Oil and gas background pg

BACKGROUND FOR NEPA REVIEWERS:

CRUDE OIL AND NATURAL GAS EXPLORATION,

DEVELOPMENT, AND PRODUCTION

Submittedto:

U.S. EnvironmentalProtectionAgency

Office of Solid Waste

SpecialWasteBranch

Crystal station

2800 Crystal Drive

Crystal City, VA 20202

Submittedby:

ScienceApplicationsInternationalCorporation

EnvironmentalandHealth SciencesGroup

7600-A LeesburgPike

Falls Church, VA 22043

DISCLAIMER AND ACKNOWLEDGEMENTS

The mentionof companyor productnamesis not to be consideredan

endorsementby the U.S. Governmentor by the U.S. Environmental

ProtectionAgency(EPA). This documentwas preparedby Science

ApplicationsInternationalCorporation(SAIC) in partial fulfillment of

EPA Contract Number68-W0-0025,Work Assignment61.

BACKGROUNDFOR NEPAREVIEWERS

TABLE OF CONTENTS

Page

INTRODUCTION ................................................. 1

OVERVIEW OF OIL AND GAS EXPLORATION AND PRODUCTION .......... 1

STATUTORY AND REGULATORY BACKGROUND..................... 1

Leasingon FederalLands ................................... 4

SafeDrinking Water Act ................................... 7

CleanWater Act ......................................... 8

Clean Air Act (CAA) ..................................... 9

ResourceConservationand RecoveryAct ......................... 10

TECHNICAL DESCRIPTIONOF EXPLORATION

AND PRODUCTION OPERATIONS ....................................

EXPLORATION AND DEVELOPMENT. .............................

Road Constructionand Maintenance ............................

Preliminary Exploration ....................................

Well Drilling ...........................................

Drilling Fluids .....................................

Drilling Fluid Wastes.................................

FormationEvaluation .................................

Well Completion ........................................

CompletionWastes ..................................

Well Stimulation. ........................................

StimulationWastes ..................................

Well Abandonment .......................................

AbandonmentWastes.................................

OIL AND GAS PRODUCTION ....................................

Field Design ...........................................

Recovery .............................................

ProductCollection (Gathering) ................................

ProducedFluid Treatment ...................................

Two-phase Separator.................................

Three-phaseSeparator ................................

Free-WaterKnockout .................................

Heater Treater.. ...................................

GasDehydration. ...................................

Sweetening/SulfurRecovery ............................

Natural GasLiquids Recovery ...........................

Compression ......................................

Skimming Pit......................................

SolidsRemoval ....................................

Produced Water....................................

Waste Management....................................... Explorationand ProductionWastes ........................

Reserve Pits......................................

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June 15, 1992 DRAFT

OIL AND GAS

Annular Disposalof Drilling Wastes ....................... 32

Centralized Disposal Pits.............................. 32

Drilling WasteMinimization ............................ 32

Storage,Settling, and SkimmingPits and Tanks ................ 33

UndergroundInjection ................................ 33

Dischargeof ProducedWatersto SurfaceWater ................ 34

Evaporationand PercolationPits .......................... 34

Land Farming ..................................... 34

SurfaceSpreadingof ProducedWaters ...................... 34

Use of ProducedWater for Irrigation ....................... 34

CentralTreatmentFacilities ............................. 35

Crude Oil Reclaimers................................. 35

RoadBuilding Materials ............................... 35

CasingVent GasRecovery ............................. 35

Gas Flares ....................................... 36

Miscellaneousand NonexemptOil Field Wastes ................ 36

Site Closure ........................................... 36

COALBED METHANE DEVELOPMENT ............................. 36

Nature of the Resource..................................... 37

Typesof CoalbedDevelopmentProjects .......................... 37

Vertical DegasificationWells in Advanceof Mining .............. 38

Horizontal DegasificationWells .......................... 38

Gob GasWells ..................................... 38

Vertical GasWells Independentof Mining .................... 38

CoalbedMethaneWell Drilling and Completion ..................... 38

CoalbedMethaneWell Stimulation ............................. 39

CoalbedMethaneProduction ................................. 40

CoalbedMethaneWasteManagement ........................... 41

POTENTIAL SIGNIFICANT ENVIRONMENTAL IMPACTS ..................... 42

POTENTIAL IMPACTS ON GROUND WATER ......................... 42

Exploratory and DevelopmentDrilling ........................... 42

Vertical Migration of Contaminants........................ 43

Ground-waterDrawdown .............................. 43

Production ........................................... 43

Migration of Stimulation Fluid to Ground Water .............. 43

Damageand Blowout of Existing Wells ................... 43

Migration of Injected Water to Ground Water............... 44

Migration of Steamand Other InjectedSolutionsto Ground Water ... 44

PotentialDamagesfrom In-situ Combustion................. 44

Migration of GatheringLine Spills to Ground Water ........... 44

Product Stock Tank Leakage.......................... 44

Waste Management.. .................................. 46

Migration of Deep Well Injected Fluids................... 46

Migration of Annular Injected Fluids.................... 46

Migration of SweeteningWastes ...................... 46

Vertical Migration from SurfaceTreatmentSites ............ 47

June 15, 1992 DRAFT

BACKGROUNDFOR NEPA REVIEWERS

Site Closure ........................................... 47

Vertical Migration of ClosedPit Contentsto GroundWater ......... 47

POTENTIAL IMPACTS ON SURFACEWATER ........................ 47

Explorationand Development ................................ 47

Site Runoff to SurfaceWaters ........................... 47

Production ............................................ 48

Migration of ProductStockTank Leaks ..................... 48

Migration of GatheringLine Leaks ......................... 48

Vertical Migration of Injection Fluids ....................... 48

WasteManagement....................................... 48

SurfaceWater Dischargesof Reduced Water .................. 48

Migration of CommingledWastes .......................... 49

Runoff from SurfaceTreatmentSites ....................... 49

Migration of SweeteningWastes .......................... 49

Site Closure ........................................... 49

Sedimentationof SurfaceWaters .......................... 49

POTENTIAL IMPACTS ON SOIL .................................. 49

Exploration and Development ................................ 50

Compactionand Erosionfrom RoadBuilding ................... 50

Site Runoff ....................................... 50

Production ............................................ 50

Compactionand ErosionDuring Production................... 50

ProductStockTank Leaks .............................. 50

Gathering Line Leaks................................. 50

Injection Fluids and SaltwaterBreakout ..................... 50

WasteManagement....................................... 51

Pit Excavation,Overtoppingand Seepage .................... 51

SweeteningWastes .................................. 51

Onsite Burial of Pit Wastes............................. 51

Landfarmingof Pit Wastes ............................. 51

Evaporationof ProducedWater .......................... 52

Site Closure ........................................... 52

Sedimentationof SurfaceWatersfrom Site Runoff. .............. 52

POTENTIAL IMPACTS ON AIR .................................... 52

Explorationand DevelopmentDrilling ........................... 52

HydrogenSulfide Emissionsfrom Active Operations ........... 52

Fugitive Dust Emissions.............................. 52

MachineryExhaustEmissions ......................... 53

Production ........................................... 53

Emissions from Gas Flaring .......................... 53

Volatilization of PetroleumFractions ..................... 53

Releaseof HydrogenSulfide from Sour Gas ................ 53

MachineryExhaustEmissions .......................... 53

WasteManagement..................................... 53

Volatilization During Evaporationand Landfarming ........... 53

June 15, 1992 DRAFT

OIL AND GAS

POTENTIAL IMPACTS ON ECOSYSTEMS ............................ 54

Abiotic EcosystemParameters................................ 54

Temperature ....................................... 54

Water .......................................... 54

Nutrients ........................................ 55

Topography....................................... 56

Soils ........................................... 56

Light ........................................... 56

Flushingof Aquatic Ecosystems.......................... 56

Salinity ......................................... 56

Turbidity andSuspendedSediments......... . .............. 57

Biotic EcosystemParameters................................. 57

Rare and EndangeredSpecies............................ 57

Dominantor ImportantSpecies........................... 57

Habitat .......................................... 57

TerrestialEcosystems ..................................... 58

EnvironmentalReleaseof Toxic Chemicals ................... 58

EnvironmentalReleaseof Other Chemicals ................... 58

PhysicalDisturbance- Woodlands......................... 59

Loss of Habitat Structure ......................... 59

Loss of Minimum Habitat Areas ..................... 59

Changesin Runoff ............................. 60

PhysicalDisturbance- Grasslandsand Scrublands ............... 60

PhysicalDisturbance- Tundra ........................... 61

Other Disturbances .................................. 62

Aquatic Ecosystems....................................... 62

Discharges to Open Waters and Wetlands .................... 63

Drilling Muds and Cuttings ........................ 63

Reduced Water ............................... 63

Summary ............................................. 64

POTENTIAL IMPACTS ON LAND USE .............................. 65

Loss of Agricultural Land ................................. 65

Loss of Agricultural Irrigation ................................ 65

POSSIBLEPREVENTION/MITIGATION MEASURES. . . . . . . . . . . . . . . . . . . . . . . . . . 66

SUMMARY OF INFORMATION THAT SHOULD BE ADDRESSED

IN NEPA DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

OTHER WASTES NOT UNIQUELY ASSOCIATEDWITH

OIL AND GAS EXPLORATION AND PRODUCTION . . . . . . . . . . . . . . . . . . . . . . 71

IDENTIFICATION OF ADDITIONAL POTENTIAL IMPACTS . . . . . . . . . . . . . . . . 72

LIST OF CONTACTS ............................................... 73

U.S. ENVIRONMENTAL PROTECTIONAGENCY ...................... 73

U.S. DEPARTMENT OF THE INTERIOR ........................... 73

June 15, 1992 DRAFT

BACKGROUND FOR NEPA REVIEWERS

U.S. FORESTSERVICE ........................................ 73

GLOSSARY ..................................................... 75

REFERENCES ................................................... 86

June 15, 1992 DRAFT

BACKGROUND FOR h-EPA REVIEW-E~

BACKGROUND FOR NEPA REVIEWERS - CRUDE OIL AND NATURAL GAS

EXPLORATION, DEVELOPMENT, AND PRODUCTION

INTRODUCTION

The primary purposeof this documentis to assistU.S. EnvironmentalProtection Agency (EPA) staff

in providing scopingcomments and comments on National Environmental Policy Act (NEPA)

documentsfor oil and gas exploration, development,and production activities proposed for Federal

lands. Pursuantto NEPA and Section309 of the CIean Air Act (CAA), EPA reviews and comments

on proposedmajor Federal agencyactionssignificantly affecting the environment. This document

was developedto assistthe EPA reviewer in consideringthoseissuesmost appropriateto oil and gas

operations in the developmentof NFPA/Section309 comments. Ultimately, the document was also

intendedto assistoperators in planning their work on Federal lands and to assist Federal land

managers in the preparation of Environmental Impact Statements(EISs).

This documentis not intendedto be all-inclusive; rather, the documentfocuseson EPA’s major

concernswith surface and ground wattr, air, and ecosystemsand sensitive receptors as related to oil

and gas. It CJU not restatetraditional NEPA concernsabout impactson floodplains, archaeological

resources,etc., sincethey may occur at any development. Furthermore, it does not discuss (in detail)

human health risks associated with oil and gas practices, since such risks are very site-specific.

Finally, it addressesonly onshoreoperations, and does not address offshore drilling and development.

The documentis organizedto provide a generaldescriptionof site operations,potential enviromnental

impacts associated with eachoperation, possiblepreventionlmitigation measures,and typesof

questions to be posed as part of the Agency’s response. EPA recognizesthat eachoil and gas

operation and each EIS is unique. Thus, reviewersmay have to conduct additional analyses to fully

understand projected impacts. The reviewer should not rely solely on this document as a defmiti\ 2

list of potential impactsor areasthat should be covered by NEPA documentation. The particular

operationsthat are stressedinclude areasthat, overall, have significant impact on the environment.

Theseoperationsinclude reservepits, driIli.ng fluids/cuttings management,produced water disposal,

well site and road construction, product gathering systems (storagetanks and pipdines), and

production operations.

OVERVIEW OF OIL AND GAS EXPLORATION AND PRODUCTION

Oil and gas exploration and production includesall activities related to the search for and extraction

of liquid and gas petrolarm from beneaththe Earth’s surface. Found almost exclusivelyin

sedimentaryrocks, oil and natural gas accumulatein geologic confinementscalled traps which, by

virtue of an impermeableoverlying layer, have stoppedthe migration of the fluid, The volume of

petroleum contained in a trap can vary from negligible to billions of barrels. The major areasof

onshoreproduction in the United Statesinclude the southwest (including California), midwwt and

Alaska, with lessorcontribution tiom the Appalachians. (SeeFigure 1.)

Though at one time such tnps may have been close enough to the surface to allow easy detection

(i.e., surfaceseepage),modern exploration relies on sophisticatedgeophysicaltesting techniquti to

June 15,1992 1 T.R.-\fT-

OlLANDGAS

Figure I. Locationof Major Oil and GasProductionin lhe U.S.

June 15, 1992 2 DUFT

BACKGROUNDFOR NEPAREV-IE\‘E~~

locatepotentiallyproducibleformations. Gravitationaland seismicsurveys of subsurface geology

provide indirect indicationsof the likelihood of finding promisinggeologicaIformations. This

processis complicatedby the fact that, at least in the U.S., the averagedepth at which one may

reasonably expectto find oil is increasingsincemanyof the largestshallowformationsare assumzd

to havebeenfound already.

If geophysicalevidencesuggeststhe possibilityof finding oil is good, operatorssecurethe required

surfaceand mineral rights to the claim and preparefor drilling. If drtiling is approved(by the

appropriateland managementagencies)an exploratory,or “wildcat” well is.drilled. In spiteof the

high level of effort dedicatedto locatingpotentialoil reserves,only 1 in 7 wildcats finds

hydrocarbons, and evenlessfind enoughoil underthe right conditionsto makeproduction

economicallyfeasible. Typically, oil and gasare found commingledin the samereservoirsand are

producedtogether. In addition, gasoccursin uniqueareasnot associatedwith economicoil

production. In thesecases,naturalgasmay be producedand marketedwithout the product treatment

facilities associatedwith oil production.

Changesin technologyand increaseddemandfor naturalgashave spurredinterestin an alternative

naturalgasresource,coalbed methane. Coaibti methaneis found in undergroundcoal seamssorbed

(adsorbedor absorbed)to particle surfaceswithin the mineral. While all coal containssomemethane,

not all coal seamswill exhibit economicallyproduciblequantitiesof gas. EstimatedreserveSof

coalbedmethanenow approachthe remainingproven reservesof conventionalnaturalgas in the U .S. Major arenaof production includethe SanJuanBasinof Coloradoand New Mexico, and the Warrior

and AppalachianBasinsof the EasternU.S. (Kuuskraa,V.A., and C.F. Brandenburg,Gctober9,

1989)

Modem well drilling involvesthe useof a rotay drill to bore through soil and rock to the desired

well depth. The drill bit is constantlywashed with a circulatingdrilling fluid, or ‘mud,’ which

servesto cool and lubricatethe bit and removethe cuttingsto the surface. If the drill reachesthe

desireddepth and fails to locatea pro&cible depositof oil or gas, the well mustbe pluggedand the

site abandoned. Even if oil and/or gas is found the well may not be producible. If the formation

fails to exhibit the right combinationof expectedvolume,porosity, and permeability,the costsof

extractionwould be prohibitive.

If an operatordeterminesa well to be producible,the well mustbe completedand preparedfor

production. In instanceswherethe reservoiris sufficientlylarge, “delineation’ wells are drilled to

determinethe boudary of the raervoir and additional‘development’wells are drilled to increasethe

rate of productionfrom the ‘field.’ Becausefew new wells in the U.S. have sufficient energy

(pressure)to force oil all the way to the surface,submersiblepumpsare placedin the wells and

productionbegii.

This first phaseof production, primary production, may continuefor severalto many years,requiring

only routine maintenance to the wells in they channeloil to the surfacefor delivery to refineries.

However, as the oil is removedfrom the formation the formation prusure decka until the wells

will no longer produce. Because70 percentof the total recoverableoil may remain in the formation,

additiorialenergymay be suppliedby the controlled injectionof water from the su.rfW into the

formation. The injectedwatezrcts to pushthe oil toward the well bores. Suchsecondaryrecovery

June 15, 1992 3 DRAFT