traded as nyse esv industry petroleum industry founded 1975 dallas 1 headquarters london united kingdom incorporation san felipe plaza houston texas usa operational 2 key people carl trowell chairman president and ceo 1 services offshore drilling well drilling revenue us 4.063 billion 2015 1 operating income us 1.243 billion 2015 1 net income us 1.594 billion 2015 1 total assets us 13.637 billion 2015 1 total equity us 6.517 billion 2015 1 number of employees 6 400 2015 1 website enscoplc.com ensco ds6 drillship taking on fuel bunkers in walvis bay namibia during the transit to angola and start of a contract with bp . ensco plc is an offshore drilling contractor headquartered in london united kingdom . the company was formerly known as blocker energy corporation named after the founder john r. blocker and energy service company inc. contents 1 current operations 2 history 2.1 financial troubles in the early 1980s 2.2 investment by richard rainwater in 1986 2.3 acquisitions 2.4 move to the united kingdom 2.5 temporary inclusion in the s & p 500 2.6 bribery allegations 2.7 environmental matters 3 references 4 external links 5 see also current operations edit ensco is the world s second largest offshore drilling and well drilling company and owns 40 offshore jack ups 9 drillships and 11 semi submersible drilling rigs . 3 in 2015 18 % of its revenues came from bp and 14 % of its revenues came from petrobras . 1 the company provides quarterly updates on the status of each rig in its fleet on its website . 4 history edit ensco s predecessor company blocker energy corporation was incorporated in 1975 by longtime oilman john r. blocker . after graduating from texas a & m in 1948 blocker worked on a gulf of mexico oil rig for several years before establishing a south texas drilling company with his father in 1954 . when an oversupply of oil on the market crippled the contract drilling business the company was dissolved and in 1958 blocker went to work for dresser industries as operations manager for the oil equipment division in argentina and venezuela a natural fit because he had grown up in south america learning spanish before english . over the next several years he learned the political and financial realities of the foreign oil business lessons that would later serve him well with blocker energy . in 1965 he moved to dresser s houston office and ultimately rose to the level of a senior vice president . his attention however was soon fixed on the drilling company due to a domestic exploration boom that resulted from the 1973 74 arab oil embargo . in 1975 blocker bought choya energy a six rig contract drilling company based in alice texas and renamed the company blocker energy . 5 blocker took advantage of his south american experience to position the company in the international market believing it was less risky than the domestic market which had 800 to 900 competitors . blocker energy expanded rapidly to meet the demand for its services and as a result soon found itself 44 million in debt . blocker took the company public to pay down some of the debt and fund further expansion . financial troubles in the early 1980s edit by 1980 the company had 1 700 employees worldwide including 211 at its texas headquarters . in the early 1980s blocker along with many other oil related companies thought the price of oil could only go higher . in 1981 and early 1982 the company borrowed heavily to expand its rig fleet to 54 rigs . however the premise of higher oil prices was a complete mistake . the price of oil plunged in late 1982 and to avoid bankruptcy blocker energy restructured giving 64 % of the company to its banks in exchange for 240 million in debt forgiveness . by 1983 the company was only operating 6 rigs although that number increased to 24 in 1984 . by 1985 the worldwide employee count of the company was down to 500 . 5 investment by richard rainwater in 1986 edit blocker energy lost nearly 3 million in 1985 and needed capital . richard rainwater s bec ventures made an investment in the company in 1986 and chose carl f. thorne to run the company which he did until his retirement 20 years later . 6 acquisitions edit in 1988 the company acquired golden gulf offshore inc. and its ten boats that supplied offshore oil rigs and another four vessels that moved the rigs massive anchors for 64 million in cash and stock . 7 in 1990 the company bought penrod holding corporation out of bankruptcy and adding 19 rigs to its fleet . penrod was owned by the hunt family . 8 in 2011 ensco acquired pride international for 7.3 billion . 9 the acquisition provided ensco access to the brazil and west african markets and diversified its asset base from being largely jack up rigs to include drillship and semi submersible rigs . as a result of the acquisition ensco closed its dallas office and consolidated into its houston office . 10 move to the united kingdom edit in 2010 ensco moved its headquarters to london and become a uk registered company . 11 temporary inclusion in the s & p 500 edit in 2012 the company was added to the s & p 500 index 12 but it was removed from the index in 2016 . 13 bribery allegations edit in 2015 petrobras alleged bribery in the negotiations of the ds 5 rig contract with pride international in 2008 before its acquisition by ensco . in 2016 petrobras terminated the contract for the rig . 14 environmental matters edit a spanish government authority is seeking 3 million in damages for an alleged environmental spill originating from the ensco 5006 rig . 1 references edit a b c d e f g h i j ensco plc 2015 form 10 k annual report contact ensco ensco about . ensco plc rig fleet a b sunny forecast hid rough waters . houston chronicle . october 24 2014 . friends return richard rainwater s investment in them as billionaire battles degenerative neurological condition . dallas morning news . november 26 2011 . the age profile and future of the osv fleet energy service r.d. smith complete closing of penrod drilling . united press international . october 26 1990 . ensco plc completes acquisition of pride international press release . business wire . may 31 2011 . ensco to close dallas office conduct layoffs ensco plc celebrates opening of new global headquarters in london press release . business wire . may 25 2010 . ensco plc set to join the s & p 500 press release . prnewswire . july 26 2012 . hologic centene set to join the s & p 500 ; others to join s & p midcap 400 and s & p smallcap 600 press release . prnewswire . march 24 2016 . petrobras ends rig contract with ensco over bribe allegations . reuters . january 6 2016 . external links edit corporate website see also edit list of oilfield service companies v t e petroleum industry petroleum primary energy benchmarks argus sour bonny light brent dubai indonesian isthmus 34 light japan cocktail opec reference basket tapis urals western canadian select west texas intermediate data natural gas consumption production reserves imports exports price petroleum consumption production reserves imports exports price of gasoline and diesel exploration core sampling geophysics integrated asset modelling petroleum engineering reservoir simulation seismic to simulation petroleum geology petrophysics reflection seismology seismic inversion seismic source drilling blowout completion squeeze job differential sticking directional drilling geosteering drilling engineering drilling fluid invasion drill stem test lost circulation measurement tracers underbalanced drilling well logging production petroleum fiscal regime concessions production sharing agreements artificial lift pumpjack submersible pump esp gas lift downstream enhanced oil recovery eor steam injection gas reinjection midstream petroleum product pipeline transport refining upstream water injection well intervention xt history 1967 oil embargo 1973 oil crisis 1979 energy crisis 1980s oil glut 1990 oil price shock 2000s energy crisis 2010s oil glut founders history of the petroleum industry nationalization opec seven sisters standard oil oil market timelines provinces and fields list of natural gas fields list of oil fields east midlands oil province east texas gulf of mexico niger delta north sea persian gulf prudhoe bay oil field russia venezuela western canadian sedimentary basin other topics acronyms peak oil mitigation timing people petrocurrency petrodollar recycling shale gas swing producer unconventional oil heavy crude oil sands oil shale companies and organisations major petroleum companies supermajors bp chevron conocophillips exxonmobil royal dutch shell total national oil companies adnoc uae cnooc china cnpc china ecopetrol colombia gazprom russia iraq national oil company indian oil corporation kuwait petroleum corporation lotos poland nigerian national petroleum corporation nioc iran nisoc iran ogdcl pakistan ongc india pdvsa venezuela pkn orlen poland pemex mexico pertamina indonesia petrobras brazil petrochina 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of petroleum engineers world petroleum council category commons v t e energy in the united kingdom companies coal anglo american asia energy bhp billiton enrc glencore rio tinto uk coal oil and gas integrated bg group bp royal dutch shell exploration and production afren bhp billiton cairn energy centrica dana petroleum desire petroleum emerald energy enquest essar energy falkland oil and gas hardy oil and gas jkx oil & gas melrose resources ophir energy perenco premier oil regal petroleum rockhopper exploration soco international star energy tullow oil supply greenergy murco petroleum support abbot group amec ensco expro hunting petrofac qserv score group weir group westerngeco1 wood group utilities generation and supply integrated centrica edf energy1 e.on uk1 rwe npower1 scottish power1 sse generation drax group falck renewables horizon nuclear power1 international power vattenfall united kingdom1 vedanta resources supply the co operative energy ecotricity esb international extra energy firmus energy first utility good energy green energy loco2 energy opus energy ovo energy phoenix natural gas telecom plus distribution electricity electricity north west1 northern powergrid1 sp energy networks1 sse power distribution uk power networks1 western power distribution1 gas firmus energy national grid northern gas networks phoenix natural gas sgn wales & west utilities1 transmission electricity national grid2 scottish hydro electric transmission sp energy networks1 gas national grid other aggreko apx group aquamarine power ecogen enserve geothermal engineering hi gen power mark group wavegen companies with headquarters and or registered office in the uk but no applicable energy operations within the country shown in italics 1ultimate parent company is not uk based 2integrated in the united states no generation or supply activities in the uk energy sources coal coal authority coal fired power stations coal mines coal mining regions confederation of uk coal producers 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