Page 102 - Handbook Of Multiphase Flow Assurance

98 5. Flow restrictions and blockages in operations

FIG. 5.1 Frequency of flow assurance issues as indicated by the participants at the 2015 SPE Flow assurance
Forum, representing both onshore, subsea and shale production.

TABLE 5.1 Perceived locations and frequency of flow assurance blockages

Location Asphaltene Wax Hydrate Scale & sand
Reservoir 1 0 1 4
Well 30 2 0 13
Flowline & riser 0 28 24 7
Injection line 0 2 4 0
Export line 0 2 6 0
Subsea process 0 0 0 0
Topsides process 3 0 0 7
Tree & manifold 0 0 2 0

shared by one of the technology providers (Oceaneering, 2018). This information may be
useful in comparison of various flow assurance strategies.
Blockages occur at all water depths. The information in the graphs below is a summary of
subsea remediation for hydrate remediation and for other flowline remediation over the recent
decade from 2008 through 2017.

Duration of hydrate and other flowline remediation

On average, hydrate remediation took 21 days; the duration was nearly independent of
water depth as shown in Fig. 5.2. Other flowline remediation average time was 25 days;