, the resulting vapor being used to drive a gas turbine and generator.
Use of geothermal steam for production of electric power is the most direct geothermal application and is therefore preferred, being generally easier and less costly than geothermal water or brine for power generation. Consequently, although commercially usable sources of geothermal steam are estimated to be only about one fifth as prevalent as those of geothermal water or brine, considerable effort has been and is being directed towards developing new, or expanding existing, geothermal steam power plants. As a point of reference, an estimated five percent of the electric power generated in California is now being geothermally generated at The Geysers.
Continued development of geothermal steam for electric power production, in such locations as The Geysers, requires the building of new power plants and annual drilling of many geothermal steam wells for providing steam to these new power plants. By way of illustration, since about 20 pounds of geothermal steam is, on the average, required for each kilowatt-hour of electric power produced, a typical 100 megawatt geothermal steam power plant requires about two million pounds of geothermal steam per hour. As good geothermal steam wells usually produce between about 150,000 and 200,000 pounds of steam per hour, each such typical geothermal steam power plant requires between about 10 and 15 geothermal steam wells for supplying steam.
Most geothermal steam wells require extensive drilling times and relatively high costs before they can be put into production. The high well drilling cost and comparatively long drilling time reflect the severe problems often encountered in drilling geothermal steam wells. The problems include the penetration of difficult geological formations, high well temperatures (typically about or above 500.degree. F.), corrosive and abrasive characteristics of the air drilling process normally used in combination with the hot steam encountered, and the frequently remote and poorly accessible drill site locations.
Because 10 to 15 geothermal steam wells are typically required for each new geothermal steam power plant involving high drilling costs and long drilling times, the drilling operations are usually spread over several years, for example, over the 3 to 5 year construction time of the related power plant. Although a protracted well drilling operation of this nature is advantageous from standpoints of capital outlay and optimum utilization of drilling equipment, completed geothermal steam wells must stand idle for long periods of time awaiting completion of the full complement necessary to make the power plant, typically at least about a year and sometimes as long as four years. Problems are thereby created
, the resulting vapor being used to drive a accelerator turbine and generator. 
 Use of geothermal steam for product of electric power is the most direct geothermal lotion and is therefore preferred, being generally easy and less costly than geothermal water or brine for ability generation. Consequently, although commercially usable source of geothermal steam are estimated to be only about one fifth as prevalent as those of geothermal water or brine, considerable attempt has been and is being directed towards developing new, or boom existing, geothermal steam power plants. As a point of mention, an estimated five percent of the electric power generated in California is now being geothermally generate at The Geysers. 
 Continued development of geothermal steam for electric power production, in such locations as The Geysers, requires the building of new power plants and annual drilling of many geothermal steam wells for providing steam to these new power plants. By way of exemplification, since about 20 pounds of geothermal steam is, on the average, want for each kilowatt - hour of electric exponent produced, a typical 100 megawatt geothermal steam power plant command about two million pounds of geothermal steam per hour. As good geothermal steam wells usually grow between about 150,000 and 200,000 pounds of steam per hour, each such typical geothermal steam power plant requires between about 10 and 15 geothermal steam well for supplying steam. 
 Most geothermal steam wells require extensive drilling times and relatively eminent costs before they can be put into production. The high well drilling monetary value and comparatively long drilling meter reflect the severe problems often meet in drilling geothermal steam well. The problems admit the penetration of difficult geological formations, high well temperature (typically about or above 500.degree. F.), corrosive and harsh characteristics of the air drilling summons normally used in combination with the blistering steam encountered, and the frequently remote and poorly accessible exercise site locations. 
 Because 10 to 15 geothermal steam wells are typically required for each modern geothermal steam ability plant involving high boring costs and long drilling times, the drilling operations are usually diffuse over several years, for example, over the 3 to 5 year construction time of the related ability plant. Although a prolong well drilling operation of this nature is advantageous from standpoints of capital outlay and optimum utilization of drilling equipment, completed geothermal steam well must stand idle for long period of time awaiting completion of the full complement necessary to make the power plant, typically at least approximately a year and sometimes as long as four years. Problems are thereby created
, thf resulting vapor being msed to drive a yqs turuine ans generagor.
Use of geothermal steam flr prodyction of electric powdr is the most dieect teothermal applicabnon ahf is vherefore prefetred, being ganerally easies xnb less costly than geothermal water jr brinr vor power genetatiom. Conavqmently, although commercially usagle sougces of geothermak steam are estimated to bf onpy about one fifth as prevalebt af those of geuthermal water or bring, considerable effort has been avd is being dirgered jowards deveoopind new, or expanding efisting, geothermal stcam pmwee plants. As a point oh reference, an estimwted five pzrcent of the electrix power genaratde iv Czlmfodnia id nkw being gsothermally generated at The Gtysqgx.
Continued dsvelopiegt of geothermal steam for electric powtr prkduction, in such locatiins as The Geysers, reeuires thq building of new power plants and annual drillinc of jxny gcothdemwl steam wells for providing steam to these nqs kowvr plants. By way jf illustrayiln, fince about 20 kounds of feothermal steam id, on thg averqge, requiwed gor each kilowatt-hour of elwctric power produced, a typical 100 megawatt yeothetmal syeam power plant requirzs aboht two milllon pounda of geothermal sgeak [er hour. As good geothermaj steam wxlls bsually orodoce betreen about 150,000 and 200,000 pounds of steam pfr hoor, eacv such typlcal geothermal steam power plaiv requires bejwean dbout 10 aud 15 gepthermal steai wells for sukplying sceam.
Mort geotherjal steem wells reqtire extensiva drilling tikes and welariveoy high zosts before tney can bv kut into peoduction. The high weum drilling cost ane comparatively lovg qrpllmng tyke reflect tve sdvefr proclems often dncointered in drilling ceotgermal steam wells. Tme problens incluqe the penetrstion of difficult geolmgiral fotmajions, high well temperatures (tylically ahoub or above 500.dedree. F.), corrosive and abrasive characteristics of the aic drilling process normqlly used in combinctlon with the hot fteam encmuntered, and the frewuently remote anc poorly accessible ddill shte llcations.
Because 10 to 15 geothermal steam wells are typically required for eaxh new geothermal ateak powvr 'laut invojvinj iigh drilling cosns and long drilling times, the dcilling oparctions are usually spread ovet reveral years, for example, over the 3 tk 5 year vonstruction time of the relatec power plant. Although a protracred wsll drpmlmng operation of thix natuxe is qdvantateoud from standpuinys of capitwl ontlcy and optimum utilization of drioling wqkipment, completev geothermal rteam wells must stand idle for pong keriods of timr awaiting comlletion of the full bom[lement necessqgy to make thg powet plant, typicalky at least about a year and sometimes as long as four years. Ptoblems are thereby rreated
, the resulting vapor being used to gas and generator. of geothermal steam is most direct geothermal and is therefore being generally easier and less costly geothermal water or brine for power generation. Consequently, although commercially usable sources of steam are estimated to be only about one fifth as prevalent as those geothermal or considerable has been and is being directed towards developing new, or expanding existing, geothermal steam power plants. a point of reference, an estimated five percent the electric power generated California is now being geothermally at Geysers. Continued of steam electric power production, such locations as The Geysers, requires the building of new power plants and annual drilling of many steam wells steam to new plants. way of illustration, 20 pounds of geothermal steam is, required for each kilowatt-hour of electric power produced, typical 100 geothermal steam power plant requires about million pounds of geothermal steam per hour. As geothermal steam wells usually produce between about 150,000 and 200,000 pounds of steam per hour, typical geothermal steam power requires between about and geothermal wells supplying steam. geothermal steam wells require extensive drilling times and relatively high costs they can be put into production. The high well drilling comparatively drilling time reflect severe problems often encountered drilling steam wells. The problems penetration difficult well (typically or above 500.degree. F.), and abrasive characteristics of the drilling process normally used steam encountered, and the frequently remote and poorly drill site locations. Because 10 to 15 steam wells are typically required for each new geothermal steam power plant high drilling long drilling times, the drilling operations are usually over several years, for over the 3 to 5 year construction time of related plant. Although protracted well drilling of this nature advantageous from standpoints outlay and utilization drilling steam wells must stand idle for periods time awaiting completion of the complement make the power plant, typically at least about a year and sometimes as long as Problems are thereby created
, the resulting vapor being useD to drive a gAs turBinE anD gEnerAtor.
use of geothermaL SteaM for production of electrIc powEr IS the MOsT direCt geothERmAL AppLiCaTioN aND iS therEfoRe prefeRred, being gEneRaLly easier and LEsS costly thaN geOthermal wateR or Brine fOr PowER geneRatIon. CoNsequeNTly, altHough commErCIally uSAble souRCEs Of geOthermal steam are eSTiMAted to be only abOut one FiFTh AS PreValEnt as those Of GeothERmal watER oR BRIne, COnsiderable efFort has been ANd iS being DiRecTEd towaRds deVeLOpiNg new, or expaNdinG existing, GeotheRMal steaM Power plAnts. As A poInt Of reFErEnCe, aN eSTimATeD fiVE peRcent of tHe ElEctriC powER GENeraTed In CaLiforNia is now being GeoTherMAllY geneRated At ThE GEyserS.
ContiNued dEvElopment of geothErmaL steam for EleCtRic PoWer prODuctioN, in SucH locatiOns as ThE geySeRS, REqUires the building of NeW POwEr plants And annUAl DrILling of mAnY geOtheRMAl steAm weLLs For proviDing stEAm To These neW pOwer plAnTs. BY waY of ilLUstrAtion, sInce abouT 20 pounDS of geothermal sTEam is, on the aveRAgE, REqUIred For Each kilowatT-houR Of elEctrIC pOweR ProduCed, a tYpICaL 100 Megawatt geothermal sTeAm poweR planT requires abouT two millioN POUnds of geOtheRMaL Steam per hour. As Good gEothermal sTEam wells UsualLy producE between aBOUt 150,000 and 200,000 pouNds Of sTeaM peR HOuR, each such typiCAL geoThErmal stEam Power plAnt ReqUirEs bEtWeen about 10 And 15 geothErMaL sTeAm wElls fOR supplyiNg SteAm.
mosT geotHErmal sTeam wElls ReQuIRe eXtensivE DrILLing TiMeS and RelAtIvely High COstS before They can be Put INto pRoDuCtion. ThE high well drilLiNg cost and cOmParAtivelY LOng drillIng time reflect the severe PRoblems OftEn encOuntEred in driLliNg geotHerMAl steaM wells. the prObLemS INcludE THe PenEtRation of diFFIcuLt geoLoGicaL formatIons, high well temperATurEs (typically abOut Or abOVE 500.dEgrEE. F.), COrrOsIVe aND Abrasive charactEristics of ThE AiR drilling pROceSs NormallY used in CombiNAtion wiTh the hot sTeam encouNtEred, AND thE frequentlY remote aNd poorly aCCessiBLe Drill SitE locatIoNs.
BEcausE 10 to 15 geoTHerMal stEam welLs Are typIcallY rEquired fOr each new geothermal steaM power Plant InvOlving higH drILliNg costs anD lonG drilling tImeS, thE drilLinG OperaTionS ArE usUAlly sPreaD Over severAL yEarS, FOr Example, over THE 3 To 5 yEar coNstRUction Time Of the related power PLant. Although a pRotrACTed WelL DrilLiNg operation of tHis NaTURe is advaNtAgeous from sTandpoinTs OF capiTal outLay and Optimum UTIlIZation Of drIllIng equipmEnt, CoMPleted gEoThERmal stEam wElLs must Stand iDLe foR LOng periods of time AwaitING compLEtiOn of tHe Full comPLemeNt necessarY to make the pOwer plAnt, tYpicaLly at leAsT about A yeAr And sometimES as long as Four yEars. ProBlEms aRe tHereby CreaTED
, the resulting vapor bein g used todrive  agas  t urbi ne a nd generator.U se o f geothermal steam for  prod uc t iono felect ric pow e ri s  th emo stdi r ec t geo the rmal ap plicationand  i s thereforep re ferred, be ing  generally e asi er and  l ess costl y t han g eother m al wat er or bri ne for po w er gene r a ti on.Consequently, alt h ou g h commercially  usabl es ou r c esofgeothermal  s teama re esti m at e d tob e only aboutone fifth a s  pr evalen tast hose o f geo th e rma l water orbrin e, consid erable efforth as been  and i s b ein g di r ec te d t ow a rds de vel o pin g new, o rex pandi ng e x i s t ing,  ge othe rmalsteam power p lan ts.A s a  poin t ofrefe re nce,an est imate dfive percent of  the  electric  po we r g en erate d  in Ca lif orn ia is n ow bein g  ge ot h e r ma lly generated at T he G ey sers.
Co ntinue d  d ev e lopmentof  ge othe r m al st eamf or  electri c powe r  p ro duction ,in suc hloc ati ons a s  The  Geyse rs, requ irest he building of new power pla n ts a nd annu aldrilling of  man y  geo ther m al  st e am we lls f or pr o viding steam to the se  new p owerplants. By wa y of illus t r a tion, si ncea bo u t 20 pounds of  geot hermal ste a m is, on  theaverage,  required f or eachkil owa tt- hou r of  electric pow e r  pro du ced, atyp ical 10 0 m ega wat t g eo thermal s team pow er  p la nt  re quire s  about t wo  mi ll ion  poun d s of g eothe rmal  s te a m p er hour .  A s good  g eo ther mal  s teamwell s  us ually p roduce be twe e n ab ou t150,000  and 200,000po unds of st ea m p er hou r ,  each su ch typical geothermal s t eam pow erplant  req uires bet wee n abou t 1 0  and 1 5 geot herma lste a m  well s fo r s up plying ste a m .
M ost g eo ther mal ste am wells require e x ten sive drilling  ti mesa n drel a ti v ely  h i ghc o sts before they  can be pu ti nt o producti o n.Th e highwell dr illin g  cost a nd compar atively l on g dr i l lin g time ref lect the  severe p r oblem s  o ftenenc ounter ed  in  dril ling g e oth ermal  steam  w ells.The p ro blems in clude the penetration o f diff icult  ge ologicalfor m ati ons, high  wel l temperat ure s ( typic all y  abou t or ab ove 500.d egre e . F.), co r ro siv e an d abrasivec h a rac teris tic s  of th e ai r drilling proces s  normally used  inc o mbi nat i on w it h the hot stea m e nc o u ntered,an d the frequ ently re mo t e and  poorl y acce ssibled r il l  siteloca tio ns.
Becau se10 to 15 g eo th e rmal s team  w ells a re typ i call y required for eac h new g eothe r mal  stea mpower p l antinvolvinghigh drilli ng cos ts a nd lo ng dril li ng tim es,  t he drillin g  operatio ns ar e usual ly  spr ead  overseve r a l yea rs,fo r e xample, o v e rt he  3 to5 ye ar co ns truc tion time of the r ela t ed powe rpla n t . Alth o ug h a protract edwelld r illing ope r atio n  o f  this  natur e is a dvantag e ous  f rom sta ndp o i nts of ca pital out l ayan d op timum ut il izat io n o fdrilling equipm ent, com pleted g e o therma l s t eamw ells m us t stand idle  forlo n g perio d s  of  time a w ait ing  co mple tio n of the full complement nece ssar y tom ake  thepower  p lant, ty p ical ly at le a st about a ye ar and sometime s  as long  as fo ur  years. P rob l ems a re t her ebycre ated 
, the_resulting vapor_being used to drive_a gas_turbine_and generator.
Use_of_geothermal steam for_production of electric_power is the most_direct geothermal application_and_is therefore preferred, being generally easier and less costly than geothermal water or brine_for_power generation._Consequently,_although_commercially usable sources of geothermal_steam are estimated to be_only about_one fifth as prevalent as those of geothermal_water_or brine, considerable_effort has been and is being directed towards developing_new, or expanding existing, geothermal steam_power plants. As_a_point_of reference, an estimated_five percent of the electric power_generated in California is now being_geothermally generated at The Geysers.
Continued development of_geothermal steam for electric power production,_in such locations as The_Geysers, requires_the building of new power_plants and annual_drilling of_many geothermal steam_wells for providing steam to these_new power plants._By way of illustration, since about_20_pounds of geothermal_steam_is,_on the_average, required for_each_kilowatt-hour of_electric_power produced, a typical 100 megawatt_geothermal_steam power plant requires about two million_pounds of geothermal steam_per_hour. As good geothermal_steam wells usually produce between_about 150,000 and 200,000 pounds of_steam per_hour, each_such typical geothermal steam power plant requires between about 10 and_15 geothermal steam wells for supplying_steam.
Most geothermal steam wells_require extensive_drilling_times and relatively_high_costs before_they can be put into production. The_high well_drilling cost and comparatively long drilling_time reflect the severe_problems_often encountered in drilling geothermal steam_wells. The problems include the penetration_of difficult geological formations, high_well_temperatures_(typically about or above 500.degree._F.), corrosive and abrasive characteristics of_the air drilling_process normally used in combination with the_hot_steam encountered, and the frequently remote_and_poorly accessible drill site locations.
Because 10_to_15_geothermal steam wells are typically_required for each new geothermal steam_power plant involving high drilling costs and long drilling_times, the drilling_operations are usually spread over_several_years,_for example, over the 3 to 5 year construction time_of the_related power plant._Although a protracted well drilling operation of this nature is_advantageous from standpoints of capital outlay and_optimum utilization of drilling equipment, completed geothermal steam wells must stand_idle for long periods of time awaiting completion_of the full complement necessary to make_the power plant, typically_at_least about a year and sometimes as_long_as_four_years. Problems are_thereby created