Processing produced fluids of high pressure gas condensate reservoirs

• US 4,474,591 A
• Filed: 07/21/1983
• Issued: 10/02/1984
• Est. Priority Date: 07/21/1983
• Status: Expired due to Fees

• Current Assignee: Amoco Corporation (BP PLC)
• Original Assignee: Standard Oil Company (BP PLC)
• Inventors: Wilson, Robert H., Arand, Dale P.
• Primary Examiner(s): Sever, Frank
• Application Number:
  US06/516,159
• Time in Patent Office: 439 Days
• Field of Search: 62/23, 62/24, 62/27, 62/28, 62/31, 62/33, 62/34, 62/25, 62/26, 62/29, 62/30, 62/9, 62/11
• US Class Current: 62/630
• CPC Class Codes: C10G 5/00 Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas
• CPC Class Codes: F25J 3/0233 separation of CnHm with 1 carbon atom or more

Abstract

A production facility utilizes a first high pressure separation zone, a second intermediate pressure separation zone, a first distillation zone, and a second distillation zone, where the vapor fraction from the second intermediate pressure separation zone and the overhead stream from the first distillation column are recompressed to about the first high pressure. Such a process can produce specification residue gas streams, natural gas liquid streams, and a stabilized condensate stream.

Claims

1. Process comprising producing a residue gas stream and recovering natural gas liquids and stabilized condensate from a produced stream from high pressure gas condensate wells by,

introducing the produced fluid stream into a first separator zone operated at about a first pressure, the first pressure being about pipeline pressure for the residue gas stream, and separating the produced fluid stream into a first liquid fraction and a first vapor fraction;

withdrawing the first liquid fraction from the first separator zone and introducing the withdrawn first liquid fraction into a second separator zone at a lower pressure of operation than the first separator zone, and separating the first liquid fraction into a second vapor fraction and a second liquid fraction, the lower pressure of operation being such that the second vapor fraction is compressible by a single stage of compression to about the first pressure;

withdrawing the second liquid fraction from the second separator zone and introducing the withdrawn second liquid fraction as feed into a first distillation column comprising a plurality of vapor-liquid contact devices and operated under conditions effective to produce a first overhead stream enriched in methane, and a first bottoms stream enriched in heavier components of the second liquid fraction, the pressure in the first overhead stream being such that the first overhead stream is compressible by a single stage of compression to about the first pressure;

withdrawing a portion of liquid from adjacent the bottom of the first distillation column, introducing a pressure differential thereinto, and circulating the withdrawn portion by forced circulation through a first reboiler and reintroducing thus reboiled fluid adjacent the bottom of the first distillation column to maintain an effective operating temperature therein;

withdrawing the first bottoms stream from the first distillation column and introducing the withdrawn first bottoms stream as feed into a second distillation column containing a plurality of vapor-liquid contact devices and operated under conditions effective to produce a second overhead stream enriched in natural gas liquid components of the first bottoms stream and a second bottoms stream enriched in heavier components of the first bottoms stream;

withdrawing a portion of liquid from adjacent the bottom of the second distillation column, introducing a pressure differential thereinto, and circulating the withdrawn portion by forced circulation through a second bottoms reboiler and back to adjacent the bottom of the second distillation column to maintain effective operating temperatures in the second distillation column; and

compressing the second vapor fraction and the first overhead stream by a single stage of compression to about the first pressure and combining the thus compressed second vapor fraction and the first overhead stream with the first vapor fraction to produce a residue gas stream at pipeline pressure.

2. Process as in claim 1 wherein:

the first bottoms reboiler is a shell-and-tube indirect heat exchanging reboiler and the second bottoms reboiler is a direct-fired reboiler, and comprising;

maintaining the operating temperature in the second distillation column at a temperature in the range between that temperature effective for causing coking in fire tubes of the second bottoms reboiler and that temperature requiring a refrigerated condenser in the overhead of the second distillation column; and

withdrawing a portion of the second bottoms stream from the second distillation column and introducing the withdrawn portion as heat exchange medium into the first bottoms reboiler as a source of heat for heating the portion of liquid circulated through the first bottoms reboiler to maintain an effective operating temperature in the first distillation column and to produce a first cooled second bottoms stream portion.

3. Process as in claim 2 further comprising:

withdrawing a portion of intermediate tray liquid from the first distillation column, passing the thus withdrawn portion in indirect heat exchange with at least a portion of the first cooled second bottoms stream to increase the temperature thereof, and reintroducing the thus heated withdrawn portion into the first distillation column and producing a second cooled second bottoms stream; and

combining the second cooled second bottoms stream with remaining portion of the first cooled second bottom stream to produce a condensate products stream.

4. Process as in claim 2 wherein:

the second distillation column is operated to produce a second overhead stream enriched in natural gas liquids components and a second bottoms stream enriched in heavy condensate fraction.

5. Process as in claim 2 wherein:

the second distillation column is operated to increase production of a second overhead stream enriched in natural gas liquids components.

6. Process as in claim 1 wherein:

each of the first bottoms reboiler and the second bottoms reboiler are direct-fired reboilers, and comprising;

withdrawing the first bottoms stream from the first distillation column;

withdrawing the second bottoms stream from the second distillation column;

introducing the withdrawn first bottoms stream into indirect heat exchange with the second bottoms stream to produce a heated first bottoms stream and a cooled second bottoms stream; and

introducing the heated first bottoms stream as feed into the second distillation column.

7. Process as in claim 6 comprising:

withdrawing a portion of intermediate tray liquid from the first distillation column and passing the withdrawn portion in indirect heat exchange with the second overhead stream to produce a cooled second overhead stream and a heated withdrawn portion reintroduced into the first distillation column.

8. Process as in claim 1, wherein:

the first pressure is in the range of about 300 to about 1200 psia;

the second separator zone is operated at a pressure in the range of about 200 to about 600 psia;

the first column is operated at a pressure in the range of about 100 to about 450 psia and at a temperature in the range of about 0°

F. to about 400°

F.; and

the second column is operated at a pressure in the range of about 50 to about 400 psia and at a temperature below about 550°

F.

9. Process as in claim 8 wherein:

the first pressure is in the range of about 600 to about 1200 psia; and

the second separator zone is operated at about one-third the pressure of the first separator zone.