Vapor Recovery in Offshore Applications

Gulf Coast Regulatory and Environmental Affairs Group Meeting

July 11, 2013

Air Quality Regulations Air Quality Regulations ► BOEM/BSEE has jurisdiction for Western/Central

Gulf of Mexico air quality for oil and gas drilling and production operations.

► East of 87.5 degrees longitude jurisdiction of OCS waters is USEPA Region 4.

► States have jurisdiction for air quality for onshore and coastal/territorial seas.

► Texas territorial waters (and county line) extend for three marine leagues (10.36 statute miles) offshore Texas

VRU Drivers – Onshore/Coastal AreasVRU Drivers – Onshore/Coastal Areas► May need vapor recovery to meet state permitting rules

or federal standard that apply to onshore, coastal and territorial seas.

► Limits flash gas to meet permit limits in general permits (Louisiana) or permit-by-rule (PBR) permits (Texas)

► Normally an option for permits, not always mandated.

► Option used to meet control requirements for storage tanks in 40 CFR 60 Subpart OOOO New Source Performance Standard - Oil and Natural Gas Sector

VRU Drivers – Western/Central GOM VRU Drivers – Western/Central GOM

30 CFR 250.1160 When may I flare or vent gas?

► (a)(5) You may not flare or vent more than an average of 50 MCF per day during any calendar month without Regional Supervisor approval. Limit of 50,000 SCFD average flash gas vent/flare gas limit (30 CFR 250.1160).

►Recover flash gas if economical to recover gas

VRU Drivers – Western/Central GOM VRU Drivers – Western/Central GOM

30 CFR 250.1160 When may I flare or vent gas?

► (b) states that must not flare or vent gas over the volume approved in your Development Operations Coordination Document (DOCD) or in Development and Production Plan (DPP) submitted to BOEM.

► Typically this volume is in the “Air Quality Review (AQR)” spreadsheets submitted with DOCD

Typical Production ProcessTypical Production Process

► Must be something generally accepted by industry and regulators.

► Options include:

1. Direct measurement of tank vent

2. Collect/analyze pressurized oil and measure gas to oil ratio (GOR)

3. Pressurized oil sample/analyses as input to Equations of State computer simulation or API E&P Tank computer pgm.

Tank Vent Gas QuantificationTank Vent Gas Quantification

Data collection (Direct Measurement)Data collection (Direct Measurement)

IQR Process – Measurement Protocol

► Simple & easy way to measure volume of vent gas with 98% accuracy

► Flow characteristics identified(very cyclical)

► Gas composition analyzed

Why Vapor Recovery?Why Vapor Recovery?

► Regulatory compliance► Recover very rich flash gas - $$► Reduce emissions of VOCs and greenhouse

gases► Improve safety of facilities

Engineered Solution Design Engineered Solution Design

► Volume & peaks of flow

► Composition(s) of gas. H2S?

► Pressures► Temperatures► Availability of utilities (power/motive gas)► Availability of booster compression► Markets for products

Types of Solution Package TechnologiesTypes of Solution Package Technologies

Traditional vapor recovery uses compressors driven by electric or natural gas engines

► Reciprocating compressors

► Rotary screw compressors

► Rotary vane compressors

► Scroll compressors

Ejector Vapor Recovery Unit (EVRU™)

Reciprocating CompressorsReciprocating Compressors

► High pressure & volumes

► Automatic bypass (recycle)

► Not recommended for wet gas

Flooded Screw CompressorsFlooded Screw Compressors► High pressure differentials

► High volume capacities

► Variable Frequency Drive (VFD)

► Oil dilution issues

Rotary Vane CompressorsRotary Vane Compressors► High volume capacities

► VFD or bypass

► No oil dilution

► Low pressure differentials 60 psig in single stage

► Vane wear

Scroll CompressionScroll Compression

► Less moving parts

► Less maintenance

► VFD

► Oil dilution issues

► 20 ppm H2S limit

Application of Scroll TechnologyApplication of Scroll Technology

► Recovering gas from oil storage tanks and heater treater and discharging pressurized gas to larger compressor

► VRU system requires electrical power and purge gas for recycle

► High molecular weight gas recovery

Scroll Compressor Case ExampleScroll Compressor Case ExampleDual CVRU package for Offshore Application

Design criteria• Recovered gas throughput: 150,000 SCFD (150 MSCFD)

• Vent gas source:  atmospheric storage tanks

• Suction Pressure: 1 to 3 inches water column

• Discharge Pressure: 100 psig

• Discharge to suction of onsite larger compressor

Offshore Scroll SystemOffshore Scroll System

SPE-127153-PP Paper ConclusionsSPE-127153-PP Paper Conclusions

► Recovers natural gas product

► Lowers emissions of VOCs and GHGs

► Lower maintenance costs than typical VRUs

► System requires smaller footprint

► Cost effective and efficient VRU for offshore environment

COMM Patented EVRU™COMM Patented EVRU™

Motive

Suction

Discharge$$$$$$$$$$$$$$$$$$

EVRU™ Case Study EconomicsEVRU™ Case Study Economics

► Investment: $120,000

► 700 BOPD of 62 API Gravity

► Average gas recovery: 175 MCFD

► $709,560/year product recovery at $6/MMBTU

► Payback period: 2 months

EVRU™EVRU™

Offshore AfricaEagle Ford Onshore

Offshore GOM EVRU™Offshore GOM EVRU™

EVRU System AdvantagesEVRU System Advantages► Simple, non-mechanical vapor recovery system

► 100% run time and on/off provides turndown

► Handles rich, wet gas & H2S

► No oil to maintain

► Small footprint

► Easy to modify► Texas allows emission control efficiency of 99%

Key Points for a VRU SolutionKey Points for a VRU Solution

► Determine regulatory requirements ► Value of natural gas recovered ► Cost of VRU capital costs and operation costs ► Knowing facility process and gas to be recovered

critical to design and effective operation of VRU► Measure & sample gas if possible► Consider redundancy or easy replacement

options

1319 West Pinhook RoadLafayette, Louisiana USA

Brian BoyerSalah Mansour(337) 237-4373

www.commengineering.com