US 2020/0270982 A1Published application

Relative Azimuth Correction For Resistivity Inversion

AssigneeHalliburton Energy Services, Inc.

InventorsLi Pan, Hsu-Hsiang Wu

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Abstract

A method may comprise: inserting into a wellbore penetrating a subterranean formation a tool comprising: a transmitter sub assembly comprising a transmitter; and a receiver sub assembly comprising a receiver; generating an electromagnetic wave at the transmitter; propagating the electromagnetic wave through the subterranean formation; receiving the electromagnetic wave in the receiver; generating a response signal in the receiver; calculating a distance to a bed boundary position in a TVDp direction, wherein the TVDp direction is a direction where an angle between the TVDp direction and a tool axis is equal to a tool inclination from a true vertical direction (TVD), wherein TVD is a direction with respect to gravity; calculating a distance to bed boundary in a TST direction, wherein the TST direction is a true stratigraphic thickness direction in a direction towards a bed boundary; calculating a distance to bed boundary in a TVD direction; generating a formation characterization comprising a visual representation of the response signal and the distance to bed boundary in the TVD direction.

Claims19

Dependent claims

A method comprising:

inserting into a wellbore penetrating a subterranean formation a tool comprising:
a transmitter sub assembly comprising a transmitter;
and
a receiver sub assembly comprising a receiver;
generating an electromagnetic wave at the transmitter;
propagating the electromagnetic wave through the subterranean formation;
receiving the electromagnetic wave in the receiver;
generating a response signal in the receiver;
calculating a distance to a bed boundary position in a TVDp direction, wherein the TVDp direction is a direction where an angle between the TVDp direction and a tool axis is equal to a tool inclination from a true vertical direction (TVD), wherein TVD is a direction with respect to gravity;
calculating a distance to bed boundary in a TST direction, wherein the TST direction is a true stratigraphic thickness direction in a direction towards a bed boundary;
calculating a distance to bed boundary in a TVD direction;
and
generating a formation characterization comprising a visual representation of the response signal and the distance to bed boundary in the TVD direction,
wherein the distance to bed boundary in the TST direction is calculated by the following equation:
distance to bed boundary in TST direction=distance to bed boundary in TVDp direction×cos(ψ)
wherein ψ is an angle between the TVDp direction and the TST direction,
wherein the distance to bed boundary in the TVD direction is calculated by the following equation:
distance


to


bed


boundary


in


TVD


direction
=
distance


to


bed


boundary


in


TST


direction
sin

(
a
)

cos

(
c
)

sin

(
b
)
+
cos

(
b
)

cos

(
a
)
,
and wherein b is a tool inclination angle obtained from a survey tool, wherein c is a relative azimuth angle obtained from pre-processing, and wherein a is an angle between an axis of the tool and the TST direction calculated by the following equation a=b−ψ.

84 more elements

A method comprising:

inserting into a wellbore penetrating a subterranean formation a drill string comprising:
a transmitter sub assembly comprising a transmitter;
a receiver sub assembly comprising a receiver;
and
a wellbore drill bit;
circulating a drilling fluid through an interior of the drill string, through the wellbore drill bit, and into an annulus defined between the wellbore and drill string;
extending the wellbore through the subterranean formation;
generating an electromagnetic wave at the transmitter;
propagating the electromagnetic wave through the subterranean formation;
receiving the electromagnetic wave in the receiver;
generating a response signal in the receiver;
measuring a tool inclination angle b;
calculating a relative azimuth angle c from pre-processing;
calculating an angle ψ between a TVDp direction and TST direction, wherein the TVDp direction is a direction where an angle between the TVDp direction and a tool axis is equal to a tool inclination from a true vertical direction (TVD), wherein TVD is a direction with respect to gravity, and wherein the TST direction is a true stratigraphic thickness direction in a direction towards a bed boundary;
calculating a distance to a bed boundary in the TST direction by the following equation:
distance to bed boundary in TST direction=distance to bed boundary in TVDp direction×cos(ψ);
calculating a distance to a bed boundary in a TVD direction by the following equation:
distance


to


bed


boundary


in


TVD


direction
=
distance


to


bed


boundary


in


TST


direction
sin

(
a
)

cos

(
c
)

sin

(
b
)
+
cos

(
b
)

cos

(
a
)
wherein a=b−ψ;
generating a formation characterization comprising a visual representation of the response signal and the distance to the bed boundary in a true vertical depth direction;
and
adjusting at least one drilling parameter based on the formation characterization.

86 more elements

An apparatus comprising:

a transmitter sub assembly comprising a transmitter;
a receiver sub assembly comprising a receiver;
a survey tool;
a wellbore drill bit;
wherein the transmitter sub assembly is configured to generate an electromagnetic wave at the transmitter and propagate the electromagnetic wave through a subterranean formation, wherein the receiver is configured to receive the electromagnetic wave and generate a response signal, and wherein the survey tool is configured to measure a tool inclination angle;
at least one processor;
and
a memory coupled to the processor to provide software that configures the processor to calculate a relative azimuth angle c from pre-processing, calculate an angle between a TVDp direction and TST direction using an inversion scheme, and calculate a distance to a bed boundary in a true vertical depth direction by the following equation:
DTBB


in


TVD


direction
=
DTBB


in


TST


direction
sin

(
a
)

cos

(
c
)

sin

(
b
)
+
cos

(
b
)

cos

(
a
)
wherein DTBB in TVD direction is the distance to the bed boundary in the true vertical depth direction and DTBB in TST direction is the distance to the bed boundary in a true stratigraphic thickness direction and where a=b−ψ, wherein the TVDp direction is a direction where an angle between the TVDp direction and a tool axis is equal to a tool inclination from a true vertical direction (TVD), wherein TVD is a direction with respect to gravity, and wherein the TST direction is a true stratigraphic thickness direction in a direction towards a bed boundary.

56 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/462,122Filed 10 Jul 2018
Published: 27 Aug 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

E21B 47/0228
Of the borehole, e.g. using geomagnetism: using electromagnetic energy or detectors therefor
E21B 47/0224
Of the borehole, e.g. using geomagnetism: using seismic or acoustic means
G01V 3/26
Specially adapted for well-logging: operating with magnetic or electric fields produced or modified either by the surrounding earth formation or…
G01V 3/38
Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation: processing…

Family

US 11,015,432 B2Related patent
US 2020/0270982 A1This patent

From the US filing history. Foreign family members aren’t listed.

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