Estimating casing wear due to drill string reciprocation

Patent metadata

Field	Value
Publication number	US-9752388-B2
Application number	US-201514917398-A
Country	US
Kind code	B2
Filing date	Jun 12, 2015
Priority date	Jun 12, 2015
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

Estimating casing wear during a reciprocation portion of a drilling operation may take into account the forces that cause casing wear during the up and down strokes independently. For example, during a drilling operation, a method may include reciprocating the drill string through the wellbore for a plurality of up strokes and a plurality of down strokes according to reciprocation parameters; calculating an up stroke normal force and a down stroke normal force for the casing or a section thereof; calculating up and down stroke casing wears based on the up and down stroke normal forces, respectively, using a reciprocation casing wear model; calculating a reciprocation casing wear based on the up and down stroke casing wears; and calculating a total casing wear for the casing or the section thereof based on the reciprocation casing wear using a total casing wear model.

First claim

The invention claimed is:

1. A method comprising:
drilling a wellbore penetrating a subterranean formation with a drill bit coupled to an end of a drill string extending into the wellbore, wherein a portion of the wellbore is lined with casing;
reciprocating the drill string within the wellbore for a plurality of up strokes and a plurality of down strokes according to reciprocation parameters that include a reciprocation operation time, a drill string revolutions per minute (rpm), a stroke length for the plurality of up and down strokes, and a stroke rate for the plurality of up and down strokes;
calculating an up stroke normal force and a down stroke normal force for the casing or a section thereof based on the reciprocation parameters using a soft string model, a stiff string model, a finite element model;
calculating an up stroke casing wear based on the up stroke normal force using a reciprocation casing wear model;
calculating a down stroke casing wear based on the down stroke normal force using the reciprocation casing wear model;
calculating a reciprocation casing wear based on the up and down stroke casing wears; and
calculating a total casing wear for the casing or the section thereof based on the reciprocation casing wear using a total casing wear model.

2. The method of claim 1 , wherein the up and down stroke casing wears are further based on a wear factor based on physical and material properties of the drill string.

3. The method of claim 1 , wherein the up and down stroke casing wears are further based on a wear factor based on physical and material properties of the casing or the section thereof.

4. The method of claim 1 , wherein the up and down stroke casing wears are further based on a wear factor based on physical and material properties of a drilling fluid contained in the wellbore.

5. The method of claim 1 , wherein the up and down stroke casing wears are further based on a contact distance per stroke according to Equation 1, where AD is the stroke length and RD is a rotational distance of the drill string
contact distance per stroke=√{square root over (AD 2 +RD 2 )}  Equation 1,

6. The method of claim 1 , wherein calculating the total casing wear is further based on a drilling casing wear caused by the drill string during drilling.

7. The method of claim 1 further comprising:
tripping the drill string through the wellbore, wherein calculating the total casing wear is further based on a tripping casing wear caused by the drill string during a tripping operation.

8. The method of claim 1 further comprising:
rotating the drill string without axially moving the drill string along the wellbore, wherein calculating the total casing wear is further based on a rotating off bottom casing wear caused by the drill string rotating the drill string without axially moving.

9. The method of claim 1 further comprising:
assigning a threshold value for the total casing wear for the casing or the section thereof; and
performing a remedial operation on the casing or the section thereof when the total casing wear exceeds the threshold value.

10. A method comprising:
simulating a drilling operation with a mathematical model of drilling a wellbore with a drill bit coupled to an end of a drill string extending into the wellbore, wherein a portion of the wellbore is lined with casing, the mathematical model being stored in a non-transitory medium readable by a processor for execution by the processor;
reciprocating the drill string through the wellbore for a plurality of up strokes and a plurality of down strokes according to reciprocation parameters that include a reciprocation operation time, a drill string revolutions per minute (rpm), a stroke length for the plurality of up and down strokes, and a stroke rate for the plurality of up and down strokes;
calculating an up stroke normal force and a down stroke normal force for the casing or a section thereof based on the reciprocation parameters using a soft string model, a stiff string model, a finite element model;
calculating an up stroke casing wear based on the up stroke normal force using a reciprocation casing wear model;
calculating a down stroke casing wear based on the down stroke normal force using the reciprocation casing wear model;
calculating a reciprocation casing wear based on the up and down stroke casing wears;
calculating a total casing wear for the casing or the section thereof based on the reciprocation casing wear using a total casing wear model;
assigning a threshold value for the total casing wear for the casing or the section thereof; and
changing at least one parameter of the drilling operation when the total casing wear exceeds the threshold value.

11. The method of claim 10 , wherein the at least one parameter of the drilling operation is a composition of the casing or the section thereof.

12. The method of claim 10 , wherein the at least one parameter of the drilling operation is a composition of the drill string or a section thereof.

13. The method of claim 10 , wherein the up and down stroke casing wears are further based on a wear factor based on physical and material properties of the drill string.

14. The method of claim 10 , wherein the up and down stroke casing wears are further based on a wear factor based on physical and material properties of the casing or the section thereof.

15. The method of claim 10 , wherein the up and down stroke casing wears are further based on a wear factor based on physical and material properties of a drilling fluid contained in the wellbore.

16. The method of claim 10 , wherein the up and down stroke casing wears are further based on a contact distance per stroke according to Equation 1, where AD is the stroke length and RD is the rotational distance of the drill string
contact distance per stroke=√{square root over (AD 2 +RD 2 )}  Equation 1.

17. The method of claim 10 , wherein calculating the total casing wear is further based on a drilling casing wear caused by the drill string during drilling.

18. The method of claim 10 further comprising:
rotating the drill string without axially moving the drill string along the wellbore, wherein calculating the total casing wear is further based on a rotating off bottom casing wear caused by the drill string rotating the drill string without axially moving.

19. A drilling system comprising:
a drill bit coupled to an end of a drill string extending into a wellbore, wherein a portion of the wellbore is lined with casing;
a pump operably connected to the drill string for circulating a drilling fluid through the wellbore;
a control system that includes a non-transitory medium readable by a processor and storing instructions for execution by the processor for performing a method comprising:
receiving reciprocation parameters related to reciprocating the drill string within the wellbore for a plurality of up strokes and a plurality of down strokes, the reciprocation parameters including a reciprocation operation time, a drill string revolutions per minute (rpm), a stroke length for the plurality of up and down strokes, and a stroke rate for the plurality of up and down strokes;
calculating an up stroke normal force and a down stroke normal force for the casing or a section thereof based on the reciprocation parameters using a soft string model, a stiff string model, a finite element model;
calculating an up stroke casing wear based on the up stroke normal force using a reciprocation casing wear model;
calculating a down stroke casing wear ba

Assignees

• Landmark Graphics Corp

Inventors

• Aniket
• Gonzales Adolfo
• Samuel Robello

Classifications

• G06F2111/10

  Numerical modelling · CPC title

• G06F30/20

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• E21B12/02 Primary

  Wear indicators · CPC title

• E21B49/003 Primary

  by analysing drilling variables or conditions (E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00) · CPC title

• G06F2217/16

  Physics · mapped topic