Downhole positioning control system with force compensation

Patent metadata

Field	Value
Publication number	US-10883340-B2
Application number	US-201616330293-A
Country	US
Kind code	B2
Filing date	Sep 22, 2016
Priority date	Sep 22, 2016
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

Methods and systems for controlling the downhole position and velocity of a work string using a downhole position and velocity controller may be configured or otherwise programmed to account for force compensation. For example, the work string may undergo significant length changes like thermal expansion and elongation or contraction due to inertial forces, self-weight, and wellbore pressure. Also, the downhole conditions (e.g., temperature, internal forces, self-weight, and wellbore pressure) can cause the work string to be overloaded and become damaged if fast or sudden manipulations occur. The dynamic model implemented with the downhole position and velocity controller may be configured to account for the downhole forces experienced by the work string due to downhole conditions to provide the position and velocity movements that should occur at the surface to achieve the desired position and velocity movements downhole.

First claim

The invention claimed is:

1. A method comprising:
conveying a work string along a wellbore penetrating a subterranean formation using a positioning tool that controls surface motion and force of the work string, the positioning tool being coupled to a controller;
measuring a surface condition selected from the group consisting of a work string condition, a wellbore pressure, a wellbore temperature, and any combination thereof;
modeling the work string with a dynamic model with the controller using the surface condition and a geometry of the wellbore as inputs of the dynamic model;
calculating a desired downhole position ({tilde over (Z)}* DH ) and a desired downhole velocity ({tilde over (Ż)}* DH ) based on the dynamic model;
calculating a surface position (Z* SF ) and a surface velocity (Ż* SF ) of the work string based on the {tilde over (Z)}* DH and the {tilde over (Ż)}* DH , and
conveying the work string with the positioning tool to the surface position and the surface velocity.

2. The method of claim 1 , wherein the positioning tool is a dual-jack.

3. The method of claim 1 , wherein the work string condition is selected from the group consisting of strain of the work string, torque applied to the work string, rotational speed of the work string, acceleration of the work string being conveyed into the wellbore, velocity of the work string being conveyed into the wellbore, position of the work string, force applied to move the work string along the wellbore, and any combination thereof.

4. The method of claim 1 further comprising:
measuring a downhole condition with a downhole sensor located within the wellbore, wherein the inputs for the dynamic model further include the downhole condition.

5. The method of claim 1 , wherein modeling the work string with the dynamic model involves estimating the work string as a set of interconnected point lumped masses.

6. The method of claim 1 , wherein the controller comprises a downhole position and velocity controller and a work string controller, and the method further comprising:
calculating a traveling head force command (F* TH ) of the positioning tool with the work string controller;
wherein calculating the {tilde over (Z)}* DH and the {tilde over (Ż)}* DH is also based on the F* TH and is performed by the downhole position and velocity controller;
calculating a set of surface position commands (Z SF ) and a set of surface velocity commands (Ż SF ) based on the {tilde over (Z)}* DH and the {tilde over (Ż)}* DH with the work string controller; and
wherein conveying the work string with the positioning tool is according to the set of surface position commands (Z SF ) and the set of surface velocity commands (Ż SF ).

7. The method of claim 6 , wherein the downhole position and velocity controller comprises an observer, a force profile estimator, a rate planner, and a second controller, and wherein calculating the desired downhole position and velocity of the work string as performed by the downhole position and velocity controller comprises:
calculating a current estimated position ({circumflex over (Z)}) and estimated velocity ({dot over ({circumflex over (Z)})}) with the observer based on a set of interconnected point lumped masses, the surface condition, and the traveling head force command;
calculating a string stress profile ([σ j ]) and a predicted disturbance frictional force ({hacek over (F)} D ) for the work string with the force profile estimator based on the {circumflex over (Z)} and the {circumflex over (Ż)};
calculating the {tilde over (Z)}* DH and the {tilde over (Ż)}* DH for the work string with the rate planner based on the [σ j ] and the {hacek over (F)} D ;
producing the {tilde over (Z)}* DH and the {tilde over (Ż)}* DH based on the surface position (Z* SF ) and the surface velocity (Ż* SF ); and
converting the Z* SF and the Ż* SF to the set of surface position commands (Z SF ) and the set of surface velocity commands (Ż SF ).

8. The method of claim 1 , wherein modeling the work string includes modeling the motion of a j th section of the work string according to Eq. (1):
m j {umlaut over (x)} j =−b j ( {dot over (x)} j −{dot over (x)} j−1 )+ b j+1 ( {dot over (x)} j+1 −{dot over (x)} j )− k j ( x j −x j−1 )+ k j+1 ( x j+1 −x j )− {circumflex over (F)} D [ j ]− F g −F p −k j ∝(Δ T j ) l j +k j+1 ∝(Δ T j+1 ) l j+1   (1)

where:
m j is a mass of the j th section of the work string x j is a displacement distance of the j th section of the work string measured from a nominal position
k j is an axial spring constant of the j th section of the work string
b j is an axial damping coefficient of the j th section of the work string
{circumflex over (F)} D is a point friction force
F g is a force due to gravity
F p is a force due to pressure difference between the internal and external of the work string
ΔT j is a change in kinetic energy
l j is a length of the j th section of the work string.

9. The method of claim 1 , wherein the dynamic model employs a Kalman filter.

10. A well system comprising:
a work string extending into a wellbore penetrating subterranean formation;
a positioning tool coupled to the work string at a surface location of the well system;
a surface sensor that measures a surface condition selected from the group consisting of a work string condition, a wellbore pressure, a wellbore temperature, and any combination thereof;
a controller communicably coupled to the positioning tool and the surface sensor, wherein the controller includes a non-transitory, tangible, computer-readable storage medium: containing a program of instructions that causes a computer system running the program of instructions to:
model the work string with a dynamic model with the controller using the surface condition and a geometry of the wellbore as inputs of the dynamic model;

calculate a desired downhole position ({tilde over (Z)}* DH ) and a desired downhole velocity ({tilde over (Ż)}* DH ) based on the dynamic model;
calculate a surface position (Z* SF ) and a surface velocity (Ż* SF ) of the work string based on the ({tilde over (Z)}* DH and the {tilde over (Ż)}* DH , and
convey the work string with the positioning tool to the surface position and the surface velocity.

11. The well system of claim 10 , wherein the positioning tool is a dual-jack.

12. The well system of claim 10 , wherein the work string condition is selected from the group consisting of strain of the work string, torque applied to the work string, rotational speed of the work string, acceleration of the work string being conveyed into the wellbore, velocity of the work string being conveyed into the wellbore, position of the work string, force applied to move the work string along the wellbore, and any combination thereof.

13. The well system of claim 10 , wherein the controller comprises a downhole position and velocity controller and a work string controller, and wherein the program of instructions further causes the computer system running the program of instructions to:
calculate a traveling head force command (F* TH ) of the positioning tool with the work string controller;
wherein the instruction to calculate the {tilde over (Z)}* DH and the {dot over ({tilde over (Z)})}* DH is also based on the F* TH and is performed by the downhole position and velocity controller;
calculate a set of surface position commands (Z SF ) and a set of surface velocity commands (Ż SF ) based on the {tilde over (Z)}* DH and the {tilde over (Ż)}* DH with the work string controller; and
wherein the i

Assignees

• Halliburton Energy Services Inc

Inventors

• Dykstra Jason D
• Wickramasinghe Imiya Manjula
• Bu Fanping

Classifications

• E21B41/00 Primary

  Equipment or details not covered by groups E21B15/00 - E21B40/00 · CPC title

• E21B47/00

  Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) · CPC title

• E21B47/007

  Measuring stresses in a pipe string or casing (for locating blocked portions of pipes E21B47/09) · CPC title

• G01P3/00

  Measuring linear or angular speed; Measuring differences of linear or angular speeds (G01P5/00 - G01P11/00 take precedence; {direction and speed indication G01P13/045}; counting mechanisms G06M) · CPC title

• E21B47/06

  Measuring temperature or pressure · CPC title