Hydrocarbon gas recovery methods

Abstract

A method of recovery of rich gas where the rich gas is a hydrocarbon gas comprising less than 50 mole % methane is disclosed. The method comprises the steps of gathering the low pressure gas, compressing the gathered gas, cooling the compressed gas in a condenser so that a portion of the compressed gas condenses to form a liquefied gas and liquefied gas vapour in the condenser, and discharging the liquefied gas and liquefied gas vapour from the condenser, in which the cooling of the compressed gas is performed using at least one heat exchanger ( 40 ).

1 - 24 . (canceled) 
     
     
         25 . An apparatus comprising:
 one or more first conduits for providing a first rich gas composition from a heater treater to a first compressor, wherein crude oil flowed to a 2-phase separator forms a sales gas stream and a liquid hydrocarbon stream, the liquid hydrocarbon stream is flowed to the heater treater to form an oil stream and the first rich composition comprising less than 50 mol % methane, and the first compressor is configured to compress the first rich gas composition;   one or more second conduits for providing a second rich gas composition from an oil storage tank to a second compressor, wherein the oil stream is flowed to the oil storage tank, the second rich gas composition comprising less than 50 mol % methane is in a headspace of the oil storage tank, and the second compressor is configured to compress the second rich gas composition; and   one or more condensers for cooling the compressed first rich gas composition and the compressed second rich gas composition so that a portion thereof condenses to form a liquified gas and liquified gas vapor in the condenser.   
     
     
         26 . The apparatus of  claim 25 , wherein the first compressor and second compressor are each associated with one or more third conduits providing the compressed first rich gas composition and the compressed second rich gas composition to the one or more condensers. 
     
     
         27 . The apparatus of  claim 25 , wherein the first and second rich gas composition have a gauge pressure of less than or equal to 1379 kPa. 
     
     
         28 . The apparatus of  claim 25 , wherein the one or more condensers discharge the liquefied gas and liquefied gas vapor into one or more storage means. 
     
     
         29 . The apparatus of  claim 28 , wherein the at least one storage means is a storage tank. 
     
     
         30 . The apparatus of  claim 25 , wherein the one or more condensers comprise a fan-cooled condenser. 
     
     
         31 . The apparatus of  claim 25 , wherein the apparatus is configured such that the first and/or second rich gas composition is gathered from one or more additional sources, the one or more additional sources being selected from a two-phase separator and a vapor recovery tower. 
     
     
         32 . The apparatus of  claim 25 , wherein:
 each of the first and second compressors is controlled by a control unit,   the control unit comprises a central processor unit and at least one pressure sensor adapted to measure a source pressure,   the source pressure is the pressure of the first or second rich gas composition at a source of such gas, and   the central processor unit turns off each compression pump associated with that source when the source pressure is at or below a predetermined pressure.   
     
     
         33 . The apparatus of  claim 25 , wherein the first and second compressor compresses the first and second rich gas composition to a gauge pressure of in the range of 1379 to 2068 kPa. 
     
     
         34 . The apparatus of  claim 25 , wherein the apparatus is configured to remove at least a portion of any sulfur, oxygen, and water from the first and/or second rich gas composition upstream of the one or more condensers. 
     
     
         35 . The apparatus of  claim 34 , wherein the apparatus further comprises one or more gas cleaners for removing at least a portion of any sulfur, oxygen, and water in the first and/or second rich gas composition upstream of the one or more condensers. 
     
     
         36 . The apparatus of  claim 25 , wherein the apparatus is configured to reduce the amount of gas flared from a well pad or an oil production facility. 
     
     
         37 . The apparatus of  claim 25 , wherein the one or more condensers discharge non-condensed gas therefrom. 
     
     
         38 . The apparatus of  claim 37 , wherein the non-condensed gas comprises a higher proportion of methane than the first and second rich gas composition. 
     
     
         39 . The apparatus of  claim 37 , wherein the non-condensed gas is added to the storage tank. 
     
     
         40 . The apparatus of  claim 37 , wherein the non-condensed gas is added to the heater treater along with the hydrocarbon stream. 
     
     
         41 . The apparatus of  claim 37 , further comprising a third compressor for compressing the non-condensed gas and adding the compressed product thereof to the compressed first rich gas composition and compressed second rich gas composition that is cooled in the condenser. 
     
     
         42 . The apparatus of  claim 37 , wherein the apparatus is configured to burn the non-condensed gas and generating electricity therefrom. 
     
     
         43 . The apparatus of  claim 25 , wherein the apparatus is configured to introduce the sales gas, natural gas formed therefrom, and/or a purified product of the sales gas into a stream of commerce. 
     
     
         44 . An apparatus comprising:
 one or more first conduits for providing a first rich gas composition from a heater treater to a compressor, wherein crude oil flowed to a 2-phase separator forms a sales gas stream and a liquid hydrocarbon stream, the liquid hydrocarbon stream is flowed to the heater treater to form an oil stream and the first rich composition comprising less than 50 mol % methane, and the compressor is configured to compress the first rich gas composition;   one or more second conduits for providing a second rich gas composition from an oil storage tank to the compressor, wherein the oil stream is flowed to the oil storage tank, the second rich gas composition comprising less than 50 mol % methane is in a headspace of the oil storage tank, and the compressor is configured to compress the second rich gas composition; and   one or more condensers for cooling the compressed first rich gas composition and the compressed second rich gas composition so that a portion thereof condenses to form a liquified gas and liquified gas vapor in the condenser.