Non-invasive gas flow measurement
using clamp-on ultrasonic technology in Underground Gas Storage operations
Several particular features of non-invasive gas flow measurement with FLUXUS®G
- extremely wide dynamic range, bi-directionality, high accuracy, tolerance of wet gas -
perfectly meet the special demands and requirements of gas storage operations.
Clamp-on ultrasound technology is not only ideally suited for gas flow applications but applicable to
all other liquid flow measurement tasks in the gas storage industry, e.g. measurement
of injected chemicals (methanol, glycol, monoethylamine) or produced water.
FLUXUS® meters have even proven
themselves as an ideal method for flow and brine concentration measurement in the construction
of salt caverns for UGS.
Solution Mining
UGS Applications
Well head gas measurement
(injection/withdrawal)
Gas injection and withdrawal is measured at the wellhead to monitor long term well performance
and gas inventories. The challenges are very similar for each storage type: wide ranging flow
regimes, wide pressure range, sometimes sand in the withdrawn gas, often wet or NGL entrained
gas, bi-directional flow. The standard technology used for well head measurement in the past
was dP orifice metering. The short-falls of dP technology in such applications are now widely
accepted : inaccuracies and meter drift with clogged dP lines, orifice plate encrustations
or even damage, liquid pockets and slugging, hydrate formation and foremost the need to have
cascading meter runs to cover the wide flow range as well as non-beveled orifice plates resulting
in higher pressure losses to measure the flow in both directions. In addition to poor measurement
performance leaking flange connections as well as plate exchange and maintenance cause
substantial methane losses. FLEXIM clamp on meters offer the solution to all of these challenges,
and they do this with increased accuracy.
Methanol injection
Injected methanol for hydrate prevention is lost forever. The injection rates are often not
optimized resulting in under-dosing or wasteful over-dosing. Methanol is often injected under
high pressure. FLEXIM meters can help optimize this injection process.
Gas dehydration
Gas flow volume, gas wetness and glycol dosage need to be of a prescribed ratio for
optimum de-hydration. Often the glycol flow is not matched to the gas flow. The US EPA
estimates that glycol overcirculation contributes significantly to an estimated 17 BCF
in annual US methane losses. Or - if measurements are performed at all - they are still done
with dP methods (orifice or even pitot tubes). FLEXIM meters measure both the gas and glycol
flow with high precision over the entire flow range and help optimize this crucial process.
HCD/NGL reduction
NGL entrained gas undergoes a variety of HDC (hydrocarbon dew point) reduction processes to
customer specifications. All of these processes require gas flow measurement to ensure proper
balance and operations. The conventional dP methods still often used here suffer from the
short falls inherent in this technology : possibilities of methane leaks, limited
turn-down, maintenance intensive, sometimes high costs because of high pressure pipes
and flanges . FLEXIM meters offer a modern and best suited alternative. FLEXIM meter measure
gas and liquids with precision, no maintenance and leak-free.
Gas compression
Centrifugal compressors often used for pressure adjustments between storage and transmission
pipelines can suffer severe flow surge damage by improper flow volume or flow balance.
FLEXIM meters offer the perfect gas measurement monitoring tool to prevent compressor surge damage.
