Composition for controlling wellbore fluid and gas invasion and method for using same
AssigneeHalliburton Energy Services, Inc.
InventorBrian Henry Tomlinson
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Abstract
Compositions for controlling wellbore fluid and gas invasion including methods for using the compositions. The compositions are initially flowable slurries preferably comprising about 70 to 30% by weight of magnesium oxychloride and about 70 to 30% by weight of water. The compositions undergo a rapid phase transition to form a substantially solid mass with a near-linear relationship between the time required for the phase transition to occur and the composition temperature at which the phase transition occurs thereby permitting accurate determination of the set time. The method includes use of the composition to control the loss of fluids and gases from the wellbore.
Claims35
A composition for controlling wellbore fluid and gas invasion which is initially a flowable slurry and forms, upon undergoing a phase transition, a substantially solid state mass comprising:
- about 70 to 30% by weight of magnesium oxychloride;
- and
- about 70 to 30% by weight of water;
- and
- wherein,
- the composition phase transition from the flowable slurry to the solid state is rapid with formation of little or no gel state;
- the composition has a near-linear relationship between the time required for the phase transition to occur and the composition temperature at which the phase transition occurs;
- and
- the phase transition occurs when the composition reaches a temperature of between about 100–140° C.
A slurry composition for controlling wellbore fluid and gas invasion which is initially in a flowable state and, upon undergoing a phase transition, is in a substantially solid state comprising:
- about 70 to 30% by weight of magnesium oxychloride;
- and
- about 70 to 30% by weight of water;
- and wherein
- the composition has a density of about 1.4–1.6 kg/L and a viscosity of about 18–30 cP when in the flowable state;
- the composition phase transition from the flowable state to the solid state is rapid with formation of little or no gel state;
- the composition undergoes the phase transition from the flowable to the solid state when the composition reaches a temperature of about 100–140° C.;
- and
- the composition has a near-linear relationship between the time required for the phase transition to occur and the composition temperature at which the phase transition occurs.
A method of treating a wellbore or a portion thereof, the method comprising:
- preparing a brine solution comprising an admixture of magnesium chloride salt and water;
- adding about 50 to 30% by weight of magnesium oxide powder to the brine solution;
- agitating the brine solution and magnesium oxide powder to form a slurry;
- placing the slurry into the well or portion thereof;
- and
- solidifying the slurry, said solidifying step being characterized by the slurry undergoing a phase transition from a flowable slurry to a substantially solid state upon reaching a slurry temperature of between about 100–140° C. said phase transition being rapid with formation of little or no gel state and the slurry having a near-linear relationship between the time required for the phase transition to occur and the slurry temperature at which the phase transition occurs;
- whereby a seal is formed along the well or a portion thereof.
Dependencies are inferred from the claim text.