Methods for formulating a cement slurry for use in a subterranean salt formation

Patent metadata

Field	Value
Publication number	US-9885223-B2
Application number	US-201414429919-A
Country	US
Kind code	B2
Filing date	May 30, 2014
Priority date	May 30, 2014
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

Methods of formulating a cement slurry for use in a subterranean salt formation, including methods for formulating a cement slurry capable of providing long-term zonal isolation within a subterranean salt formation. The methods also take into account the effects of treatment fluids on the cement slurry, such as drilling fluids, spacer fluids, flush fluids, or other relevant fluids used to perform a subterranean formation operation.

First claim

The invention claimed is:

1. A method comprising:
(a) calculating a theoretical first wellbore radius in a subterranean salt formation having a treatment fluid therein based on salt creep analysis in the presence of formation-treatment fluid;
(b) calculating a theoretical second wellbore radius in the subterranean salt formation during a cementing operation with a proposed cement slurry based on salt creep analysis in the presence of formation-cement slurry,
wherein the cementing operation involves forming a proposed cement sheath within the wellbore, and wherein the proposed cement sheath must withstand a wellbore load to prevent failure of the cement sheath in the wellbore;

(c) determining experimentally a rheology of the proposed cement slurry versus salt dissolution curve;
(d) determining experimentally and based on a convection-diffusion equation a salt dissolution versus flow rate curve;
(e) calculating a theoretical final wellbore radius in the subterranean salt formation based on the theoretical first wellbore radius, the theoretical second wellbore radius, and salt dissolution expected after the proposed cement sheath is theoretically formed;
(f) determining a rheology of the proposed cement slurry versus flow rate curve;
(g) calculating theoretically whether the proposed cement sheath is capable of withstanding the wellbore load by calculating theoretical thermal and thermo-mechanical properties of the proposed cement slurry based on salt creep analysis in the presence of formation-cement sheath;
(h) determining experimentally whether the proposed cement sheath is capable of withstanding the wellbore load based on an ultrasonic cement analyzer test and actual thermal and thermo-mechanical properties of the proposed cement slurry after salt dissolution;
(i) calculating theoretically a theoretical pump time and a theoretical pump pressure for the treatment fluid and the proposed cement slurry based on a computational fluid dynamics model,
wherein the theoretical pump pressure for the treatment fluid and the proposed cement slurry is between a pore pressure and a fracture gradient of the subterranean salt formation, and
wherein the theoretical pump time for the treatment fluid and the proposed cement slurry is such that the proposed cement slurry will theoretically permit formation of the proposed cement sheath in the wellbore without substantial premature curing;

(j) determining experimentally whether the theoretical pumping time for the treatment fluid and the proposed cement slurry will permit formation of the proposed cement sheath in the wellbore without substantial premature curing based on a thickening time test of the proposed cement slurry;
(k) performing steps (g)-(h) before steps (i)-(j), or
performing steps (i)-(j) before steps (g)-(h);

(l) establishing a final cement slurry, a final pumping pressure and time for the treatment fluid, and a final pumping pressure and time for the cement slurry;
(m) performing a wellbore operation with the treatment fluid using the final pumping time and pressure for the treatment fluid; and
(n) performing the cementing operation with the final cement slurry using the final pumping time and pressure for the final cement slurry.

2. The method of claim 1 , wherein step (k) comprises performing steps (g)-(h) before steps (i)-(j), and
further comprising manipulating the proposed cement slurry after at least one of:
step (g), and repeating steps (b)-(g) until the proposed cement sheath based on the proposed cement slurry that has been manipulated is theoretically capable of withstanding the wellbore load,
step (h), and repeating steps (b)-(h) until the proposed cement sheath based on the proposed cement slurry that has been manipulated is experimentally capable of withstanding the wellbore load,
step (i), and repeating steps (b)-(i) until the theoretical pumping pressure for the treatment fluid and the proposed cement slurry that has been manipulated is theoretically between the pore pressure and the fracture gradient of the subterranean salt formation and the theoretical pumping time for the treatment fluid and the proposed cement slurry that has been manipulated theoretically permits formation of the proposed cement sheath with the proposed cement slurry that has been manipulated in the wellbore without substantial premature curing, and
step (j), and repeating steps (b)-(j) until the theoretical pumping time experimentally permits formation of the proposed cement sheath in the wellbore with the proposed cement slurry that has been manipulated without substantial premature curing.

3. The method of claim 1 , wherein step (k) comprises performing steps (i)-(j) before steps (g)-(h), and
further comprising manipulating the proposed cement slurry after at least one of:
step (i), and repeating steps (b)-(f) and (i) until the theoretical pumping pressure for the treatment fluid and the proposed cement slurry that has been manipulated is theoretically between the pore pressure and the fracture gradient of the subterranean salt formation and the theoretical pumping time for the treatment fluid and the proposed cement slurry that has been manipulated theoretically permits formation of the proposed cement sheath with the proposed cement slurry that has been manipulated in the wellbore without substantial premature curing,
step (j), and repeating steps (b)-(f) and (i)-(j) until the theoretical pumping time experimentally permits formation of the proposed cement sheath in the wellbore with the proposed cement slurry that has been manipulated without substantial premature curing,
step (g), and repeating steps (b)-(f), (i)-(j), and (g) until the proposed cement sheath based on the proposed cement slurry that has been manipulated is theoretically capable of withstanding the wellbore load, and
step (h), and repeating steps (b)-(f), (i)-(j), and (g)-(h) until the proposed cement sheath based on the proposed cement slurry that has been manipulated is experimentally capable of withstanding the wellbore load.

4. The method of claim 1 , wherein the computational fluid dynamics model of step (i) is used to determine the theoretical pump time and pressure of the treatment fluid and the proposed cement slurry based on: a flow rate of the treatment fluid, a flow rate of the proposed cement slurry, rheology parameters of the treatment fluid, rheology parameters of the proposed cement slurry, a standoff profile, and the theoretical final wellbore radius.

5. The method of claim 4 , wherein at least one of the flow rate of the treatment fluid and the flow rate of the cement slurry are manipulated and step (i) is repeated.

6. The method of claim 4 , wherein the rheology parameters of the treatment fluid and the rheology parameters of the proposed cement slurry are selected from the group consisting of plastic viscosity, Bingham model yield point, Herschel-Bulkley model parameters, and any combination thereof.

7. The method of claim 1 , wherein the theoretical thermal and thermo-mechanical properties of the proposed cement slurry are calculated based on at least one of thermal conductivity, thermal diffusivity, tensile strength, compressive strength, hydration volume change, Young's modulus, and Poisson's ratio.

8. The method of claim 1 , wherein the salt creep analysis is based on secondary salt creep; a combination of secondary salt creep and tertiary salt creep; or a combination of primary salt creep, secondary salt creep, and tertiary salt creep.

9. The method of claim 1 , wherein rheology parameters of the proposed cement slurry are used in step (c) to determine experimentally the rheology of the proposed cement slurry versus salt dissolution curve, and
wherein the rheology parameters a

Assignees

• Halliburton Energy Services Inc

Inventors

• Jandhyala Siva Rama Krishna
• Ravi Krishna
• Patil Sandip Prabhakar
• Yerubandi Krishna Babu
• Deshpande Abhimanyu
• Barhate Yogesh Ramesh
• Patil Rahul Chandrakanth

Classifications

• E21B47/08

  Measuring diameters or related dimensions at the borehole · CPC title

• E21B33/13 Primary

  Methods or devices for cementing, for plugging holes, crevices or the like · CPC title

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• G01V1/40

  specially adapted for well-logging · CPC title

• C09K8/42

  Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells (compositions for plastering C09K8/50) · CPC title