Enviromental Safety Assessment of Drilling Operations in the Marcellus-shale Gas Development.desbloqueado (1)

7/25/2019 Enviromental Safety Assessment of Drilling Operations in the Marcellus-shale Gas Development.desbloqueado (1)

1/62012 SPE Drilling & Completion 1

Environmental Safety Assessment ofDrilling Operations in the MarcellusShale

!as Development"ichar# Ola$oyin% SPE% &ohn '()ang% SPE% an# Samuel A( Oye$ole% Pennsylvania State *niversity

Summary

+he process of gas #evelopment is intensive an# involves ris, to the environment( Statistics confirm that 0(- to 1. of $ells #rille# resultin a /lo$out( Causes of these eploration ris,s are i#entifie# as violations of environmental la$s enforce# /y the PennsylvaniaDepartment of Environmental Protections DEP% operational pol lution acci#ental spills an# lea,s% an# operator3s policy( 4n a##ressingthis concern% a ris,assessment metho#ology $as use# to evaluate all violations /y operators in the State of Pennsylvania from anuary2005 to 6ovem/er 2010% /y use of Statistical Anal ysis Soft$are SAS( +he most significant causes of environmen tal #amage an#ris, $ere #etermine# /y use of the #ou/ly repeate# measure analysis of covariance A6CO7A( +he cate gory effect an#interaction effect $ere use# to prove the useful ness of the #evelope# mo#el% $hich helps eplain the safety level of the locality( +here$ere a total of 2%801 violations /et$een2005 an# 2010 committe# /y 8- #ifferent operators in the Marcel lus Shale% out of $hich only 29 of the operators sho$e# significance #ifference /ase# on environmentally #amaging violationsran,e# - to 10( A statistical comparison $as ma#e to un#erstan# the #ifference /et$een the operators /ase# on the 2%801 total violations( +he most significant inci#ents are ran,e# :on the /asis of;or#a count Saari 1% -%

of natural gas from shalegasformations Big( 1( +o$ar# this en#% there has /een a huge capitalintensive investment in the Marcellus shale /y someinternational energy firms in regar# to #eveloping pro#uctive fiel#s% provi#ing a#vance# technology% an# eploring the naturalresource of interestgas(

+hese events are ne$ to many to$ns that never eperience# #rilling an# pro#uction activities an# are intensifie# in regionsthat previously eperience# little petroleum-#evelopment activ ity( Even though the pro#uction of natural gas to meet current

energyconsumption re@uirements is essential to the survival of the human population at large% it is also ironically #etrimental to thegeneral $ell/eing of continue# human eistence.+here has /een a gro$ing concern a/out the treatment use# in the stimula tion ofshale-gas pro#uction in the Marcellus shale% ranging from contamination of #rin,a/le $ell $ater to ecessive $ater $ith #ra$al fromthe $atershe#s an# other relate# environmentalpsy chosocial effects of /oth the #rilling operations an# the #isposal of flo$/ac,flui#s generate# from hy#raulic fracturing.)aste $ater is usually pro#uce# alongsi#e the gas% an# the $aste $ater contains toins that

potentially contain human carcinogens,such as naturally occurring ra#ium 228 pic,e# up from the su/surface( +otal #issolve# soli#s inhigh concentrations are also present in this $aste $ater together $ith some of the chemical a##itives a##e# to the hy#raulicfracturingflui#. Data provi#e# /y the DEP confirm the various violations /y the operators in the Mar cellus shale area% an# it is evi#ent that,in some areas in Pennsyl vania,these flui#s $aste $ater an# un#ilute# fracturing chemicals $ere either acci#entally spille# into the$aters or% in some cases% #ischarge# into $ater /o#ies /ecause of the unavail a/ility of proy treatment plants(

Marcellus Shale

Shale is a roc, forme# from the compaction of fragments of other materials% usually silt an# claysi?e# particles( Shale is a se#i mentaryroc, $ith finegraine# teture that forms from the com paction of silt an# mu#( +he geologic age of the Marcellus shale is Devonian

>-01- million years ago( +he Devonian perio# $as mar,e# /y a su/stantial #eposit of organisms an# algae on the sea /ottom%$hich $as #evoi# of oygenF these organisms $ere a/le to settle an# #ecompose /ecause of lo$ circulation an# the prevalentanaero/ic con#itions( After a perio# of time% the #ecompose# matter $as transforme# into car/on materials% an# once hy#rate#% these

/ecame hy#rocar/ons( +hese hy#rocar/ons inclu#e petroleum an# natural gases% such as cru#e oil an# meth ane gas( +he #epositioncycle #uring the Devonian perio# that forme# the Marcellus shale $as /asically richer in car/onate than other shale formations( 6aturalgas is mostly #eposite# in the frac tures of these roc,s in the form of unrestricte# gas or as a#sor/e# gas on the clay surfaces an#,erogen insi#e the shaleroc, matri Gaines 2008( +he shale roc,s trap the flui#s an# ma,e it chal lenging to etract these flui#scommercialy from the roc,% ecept $hen natural fractures or in#uce# fractures are connecte#( +he Marcellus shale is situate# in theeastern region of the *nite# States an# some parts of Cana#a( +he lateral etent of the Marcel lus shale is approimately


2/62 2012 SPE Drilling & Completion

ferent types of #rilling flui#s vary consi#era/ly( Bor );Bs% the constituents inclu#e /rine$ater 98.% /arite 1.% claypoly mer8.% an# other .( +he nona@ueous flui#s are compose# of nona@ueous flui# 8.% /arite >>.% /rine 15.% emulsifiers 2.%an# gellantsother 1. Clar, 1


3/62012 SPE Drilling & Completion -

Chesapea,e Energy 2002. increase in the inci#ence of potentially ris,y vio lations from 2005 to 2010, compare# $ith the total violationscom mitte# /et$een 2005 an# 2010, $hich sho$e# a 110. increase( 4t $as i#entifie# from the #ata ma#e availa/le /y thePennsylvania DEP that operators in the Marcellus shale violate# the state3s oil an# gas rules an# regulations a total of 2,801 times from 1anuary 2005 to >0 6ovem/er 2010.Of these,2,05> violations or 50. of the total violations committe# $ere potential threats to the

environment.



+he original #ata $ere processe# an# groupe# /y year of inci #ents 20052010F each year has 1> varia/les( +he first varia/le isKOperators in the Marcellus ShaleL 8- that is referre# to as KcompanyL in the co#e( +he secon# to 11th varia/les% calle# KSeverity of7iolations%L are the num/ers of violations in each ran, 1 through 10( +hese are #enote# /y Kr1 to r10L in the SAS co#e( +hey are alsocalle# KcategoryL in the create# mo#el or fac tor #etermination( +he last t$o varia/les in the #ata are K+otalL an# K)eight(L +hese arerecalculate# /y use of the SAS co#e(

)eighte# Average of 7iolations( +he violation averages $ere calculate# /y use of the $eights that are ran,e# 1 to 10 to separate thecompanies into four groups( +he average of violations an# not the sum of violations is use# so that the severity of #ifferent viola tions ista,en into account( Bor eample% 10 violations $ith ran, ing num/er 1 are #ifferent from one violation $ith ran,ing num/er 10(+he $eighte# averages $ere calculate# /y use of SAS% as follo$sH

Statistical O/Jectives of Stu#y( Classify operators on the /asis of severity rate i(e(% severity of the violations on the /asis of significant values( Develop a statistical co#e /y use of SAS $ith A6CO7A for pre#ictive mo#eling an# real visuali?ation of the situation(

Previous Stu#ies vs( +his Stu#y( 4n previous stu#ies% the envi ronmental impacts of the #rilling activities $ere #escri/e# /y use ofviolation per $ell inci#ent rate% $hich #i# not account for the magnitu#e of impact of the inci#ents on the Marcellusshale environmentF therefore% the safety levels analy?e# $ere not accurate( 4n some cases% operators $ere foun# to have violate# severaltimes% /ut the violations $ere neutral to the Marcellusshale envi ronment( +his current stu#y highlights the severity of gas#evelopment activities an# also corrects misconceptions concerning #rilling activities in the Marcellusshale environment( +he main varia/lesare presente# in the follo$ing(

Analytical Summary

+he total num/er of violations for the > years analy?e# $as 2%801( Brom the analysis% the response varia/les $ere the num/er of violations of operators each year% an# the factor is the category ran,1 through 10F the covariates $ere the years 2005 to 2010% an# the A6CO7A repeate# measure $as use# for KyearL an#Kcategory(L +here $ere 8- in#epen#ent companies for the > years% in category ran, 1 to 10( ;y use of the mie# proce#ure% the total

num/er of o/servations rea# an# use# $as 1%2


5/62012 SPE Drilling & Completion 9

through -% t values of -(9F Category ran, 9 through ( +he measures as suggeste# in +a/le >% if consi#ere#% are usefulplans in minimi?ing environmental ris,s% #uring the #evel opment of natural gas from the shale formation(

"ecommen#ations an# Applications

+his research $or, #emonstrates ho$ ris,assessment techni@ues /y use of statistics such as #ou/ly repeate# A6CO7A are effec tivein the #etermination of the severity of impact an# inci#ents

on the /asis of the comparative responses inci#ents% suggeste# /y violations in this case of the significant categories( 4t also sho$s theetent of violation contri/utions to environmental #amage an# i#entification of severity rates /ecause of gas#evelopment activ ities inthe Marcellusshale area( +he DEP coul# use this mo#el to vali#ate claims /y several interest groups on the etent of #egra#a tion inthese active areas( 4f the most significant inci#ents ran,s >%-%



sreputation $hile #oing /usiness profita/ly $ith an increasing pu/ lic trust evi#ent in the #ominant sharehol#er value of the firm(

Conclusions

+he Marcellus shale has /ecome an economically important region in the $orl# /ecause of the huge naturalgas #eposits sit tingsome 5%000 ft /elo$ the surface( Shalegas #evelopment has /rought several changes to the region% inclu#ing population increase%infrastructural #evelopment% increase in Jo/ opportuni ties% an# provision of su/stantial revenue( Go$ever% the environ mental ha?ar#s

presente# /y this challenging situation of natural gas etraction from the Marcellusshale area are enormous( ;y use of the ris,evaluation techni@ue in analy?ing the prevailing situation% the maJor causes of the safety threat in the environment $ere i#entifie#accurately( +here $as a >2. increase in inci #ents of potentially ris,y violations #uring 2000 6ovem/er2010F 50. of the total violations committe# $ere potential threats to the environment( Of the 8 companies currently involve# in e

ploration activities in the area% only 29 $ere i#entifie# as significant contri/utors to environmental ris, /ecause of the high values in the ris,ran,ing num/ers of >% -% year perio#( 4n a

/roa#er perspective% the economic importance of a#e@uate inter vention in these categories is essential( 4f these highly significantcategories are effectively ta,en care of% this $oul# certainlyenhance the usefulness of the safety mo#el #evelope# an# conse @uently minimi?e the environmental footprints from gas#evelopment activities in the Marcellusshale area( +o$ar# this en#% a synergy is achieva/le /et$een gas pro#uction in the Marcellus shale an#,eeping the environment safe from pollution% through theeffective a#option of /estmanagement practices ;MPs(

+he ris, analysis ela/orate# the severity rate $ith a total num /er of 1%> violations in 2010% inclu#ing #irect #ischarge of su/stances into $ater /o#ies( +his raises concern on the potential impact of the eploration activities on the health an# safety of theresi#ents in the Marcellus Shale area( 4t is important for operators to consi#er effective mitigation plans $hich $ill re#uce theseris,s( 4n vie$ of the recent tren#s in the etraction of gas in theMarcellus shale% it is imperative for operators to comply $ith an# rea#ily an# a#e@uately implement the ;MPs in accor#ance $ithall slate# local an# state regulations in the MarcellusShale area( +his fit $ill not only #iminish the ris, associate# $ith natural resourceeploration /ut also $ill create a means of safety$here/y the nee#e# energy for human survival is availa/le along si#e a pristine environment( +he economic importance of the Marcellusshale #rilling is huge an# must /e /alance# out( Enormous attention is re@uire# in $ater management in this area to avoi# carryingout #rilling an# hy#raulic fracturing for shortterm /enefits at the #etriment of environmental preservation in the long run(

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Enviromental Safety Assessment of Drilling Operations in the Marcellus-shale Gas Development.desbloqueado (1)