Controlling the formation of crystalline hydrates in fluid systems

Abstract

Controlling the formation of crystalline hydrates in various fluid systems, most notably, gas and oil transmission pipeline systems by contacting the systems with certain polymers or polymers associated with solid particles. The polymers useful are chelating polymers capable of interacting with charged gaseous molecules such as carbon dioxide, by removing the carbon dioxide, or more practically by scavenging for the carbon dioxide, to prevent the methane or ethane hydrate structures from forming since they require carbon dioxide to stabilize their structures.

Description

BACKGROUND OF THE INVENTION [0001] The invention disclosed and claimed herein deals with compositions that control the formation of crystalline hydrates in various systems, most notably, gas and oil transmission pipeline systems. The compositions are comprised of carbon dioxide sorbing polymers that also have the capability of driving the formation of hydrate crystals into the polymeric matrix. [0002] Crystalline hydrates can form in oil and gas pipelines carrying oil and gas if the chemical composition of the produced fluids includes water, either or both of ethane or methane with carbon dioxide and sometimes, other hydrocarbon gases and / or sulfur dioxide. In addition to the chemical composition, there is a need for a driving force for such hydrate nucleation involving the physical and environmental conditions. [0003] The fluid composition generally is at an elevated temperature, typically above 70° C. and it will cool to a lower temperature, typically below 16° C., whereby the gas...

AI Technical Summary

Benefits of technology

[0012] The polymers disclosed herein are chelating polymers capable of interacting with charged gaseous molecules such as the carbon dioxide by removing the carbon dioxide or more practically by scavenging for the carbon dioxide to encourage the methane and / or ethane hydrate structures to form within the embodiment of the polymer substrate structure. Such formation will encapsulate the seeded hydrate structure thus preventing the hydrate seeded structures from agglomerating as would have been the case if formed within the pipeline fluids.

[0015] Thus, there is a need for an economical, highly efficient process for controlling the formation of crystalline hydrate crystals in various fluid systems, such as gas and oil production and the invention provides such a process, along with novel materials for carrying out the process and making it highly effective.

Problems solved by technology

These solid hydrates, once formed, will grow in size to eventually plug flow lines, and have high potential to block fluid flow and in the worst case cause rupture of the pipe line.

Thus, the formation of hydrates is a costly and potentially environmental challenge for the oil and gas industry.

As global offshore deepwater production of oil and gas increases, the challenges of preventing or controlling the formation of hydrates remains the industry technical challenge.

Of these, methanol, ethanol and glycol are currently practiced but the environmental and financial costs are high.

The costs are high but the logistics for supply and storage offshore and more importantly pumping to sub-sea producer wells are significant and cumbersome.

Offshore dehydration is not feasible for production from sub-sea producing wells and the strategic option for warming the pipeline by heated water or other fluids from the processing platform requires double wall pipeline, that is both expensive and logistically, a difficult operational process.

Heating the flow lines when sub-sea is also expensive and logistically problematic and flawed with respect to reliability.

However, the tolerance is not as great as the industry requires and they fail in the majority of demanding situations.