Asset area debottlenecking to enable new (accelerated) field development

In the study the DPS was used to debottleneck an entire asset area by removing the water from one of the major infield pipelines and thus open for an early field development of a new discovery in the area

Challenge

The operator has discovered a new field in the vicinity of the existing FPSO and has some more discoveries in the same areal to be drilled as part of an extension plan.

The challenge is twofold: The FPSO has water handling constrains and the existing actual pipeline in the new field area is filled with water (>70%) from a producing satellite. The distance from the new discovery back to FPSO cannot, economically, justify separate pipeline and the additional discoveries face the same challenge.

The option is to utilize the existing 12’’ 20 km pipeline currently filled with >70% water and seek a solution avoiding or reducing the back-out penalty from the now producing field (lost production due to pipeline constrains).

Solution

By removing all produced water from the existing producing wells and hook up the new discoveries at the same subsea module the existing 12’’ pipeline can easily comply with expected total oil and gas production.

Locating the DPS module at the existing satellite and use existing power and control umbilical linked between the well head and the DPS module to minimize the subsea intervention.

Benefit

Faster and more efficient development of the area and avoiding backout penalty on existing producer.

Minimized SURF activity due to shorter distance between the wells.

Knowing operational problems as experienced on the Troll Pilot producing four wells having different water cuts is avoided in the DPS system. Troll Pilot experienced severe problems due to creation of stable multiple dispersions by comingling different water cut into same pipeline. As a result of this phenomenon Norsk Hydro proved that this production challenge is avoided if a pipeline having different velocities between the oil and the water is created. This phenomenon is one of the key principles of the DPS system.

Two options are investigated:

Subsurface discharge of produced water using a combination of DPS and a Compact Flotation Unit (CFU). This solution is a low/no power requirement solution. The IOR potential is provided by less lifting requirement of water (approx. 10 bar)

Option two is further IOR by installing a produced water injection pump and a multi-phase pump giving combined effect by reducing the operational pressure at the subsea separation to a pressure I.E. less than 10 bars.