Methods for controlling temperatures in the environments of gas and oil wells

Abstract

Methods and apparatus are provided for controlling temperatures in the environments of oil, gas condensate, or gas wells. Methods are provided for reducing the melting of glaciers and ice dams through the deployment of hydrate-forming substances. Active methods involve employing a vapor-compression refrigerator / heat pump cycle in an annulus lying between the relatively hot production string and the relatively cold outer pipe. Passive methods include: deploying cold hydrate-forming fluids into the external ice-laden environment of an oil, gas condensate, or gas well in a permafrost area and allowing those hydrate forming fluids to mix with any melt-water that may be present or that may subsequently form due to the loss of heat from the oil, gas condensate, or gas well. Mixtures of the hydrate forming fluids and the melt-water will set up into a solid having a much higher melting point and a much lower thermal conductivity than those of ice.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of the filing date of and priority to U.S. Provisional Application Ser. No. 61 / 207,464 entitled “Methods for controlling temperatures in the environments of gas and oil wells” and filed Feb. 12, 2009, Confirmation No. 3995. Said provisional application is incorporated by reference herein.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not Applicable.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]Embodiments disclosed herein relate generally to the recovery of oil, gas condensate, and gaseous hydrocarbons. In particular, embodiments disclosed herein relate to the recovery of oil, gas condensate, and gaseous hydrocarbons from subterranean petroliferous reservoirs wherein there is a need to limit the transfer of heat from the relatively hot produced fluids into the environment surrounding the production string of pipe.[0005]2. Background Art[0006]Production of oil, gas...

AI Technical Summary

Benefits of technology

[0021]In a closely related aspect of the present invention, when cold, often super-cooled, high pressure water exists in the vicinity of an iceberg or behind an ice dam, the deployment of cold hydrate-forming fluids can reduce or eliminate the cold liquid water by converting it into hydrate form. Often the super-cooled, high pressure water flows beneath or in the lower parts of an iceberg and the friction of flow through this environment leads to heating and further melting. By arresting the flow upon the solidification of this water into hydrate form, this heating mechanism is reduced or eliminated and the subsequent further melting is minimized. Additionally, the melting point of the thus formed hydrate will typically be higher than that of ice, so subsequent melting will be rendered less likely. This aspect of the present invention differs from the other aspects in that the production of relatively hot fluids is optional and indeed need not necessarily be involved.

[0031]The passive methods include: deploying cold hydrate-forming fluids into the external ice-laden environment of an oil, gas condensate, or gas well in a permafrost area and allowing those hydrate forming fluids to mix with any melt-water that may be present or that may subsequently form due to the loss of heat from the oil, gas condensate, or gas well. The mixture of the hydrate forming fluids and the melt-water will set up into a solid having a much higher melting point and a much lower thermal conductivity than those of ice. Similar deployment of cold hydrate-forming fluids can reduce or eliminate the melting of glaciers and ice darns.

[0032]Other passive methods include: deploying a low-pressure-gas-filled weir in an annulus lying between the relatively hot production string and the relatively cold outer pipe. The low-pressure gas is characterized by very low conductive heat loss and in combination with the weir, which acts as a baffle, by very low convective heat loss. Additionally, the weir will trap any condensate that happens to occur in the low-pressure gas, causing any heat loss due to condensation to be reduced to a one-time only occurrence.

[0033]It is believed that one or a combination of these methods can augment or replace the two strategies known in the prior art for diminishing the transfer of heat from the relatively hot produced fluids into the environment surrounding the production string—the deployment of vacuum insulated tubulars (VITs) and insulating packer fluids (IPFs).

Problems solved by technology

Additionally, the thermal conductance of melt-water is higher than those of ice or hydrate; consequently, the elimination of melt-water limits the transfer of heat subsequently.

Often the super-cooled, high pressure water flows beneath or in the lower parts of an iceberg and the friction of flow through this environment leads to heating and further melting.

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