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US-12624865-B2 - Forming high-efficiency geothermal wellbores

US12624865B2US 12624865 B2US12624865 B2US 12624865B2US-12624865-B2

Abstract

Wellbore synthesis techniques are disclosed suitable for use in geothermal applications. Embodiments are provided where open hole drilled wellbores are sealed while drilling in sequenced operations with utilization of phase change materials to form an impervious layer at the wellbore/formation interface in high temperature applications. The techniques may be chemical, thermal, mechanical, biological and are fully intended to irreversibly damage the formation in terms of the permeability thereof. With the permeability negated, the wellbore may be used to create a closed loop surface to surface geothermal well operable in the absence of well casing for heat transfer surfaces for maximizing thermal transfer to a circulating working fluid. Formulations for the working and drilling fluids are disclosed.

Inventors

  • Matthew Toews
  • Michael Holmes
  • Jonathan HALE
  • Andrew CURTIS-SMITH
  • Peter Andrews
  • Paul Cairns
  • ARIEL TORRE

Assignees

  • EAVOR TECHNOLOGIES INC.

Dates

Publication Date
20260512
Application Date
20241111
Priority Date
20201119

Claims (20)

  1. 1 . A method, comprising: limiting, with an insulative drill string disposed in a wellbore and having a preselected thermal conductivity, thermal transfer between a drilling fluid introduced to a rock face and the drilling fluid returning to a terranean surface of said wellbore to maintain a temperature differential of at least 90° Celsius (C) between the rock face and the drilling fluid contacting the rock face; drilling at a specified rate of penetration of said drill string into said a geothermal zone of a geological formation, the geothermal zone having a higher temperature than the drilling fluid contacting the rock face, while maintaining said temperature differential, the specified rate of penetration higher than a rate of penetration absent said maintaining said temperature differential; and sealing, by flowing a sealant downhole, pore spaces along at least a portion of the wellbore.
  2. 2 . The method as set forth in claim 1 , wherein the rock face is part of a high temperature geologic formation having a temperature that is above a maximum rated operating temperature of the drill string, and wherein maintaining the temperature differential comprises maintaining a temperature of the drilling fluid between 90° C. and 190° C. below the temperature of the geologic formation when the drilling fluid exits the drill string to contact the rock face.
  3. 3 . The method as set forth in claim 1 , wherein the sealing comprises flowing the sealant while drilling.
  4. 4 . The method of claim 1 , further comprising alternating between drilling with said drilling fluid and flowing the sealant.
  5. 5 . The method of claim 1 , wherein said sealant comprises an alkali silicate composition.
  6. 6 . The method of claim 1 , further comprising circulating a chemical composition within said wellbore capable of inducing precipitate formation.
  7. 7 . The method of claim 1 , further comprising circulating a working fluid and wherein said working fluid comprises the sealant.
  8. 8 . The method of claim 1 , wherein drilling into said formation comprises drilling an inlet well and an outlet well to form a closed loop, at least a portion of said closed loop disposed within a thermally productive area of said formation.
  9. 9 . The method of claim 8 , wherein said closed loop comprises an L shaped well with a closed terminal end, tube-in-tube well arrangement, grouped closed loop U shaped wells in spaced relation with an output well member in said group connected to an input well of another group member, a closed loop U shaped well having a plurality of lateral wells commonly connected to a respective inlet well and outlet well, a plurality of closed loop U shaped wells having a plurality of lateral wells commonly connected to a respective inlet well and outlet well arranged with lateral wells of said plurality arranged with said laterals at least partially interdigitated for thermal contact and combinations thereof.
  10. 10 . The method of claim 8 , wherein said thermally productive area is a geothermal zone.
  11. 11 . A well system for use in drilling a wellbore: a drill string disposed a wellbore; a drilling fluid flowing through the drill string and returning to a terranean surface, the drill string being insulative and having a preselected thermal conductivity to limit thermal transfer between a drilling fluid introduced to a rock face and the drilling fluid returning to a terranean surface of said wellbore to maintain a temperature differential of at least 90° Celsius (C) between the rock face and the drilling fluid contacting the rock face to drill at a specified rate of penetration into a geothermal zone of a geological formation, the geothermal zone having a higher temperature than the drilling fluid contacting the rock face, the specified rate of penetration higher than a rate of penetration absent said maintaining said temperature differential; and a supply of sealant configured to be flowed downhole in the wellbore to seal pore spaces along at least a portion of the wellbore.
  12. 12 . The system as set forth in claim 11 , wherein the rock face is part of a high temperature geologic formation having a temperature that is above a maximum rated operating temperature of the drill string, and wherein maintaining the temperature differential comprises maintaining a temperature of the drilling fluid between 90° C. and 190° C. below the temperature of the geologic formation when the drilling fluid exits the drill string to contact the rock face.
  13. 13 . The system as set forth in claim 11 , wherein the system is configured to be flow the sealant downhole while drilling.
  14. 14 . The system of claim 11 , wherein the system is configured to alternate between drilling with said drilling fluid and flowing the sealant.
  15. 15 . The system of claim 11 , wherein said sealant comprises an alkali silicate composition.
  16. 16 . The system of claim 11 , further comprising a supply of chemical composition configured to, when disposed within the wellbore, induce precipitate formation.
  17. 17 . The system of claim 11 , further comprising a supply of working fluid configured to be circulated in the wellbore, the working fluid comprising the sealant.
  18. 18 . The system of claim 11 , wherein the wellbore is a wellbore of a closed loop well system, at least a portion of the wellbore disposed within a thermally productive area of said formation.
  19. 19 . The system of claim 18 , wherein said closed loop well system comprises an L shaped well with a closed terminal end, tube-in-tube well arrangement, grouped closed loop U shaped wells in spaced relation with an output well member in said group connected to an input well of another group member, a closed loop U shaped well having a plurality of lateral wells commonly connected to a respective inlet well and outlet well, a plurality of closed loop U shaped wells having a plurality of lateral wells commonly connected to a respective inlet well and outlet well arranged with lateral wells of said plurality arranged with said laterals at least partially interdigitated for thermal contact and combinations thereof.
  20. 20 . The system of claim 18 , wherein said thermally productive area is a geothermal zone.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 17/126,153, filed Dec. 18, 2020, claims the benefit of U.S. Provisional Application No. 63/012,952, filed Apr. 21, 2020, and claims priority to Canadian Application Serial No. 3100013, filed Nov. 19, 2020, of the contents of which are incorporated by reference herein. FIELD OF THE INVENTION The present invention relates to geothermal wellbore creation with drilling techniques and sequencing and more particularly, the present invention relates to methods for modifying the permeability of a given formation for creating high efficiency geothermal wellbores with improved thermal and mechanical characteristics additionally with working fluid formulations including phase change materials which facilitate drilling in high temperature formations. BACKGROUND OF THE INVENTION Geothermal energy recovery is an attractive method of capturing energy and has obvious environmental appeal considering the renewability aspect. The prior art has focused on numerous issues in respect of permeability, well geometries, working fluids, multilateral well configuration, power production and temperature issues. Examples of attempts to ameliorate these issues will be discussed in turn. Initially, in respect of formation damage, Badalyan et al., in Laboratory Study on Formation Damage in Geothermal Reservoirs Due to Fines Migration, Proceedings World Geothermal Congress 2015 Melbourne, Australia, 19-25 Apr. 2015, teach: “Here we present a new method to assess formation damage in geothermal reservoirs. It is long known that formation damage is caused by mobilisation, migration and straining of natural reservoir fines . . . . Velocity-induced fines migration is responsible for a non-significant reduction of rock permeability leading to initial formation damage. Following low-ionic strength water injection increases electrostatic repulsion force between clay particles and sand surface, further mobilizes particle resulting in formation damage. Mobilised fines with mixed-layer illite/chlorite mineralogy are responsible for rock permeability reduction due to pore-throats clogging.”Fines migration is one of the most widely spread physics mechanisms of formation damage in oil and gas wells. Numerous recent publications report well impairment by fines migration in geothermal fields. [Emphasis mine] In Mechanisms of Formation Damage in Matrix Permeability Geothermal Wells Conference: International Geothermal Drilling and Completions Technology Conference, Albuquerque, NM, USA, 21 Jan. 1981, Bergosh et al. indicate in an abstract of their presentation: “Matrix permeability geothermal formations are subject to damage during well drilling and completion. Near well bore permeability impairment that may occur as a result of particulate invasion, and chemical interaction between formation clays, drilling mud filtrates and formation brines is investigated. Testing of various filtration chemistries on the permeability of East Mesa sandstone indicates that permeability is significantly impaired by the flow of low salinity formation brines. This damage is attributed to cation exchange and removal processes which alter the stability of clay structures. Fluid shearing dislodges particles, which clog pore throats, irreversibly reducing permeability. The test program investigating the effects of mud-transported particles on geothermal formations is still in progress. The rationale, apparatus and test procedures are described. Final results of this testing will be presented at the conference.” [Emphasis mine] Clearly, the loss of permeability in these geothermal environments has significant impact on the production of the wellbore and concomitant energy recovery. Tchistiakov, in Physico-Chemical Aspects of Clay Migration and Injectivity Decrease of Geothermal Clastic Reservoirs, Proceedings World Geothermal Congress 2000, Kyushu-Tohoku, Japan, May 28-Jun. 10, 2000, states in his summary: “The permeability damage potential can be evaluated only via broad-minded and interdisciplinary thinking, rather than through automatic application of mathematical equations and laboratory test results. We are convinced that better understanding of the fundamental physico-chemical principles of clay particle stability and transport in porous media will help the reservoir specialists to develop better techniques and apply more effective existing ones for preventing in-situ clay induced formation damage of geothermal reservoirs.” The paper establishes the clay damage to permeability of the drilled well. Barrios et al., at the Short Course on Geothermal Development and Geothermal Wells, organized by UNU-GTP and LaGeo, in Santa Tecla, El Salvador, Mar. 11-17, 2012, Acid Stimulation of Geothermal Reservoirs. In the presentation, the authors indicate: “Both injection and production wells can be clogged, reducing their production capac