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US 2021/0277762 A1Published application
Systems and Methods for Determining Mud Weight Window during Wellbore Drilling
AssigneeSaudi Arabian Oil Company
InventorsChao LIU, Yanhui HAN, Dung PHAN, Younane N. ABOUSLEIMAN
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Abstract
Systems and methods for determining a time-dependent mud weight window are disclosed. The existence of fractures in formation rock along with a type of the formation rock are used to determine the use of a particular solution to determine the mud weight window at a particular time of a wellbore drilling operation.
Claims14
A computer-implemented method performed by one or more processors for automatically controlling a drilling mud weight, the method comprising the following operations:
- determining a rock type of a formation rock and the presence of fractures in the formation rock;
- selecting a drained solution or undrained solution based on the determined rock type and fracture nature of the formation rock;
- selecting a poroelastic model or dual-poroelastic model based on whether the formation rock includes fractures;
- selecting a combined solution based on the selected drained or undrained solution and the selected poroelastic or dual-poroelastic model;
- determining in-situ stresses, pore pressure, and mechanical properties of the formation rock;
- applying wellbore trajectory parameters, the determined in-situ stresses, pore pressure, and mechanical properties of the formation rock to the combined solution to determine effective stresses;
- calculating a mud weight window by combining the determined effective stresses with a shear failure criterion and a tensile failure criterion;
- and
- controlling a weight of mud used in a drilling operation based on the mud weight window.
6 more elements
A method for controlling a drilling mud weight comprises:
- drilling a wellbore to determine a rock type of a formation rock and the presence of fractures in the formation rock;
- selecting a drained solution or undrained solution based on the determined rock type and fracture nature of the formation rock;
- selecting a poroelastic model or dual-poroelastic model based on whether the formation rock includes fractures;
- selecting a combined solution based on the selected drained or undrained solution and the selected poroelastic or dual-poroelastic model;
- determining in-situ stresses, pore pressure, and mechanical properties of the formation rock;
- applying wellbore trajectory parameters, the determined in-situ stresses, pore pressure, and mechanical properties of the formation rock to the combined solution to determine effective stresses;
- calculating a mud weight window by combining the determined effective stresses with a shear failure criterion and a tensile failure criterion;
- and
- controlling a weight of mud used in a drilling operation based on the mud weight window.
6 more elements
Dependencies are inferred from the claim text.