. ▁Other ▁companies ▁soon ▁followed ▁the ▁Nob els ' ▁lead . ▁ ▁The ▁older ▁Nobel ▁brothers ▁founded ▁the ▁Nobel ▁Brothers ▁O il ▁Ext raction ▁Part ners hip ▁in ▁ 1 8 7 9 , ▁and ▁were ▁soon ▁in ▁control ▁of ▁ 7 5 % ▁of ▁the ▁oil ▁industry ▁in ▁B aku . ▁As ▁of ▁October ▁ 1 8 8 5 ▁most ▁of ▁the ▁B aku ▁ref iner ies ▁were ▁in ▁Black ▁City . ▁The ▁oil ▁was ▁moved ▁by ▁pip es ▁ ▁in ▁diameter ▁rest ing ▁on ▁the ▁ground ▁and ▁conform ing ▁to ▁its ▁curv ature . ▁There ▁were ▁twelve ▁res er voir s ▁in ▁all , ▁two ▁owned ▁by ▁the ▁Nob els . ▁The ▁smaller ▁ref in ers ▁had ▁to ▁make ▁use ▁of ▁the ▁res er voir s ▁owned ▁by ▁the ▁larger ▁fir ms . ▁ ▁Later ▁develop ments ▁Bal akh any ▁was ▁an ▁oil - rich ▁area ▁ ▁from ▁B aku ▁city . ▁ ▁The ▁Swedish ▁expl orer ▁S ven ▁Hed in ▁visited ▁the ▁Bal akh any ▁oil ▁fields ▁in ▁ 1 8 9 0 . ▁There ▁were ▁then ▁ 4 1 0 ▁well s , ▁of ▁which ▁the ▁Nob els ▁owned ▁ 1 1 6 , ▁mostly ▁ ▁deep . ▁ ▁One ▁of ▁the ▁Nobel ▁well s ▁g ushed ▁ 1 5 0 , 0 0 0 ▁po ods ▁per ▁day , ▁and ▁the ▁Nob els ▁p ump ed ▁ 2 3 0 , 0 0 0 ▁po ods ▁of ▁cru de ▁each ▁day ▁to ▁Black ▁City ▁through ▁two ▁lines ,