Page 47 - Handbook Of Multiphase Flow Assurance

42 2. Initial diagnosis and solution of flow assurance production problems in operations

In absence of a proper laboratory CPM, a field-grade cross-polarized microscopy may be
performed using two polarizer camera filters or two pairs of polarized eyeglasses. A thin
sample of solid (such as wax) is placed between the two polarizers, and polarizers are turned
relative to each other until no visible light passes through the assembly. Some crystals such
as wax or ice can rotate the plane of light polarization, which can be observed in CPM as
light passing through the crossed polarizers. A light shining through the sample in a CPM
helps tell whether this flow assurance sample is one of the deposits which can rotate light
polarization.

Typical blockage remediation plan

1. Gather system knowledge: fluids, samples, profile, insulation, internal and ambient
conditions
identify possible incompatibilities (wet gas + cold T, methanol + brine, LDHI + CI,
etc.) in system
identify probable locations (T < T_solid, jumpers/low spots, riser base, chokes), model
pressure
identify line MAOP (take into account design corrosion rates, performed inspections)
2. Review remediation plan: SMEs, services, logistics (access points, deck space, vessels)
clarify blockage(s′) properties (dP1-dP2, permeability, consistency)
how to reverse cause (P↓, T↑, flow back, solvent), possibility of transient movement
check accessibility w.r.t different remediation technologies, availability of vendors,
regional HSE
3. Organize: Asset Operations Manager in charge, specialists and services in support
designate accountabilities, appoint Project Manager
state primary and additional objectives, metrics; contracts and service agreements
4. Plan the Actions being honest about time and budget:
allow 2× time for every “if” (e.g., if permeable plug, if sea is calm, if through gaslift)
assess economics for each route
pick one with least uncertainty (ifs), then best economics
line up and inform your picked solvent or technology vendor(s)
5. Execute the plan:
interface management is key; Project Manager to keep vendors informed of status/
plan
simultaneous operations may affect timing—plan ahead
enforce time limit for execution based on asset value
6. Learn:
record blockage frequency, downtime, record what worked/didn't work
new designs to increase NPV reducing downtime by accommodating remediation plan
update remediation plans for this and other assets: who you're gonna call?
Key suggestions: Be prepared for a blockage, understand your system and resources.