Recent Developments in Natural Recent Developments in Natural Gas Hydrate Inhibitors with Gas Hydrate Inhibitors with

Emphasis on LDHIEmphasis on LDHI

Prepared By: Taiwo Bolaji Abass

September 7th , 2006

Baker Petrolite Presentation

ContentsContents IntroductionIntroduction Hydrate Control MethodHydrate Control Method

- Engineering SolutionEngineering Solution

- Chemical SolutionChemical Solution Chemical Inhibition Chemical Inhibition –– (LDHIs) (LDHIs)

- Thermodynamic InhibitionThermodynamic Inhibition

- LDHILDHI

- Case StudiesCase Studies ConclusionConclusion AcknowledgementAcknowledgement ReferencesReferences

IntroductionIntroduction

What is a Gas Hydrate?What is a Gas Hydrate?

Hydrate formationHydrate formation

LDHIs- low Dosage hydrate InhibitorsLDHIs- low Dosage hydrate Inhibitors

Chemical Composition of LDHIsChemical Composition of LDHIs

What is a Gas Hydrate?What is a Gas Hydrate? A hydrate is a compound formed by the addition of water A hydrate is a compound formed by the addition of water

to a host molecule. Thus ethanol could be considered to be to a host molecule. Thus ethanol could be considered to be

the hydrate of ethylene. the hydrate of ethylene.

Gas hydrates are crystalline, ice-like solids formed from Gas hydrates are crystalline, ice-like solids formed from

water and a range of low molecular weight gas molecules. water and a range of low molecular weight gas molecules.

Depending on temperature and pressure, hydrates may Depending on temperature and pressure, hydrates may

form during long distance transport of well-streams form during long distance transport of well-streams

containing oil, gas and water. The formation of hydrate containing oil, gas and water. The formation of hydrate

plugs may restrain or even block the fluid transport plugs may restrain or even block the fluid transport

completelycompletely

Hydrate formationHydrate formation The formation of natural gas hydrates was first brought to the The formation of natural gas hydrates was first brought to the

attention of the natural gas industry by Hammer- Schmidt (1934), attention of the natural gas industry by Hammer- Schmidt (1934),

when he determined that freezing in gas pipelines was not due to when he determined that freezing in gas pipelines was not due to

ice but to gas hydrates.ice but to gas hydrates.

The two major conditions that promotes hydrate formation areThe two major conditions that promotes hydrate formation are

thus: thus:

High gas pressure and low gas temperature High gas pressure and low gas temperature

The gas at or below its water dew point with "free water" The gas at or below its water dew point with "free water" present present

LDHIs- low Dosage LDHIs- low Dosage hydrate hydrate InhibitorsInhibitors

Low dosage hydrate inhibitors (LDHIs) are recent and alternative Low dosage hydrate inhibitors (LDHIs) are recent and alternative

technology to thermodynamic inhibitors for preventing gas technology to thermodynamic inhibitors for preventing gas

hydrates from plugging oil and gas production wells and pipelines. hydrates from plugging oil and gas production wells and pipelines.

LDHIs are divided into two main categories, kinetic inhibitors LDHIs are divided into two main categories, kinetic inhibitors

(KHIs) and anti-agglomerants (AAs), both of which are successfully (KHIs) and anti-agglomerants (AAs), both of which are successfully

being used in field applications. This presentation reviews the being used in field applications. This presentation reviews the

recent research and development of LDHIs with emphasis on the recent research and development of LDHIs with emphasis on the

important usage that have been designed and tested. important usage that have been designed and tested.

Chemical Composition of Chemical Composition of LDHIsLDHIs

• A is PVP- Polyvinylprrolidone (KHI)A is PVP- Polyvinylprrolidone (KHI)• B is VC-713 – Terpolymer of N-vinylpyrrolidone (KHI)B is VC-713 – Terpolymer of N-vinylpyrrolidone (KHI)• C is Quaternary Ammonium Salt (AA)C is Quaternary Ammonium Salt (AA) This composition varies based on different application and This composition varies based on different application and

organizationorganization

Hydrate Control MethodHydrate Control Method

Engineering SolutionEngineering Solution– DehydrationDehydration– InsulationInsulation– HeatingHeating

Chemical SolutionChemical Solution– Thermodynamic InhibitorsThermodynamic Inhibitors– Low Dosage Hydrate InbitorsLow Dosage Hydrate Inbitors

Kinetic Hydrate Inhibitors (KHI)Kinetic Hydrate Inhibitors (KHI) Anti-Angglomerants Anti-Angglomerants (AA) (AA)Selection, Deployment and MonitoringSelection, Deployment and Monitoring

Engineering Solution Engineering Solution

DehydrationDehydration Insulation Insulation- Absorption- Absorption - Wet Insulation- Wet Insulation- Adsorption- Adsorption - Dry Insulation- Dry Insulation- Condensation- Condensation - Trenched and buried- Trenched and buried- Others- Others

HeatingHeating- Hot fluid circulation- Hot fluid circulation- Direct electrical heating- Direct electrical heating- Induction heating- Induction heating

Chemical SolutionChemical Solution

• Thermodynamic InhibitorsThermodynamic Inhibitors

• Low Dosage Hydrate Inhibitors (LDHIs)Low Dosage Hydrate Inhibitors (LDHIs)

– Kinetic Hydrate Inhibitors (KHIs)Kinetic Hydrate Inhibitors (KHIs)

– Anti- Agglomerants (AA)Anti- Agglomerants (AA)

– Selection, Deployment and MonitoringSelection, Deployment and Monitoring

Chemical Inhibitors - LDHIsChemical Inhibitors - LDHIs

• Thermodynamic InhibitorsThermodynamic Inhibitors

• Low dosage Hydrate Inhibitors LDHIsLow dosage Hydrate Inhibitors LDHIs

• Case StudiesCase Studies

Thermodynamic InhibitorsThermodynamic Inhibitors

• MethanolMethanol

• Mono-ethylene glycol (MEG)Mono-ethylene glycol (MEG)

• AmmoniaAmmonia

• SaltsSalts

• Others (DEG, TEG, Ethanol e.t.c)Others (DEG, TEG, Ethanol e.t.c)

Low Dosage Hydrate Inhibitors Low Dosage Hydrate Inhibitors (LDHIs)(LDHIs)

• Industrial Application of LDHIsIndustrial Application of LDHIs

• Why LDHI TechnologyWhy LDHI Technology

• LDHI Vs ThermodynamicLDHI Vs Thermodynamic

• KHI Vs AAKHI Vs AA

• Factors to consider - LDHIFactors to consider - LDHI

• Equipment for LDHI EvaluationEquipment for LDHI Evaluation

• Performance Measurement CriteriaPerformance Measurement Criteria

• Case StudyCase Study

Industrial Application of Industrial Application of LDHIsLDHIs

• Low-dosage kinetic inhibitors control hydrate formation Low-dosage kinetic inhibitors control hydrate formation

within pipelines, which are effective at concentrations of within pipelines, which are effective at concentrations of

about 0.5 vol%. These new inhibitors are designed either about 0.5 vol%. These new inhibitors are designed either

to delay hydrate formation (such that the time required to delay hydrate formation (such that the time required

for the hydrate to form is longer than the residence time for the hydrate to form is longer than the residence time

of the gas in the pipeline) or to modify the hydrate of the gas in the pipeline) or to modify the hydrate

crystal morphology (such that only very small hydrate crystal morphology (such that only very small hydrate

particles are formed which can be easily pumped through particles are formed which can be easily pumped through

the pipeline). Clearly, major improvements in controlling the pipeline). Clearly, major improvements in controlling

hydrate formation, both economic and ecological; can be hydrate formation, both economic and ecological; can be

made if a suitable cost-effective low-dosage inhibitor can made if a suitable cost-effective low-dosage inhibitor can

be foundbe found

Why LDHIs TechnologyWhy LDHIs Technology

• Lower Cost of OperationLower Cost of Operation Total chemical spendTotal chemical spend 30-50%30-50%Logistics costs (tanks / supply boats)Logistics costs (tanks / supply boats) 90%90%Environmental $ Safety ExposureEnvironmental $ Safety Exposure $$$$CAPEX (Space $weight, Umbilical)CAPEX (Space $weight, Umbilical) $ MM$ MMPump Operating $ Maintenance CostPump Operating $ Maintenance Cost $ K$ KRisk of Methanol in Crude PenaltiesRisk of Methanol in Crude Penalties $/bbl$/bblRisk of Chemical IncompatibilityRisk of Chemical Incompatibility $ K$ KNeed for crude washingNeed for crude washing $ k$ kHydrate Risk of New projectsHydrate Risk of New projects $ MM$ MMWell Start up TimeWell Start up Time $ m$ m

LDHI Vs ThermodynamicLDHI Vs Thermodynamic• LDHILDHI

Low CAPEX Low CAPEX Easy of HandlingEasy of HandlingLow Effective DosageLow Effective DosageSmall Storage SpaceSmall Storage SpaceNo loss to HC PhasesNo loss to HC PhasesLow Transportation CostLow Transportation CostLow maintenanceLow maintenanceEnvironmentally FriendlyEnvironmentally FriendlyGood CompatibilityGood CompatibilityX Can’t Melt HydratesX Can’t Melt HydratesX Can’t Inhibit IceX Can’t Inhibit Ice

• ThermodynamicThermodynamicX High CAPEXX High CAPEXX Handling ConstraintsX Handling ConstraintsX High Effective DosageX High Effective DosageX High Effective DosageX High Effective DosageX Significant Loss to HCX Significant Loss to HCX High Transportation CostX High Transportation CostX High MaintenanceX High MaintenanceX Flammable, Safety X Flammable, Safety hazardhazardX Low CompatibilityX Low Compatibility Hydrate DissolversHydrate DissolversFP DepressantsFP Depressants

KHI Vs AAKHI Vs AA

• Kinetic Hydrate Kinetic Hydrate InhibitorsInhibitors– Extended induction timeExtended induction time

– No hydratesNo hydrates

– HC not neededHC not needed

– Low pressure dropLow pressure drop

– High viscosityHigh viscosity

– Environmentally friendlyEnvironmentally friendly

– Medium Sub-coolingMedium Sub-cooling

– Affected by shut-inAffected by shut-in

• Anti-AgglomerantsAnti-Agglomerants– Short induction timeShort induction time

– Disperse slush hydratesDisperse slush hydrates

– Require HCRequire HC

– High pressure dropHigh pressure drop

– Low viscosityLow viscosity

– More biodegradableMore biodegradable

– High Sub-coolingHigh Sub-cooling

– Less impact from shut-Less impact from shut-

inin

Factors to consider - LDHIFactors to consider - LDHI• Injection Point (Subsea tree, manifold, flowline Injection Point (Subsea tree, manifold, flowline

or below the seafloor)or below the seafloor)• Hydrocarbon effect on performanceHydrocarbon effect on performance• Compatibility (materials & chemical)Compatibility (materials & chemical)• Environmental impactEnvironmental impact• Lowest critical solution temperatureLowest critical solution temperature• Solvent strippingSolvent stripping• In-situ vs. standard water production rateIn-situ vs. standard water production rate• Other physical properties (flash point, pour Other physical properties (flash point, pour

point, viscosity)point, viscosity)• SolidSolid

Equipment for LDHI Equipment for LDHI EvaluationEvaluation

Performance Measurement Performance Measurement CriteriaCriteria• KHIKHI

– No pressure dropNo pressure drop– No gas consumptionNo gas consumption– No water lossNo water loss– No visible hydrateNo visible hydrate

• AAAA− Fluid free flowingFluid free flowing− Moderate viscosity increaseModerate viscosity increase− Moderate torque increaseModerate torque increase− No large hydrate agglomeratesNo large hydrate agglomerates− No adhering hydrate particlesNo adhering hydrate particles

Case Studies- Baker Case Studies- Baker PetrolitePetrolite

HI-M-PACT 4394HI-M-PACT 4394 Low dosage hydrate Inhibitors Low dosage hydrate Inhibitors

Deepwater Field ApplicationDeepwater Field Application In Subsea LineIn Subsea Line

ProblemProblem

A deepwater Gulf of Mexico operator approached Baker Peterolite Corporation when A deepwater Gulf of Mexico operator approached Baker Peterolite Corporation when

one of three subsea wells began producing excessive water. Maximum injection rate one of three subsea wells began producing excessive water. Maximum injection rate

was insufficient to control hydrates in the 24-miles gas condensate flowline. As a was insufficient to control hydrates in the 24-miles gas condensate flowline. As a

result, the operator was forced to cut back production from the water producing well.result, the operator was forced to cut back production from the water producing well.

SolutionSolution

BakerBaker Petrolite recommended its Petrolite recommended its HI-M-PACT™ 4394 low-dosage hydrate inhibitor at HI-M-PACT™ 4394 low-dosage hydrate inhibitor at

a low dosage rate of 0.35 gal/bbl water. The inhibitor was slowly phased into the sea a low dosage rate of 0.35 gal/bbl water. The inhibitor was slowly phased into the sea

system while methanol was phased out.system while methanol was phased out.

Case Studies- Baker Case Studies- Baker PetrolitePetrolite

Results and BenefitsResults and Benefits

The benefits of this application to this customer are listed below for The benefits of this application to this customer are listed below for

illustrative purposes only. The results may vary between applicationsillustrative purposes only. The results may vary between applications..

DueDue to the low dosage rate and low viscosity ofto the low dosage rate and low viscosity of the anti-agglomerant the anti-agglomerant

inhibitor, the operator wasinhibitor, the operator was able to increase production from the waterable to increase production from the water

producing well by 20 mmscfd. Theproducing well by 20 mmscfd. The increase inincrease in gas and condensate gas and condensate

production, reducedproduction, reduced transportation costs, and reduced pumptransportation costs, and reduced pump

maintenance hasmaintenance has resulted in a multi-millionresulted in a multi-million dollar reduction in the annual dollar reduction in the annual

totaltotal cost ofcost of operations. Increased capacity afforded by theoperations. Increased capacity afforded by the HI-M-PACT HI-M-PACT

4394 hydrate inhibitor program4394 hydrate inhibitor program allowed the operator to recover an allowed the operator to recover an

additional 11additional 11 bcf in hydrocarbon reserves from the field. Thebcf in hydrocarbon reserves from the field. The operator operator

cites an $8 million net present valuecites an $8 million net present value (NPV) improvement for this project(NPV) improvement for this project..

ConclusionConclusion• Laboratory studies and previous onshore field experience had indicated Laboratory studies and previous onshore field experience had indicated

that hydrate inhibition synergy is gained through the combination of that hydrate inhibition synergy is gained through the combination of

thermodynamic inhibitors and LDHI.1. This is termed a Hybrid Hydrate thermodynamic inhibitors and LDHI.1. This is termed a Hybrid Hydrate

Inhibitor (HHI). Because of the performance, logistical and cost drivers Inhibitor (HHI). Because of the performance, logistical and cost drivers

presented by the use of methanol, any alternative approach would presented by the use of methanol, any alternative approach would

have to consider those three factors. The performance had to do with have to consider those three factors. The performance had to do with

hydrate dissolution in the event a hydrate formed during operations.hydrate dissolution in the event a hydrate formed during operations.

• This described here created a synergy that assuaged the concerns of This described here created a synergy that assuaged the concerns of

operations, technical, logistics, HS&E and personnel. After observing operations, technical, logistics, HS&E and personnel. After observing

that hydrate dissolution is still possible at a lower dosage with less that hydrate dissolution is still possible at a lower dosage with less

handling and at a comparable cost, the HHI treatment became a handling and at a comparable cost, the HHI treatment became a

permanent hydrate prevention method. This was a success with permanent hydrate prevention method. This was a success with

possible future expansion.possible future expansion.

AcknowledgementAcknowledgement

• I will like to thank the management I will like to thank the management team of Baker Petrolite Kirkby, team of Baker Petrolite Kirkby, Liverpool for believing in me and Liverpool for believing in me and inviting me for the second interview inviting me for the second interview to present this topic.to present this topic.

ThanksThanks

ReferencesReferences

• Clathrate Hydrates of Natural Gas, E Clathrate Hydrates of Natural Gas, E Dendy Sloan, 1Dendy Sloan, 1stst Jan 1998 Jan 1998..

•http://pubs.acs.org

• Baker Hughes websiteBaker Hughes website

•http://web.unic/ceor/hydrates/200 5pres.html

•www.spe.org

•http://en.wikipedia.org/wiki/Gas_hydrate