The subsea gas development of Block 2 offshore Tanzania described in this paper is characterized by water depths of up to 2600 meters and tie-back distance to shore of around 100 km. The seabed consists of deep, large scale canyons and steep inclinations towards shore. The reservoir fluids contain very little condensate and the pipeline flow is typically low liquid loading conditions at high water fractions.

Extensive studies have been carried out during the last 5 years by the Equinor Tanzania Gas Development Project to verify multiphase flow models for our flow conditions.

The key focus of work presented at the MPT 2015 was related to liquid accumulation. However, this work also revealed that

  • frictional pressure drop increases significantly with high water fractions,

  • existing flow models severely under predicts frictional pressure drop at high water fractions, and they are not able to predict the effect of water fraction on the frictional pressure drop

  • little experimental data exist for such conditions (low liquid loading three phase flow at high superficial gas velocities).

The work and results related to frictional pressure drop in vertical flow were presented at the MPT 2017, while the key focus of the presentations this time is related to frictional pressure drop in near horizontal flow in low liquid loading at high water fractions.

To support model development and model verification experiments have been conducted during 2017 and 2018 in both 8 and 12 inch near horizontal pipes at the Tiller test facility in Norway, while model development and model verification studies have been carried out with both Schlumberger (OLGA) and SINTEF (Ledaflow).

This presentation gives an overview of the Tanzania deep water gas development with focus on the flow assurance challenges relates to the subsea to beach concept and the background, motivation for the conducted work, while the experiments (SINTEF)", the model development and verification (Schlumberger and SINTEF) are presented in detail in separate presentations.

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