Systems and methods for achieving three-phase separation and core annular flow in pipelines

A method for the subsea transport of a multi-phase production fluid from a wellhead to a point remote from the wellhead, the multi-phase production fluid comprising a water phase, an oil phase and a gas phase, the method comprising:

• introducing the multi-phase production fluid into a pipeline, the pipeline extending from proximate the wellhead to a point remote from the wellhead;
• and
• imparting rotational motion to the multi-phase production fluid, wherein the rotational motion of the multi-phase production fluid separates the water phase from the oil phase and the gas phase;
• creating a core-annular flow within the pipeline comprising a center gas phase, an annulus of the oil phase surrounding the center gas phase, and a thin annulus of the water phase surrounding the annular oil phase;
• maintaining the thin annulus of the water phase, wherein the thin annulus of the water phase is formed between the wall of the pipeline and the annulus of the oil phase within the pipeline, and wherein the thickness of the thin annulus of the water phase is at least 6% of the diameter of the pipeline.

A method for reducing hydrate formation during the subsea transport of a multi-phase production fluid from a wellhead to a point remote from the wellhead, the method comprising:

• introducing the multi-phase production fluid into a pipeline, the pipeline extending from proximate the wellhead to a point remote from the wellhead;
• and
• imparting rotational motion to the multi-phase production fluid;
• wherein the rotational motion of the multi-phase production fluid separates the water phase from the oil phase and the gas phase;
• creating a core-annular flow within the pipeline comprising a center gas phase, an annulus of the oil phase surrounding the center gas phase, and a thin annulus of the water phase surrounding the annulus of the oil phase, wherein the creation of the separated annular phase flow within the pipeline reduces hydrate formation within the pipeline;
• and
• maintaining a thin annulus of the water phase, wherein the thin annulus of the water phase is formed between the wall of the pipeline and the annulus of the oil phase within the pipeline, and wherein the thickness of the thin annulus of the water phase is at least 6% of the diameter of the pipeline.