Gas Hydrate Mitigation Using an Organic Extract in a Simulated Offshore Environment

Abstract

As deep-water activities and development into deeper operations (depth of 6,000ft or more) increases, temperatures and pressures become favorable for hydrate nucleation and growth. This results in additional risk and challenges as to how to prevent formation of gas hydrates. This paper takes a look at the performance of a local surfactant derived from plant material in a laboratory mini flow loop made of a 0.5-inch internal diameter 316 stainless steel pipe enclosed in a 4-inch PVC pipe mounted on an external metal frame work. The performance of the local surfactant (Surf. X) was compared with that of the conventional hydrate inhibitor N-Vinyl Caprolactam (N-VCap). Varying weights of Surf. X were evaluated in the laboratory mini flow loop. Pressure versus Temperature, change in Pressure versus Time plots showed that Surf. X performed better than the conventional N-VCap in almost all the concentrations considered (except at 0.04wt %). The optimum concentration for inhibition was 0.02wt% with inhibition efficiency of 81.58% while that of N-VCap was 77.19%. The inhibition efficiency of Surf. X for 0.01, 0.03 and 0.04wt % were 72.81% and 75.44% respectively. Surf. X is locally sourced, readily available in commercial quantity and also eco-friendly because it is plant based unlike the N-VCap which is toxic and expensive. It is advised that the local surfactant X be developed as an alternative to the conventional inhibitor for gas hydrate inhibition.

Gas Hydrate Treatments in Pipeline Using Locally Sourced Material as Green Inhibitor

“…If the pipeline temperature and pressure falls within the hydrate region [25], gas hydrate may occur. When this temperature and pressure falls into the hydrate zone, condensation (water) is felt, slowly forming solid crystals that build up and result to blockages (or plugs) of onshore and offshore pipelines [13]. The pipe plug splits the tubing onto two pressure sections in both the root of the well or the source of high pressure gas as well as the plug and a secondary section under reduced pressure between both the plug and the gas recovery system.…”

“…The alternative approach that also meets the industry standard remains low dosage hydrate inhibitors (LDHIS) [13,15,23]. Low-dose hydrate inhibitor application required a small inhibitor concentration for injection (< 1% of the water weight) [35].…”

“…These KH1 polymers are based on copolymers or cyclic amide homopolymers (Lactam). Types of polymers are poly (N-vinylpyrrolidone) (PVP), poly (Nvinylcaprolactam) (PVCap), poly (N-vinylacetamide) (VIMA), poly (N-vinylvalerolactam) (PVVam) and poly (acryoylpyrrolidone) (PAPYD) or other amides such as Nmethyl-N-vinylacetamide and ploy ethyloxazoline [13]. KHI is nonpolymer, tetrapenty lammonium bromide and butoxy ethnol are the category of inhibitors.…”