Systems and methods for torque and drag analysis of downhole systems
A method of analyzing torque and drag of a drill string in a wellbore includes receiving wellbore data including a trajectory of the wellbore, and receiving drill string data for the drill string, at least a portion of the drill string including an inner string positioned inside of the drill string. The method includes generating a virtual wellbore associated with the inner string based on an inner diameter of the drill string and based on the trajectory of the wellbore, and determining a set of inner forces for the inner string including an axial force based on the weight of the inner string and a set of contact forces between the inner string and the virtual wellbore. The method includes identifying a set of normal forces between the drill string and the wellbore based on simulating the inner forces as applied forces to the drill string.
1 . A method of analyzing torque and drag of a drill string in a wellbore, comprising:
receiving wellbore data including a trajectory of the wellbore at a range of measurement depths of interest;
receiving drill string data for the drill string, the drill string data identifying components that make up the drill string, the components including a liner string and an inner string positioned inside of the liner string, the drill string data further identifying geometry and material properties of the components;
solving a first single-layer finite element analysis (FEA) model for the inner string without the liner string, comprising:
generating a virtual wellbore associated with the inner string based on an inner diameter of the liner string and based on the trajectory of the wellbore;
constraining the virtual wellbore to be rigid and fixed along the trajectory of the wellbore;
applying one or more inner boundary conditions for the inner string including constraining an uphole end of the inner string to be fixed with respect to the virtual wellbore;
determining an inner axial force for the inner string based on a weight of the inner string; and
determining, based on the trajectory of the virtual wellbore, a set of inner contact forces on the inner string at one or more locations where the inner string contacts the virtual wellbore; and
solving a second single-layer FEA model for the liner string without the inner string, comprising:
applying one or more liner boundary conditions to the liner string, including fixing the liner string at a top of the wellbore;
applying a set of applied forces to the liner string, the set of applied forces including the inner axial force and a set of reaction forces corresponding to the set of inner contact forces on the inner string; and
identifying, based on the set of applied forces, a set of normal forces between the drill string and the wellbore;
simulating a movement of the drill string in the wellbore to determine, using the set of normal forces, one or more axial frictional forces and one or more torsional frictional forces acting on the drill string during the movement of the drill string, the movement representing a wellbore operation including at least one of pulling the drill string out of the wellbore, advancing the drill string into the wellbore, or rotating the drill string within the wellbore;
simulating axial tension of the drill string based on the one or more axial frictional forces;
simulating torque of the drill string based on the one or more torsional frictional forces;
identifying, based on the drill string data, one or more working limits for one or more components of the components that make up the drill string; and
predicting whether the wellbore operation will cause the one or more working limits to be met or exceeded for the one or more components based on the axial tension and the torque.
2 . The method of claim 1 , further comprising generating a plot of the axial tension of the drill string at one or more measurement depths of the range of measurement depths of interest.
3 . The method of claim 1 , further comprising generating a plot of the torque of the drill string at one or more measurement depths of the range of measurement depths of interest.
4 . The method of claim 1 , wherein determining the set of inner contact forces and identifying the set of normal forces includes simulating an axial load applied to the drill string to pull the drill string out of the wellbore.
5 . The method of claim 1 , wherein determining the set of inner contact forces and identifying the set of normal forces includes simulating an axial load applied to the drill string to advance the drill string into the wellbore.
6 . The method of claim 1 , wherein determining the set of inner contact forces and identifying the set of normal forces includes the simulating of the torque.
7 . The method of claim 1 , wherein solving the first single-layer FEA model further includes constraining a downhole end of the inner string to be laterally fixed with respect to the virtual wellbore.
8 . The method of claim 1 , wherein constraining the uphole end of the inner string to be fixed includes constraining the uphole end of the inner string to be axially, laterally, and rotationally fixed with respect to the virtual wellbore.
9 . The method of claim 1 , wherein the set of normal forces between the drill string and the wellbore is identified independent of determining the set of inner contact forces of the inner string.
10 . The method of claim 1 , wherein determining the set of inner contact forces includes ignoring friction between the inner string and the drill string.
11 . The method of claim 1 , wherein the liner string is connected to a downhole end of a landing string.
12 . The method of claim 11 , wherein the liner string is a casing for cementing to the wellbore.
13 . A system, comprising:
at least one processor:
memory in electronic communication with the at least one processor; and
instructions stored thereon in the memory, the instructions being executable by the at least one processor to:
receive wellbore data including a trajectory of a wellbore at a range of measurement depths of interest;
receive drill string data for a drill string, the drill string data identifying components that make up the drill string, the components including a liner string and an inner string positioned inside of the liner string, the drill string data further identifying geometry and material properties of the components;
solve a first single-layer finite element analysis (FEA) model for the inner string without the liner string, comprising:
generate a virtual wellbore associated with the inner string based on an inner diameter of the liner string and based on the trajectory of the wellbore;
constrain the virtual wellbore to be rigid and fixed along the trajectory of the wellbore;
apply one or more inner boundary conditions for the inner string including constraining an uphole end of the inner string to be fixed with respect to the virtual wellbore;
determine an inner axial force for the inner string based on a weight of the inner string; and
determine, based on the trajectory of the virtual wellbore, a set of inner contact forces on the inner string at one or more locations where the inner string contacts the virtual wellbore; and
solve a second single-layer FEA model for the liner string without the inner string, comprising:
apply one or more liner boundary conditions to the liner string, including fixing the liner string at a top of the wellbore;
apply a set of applied forces to the liner string, the set of applied forces including the inner axial force and a set of reaction forces corresponding to the set of inner contact forces on the inner string; and
identify, based on the set of applied forces, a set of normal forces between the drill string and the wellbore;
simulate a movement of the drill string in the wellbore to determine, using the set of normal forces, one or more axial frictional forces and one or more torsional frictional forces acting on the drill string during the movement of the drill string, the movement representing a wellbore operation including at least one of pulling the drill string out of the wellbore, advancing the drill string into the wellbore, or rotating the drill string within the wellbore;
simulate axial tension of the drill string based on the one or more axial frictional forces;
simulate torque of the drill string based on the one or more torsional frictional forces;
identify, based on the drill string data, one or more working limits for one or more components of the components that make up the drill string; and
predict whether the wellbore operation will cause the one or more working limits to be met or exceeded for the one or more components based on the axial tension and the torque.
14 . A computer-readable storage medium including instructions that, when executed by at least one processor, cause the processor to:
receive wellbore data including a trajectory of a wellbore at a range of measurement depths of interest;
receive drill string data for a drill string, the drill string data identifying components that make up the drill string, the components including a liner string and an inner string positioned inside of the liner string, the drill string data further identifying geometry and material properties of the components;
solve a first single-layer finite element analysis (FEA) model for the inner string without the liner string, comprising:
generate a virtual wellbore associated with the inner string based on an inner diameter of the liner string and based on the trajectory of the wellbore;
constrain the virtual wellbore to be rigid and fixed along the trajectory of the wellbore;
apply one or more inner boundary conditions for the inner string including constraining an uphole end of the inner string to be fixed with respect to the virtual wellbore;
determine an inner axial force for the inner string based on a weight of the inner string; and
determine, based on the trajectory of the virtual wellbore, a set of inner contact forces on the inner string at one or more locations where the inner string contacts the virtual wellbore; and
solve a second single-layer FEA model for the liner string without the inner string, comprising:
apply one or more liner boundary conditions to the liner string, including fixing the liner string at a top of the wellbore;
apply a set of applied forces to the liner string, the set of applied forces including the inner axial force and a set of reaction forces corresponding to the set of inner contact forces on the inner string; and
identify, based on the set of applied forces, a set of normal forces between the drill string and the wellbore;
wherein solving the first and second single-layer FEA models includes solving the first and second single-layer FEA models without solving a multilayer FEA model of the inner string and the liner string;
simulate a movement of the drill string in the wellbore to determine, using the set of normal forces, one or more axial frictional forces and one or more torsional frictional forces acting on the drill string during the movement of the drill string, the movement representing a wellbore operation including at least one of pulling the drill string out of the wellbore, advancing the drill string into the wellbore, or rotating the drill string within the wellbore;
simulate axial tension of the drill string based on the one or more axial frictional forces;
simulate torque of the drill string based on the one or more torsional frictional forces;
identify, based on the drill string data, one or more working limits for one or more components of the components that make up the drill string; and
predict whether the wellbore operation will cause the one or more working limits to be met or exceeded for the one or more components based on the axial tension and the torque.
15 . The method of claim 1 , further comprising solving the first single-layer FEA model and solving the second single-layer FEA model without solving a multilayer FEA model of the inner string and the liner string.