Patent Publication Number: US-2022212964-A1

Title: Water treatment for injection in hydrocarbon recovery

Description:
TECHNICAL FIELD 
     This disclosure relates to water treatment, and in particular, to produce injection fluid for enhanced hydrocarbon recovery. 
     BACKGROUND 
     Primary hydrocarbon recovery involves the extraction of hydrocarbons from a subterranean formation either by the natural pressure within the subterranean formation or facilitation by an artificial lift device, such as an electric submersible pump. Secondary hydrocarbon recovery involves injection of fluid into a subterranean formation to displace hydrocarbons and produce them to the surface. Enhanced oil recovery involves altering a property of the hydrocarbons and/or the subterranean formation to make the hydrocarbons more conducive to extraction. 
     SUMMARY 
     This disclosure describes technologies relating to water treatment, and in particular, to produce injection fluid for enhanced hydrocarbon recovery. Certain aspects of the subject matter described can be implemented as a method. An aqueous feed stream having a first total dissolved solids (TDS) level is flowed to a forward osmosis separator. The aqueous feed stream includes seawater. An aqueous draw stream having a second TDS level is flowed to the forward osmosis separator. The second TDS level is greater than the first TDS level. A disposal stream and an injection fluid stream is produced by the forward osmosis separator by allowing water to pass from the aqueous feed stream to the aqueous draw stream through a membrane of the forward osmosis separator based on a difference between the first TDS level and the seconds TDS level. The injection fluid stream is flowed from the osmosis separator to a subterranean formation. 
     This, and other aspects, can include one or more of the following features. 
     In some implementations, the aqueous draw stream includes water from the subterranean formation to which the injection fluid stream is flowed. 
     In some implementations, the second TDS level is at least 150% of the first TDS level. 
     In some implementations, the method includes measuring a flow rate of the injection fluid stream from the forward osmosis separator. In some implementations, the method includes adjusting a flow rate of the disposal stream from the forward osmosis separator based on the measured flow rate of the injection fluid stream from the forward osmosis separator. 
     In some implementations, the method includes measuring a flow rate of the injection fluid stream from the forward osmosis separator. In some implementations, the method includes adjusting a flow rate of the aqueous feed stream to the forward osmosis separator based on the measured flow rate of the injection fluid stream from the forward osmosis separator. 
     In some implementations, the method includes measuring a TDS level of the injection fluid stream. In some implementations, the method includes adjusting a flow rate of the aqueous feed stream to the forward osmosis separator based on the measured TDS level of the injection fluid stream. 
     In some implementations, the method includes flowing a second aqueous feed stream having a third TDS level to a second forward osmosis separator. In some implementations, the method includes flowing a second aqueous draw stream having a fourth TDS level to the second forward osmosis separator. In some implementations, the fourth TDS level is greater than the third TDS level. In some implementations, the second aqueous draw stream includes seawater. In some implementations, the method includes producing, by the second forward osmosis separator, a second disposal stream and the aqueous feed stream having the first TDS level by allowing water to pass from the second aqueous feed stream to the second aqueous draw stream through a second membrane of the second forward osmosis separator based on a difference between the third TDS level and the fourth TDS level. 
     In some implementations, the fourth TDS level is at least 150% of the third TDS level. 
     Certain aspects of the subject matter described can be implemented as a method. A feed stream having a first TDS level is flowed to a forward osmosis separator. The feed stream includes a treated sewage effluent. Seawater is processed to produce a draw stream and a permeate stream. The draw stream has a second TDS level that is greater than the first TDS level. The permeate stream has a third TDS level that is less than the second TDS level. The draw stream is flowed to the forward osmosis separator. A disposal stream and an injection fluid stream is produced by the forward osmosis separator by allowing water to pass from the feed stream to the draw stream through a membrane of the forward osmosis separator based on a difference between the first TDS level and the second TDS level. The injection fluid stream is flowed from the forward osmosis separator to a subterranean formation. 
     This, and other aspects, can include one or more of the following features. 
     In some implementations, the second TDS level is at least 150% of the first TDS level. 
     In some implementations, the method includes measuring a flow rate of the injection fluid stream from the forward osmosis separator. In some implementations, the method includes adjusting a flow rate of the draw stream to the forward osmosis separator based on the measured flow rate of the injection fluid stream from the forward osmosis separator. 
     In some implementations, the method includes measuring a TDS level of the injection fluid stream. In some implementations, the method includes adjusting a flow rate of the feed stream to the forward osmosis separator based on the measured TDS level of the injection fluid stream. 
     Certain aspects of the subject matter described can be implemented as a system. The system includes an aqueous feed stream, an aqueous draw stream, and a forward osmosis separator. The aqueous feed stream has a first TDS level. The aqueous feed stream includes seawater. The aqueous draw stream has a second TDS level that is greater than the first TDS level. The forward osmosis separator includes a feed compartment, a draw compartment, and a membrane disposed between the feed compartment and the draw compartment. The feed compartment includes a feed inlet and a disposal outlet. The feed inlet is configured to receive the aqueous feed stream into the feed compartment. The disposal outlet is configured to discharge a disposal stream from the feed compartment. The draw compartment includes a draw inlet and an injection fluid outlet. The draw inlet is configured to receive the aqueous draw stream into the draw compartment. The injection fluid outlet is configured to discharge an injection fluid stream from the draw compartment. The membrane is configured to allow passage of water between the feed compartment and the draw compartment through the membrane based on a difference between the first TDS level and the second TDS level, thereby forming the disposal stream and the injection stream. The injection stream is configured to be flowed to a subterranean formation. 
     This, and other aspects, can include one or more of the following features. 
     In some implementations, the aqueous draw stream includes water from the subterranean formation to which the injection fluid stream is to be flowed. 
     In some implementations, the second TDS level is at least 150% of the first TDS level. 
     In some implementations, the system includes a flow control subsystem. 
     In some implementations, the flow control subsystem includes a flowmeter configured to measure a flow rate of the injection fluid stream. In some implementations, the flow control subsystem includes a control valve configured to adjust a flow rate of the disposal stream. In some implementations, the flow control subsystem includes a controller communicatively coupled to the flowmeter and the control valve. In some implementations, the controller is configured to adjust a position of the control valve to adjust the flow rate of the disposal stream based on the flow rate of the injection fluid stream measured by the flowmeter. 
     In some implementations, the flow control subsystem includes a flow meter configured to measure a flow rate of the injection fluid stream. In some implementations, the flow control subsystem includes a pump configured to flow the aqueous feed stream to the feed inlet of the feed compartment. In some implementations, the flow control subsystem includes a controller communicatively coupled to the flowmeter and the pump. In some implementations, the controller is configured to adjust a speed of the pump to adjust the flow of the aqueous feed stream to the feed inlet of the feed compartment based on the flow rate of the injection fluid stream measured by the flowmeter. 
     In some implementations, the flow control subsystem includes a TDS meter configured to measure a TDS level of the injection fluid stream. In some implementations, the flow control subsystem includes a control valve configured to adjust a flow rate of the aqueous feed stream. In some implementations, the flow control subsystem includes a controller communicatively coupled to the TDS meter and the control valve. In some implementations, the controller is configured to adjust a position of the control valve to adjust the flow rate of the aqueous feed stream based on the TDS level of the injection fluid stream measured by the TDS meter. 
     In some implementations, the system includes a second aqueous feed stream having a third TDS level. In some implementations, the system includes a second aqueous draw stream having a fourth TDS level that is greater than the third TDS level. In some implementations, the second aqueous draw stream includes seawater. In some implementations, the system includes a second forward osmosis separator. In some implementations, the second forward osmosis separator includes a second feed compartment, a second draw compartment, and a second membrane disposed between the second feed compartment and the second draw compartment. In some implementations, the second feed compartment includes a second feed inlet and a second disposal outlet. In some implementations, the second feed inlet is configured to receive the second aqueous feed stream into the second feed compartment. In some implementations, the second disposal outlet is configured to discharge a second disposal stream from the second feed compartment. In some implementations, the second draw compartment includes a second draw inlet and a feed outlet. In some implementations, the second draw inlet is configured to receive the second aqueous draw stream into the second draw compartment. In some implementations, the feed outlet is configured to discharge the aqueous feed stream from the second draw compartment. In some implementations, the second membrane is configured to allow passage of water between the second feed compartment and the second draw compartment through the second membrane based on a difference between the third TDS level and the fourth TDS level, thereby forming the second disposal stream and the aqueous feed stream having the first TDS level. 
     In some implementations, the fourth TDS level is at least 150% of the third TDS level. 
     The details of one or more implementations of the subject matter of this disclosure are set forth in the accompanying drawings and the description. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a schematic diagram of an example well. 
         FIG. 1B  is a schematic diagram of an example well. 
         FIG. 2A  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2B  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2C  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2D  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2E  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2F  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2G  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2H  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2J  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2K  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 2L  is a schematic diagram of an example water treatment system to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 3A  is a flow chart of an example method for treating water to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 3B  is a flow chart of an example method for treating water to form an injection fluid that can be flowed to the well of  FIG. 1A . 
         FIG. 4  is a schematic diagram of an example controller that can be used in fluid flow control. 
     
    
    
     DETAILED DESCRIPTION 
     Water is typically produced with hydrocarbons (for example, crude oil) from subterranean formations. The production stream from the subterranean formation is processed to separate the water from the hydrocarbons. In some cases, the water that has been separated from the hydrocarbons can be further processed to form an injection fluid that can be flowed back into the subterranean formation to improve hydrocarbon production from the subterranean formation. For example, the injection fluid formed from the processed water can be flowed into the subterranean formation to alter characteristic(s) of the subterranean formation to improve hydrocarbon mobility and, in turn, production from the subterranean formation. 
     The subject matter described in this disclosure can be implemented in particular implementations, so as to realize one or more of the following advantages. The use of groundwater for water injection in enhanced oil recovery can be reduced. The systems and methods described in this disclosure can be implemented with decreased capital and operating costs in comparison to conventional seawater desalination technologies for producing injection fluid for enhanced oil recovery. The systems and methods described in this disclosure can be implemented with decreased spacing requirements in comparison to conventional seawater desalination technologies for producing injection fluid for enhanced oil recovery. In some cases, two osmosis separators in a series configuration can be implemented to allow for use of sewage water in reservoir pressure maintenance. 
       FIGS. 1A and 1B  depict an example well  100  constructed in accordance with the concepts herein. The well  100  extends from the surface  106  through the Earth  108  to one more subterranean zones of interest  110  (one shown). The well  100  enables access to the subterranean zones of interest  110  to allow recovery (that is, production) of fluids to the surface  106  and, in some implementations, additionally or alternatively allows fluids to be placed in the Earth  108 . In some implementations, the subterranean zone  110  is a formation within the Earth  108  defining a reservoir, but in other instances, the zone  110  can be multiple formations or a portion of a formation. The subterranean zone can include, for example, a formation, a portion of a formation, or multiple formations in a hydrocarbon-bearing reservoir from which recovery operations can be practiced to recover trapped hydrocarbons. In some implementations, the subterranean zone includes an underground formation of naturally fractured or porous rock containing hydrocarbons (for example, oil, gas, or both). In some implementations, the well can intersect other types of formations, including reservoirs that are not naturally fractured. For simplicity&#39;s sake, the well  100  is shown as a vertical well, but in other instances, the well  100  can be a deviated well with a wellbore deviated from vertical (for example, horizontal or slanted), the well  100  can include multiple bores forming a multilateral well (that is, a well having multiple lateral wells branching off another well or wells), or both. 
     In some implementations, as shown in  FIG. 1A , the well  100  is an injection well that is used to inject fluid from the surface  106  and into the subterranean zones of interest  110 . The concepts herein, though, are not limited in applicability to injection wells, and could be used in production wells (such as gas wells or oil wells) as shown in  FIG. 1B , wells for producing other gas or liquid resources or could be used in injection wells, disposal wells, or other types of wells similarly used in placing fluids into the Earth. The term “gas well” refers to a well that is used in producing hydrocarbon gas (such as natural gas) from the subterranean zones of interest  110  to the surface  106 . While termed “gas well,” the well need not produce only dry gas, and may incidentally or in much smaller quantities, produce liquid including oil, water, or both. The term “oil well” refers to a well that is used in producing hydrocarbon liquid (such as crude oil) from the subterranean zones of interest  110  to the surface  106 . While termed an “oil well,” the well not need produce only hydrocarbon liquid, and may incidentally or in much smaller quantities, produce gas, water, or both. In some implementations, the production from a gas well or an oil well can be multiphase in any ratio. In some implementations, the production from a gas well or an oil well can produce mostly or entirely liquid at certain times and mostly or entirely gas at other times. For example, in certain types of wells, it is common to produce water for a period of time to gain access to the gas in the subterranean zone. 
     The wellhead defines an attachment point for other equipment to be attached to the well  100 . For example,  FIG. 1B  shows well  100  being produced with a Christmas tree attached to the wellhead. The Christmas tree includes valves used to regulate flow into or out of the well  100 . The wellbore of the well  100  is typically, although not necessarily, cylindrical. All or a portion of the wellbore is lined with a tubing, such as casing  112 . The casing  112  connects with a wellhead at the surface  106  and extends downhole into the wellbore. The casing  112  operates to isolate the bore of the well  100 , defined in the cased portion of the well  100  by the inner bore  116  of the casing  112 , from the surrounding Earth  108 . The casing  112  can be formed of a single continuous tubing or multiple lengths of tubing joined (for example, threadedly) end-to-end. In  FIGS. 1A  and  1 B, the casing  112  is perforated in the subterranean zone of interest  110  to allow fluid communication between the subterranean zone of interest  110  and the bore  116  of the casing  112 . In some implementations, the casing  112  is omitted or ceases in the region of the subterranean zone of interest  110 . This portion of the well  100  without casing is often referred to as “open hole.” 
     In particular, casing  112  is commercially produced in a number of common sizes specified by the American Petroleum Institute (the “API”), including 4-1/2, 5, 5-1/2, 6, 6-5/8, 7, 7-5/8, 7-3/4, 8-5/8, 8-3/4, 9-5/8, 9-3/4, 9-7/8, 10-3/4, 11-3/4, 11-7/8, 13-3/8, 13-1/2, 13-5/8, 16, 18-5/8, and 20 inches, and the API specifies internal diameters for each casing size. 
       FIG. 2A  depicts a system  200  that can be used to treat water to form an injection fluid, which can be used as a treatment fluid to improve hydrocarbon production from a subterranean formation (for example, using the well  100 ). The system  200  includes an osmosis separator  201 . The osmosis separator  201  transfers water from one fluid stream to another fluid stream via osmotic pressure difference. In some implementations, the osmosis separator  201  is a forward osmosis separator or a pressure retarded osmosis separator. The osmosis separator  201  includes a feed compartment  203 , a draw compartment  205 , and a membrane  207  that is disposed between the feed compartment  203  and the draw compartment  205 . 
     The feed compartment  203  includes a feed inlet  203   a  and a disposal outlet  203   b . The feed inlet  203   a  is configured to receive an aqueous feed stream  202  into the feed compartment  203 . The aqueous feed stream  202  has a first total dissolved solids (TDS) level. In some implementations, the aqueous feed stream  202  includes seawater. In some implementations, the first TDS level of the aqueous feed stream  202  is at least 10,000 parts per million (ppm), at least 15,000 ppm, at least 20,000 ppm, at least 25,000 ppm, at least 30,000 ppm, or at least 35,000 ppm. In some implementations, the first TDS level of the aqueous feed stream  202  is about 55,000 ppm, 50,000 ppm, about 45,000 ppm, about 40,000 ppm, about 35,000 ppm, about 30,000 ppm, about 25,000 ppm, about 20,000 ppm, about 15,000 ppm, or about 10,000 ppm. In some implementations, the aqueous feed stream  202  includes a treated sewage effluent (TSE). In some implementations, the first TDS level of the aqueous feed stream  202  is less than 1,000 ppm. 
     The draw compartment  205  includes a draw inlet  205   a  and an injection fluid outlet  205   b . The draw inlet  205   a  is configured to receive an aqueous draw stream  204  into the draw compartment  205 . The aqueous draw stream  204  has a second TDS level that is greater than the first TDS level of the aqueous feed stream  202 . In some implementations, the second TDS level of the aqueous draw stream  204  is at least 150% of the first TDS level of the aqueous feed stream  202 . For example, if the first TDS level of the aqueous feed stream  202  is 30,000 ppm, then the second TDS level of the aqueous draw stream  204  is at least 45,000 ppm. 
     The membrane  207  is configured to allow passage of water between the feed compartment  203  and the draw compartment  205  through the membrane  207  based on a difference between the first TDS level of the aqueous feed stream  202  and the second TDS level of the aqueous draw stream  204 . Because the second TDS level of the aqueous draw stream  204  is greater than the first TDS level of the aqueous feed stream  202 , the aqueous draw stream  204  has a greater osmotic pressure than the aqueous feed stream  202 . Osmotic pressure can be calculated by Equation (1): 
       π= CRT   (1)
 
     where C is concentration of ions (for example, TDS level), R is the universal gas constant, and T is the operating temperature in absolute units (such as Kelvin or Rankine). Because osmotic pressure depends on operating temperature, a heating or cooling device (such as a heat exchanger) can be provided to control the operating temperature of fluid entering the osmosis separator  201 . Because osmotic pressure is directly proportional to TDS level, in some implementations, the osmotic pressure of the aqueous draw stream  204  is at least 150% of the osmotic pressure of the aqueous feed stream  202 . For example, if the osmotic pressure of the aqueous feed stream  202  is psi, then the osmotic pressure of the aqueous draw stream  204  is at least psi. 
     Water preferentially flows from aqueous feed stream  202  in the feed compartment  203  through the membrane  207  to the aqueous draw stream  204  in the draw compartment  205  (depicted by dotted arrow). Consequently, within the osmosis separator  201 , water transfers out of the aqueous feed stream  202  to form a disposal stream  206 , and water transfers into the aqueous draw stream  204  to form an injection fluid stream  208 . Estimated water flux (rate of transfer) through the membrane  207  can be calculated by Equation (2): 
         J   w   =K   w (Δ P −Δπ)  (2)
 
     where J w  is water flux through the membrane  207 , K w  is the permeability coefficient for water for the membrane  207  (related to cross-sectional area and thickness of the membrane  207 ), ΔP is hydraulic pressure differential across the membrane  207 , and Δπ is osmotic pressure differential across the membrane  207 . 
     The disposal outlet  203   b  is configured to discharge the disposal stream  206  from the feed compartment  203 . The injection fluid outlet  205   b  is configured to discharge the injection fluid stream  208  from the draw compartment  205 . The disposal stream  206  exiting the osmosis separator  201  has a greater concentration of TDS in comparison to the aqueous feed stream  202  entering the osmosis separator  201 . The injection fluid stream  208  exiting the osmosis separator  201  has a smaller concentration of TDS in comparison to the aqueous draw stream  204  entering the osmosis separator  201 . In effect, the aqueous feed stream  202  is used to dilute the aqueous draw stream  204 . 
     The disposal stream  206  can be disposed. The injection fluid stream  208  can be flowed to a subterranean formation (for example, using the injection well  100  of  FIG. 1A ). In some implementations, the injection fluid stream  208  is processed before it is flowed to the subterranean formation. 
     In some implementations, the aqueous draw stream  204  includes water the same subterranean formation to which the injection fluid stream  208  is flowed. For example, the production well of  FIG. 1B  and the injection well of  FIG. 1A  penetrate the subterranean formation, and water that is produced along with hydrocarbons from the production well is separated from the produced hydrocarbons. In some implementations, the aqueous draw stream  204  is the water that is separated from the produced hydrocarbons. 
       FIG. 2B  depicts an implementation of the system  200  that includes a crude oil processing unit  250 . The crude oil processing unit  250  receives a production stream (for example, from the production well  100  of  FIG. 1B ) and processes the production stream to produce a dry crude oil product. Processing in the crude oil processing unit  250  includes separating water that has been produced along with the hydrocarbons from the production well. The water separated from the hydrocarbons by the crude oil processing unit  250  can be used as the aqueous draw stream  204 . 
     The system  200  includes a flow control subsystem  290  that controls fluid flow in the system  200 . The flow control subsystem  290  can control the flow of the injection fluid stream  208  to an injection well (for example, the injection well  100  of  FIG. 1A ). The flow control system  290  includes a controller  291 , which is also shown in  FIG. 4  and described in more detail later. 
     In some implementations, the flow control subsystem  290  includes a flowmeter  293  and a control valve  295 . The flowmeter  293  can be configured to measure a flow rate of the injection fluid stream  208 . The control valve  295  can be configured to adjust a flow rate of the disposal stream  206 . In some implementations, the controller  291  is communicatively coupled to the flowmeter  291  and the control valve  293 . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295  to adjust the flow rate of the disposal stream  206  based on the flow rate of the injection fluid stream  208  measured by the flowmeter  293 . For example, the controller  291  receives the measured flow rate of the injection fluid stream  208  from the flowmeter  293 . Based on the measured flow rate, the controller  291  can transmit a signal to the control valve  295  to adjust the percent opening of the control valve  295  to adjust the flow rate of the disposal stream  206  exiting the osmosis separator  201 . 
       FIG. 2C  depicts an implementation of the system  200  that includes the crude oil processing unit  250  and the flow control subsystem  290 . Similar to the system  200  of  FIG. 2B , the flow control subsystem  290  of  FIG. 2C  includes the flowmeter  293  configured to measure the flow rate of the injection fluid stream  208 . In some implementations, the flow control subsystem  290  includes a pump  297  that is configured to flow the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  of the osmosis separator  201 . In some implementations, the pump  297  is a variable speed drive (VSD) pump. In some implementations, the controller  291  is communicatively coupled to the flowmeter  293  and the pump  297 . The controller  291  can be configured to adjust a speed of the pump  297  to adjust the flow of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the flow rate of the injection fluid stream  208  measured by the flowmeter  293 . For example, the controller  291  receives the measured flow rate of the injection fluid stream  208  from the flowmeter  293 . Based on the measured flow rate, the controller  291  can transmit a signal to the pump  297  to adjust the speed of the pump  297  to adjust a flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
       FIG. 2D  depicts an implementation of the system  200  that includes the crude oil processing unit  250  and the flow control subsystem  290 . Similar to the system  200  of  FIG. 2B , the flow control subsystem  290  of  FIG. 2D  includes the flowmeter  293  configured to measure the flow rate of the injection fluid stream  208  and the control valve  295 . In some implementations, at least a portion of the aqueous draw stream  204  bypasses the osmosis separator  201  and mixes with the injection fluid stream  208  before the injection fluid stream  208  is flowed to the subterranean formation. In some implementations, the control valve  295  is configured to adjust a flow rate of the portion of the aqueous draw stream  204  that bypasses the osmosis separator  201 . Similar to that of the flow control subsystem  290  of  FIG. 2B , the controller  291  is communicatively coupled to the flowmeter  293  and the control valve  295 . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295  to adjust the flow rate of the portion of the aqueous draw stream  204  that bypasses the osmosis separator  201  based on the flow rate of the injection fluid stream  208  measured by the flowmeter  293 . For example, the controller  291  receives the measured flow rate of the injection fluid stream  208  from the flowmeter  293 . Based on the measured flow rate, the controller  291  can transmit a signal to the control valve  295  to adjust the percent opening of the control valve  295  to adjust the flow rate of the portion of the aqueous draw stream  204  that bypasses the osmosis separator  201 . 
       FIG. 2E  depicts an implementation of the system  200  that includes the crude oil processing unit  250  and the flow control subsystem  290 . Similar to the system  200  of  FIG. 2B , the flow control subsystem  290  of  FIG. 2E  includes the control valve  295 . In some implementations, the control valve  295  is configured to the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  of the osmosis separator  201 . In some implementations, the flow control subsystem  290  includes a TDS meter  299 . The TDS meter  299  can be configured to measure a TDS level of the injection fluid stream  208 . Similar to that of the flow control subsystem  290  of  FIG. 2B , the controller  291  is communicatively coupled to the TDS meter  299  and the control valve  295 . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the TDS level of the injection fluid stream  208  measured by the TDS meter  299 . For example, the controller  291  receives the measured TDS level of the injection fluid stream  208  from the TDS meter  299 . Based on the measured TDS level, the controller  291  can transmit a signal to the control valve  295  to adjust the percent opening of the control valve  295  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
       FIG. 2F  depicts an implementation of the system  200  in which the aqueous feed stream  202  is TSE. In some implementations, the aqueous draw stream  204  includes seawater. In some implementations, the aqueous draw stream  204  is a stream from a water treatment unit. For example, the water treatment unit includes a reverse osmosis separator which receives seawater and produces a permeate stream (low TDS) and a concentrate stream (high TDS), and the aqueous draw stream  204  is the concentrate stream. 
     Similar to the system  200  of  FIG. 2E , the system  200  includes the flow control subsystem  290  that includes a control valve  295   a  and the TDS meter  299 . The control valve  295   a  is configured to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 , and the TDS meter  299  is configured to measure the TDS level of the injection fluid stream  208 . Similar to that of the flow control subsystem  290  of  FIG. 2E , the controller  291  is communicatively coupled to the TDS meter  299  and the control valve  295   a . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the TDS level of the injection fluid stream  208  measured by the TDS meter  299 . For example, the controller  291  receives the measured TDS level of the injection fluid stream  208  from the TDS meter  299 . Based on the measured TDS level, the controller  291  can transmit a signal to the control valve  295   a  to adjust the percent opening of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
     Similar to the system  200  of  FIG. 2B , the flow control subsystem  290  of  FIG. 2F  includes the flowmeter  293  configured to measure the flow rate of the injection fluid stream  208 . In some implementations, the flow control subsystem  290  includes a control valve  295   b . The control valve  295   b  is configured to adjust the flow rate of the aqueous draw stream  204  to the draw inlet  205   a  of the draw compartment  205  of the osmosis separator  201 . Similar to that of the flow control subsystem  290  of  FIG. 2B , the controller  291  is communicatively coupled to the flowmeter  293  and the control valve  295   b . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   b  to adjust the flow rate of the aqueous draw stream  204  to the draw inlet  205   a  of the draw compartment  205  based on the flow rate of the injection fluid stream  208  measured by the flowmeter  293 . For example, the controller  291  receives the measured flow rate of the injection fluid stream  208  from the flowmeter  293 . Based on the measured flow rate, the controller  291  can transmit a signal to the control valve  295   b  to adjust the percent opening of the control valve  295   b  to adjust the flow rate of aqueous draw stream  204  to the draw inlet  205   a  of the draw compartment  205 . 
       FIG. 2G  depicts an implementation of the system  200  that includes multiple osmosis separators  201  (labeled as  201  and  201 ′). The second osmosis separator  201 ′ can be substantially the same as the first osmosis separator  201 . In some implementations, the osmosis separator  201  and the second osmosis separator  201 ′ are in a parallel configuration (as shown in  FIG. 2G ). 
     Similar to the system  200  of  FIG. 2F , the aqueous feed stream  202  can be TSE, and aqueous draw stream  204  can be the concentrate stream from the water treatment unit. Similar to the system  200  of  FIG. 2F , the system  200  includes the flow control subsystem  290  including the flowmeter  293 , the control valve  295   a , the control valve  295   b , and the TDS meter  299 . 
     The control valve  295   a  is configured to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 , and the TDS meter  299  is configured to measure the TDS level of the injection fluid stream  208 . Similar to that of the flow control subsystem  290  of  FIG. 2F , the controller  291  is communicatively coupled to the TDS meter  299  and the control valve  295   a . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the TDS level of the injection fluid stream  208  measured by the TDS meter  299 . For example, the controller  291  receives the measured TDS level of the injection fluid stream  208  from the TDS meter  299 . Based on the measured TDS level, the controller  291  can transmit a signal to the control valve  295   a  to adjust the percent opening of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
     The flowmeter  293  is configured to measure the flow rate of the injection fluid stream  208 . The control valve  295   b  is configured to adjust the flow rate of the aqueous draw stream  204  to the draw inlet  205   a  of the draw compartment  205  of the osmosis separator  201 . Similar to that of the flow control subsystem  290  of  FIG. 2F , the controller  291  is communicatively coupled to the flowmeter  293  and the control valve  295   b . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   b  to adjust the flow rate of the aqueous draw stream  204  to the draw inlet  205   a  of the draw compartment  205  based on the flow rate of the injection fluid stream  208  measured by the flowmeter  293 . For example, the controller  291  receives the measured flow rate of the injection fluid stream  208  from the flowmeter  293 . Based on the measured flow rate, the controller  291  can transmit a signal to the control valve  295   b  to adjust the percent opening of the control valve  295   b  to adjust the flow rate of aqueous draw stream  204  to the draw inlet  205   a  of the draw compartment  205 . 
     In some implementations, TSE flows to a second feed inlet  203   a ′ of a second feed compartment  203 ′ of the second osmosis separator  201 ′ as a second aqueous feed stream  202 ′. In some implementations, a portion of the seawater flows to a second draw inlet  205   a ′ of a second draw compartment  205 ′ of the second osmosis separator  201 ′ as a second aqueous draw stream  204 ′. The second aqueous feed stream  202 ′ has a third TDS level, and the second aqueous draw stream  204 ′ has a fourth TDS level that is greater than the third TDS level of the second aqueous feed stream  202 ′. In some implementations, the fourth TDS level of the second aqueous draw stream  204 ′ is at least 150% of the third TDS level of the second aqueous feed stream  202 ′. In some implementations, the osmotic pressure of the second aqueous draw stream  204 ′ is at least 150% of the osmotic pressure of the second aqueous feed stream  202 ′. 
     A second membrane  207 ′ of the second osmosis separator  201 ′ is configured to allow passage of water between the feed compartment  203  and the draw compartment  205  through the second membrane  207 ′ based on a difference between the third TDS level of the second aqueous feed stream  202 ′ and the fourth TDS level of the second aqueous draw stream  204 ′. Because the fourth TDS level of the second aqueous draw stream  204 ′ is greater than the third TDS level of the second aqueous feed stream  202 ′, the second aqueous draw stream  204 ′ has a greater osmotic pressure than the second aqueous feed stream  202 ′. Water preferentially flows from second aqueous feed stream  202 ′ in the second feed compartment  203 ′ through the second membrane  207 ′ to the second aqueous draw stream  204 ′ in the second draw compartment  205 ′ (depicted by dotted arrow). In some implementations, within the second osmosis separator  201 ′, water transfers out of the second aqueous feed stream  202 ′ to form a second disposal stream  206 ′, and water transfers into the second aqueous draw stream  204 ′ to form a second injection fluid stream  208 ′. 
     A second disposal outlet  203   b ′ of the second feed compartment  203 ′ is configured to discharge the second disposal stream  206 ′ from the second feed compartment  203 ′. A second injection fluid outlet  205   b ′ of the second draw compartment  205 ′ is configured to discharge the second injection fluid stream  208 ′ from the second draw compartment  205 ′. The second disposal stream  206 ′ exiting the second osmosis separator  201 ′ has a greater concentration of TDS in comparison to the second aqueous feed stream  202 ′ entering the second osmosis separator  201 ′. The second injection fluid stream  208 ′ exiting the second osmosis separator  201 ′ has a smaller concentration of TDS in comparison to the second aqueous draw stream  204 ′ entering the second osmosis separator  201 ′. In effect, the second aqueous feed stream  202 ′ is used to dilute the second aqueous draw stream  204 ′. 
     The second disposal stream  206 ′ can be disposed. The second injection fluid stream  208 ′ can be flowed to a subterranean formation (for example, using the injection well  100  of  FIG. 1A ). In some implementations, the second injection fluid stream  208 ′ is processed before it is flowed to the subterranean formation. In some implementations, the injection fluid stream  208  and the second injection fluid stream  208 ′ are combined and flow together to the subterranean formation. 
     In some implementations, the flow control subsystem  290  includes a second control valve  295   a ′ and a second TDS meter  299 ′. The second control valve  295   a ′ is configured to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′, and the second TDS meter  299 ′ is configured to measure the TDS level of the second injection fluid stream  208 ′. Similar to that of the flow control subsystem  290  of  FIG. 2E , the controller  291  is communicatively coupled to the second TDS meter  299 ′ and the second control valve  295   a ′. The controller  291  can be configured to adjust a position (percent opening) of the second control valve  295   a ′ to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′ based on the TDS level of the second injection fluid stream  208 ′ measured by the second TDS meter  299 ′. For example, the controller  291  receives the measured TDS level of the second injection fluid stream  208 ′ from the second TDS meter  299 ′. Based on the measured TDS level, the controller  291  can transmit a signal to the second control valve  295   a ′ to adjust the percent opening of the second control valve  295   a ′ to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′. 
     In some implementations, the flow control subsystem  290  includes a second flowmeter  293 ′ and a third control valve  295   b ′. The second flowmeter  293 ′ is configured to measure the flow rate of the second injection fluid stream  208 ′. The third control valve  295   b ′ is configured to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ of the second osmosis separator  201 ′. Similar to that of the flow control subsystem  290  of  FIG. 2F , the controller  291  is communicatively coupled to the second flowmeter  293 ′ and the third control valve  295   b ′. The controller  291  can be configured to adjust a position (percent opening) of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ based on the flow rate of the second injection fluid stream  208 ′ measured by the second flowmeter  293 ′. For example, the controller  291  receives the measured flow rate of the second injection fluid stream  208 ′ from the second flowmeter  293 ′. Based on the measured flow rate, the controller  291  can transmit a signal to the third control valve  295   b ′ to adjust the percent opening of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′. 
       FIG. 2H  depicts an implementation of the system  200  that includes the second osmosis separator  201 ′, the crude oil processing unit  250 , the flow control subsystem  290 . As mentioned previously, in some implementations, the water separated from the hydrocarbons by the crude oil processing unit  250  is used as the aqueous draw stream  204  flowing to the draw compartment  205  of the osmosis separator  201 . In some implementations, a first portion of TSE is used as the aqueous feed stream  202  flowing to the feed compartment  203  of the osmosis separator  201 . In some implementations, a second portion of TSE is used as the second aqueous feed stream  202 ′ flowing to the second feed compartment  203 ′ of the second osmosis separator  201 ′. In some implementations, seawater is used as the second aqueous draw stream  204 ′ flowing to the second draw compartment  205 ′ of the second osmosis separator  201 ′. 
     Similar to the flow control subsystem  290  of  FIG. 2E , the control valve  295   a  is configured to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 , and the TDS meter  299  is configured to measure the TDS level of the injection fluid stream  208 . Similar to that of the flow control subsystem  290  of  FIG. 2E , the controller  291  is communicatively coupled to the TDS meter  299  and the control valve  295   a . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the TDS level of the injection fluid stream  208  measured by the TDS meter  299 . For example, the controller  291  receives the measured TDS level of the injection fluid stream  208  from the TDS meter  299 . Based on the measured TDS level, the controller  291  can transmit a signal to the control valve  295   a  to adjust the percent opening of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
     Similar to the flow control subsystem  290  of  FIG. 2G , the second control valve  295   a ′ is configured to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′, and the second TDS meter  299 ′ is configured to measure the TDS level of the second injection fluid stream  208 ′. Similar to that of the flow control subsystem  290  of  FIG. 2G , the controller  291  is communicatively coupled to the second TDS meter  299 ′ and the second control valve  295   a ′. The controller  291  can be configured to adjust a position (percent opening) of the second control valve  295   a ′ to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′ based on the TDS level of the second injection fluid stream  208 ′ measured by the second TDS meter  299 ′. For example, the controller  291  receives the measured TDS level of the second injection fluid stream  208 ′ from the second TDS meter  299 ′. Based on the measured TDS level, the controller  291  can transmit a signal to the second control valve  295   a ′ to adjust the percent opening of the second control valve  295   a ′ to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′. 
     Similar to the flow control subsystem  290  of  FIG. 2G , the second flowmeter  293 ′ is configured to measure the flow rate of the second injection fluid stream  208 ′. The third control valve  295   b ′ is configured to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ of the second osmosis separator  201 ′. Similar to that of the flow control subsystem  290  of  FIG. 2G , the controller  291  is communicatively coupled to the second flowmeter  293 ′ and the third control valve  295   b ′. The controller  291  can be configured to adjust a position (percent opening) of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ based on the flow rate of the second injection fluid stream  208 ′ measured by the second flowmeter  293 ′. In some implementations, the flow control subsystem  290  includes a third flowmeter  293 ″ configured to measure a combined flow rate of the injection fluid stream  208  and the second injection fluid stream  208 ′. The controller  291  can be communicatively coupled to the third flowmeter  293 ″. In some implementations, the controller  291  can be configured to adjust the position (percent opening) of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ based on the combined flow rate of the injection fluid stream  208  and the second injection fluid stream  208 ′ measured by the third flowmeter  293 ″. 
     For example, the controller  291  receives the measured flow rate of the second injection fluid stream  208 ′ from the second flowmeter  293 ′ and/or the measured flow rate of the combined injection fluid stream  208  and the second injection fluid stream  208 ′ from the third flowmeter  293 ″. Based on the measured flow rate, the controller  291  can transmit a signal to the third control valve  295   b ′ to adjust the percent opening of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′. 
       FIG. 2J  depicts an implementation of the system  200  that includes the second osmosis separator  201 ′, the crude oil processing unit  250 , the flow control subsystem  290 . As mentioned previously, in some implementations, the water separated from the hydrocarbons by the crude oil processing unit  250  is used as the aqueous draw stream  204  flowing to the draw compartment  205  of the osmosis separator  201 . In some implementations, a first portion of seawater is used as the aqueous feed stream  202  flowing to the feed compartment  203  of the osmosis separator  201 . In some implementations, a second portion of seawater is used as the second aqueous draw stream  204 ′ flowing to the second draw compartment  205 ′ of the second osmosis separator  201 ′. In some implementations, TSE is used as the second aqueous feed stream  202 ′ flowing to the second feed compartment  203 ′ of the second osmosis separator  201 ′. 
     Similar to the flow control subsystem  290  of  FIG. 2H , the control valve  295   a  is configured to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 , and the TDS meter  299  is configured to measure the TDS level of the injection fluid stream  208 . Similar to that of the flow control subsystem  290  of  FIG. 2E , the controller  291  is communicatively coupled to the TDS meter  299  and the control valve  295   a . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the TDS level of the injection fluid stream  208  measured by the TDS meter  299 . For example, the controller  291  receives the measured TDS level of the injection fluid stream  208  from the TDS meter  299 . Based on the measured TDS level, the controller  291  can transmit a signal to the control valve  295   a  to adjust the percent opening of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
     Similar to the flow control subsystem  290  of  FIG. 2H , the second control valve  295   a ′ is configured to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′, and the second TDS meter  299 ′ is configured to measure the TDS level of the second injection fluid stream  208 ′. Similar to that of the flow control subsystem  290  of  FIG. 2H , the controller  291  is communicatively coupled to the second TDS meter  299 ′ and the second control valve  295   a ′. The controller  291  can be configured to adjust a position (percent opening) of the second control valve  295   a ′ to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′ based on the TDS level of the second injection fluid stream  208 ′ measured by the second TDS meter  299 ′. For example, the controller  291  receives the measured TDS level of the second injection fluid stream  208 ′ from the second TDS meter  299 ′. Based on the measured TDS level, the controller  291  can transmit a signal to the second control valve  295   a ′ to adjust the percent opening of the second control valve  295   a ′ to adjust the flow rate of the second aqueous feed stream  202 ′ to the second feed inlet  203   a ′ of the second feed compartment  203 ′. 
     Similar to the flow control subsystem  290  of  FIG. 2H , the second flowmeter  293 ′ is configured to measure the flow rate of the second injection fluid stream  208 ′. The third control valve  295   b ′ is configured to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ of the second osmosis separator  201 ′. Similar to that of the flow control subsystem  290  of  FIG. 2H , the controller  291  is communicatively coupled to the second flowmeter  293 ′ and the third control valve  295   b ′. The controller  291  can be configured to adjust a position (percent opening) of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ based on the flow rate of the second injection fluid stream  208 ′ measured by the second flowmeter  293 ′. Similar to the flow control subsystem  290  of  FIG. 2H , the third flowmeter  293 ″ is configured to measure a combined flow rate of the injection fluid stream  208  and the second injection fluid stream  208 ′. The controller  291  can be communicatively coupled to the third flowmeter  293 ″. In some implementations, the controller  291  can be configured to adjust the position (percent opening) of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′ based on the combined flow rate of the injection fluid stream  208  and the second injection fluid stream  208 ′ measured by the third flowmeter  293 ″. 
     For example, the controller  291  receives the measured flow rate of the second injection fluid stream  208 ′ from the second flowmeter  293 ′ and/or the measured flow rate of the combined injection fluid stream  208  and the second injection fluid stream  208 ′ from the third flowmeter  293 ″. Based on the measured flow rate, the controller  291  can transmit a signal to the third control valve  295   b ′ to adjust the percent opening of the third control valve  295   b ′ to adjust the flow rate of the second aqueous draw stream  204 ′ to the second draw inlet  205   a ′ of the second draw compartment  205 ′. 
       FIG. 2K  depicts an implementation of the system  200  that includes the second osmosis separator  201 ′, the crude oil processing unit  250 , the flow control subsystem  290 . In some implementations, the osmosis separator  201  and the second osmosis separator  201 ′ are in a series configuration (as shown in  FIG. 2K ). As mentioned previously, in some implementations, the water separated from the hydrocarbons by the crude oil processing unit  250  is used as the aqueous draw stream  204  flowing to the draw compartment  205  of the osmosis separator  201 . In some implementations, seawater is used as the second aqueous draw stream  204 ′ flowing to the second draw compartment  205 ′ of the second osmosis separator  201 ′. In some implementations, TSE is used as the second aqueous feed stream  202 ′ flowing to the second feed compartment  203 ′ of the second osmosis separator  201 ′. In some implementations, the stream exiting the second draw compartment  205 ′ of the second osmosis separator  201 ′ (previously referred to as the second injection fluid stream  208 ′) is used as the aqueous feed stream  202  flowing to the feed compartment  203  of the osmosis separator  201 . 
     Similar to the system  200  of  FIG. 2E , the system  200  includes the flow control subsystem  290  that includes a control valve  295   a  and the TDS meter  299 . The control valve  295   a  is configured to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 , and the TDS meter  299  is configured to measure the TDS level of the injection fluid stream  208 . Similar to that of the flow control subsystem  290  of  FIG. 2E , the controller  291  is communicatively coupled to the TDS meter  299  and the control valve  295   a . The controller  291  can be configured to adjust a position (percent opening) of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203  based on the TDS level of the injection fluid stream  208  measured by the TDS meter  299 . For example, the controller  291  receives the measured TDS level of the injection fluid stream  208  from the TDS meter  299 . Based on the measured TDS level, the controller  291  can transmit a signal to the control valve  295   a  to adjust the percent opening of the control valve  295   a  to adjust the flow rate of the aqueous feed stream  202  to the feed inlet  203   a  of the feed compartment  203 . 
       FIG. 2L  depicts the implementation of system  200  in  FIG. 2K  but also shows additional details of the crude oil processing unit  250 . The crude oil processing unit  250  separates water, salt, and vapors from the wet crude produced from a well (for example, the production well  100  of  FIG. 1B ) to produce a dry crude oil product. In some implementations, the crude oil processing unit  250  is configured to produce a dry crude oil product having a salt content of at most 10 pounds per 1,000 barrels. In some implementations, the crude oil processing unit  250  is configured to produce a dry crude oil product having a basic sediment and water (BS&amp;W) content of at most 0.3 volume percent (vol. %). In some implementations, the crude oil processing unit  250  is configured to produce a dry crude oil product having a hydrogen sulfide content of less than 60 parts per million (ppm). In some implementations, the crude oil processing unit  250  is configured to produce a dry crude oil product having a Reid vapor pressure (RVP) of at most 7 pounds per square inch absolute (psia) and a true vapor pressure (TVP) of at most 13.5 psia at 130 degrees Fahrenheit (° F.). 
     In some implementations, the crude oil processing unit  250  includes a high pressure production trap  251 . In some implementations, the crude oil processing unit  250  includes a low pressure production trap  253 . In some implementations, the crude oil processing unit  250  includes a low pressure degassing tank  255 . In some implementations, the crude oil processing unit  250  includes a dehydrator  257 . In some implementations, the crude oil processing unit  250  includes a 1 st  stage desalter  259 . In some implementations, the crude oil processing unit  250  includes a 2 nd  stage desalter  261 . In some implementations, the crude oil processing unit  250  includes a stabilizer column  263 . In some implementations, the crude oil processing unit  250  includes a water/oil separation unit  265 . 
     Wet crude from a production well (for example, the production well  100  of  FIG. 1B ) flows to the high pressure production trap  251 . The high pressure production trap  251  is a three-phase separator and removes a majority of the vapors and water from the crude oil. In some implementations, the operating pressure of the high pressure production trap  251  is about 150 pounds per square inch gauge (psig). In some implementations, the operating temperature of the high pressure production trap  251  is in a range of from about 65° F. to about 130° F. Vapors exit from the high pressure production trap  251 . The water flows from the high pressure production trap  251  to the water/oil separation unit  265 . The crude oil flows from the high pressure production trap  251  to the low pressure production trap  253 . 
     The low pressure production trap  253  is a three-phase separator and further removes vapors and water from the crude oil. In some implementations, the operating pressure of the low pressure production trap  253  is about 50 psig. In some implementations, the operating temperature of the low pressure production trap  253  is in a range of from about 65° F. to about 130° F. Vapors exit from the low pressure production trap  253 . The water flows from the low pressure production trap  253  to the water/oil separation unit  265 . The crude oil flows from the low pressure production trap  253  to the low pressure degassing tank  255 . In some implementations, the crude oil flowing from the low pressure production trap  253  to the low pressure degassing tank  255  is heated (for example, by a heat exchanger) to increase the crude oil&#39;s temperature before entering the low pressure degassing tank  255 . 
     The operating pressure in the low pressure degassing tank  255  is in a range of from about 3 psig to 5 psig. In some implementations, the operating temperature of the low pressure degassing tank  255  is in a range of from about 65° F. to about 130° F. Vapors exit from the low pressure degassing tank  255 . The water flows from the low pressure degassing tank  255  to the water/oil separation unit  265 . The crude oil flows from the low pressure degassing tank  255  to the dehydrator  257  and to the 1 st  and 2 nd  stage desalters  259 ,  261 . In some implementations, the crude oil flowing from the low pressure degassing tank  255  to the dehydrator  257  is heated (for example, by a heat exchanger) to increase the crude oil&#39;s temperature before entering the dehydrator  257 . 
     The water flows from the dehydrator  257  to the water/oil separation unit  265 . In some implementations, at least a portion of the water from the 1 st  stage desalter  259  is recycled upstream of the dehydrator  257 . In some implementations, at least a portion of the water from the 2 nd  stage desalter  261  is recycled upstream of the 1 st  stage desalter  259 . In some implementations, wash water is provided upstream of the 2 nd  stage desalter  261 . The crude oil flows from the 2 nd  stage desalter  261  to the stabilizer column  263 . The bottoms product from the stabilizer column  263  is the dry crude oil product. 
     The water streams from the high pressure production trap  251 , the low pressure production trap  253 , the low pressure degassing tank  255 , and the dehydrator  257  are treated in the water/oil separation unit  265  (for example, to remove oil). In the implementation shown in  FIG. 2L , the treated water stream flows from the water/oil separation unit  265  to the osmosis separator  201  and is used as the aqueous draw stream  204 . 
       FIG. 3A  is a flow chart of an example method  300  for treating water to produce an injection fluid stream (such as the injection fluid stream  208 ) that can be used to treat a subterranean formation. The system  200  can be used to implement method  300 . At step  302 , an aqueous feed stream (such as the aqueous feed stream  202 ) having a first TDS level is flowed to an osmosis separator (such as the osmosis separator  201 ). As mentioned previously, in some implementations, the osmosis separator  201  is a forward osmosis separator, and the aqueous feed stream  202  includes seawater. For example, the aqueous feed stream  202  is flowed at step  302  to the feed inlet  203   a  of the feed compartment  203  of the osmosis separator  201 . 
     At step  304 , an aqueous draw stream (such as the aqueous draw stream  204 ) having a second TDS level is flowed to the osmosis separator  201 . As mentioned previously, the second TDS level of the aqueous draw stream  204  is greater than the first TDS level of the aqueous feed stream  202 . In some implementations, the second TDS level is at least 150% of the first TDS level. For example, the aqueous draw stream  204  is flowed at step  304  to the draw inlet  205   a  of the draw compartment  205  of the osmosis separator  201 . 
     At step  306 , a disposal stream (such as the disposal stream  206 ) and an injection fluid stream (the injection fluid stream  208 ) is produced by the osmosis separator  201 . The disposal stream  206  and the injection fluid stream  208  can be produced by the osmosis separator  201  at step  306  by allowing water to pass from the aqueous feed stream  202  to the aqueous draw stream  204  through a membrane (such as the membrane  207 ) of the osmosis separator  201  based on a difference between the first TDS level of the aqueous feed stream  202  and the second TDS level of the aqueous draw stream  204 . 
     At step  308 , the injection fluid stream  208  is flowed from the osmosis separator  201  to a subterranean formation. For example, the injection fluid stream  208  is discharged from the injection fluid outlet  205   b  of the draw compartment  205  of the osmosis separator  201  and flowed at step  308  to the injection well  100  of  FIG. 1A . In some implementations, the aqueous draw stream  204  flowed at step  304  includes water from the subterranean formation to which the injection fluid stream  208  is flowed at step  208 . 
     In some implementations, method  300  includes measuring a flow rate of the injection fluid stream  208  from the osmosis separator  201 , for example, using the flowmeter  293 . In some implementations, method  300  includes adjusting a flow rate of the disposal stream  206  from the osmosis separator  201  based on the measured flow rate of the injection fluid stream  208  from the osmosis separator  201 . In some implementations, method  300  includes adjusting a flow rate of the aqueous feed stream  202  to the osmosis separator  201  based on the measured flow rate of the injection fluid stream  208  from the osmosis separator  201 . In some implementations, method  300  includes measuring a TDS level of the injection fluid stream  208 . In some implementations, method  300  includes adjusting the flow rate of the aqueous feed stream  202  to the osmosis separator  201  based on the measured TDS level of the injection fluid stream  208 . 
     In some implementations, method  300  includes flowing a second aqueous feed stream (such as the second aqueous feed stream  202 ′) having a third TDS level to a second osmosis separator (such as the second osmosis separator  201 ′). In some implementations, the second osmosis separator  201 ′ is a forward osmosis separator. In some implementations, method  300  includes flowing a second aqueous draw stream (such as the second aqueous draw stream  204 ′) having a fourth TDS level to the second osmosis separator  201 ′. As mentioned previously, the fourth TDS level of the second aqueous draw stream  204 ′ is greater than the third TDS level of the second aqueous feed stream  202 ′. In some implementations, the fourth TDs level is at least 150% of the third TDS level. In some implementations, the second aqueous draw stream  204 ′ includes seawater. In some implementations, method  300  includes producing, by the second osmosis separator  201 ′, a second disposal stream (such as the second disposal stream  206 ′) and the aqueous feed stream  202  having the first TDS level. The second disposal stream  206 ′ and the aqueous feed stream  202  are produced by the second osmosis separator  201 ′ by allowing water to pass from the second aqueous feed stream  202 ′ to the second aqueous draw stream  204 ′ through a second membrane (such as the second membrane  207 ′) of the second osmosis separator  201 ′ based on a difference between the third TDS level of the second aqueous feed stream  202 ′ and the fourth TDS level of the second aqueous draw stream  204 ′. 
       FIG. 3B  is a flow chart of an example method  350  for treating water to produce an injection fluid stream (such as the injection fluid stream  208 ) that can be used to treat a subterranean formation. The system  200  can be used to implement method  350 . At step  352 , a feed stream (such as the aqueous feed stream  202 ) having a first TDS level is flowed to an osmosis separator (such as the osmosis separator  201 ). As mentioned previously, in some implementations, the osmosis separator  201  is a forward osmosis separator, and the aqueous feed stream  202  includes TSE. For example, the aqueous feed stream  202  is flowed at step  352  to the feed inlet  203   a  of the feed compartment  203  of the osmosis separator  201 . 
     At step  354 , seawater is processed to produce a permeate stream (low TDS) and a condensate stream (high TDS). As mentioned previously, the condensate stream can be used as the aqueous draw stream  204 , which has a second TDS level greater than the first TDS level of the aqueous feed stream  202 . The permeate stream has a TDS level that is less than the second TDS level of the aqueous draw stream  204 . In some cases, the permeate stream has a TDS level that is less than the first TDS level of the aqueous feed stream  202 . In some implementations, the second TDS level is at least 150% of the first TDS level. 
     At step  356 , the aqueous draw stream  204  is flowed to the osmosis separator  201 . For example, the aqueous draw stream  204  is flowed at step  356  to the draw inlet  205   a  of the draw compartment  205  of the osmosis separator  201 . 
     At step  358 , a disposal stream (such as the disposal stream  206 ) and an injection fluid stream (the injection fluid stream  208 ) is produced by the osmosis separator  201 . The disposal stream  206  and the injection fluid stream  208  can be produced by the osmosis separator  201  at step  358  by allowing water to pass from the aqueous feed stream  202  to the aqueous draw stream  204  through a membrane (such as the membrane  207 ) of the osmosis separator  201  based on a difference between the first TDS level of the aqueous feed stream  202  and the second TDS level of the aqueous draw stream  204 . 
     At step  360 , the injection fluid stream  208  is flowed from the osmosis separator  201  to a subterranean formation. For example, the injection fluid stream  208  is discharged from the injection fluid outlet  205   b  of the draw compartment  205  of the osmosis separator  201  and flowed at step  308  to the injection well  100  of  FIG. 1A . 
     In some implementations, method  350  includes measuring a flow rate of the injection fluid stream  208  from the osmosis separator  201 , for example, using the flowmeter  293 . In some implementations, method  350  includes adjusting a flow rate of the aqueous draw stream  204  to the osmosis separator  201  based on the measured flow rate of the injection fluid stream  208  from the osmosis separator  201 . In some implementations, method  350  includes measuring a TDS level of the injection fluid stream  208 . In some implementations, method  350  includes adjusting the flow rate of the aqueous feed stream  202  to the osmosis separator  201  based on the measured TDS level of the injection fluid stream  208 . 
       FIG. 4  is a block diagram of an example controller  291  used to provide computational functionalities associated with described algorithms, methods, functions, processes, flows, and procedures, as described in this specification, according to an implementation. The illustrated controller  291  is intended to encompass any computing device such as a server, desktop computer, laptop/notebook computer, one or more processors within these devices, or any other processing device, including physical or virtual instances (or both) of the computing device. Additionally, the controller  291  can include a computer that includes an input device, such as a keypad, keyboard, touch screen, or other device that can accept user information, and an output device that conveys information associated with the operation of the controller  291 , including digital data, visual, audio information, or a combination of information. 
     The controller  291  includes a processor  405 . Although illustrated as a single processor  405  in  FIG. 4 , two or more processors may be used according to particular needs, desires, or particular implementations of the controller  291 . Generally, the processor  405  executes instructions and manipulates data to perform the operations of the controller  291  and any algorithms, methods, functions, processes, flows, and procedures as described in this specification. 
     The controller  291  also includes a memory  407  that can hold data for the controller  291  or other components (or a combination of both) that can be connected to the network. Although illustrated as a single memory  407  in  FIG. 4 , two or more memories  407  (of the same or combination of types) can be used according to particular needs, desires, or particular implementations of the controller  291  and the described functionality. While memory  407  is illustrated as an integral component of the controller  291 , memory  407  can be external to the controller  291 . The memory  407  can be a transitory or non-transitory storage medium. 
     The memory  407  stores computer-readable instructions executable by the processor  405  that, when executed, cause the processor  405  to perform operations, such as controlling fluid flow in a system (for example, system  200 ). There may be any number of controllers  291  associated with, or external to, a computer system containing controller  291 , each controller  291  communicating over the network. Further, the term “client,” “user,” “operator,” and other appropriate terminology may be used interchangeably, as appropriate, without departing from this specification. Moreover, this specification contemplates that many users may use one controller  291 , or that one user may use multiple controllers  291 . 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations, separately, or in any sub-combination. Moreover, although previously described features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     As used in this disclosure, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed in this disclosure, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section. 
     As used in this disclosure, the term “about” or “approximately” can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range. 
     As used in this disclosure, the term “substantially” refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more. 
     Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “0.1% to about 5%” or “0.1% to 5%” should be interpreted to include about 0.1% to about 5%, as well as the individual values (for example, 1%, 2%, 3%, and 4%) and the sub-ranges (for example, 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “X, Y, or Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise. 
     Particular implementations of the subject matter have been described. Other implementations, alterations, and permutations of the described implementations are within the scope of the following claims as will be apparent to those skilled in the art. While operations are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed (some operations may be considered optional), to achieve desirable results. In certain circumstances, multitasking or parallel processing (or a combination of multitasking and parallel processing) may be advantageous and performed as deemed appropriate. 
     Moreover, the separation or integration of various system modules and components in the previously described implementations should not be understood as requiring such separation or integration in all implementations, and it should be understood that the described components and systems can generally be integrated together or packaged into multiple products. 
     Accordingly, the previously described example implementations do not define or constrain the present disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of the present disclosure.