or (ii) reduce or remove the bed boundary effect and thereby enhance the formation resistivity anisotropy effect;

measuring an angular position of the tool body relative to the wellbore with the sensor; and

correlating the formation parameter with the measured angular position of the tool body.

2. The method of claim 1, further comprising driving currents to the first and second axial antennas for generating axial magnetic moments in opposite directions, thereby inducing a voltage signal in the wire winding of the transverse antenna related to a parameter of an adjacent bed boundary.

3. The method of claim 1, further comprising driving currents to the first and second axial antennas for generating axial magnetic moments in the same direction, thereby inducing a voltage signal in the wire winding of the transverse antenna related to a parameter of formation resistivity anisotropy.

4. The method of claim 1, further comprising:

partitioning a circumference of the tool body into M number of sectors;

defining each data point of the resistivity information by a fidelity function g(Φ

);

assigning to each data point a weight for each of the M number of sectors, wherein the weight is associated with an integral of the fidelity function g(Φ

) over the sector; and

computing an average of the data points weighted by their respective weights for each of the M sectors.

5. The method of claim 1, further comprising providing multiple transverse antennas disposed proximate to the outer surface of the tool body and azimuthally-spaced around a circumference of the tool body.