Certified vapor recovery

11988,577

18/036726

November 19, 2021

Disclosed is a system and method for monitoring a hydrocarbon storage system. The system and method for using the system allows the operator to determine if any undesired releases of gaseous hydrocarbons are occurring. The method utilizes a computer programmed with a process simulator function suitable for miming equations of state and determining the unwanted release of hydrocarbons from a hydrocarbon storage system.

FLOGISTIX, LP (Oklahoma City, OK, US)

Flogistix, LP (Oklahoma City, OK, US)

1. A method for identifying unwanted venting of gaseous hydrocarbons from a hydrocarbon storage system comprising the steps of: providing a database for storage of pressure, flow rate and temperature data; providing a central processor programmed to perform a process simulator function and mass balance operations, the process simulator function programmed to run equations of state and to receive data from said database for use in the equations of state; providing a site-specific schematic of said hydrocarbon storage system for use by said process simulator function; said site-specific schematic of said hydrocarbon storage system identifies at least one onsite unit selected from the group consisting of: a compressor associated with a hydrocarbon vapor recovery line; a flare associated with a hydrocarbon vapor recovery line; a flare associated with a crude oil storage tank; a flare associated with a produced water storage tank; a storage unit containing hydrocarbon vapors; a processing unit in said hydrocarbon storage system which produces or isolates hydrocarbon vapors; a temperature sensor associated with a storage unit containing hydrocarbon vapors, wherein each temperature sensor provides data to said database; a temperature sensor associated with a processing unit which produces or isolates hydrocarbon vapors, wherein each temperature sensor provides data to said database; a flow sensor associated with conduits into and out of each storage unit containing hydrocarbon vapors, wherein each flow sensor provides data to said database; a flow sensor associated with conduits into and out of each processing unit which produces or isolates hydrocarbon vapors, wherein each flow sensor provides data to said database; a flow sensor associated with conduits into and out of each compressor associated with a hydrocarbon recovery line, wherein each flow sensor provides data to said database; a flow sensor associated with conduits into and out of each compressor associated with a hydrocarbon storage tank, wherein each flow sensor provides data to said database; a flow sensor associated with conduits into and out of each compressor associated with a hydrocarbon processing unit, wherein each flow sensor provides data to said database; a pressure sensor associated with conduits into and out of each storage unit containing hydrocarbon vapors, wherein each pressure sensor provides data to said database; a pressure sensor associated with conduits into and out of each processing unit which produces or isolates hydrocarbon vapors, wherein each pressure sensor provides data to said database; receiving fluids; identifying the received fluids in terms of relative percentages of gaseous and liquid hydrocarbons and any aqueous fluids entering the hydrocarbon storage system; inputting the relative percentages of gaseous and liquid hydrocarbons and aqueous fluids of the received fluids into said database for use by said process simulator function; wherein each compressor processing a total gas volume; monitoring the total gas volume processed by each compressor using a virtual or real flow meter; setting a user defined total error percentage for the flow sensors (TOTAL ERROR %); using the flowrate data from each flow sensor as stored in the database, determine a total metered hydrocarbon vapor volume (TVM) handled by the hydrocarbon storage system; using the process simulator function to run the equations of state, compute the Process Simulator Rate in terms of volume handled by the hydrocarbon storage system where the Process Simulator Rate volume of the hydrocarbon storage system equals the total estimated volume of vapors flashing on site from any tanks or vessels producing or storing any liquid hydrocarbon that could change to gas and be fed to into a vapor recovery system; performing mass balance operations to compute a total vent volume of all storage and processing units in the hydrocarbon storage system where the total vent volume is Process Simulator Rate (PSR) −TVM±TOTAL ERROR %; determining if unwanted venting of gaseous hydrocarbons has occurred where unwanted venting is indicated when the total vent volume is greater than zero.

2. The method of claim 1 , wherein the step of identifying the makeup of the hydrocarbons in terms of aqueous, gaseous and hydrocarbon fluids entering the hydrocarbon storage system is repeated and if the makeup of the hydrocarbons has changed, then the step of setting a user defined total error percentage for the flow sensors (TOTAL ERROR %) is repeated.

3. The method of claim 2 , wherein the frequency of repeating the step of identifying the makeup of the hydrocarbons in terms of aqueous, gaseous and hydrocarbon fluids entering the hydrocarbon storage system is performed in response to a change in temperature as determined by any one of the temperature sensors found in said hydrocarbon storage system.

4. The method of claim 2 , wherein the frequency of repeating the step of identifying the makeup of the hydrocarbons in terms of aqueous, gaseous and hydrocarbon fluids entering the hydrocarbon storage system is performed in response to a change in pressure as determined by any one of the pressure sensors found in said hydrocarbon storage system.

5. The method of claim 2 , wherein the frequency of repeating the step of identifying the makeup of the hydrocarbons in terms of aqueous, gaseous and hydrocarbon fluids entering the hydrocarbon storage system is performed in response to a change in fluid flow rate as determined by any one of the flow sensors found in said hydrocarbon storage system.

6. A system for identifying venting of natural gas from a hydrocarbon storage system comprising: a source of hydrocarbons; a first separator in fluid communication with said source of hydrocarbons; said first separator configured to provide an initial separation of said hydrocarbons into a first gas fraction, a first aqueous based fraction and a first liquid hydrocarbon fraction; said first separator in fluid communication with a first gas separator, a heater treater and a produced water tank; a first valve controls fluid flow from said first separator to said heater treater; at least one oil tank in fluid communication with said heater treater; said heater treater is in fluid communication with a gas line, at least one hydrocarbon storage tank and at least one produced water tank; at least one pressure sensor positioned to monitor vapor pressure within said at least one hydrocarbon storage tank; at least one pressure sensor positioned to monitor vapor pressure within said produced water tank; a first temperature sensor positioned to monitor a temperature of the first separator; a second temperature sensor positioned to monitor a temperature of the heater treater; a third temperature sensor positioned to monitor a temperature of the produced water tank; a fourth temperature sensor positioned to monitor a temperature of the hydrocarbon storage tank; a first flow meter positioned to monitor a gas flow rate of a gas passing from the first separator to the first gas separator; a second flow meter positioned to monitor a fluid flow rate of a fluid passing from the first separator to the heater treater; a third flow meter positioned to monitor a produced water flow rate of produced water flowing from the first separator to the produced water tank; a database configured to store data input from said at least one pressure sensor monitoring a pressure within said at least one hydrocarbon storage tank, said at least one pressure sensor positioned to monitor vapor pressure within said produced water tank, each of said first, second, third and fourth temperature sensors and each of said first, second and third flow meters; a computer programmed with a process simulator function, said process simulator function utilizing equations of state which interpret the following variables: pressure, flow rate and temperature; said computer also programmed to display a schematic of said hydrocarbon storage system; said computer also programmed to receive data from said database and to utilize the received data when running equations of state; said process simulator function analyzes results produced by the equations of state and determines gas vent volumes from each of said hydrocarbon storage tank and said produced water tank to provide a total gas vent volume and to trigger an alert when the total gas vent volume is greater than a predetermined value.

7. The system of claim 6 for identifying venting of natural gas from a hydrocarbon storage system further comprising: a vapor recovery tower located between the heater treater and the oil tank.

5499531 March 1996 Henderson
5719785 February 1998 Standifer
5883815 March 1999 Drakulich et al.
8992838 March 2015 Mueller
9334109 May 2016 Mueller
9764255 September 2017 Mueller
9776155 October 2017 Mueller
10745266 August 2020 Vernon
20040248307 December 2004 Grof et al.
20070283870 December 2007 Lovie et al.
20080047871 February 2008 Brons et al.
20150267129 September 2015 Meyer
20180217615 August 2018 Westmoreland
20190211662 July 2019 Elmer
20200133251 April 2020 Rossi
111860938 October 2020
2014173599 October 2014

edspgr.11988577