US3095889A

US3095889A - Satellite gathering system

Info

Publication number: US3095889A
Authority: US
Inventors: Barroll Alfred Edwin; Kretzschmar Karl Herman
Original assignee: Socony Mobil Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1959-11-05
Filing date: 1959-11-05
Publication date: 1963-07-02
Anticipated expiration: 1980-07-02

Description

y 1963 A. E. BARROLL ETAL 3,0 8

SATELLITE GATHERING SYSTEM Filed Nov. 5, 1959 3 Sheets-Sheet 1 25b 24b 23b 221: lb

Xq' 'l'l 01 L J mm mm 25a 24a 23a 2202!!! 20a July 2, 1963 A. E. BARROLL ETAL 3,

SATELLITE GATHERING SYSTEM Filed Nov. 5, 1959 3 Sheets-Sheet 2 538W LIQUID GAS July 2, 1963 A. E. BARROLL ETAL 3,095,889

SATELLITE GATHERING SYSTEM 3 Sheets-Sheet 3 FIG.6

I II

III

a 5 m C m n K L m vc 2 9 I H 2 000 00 I w 3 00000 0 0 0 0 0 0 8 0 0 0 0 0 000090 0 I I a W 4 B I W 0 0 0 0 0 I 0 0 0 0 0 00000 7 0 0 0 0 0 0 0NOMOMON0 6 I I 00000 I H 6 0 5 Xx m fix? a 3 OI W B r B Q I 6 2 I 3 T 3 I w m IIO United States Patent 3,095,889 SATELLEITE GATHERING SYSTEM Alfred Edwin Barr-ell and Karl Herman Kretzschmar, Calgary, Alberta, Canada, assignors to Socony Mobil Oil Company, Inc, a corporation of New York Filed Nov. 5, 1959, Ser. No. 851,062 18 Claims. (Cl. 137-14) This invention relates to production and gathering of oil and gas from a plurality of wells connected to a central gathering and treating station and more particularly to the measuring and testing of a plurality of subgroups of wells each of which flows into a main production flow line leading to a central station.

It has been found desirable systematically to test and deliver oil from producing wells to a central gathering and treating station and automatically to carry out as many operations t-hus involved as possible. In the past it has been common procedure to provide a battery of tanks serving several wells for temporary storage of oil prior to its delivery to a pipe line. In order to measure the production from a given well, flow is maintained into a tank until it is filled whereupon the Well is switched to a second tank. While the second tank is being filled, the first one is gauged and the contents sampled and tested so that the production from a given well or from a plurality of wells in a given lease can be definitely ascertained. In an attempt to eliminate the time consuming and costly operations involved in gauging production by such methods, developments have led toward automatic operations of leases which, to a degree, have been found to be successful.

Applicants have provided a method of producing oil and gas wells in a manner which has been found to be advantageous over available systems. More particularly, applicants have provided :a method of controlling production of oil and gas wells in which fluids from each of a plurality of sub-groups of wells are commingled for flow to a central gathering and treating station. Each Well in each of the sub-groups is periodically diverted through a gas-liquid separating zone prior to commingling the fluid from a well under test with the flow from the remainder of the wells. The gas and liquids issuing from the separating zone are then measured while maintaining the separating zone and measured fluids at a predetermined pressure difierential above the pressure of the flow to the central gathering and treating station. By this means it is assured that an accurate measure may be obtained of the liquids and gas produced. In a preferred embodiment, suitable control is provided for automatically determining the sequence of flow through the separating zone. Flow from each of a plurality of such subgroups may then proceed through a main production flow line to a central gathering and treating station where the total flow may be prepared for delivery to a market outlet.

In accordance with a more specific aspect of the present invention, a system is provided for control-ling and selectively testing production from a plurality of oil wells which are adjacent to a main production flow line leading to a central gathering and treating station. The testing system includes a test line leading to a gas-liquid separator and a gas flow line leading from said separator to the main production flow line. The gas flow line includes means for measuring the volume of gas flowing therein. A liquid fio-w line is also provided leading from the gasliquid separator to the main production flow line which includes a flow control means and a positive displacement meter between the How control means and the separator for continuously measuring the volume of liquid flowing from the separator to the main production flow line. The pressure in the separator is controlled in order to main- 3,995,889 Patented July 2., 1963 tain at a predetermined minimum the differencein the pressure between the main production flow line and the separator so that liquid will flow through said meter with out separation of gas therein. Gathering lines leading from each of the wells in said unit are then adapted successively to be connected to the test line with the remainder of the wells in said unit connected directly to said main production flow line.

In accordance with a further aspect of the invention, an oil-liquid separator is provided with a test line leading thereto and a gas flow line and a liquid flow line leading therefrom to a main production flow line. The separator is located close to the main production flow line. A gas back pressure valve is provided in said gas flow line together with means for measuring the gas flow therein continuously to indicate gas flow and to maintain at a minimum the pressure difference between the separator and the main production flow line. A meter is provided in the liquid flow line in series with and ahead on? the liquid flow control means in said liquid flow line. Gas and liquids are thus separated temporarily at the sites of sub-unit producing centers for separate measurement of the components while maintaining flow of both gas and liquid to a main production flow line without the further separation of gases from said liquids in the course of flow FIG. '1 is a diagrammatic representation of the present invention;

FIG. 2 is a more detailed flow diagram of one of the sub-groups of FIG. 1;

FIG. 3 is a plan view of a measuring station for a subp;

FIG, 4 is an elevation of the system of FIG. 3 taken along the lines 44 of FIG. 3;

FlG. 5 is a plan view of a further modification of the invention; and

FIG. 6 is an elevation taken along the lines 6-6 of FIG. 5.

Referring to FIG. 1, there is illustrated an oil and gas gathering system wherein wells in a plurality of subgroups of wells are connected to individual separating and measuring stations. The output of each such station is commingled for flow with fluids trom other such stations to a central gathering and treating station. Fluid flow from each Well in each of the sub-groups in sequence is passed through a gas-liquid separating zone from which the gas and liquids separately are measured prior to commingling with how from the other wells. By this means a single central gathering and treating station may be employed for receiving production from a plurality of widely separated sub-groups of producing Wells with a minimum of expense for treating equipment. At the same time there is maintained, as will hereinafter be shown, an accurate and systematic record of the prodlidtion from each Well in each of the sub-groups.

More particularly, and as illustrated in FIG. 1, a central gathering and treating station it) is provided. Included at station 10 are a separator 10a for separating gas components from liquid components, a dehydrator 10b for separating water from the liquids, and facilities 10c, 10d, and lile for gas, oil, and salt water storage and/or disposal, respectively. Station 14 is connected to receive flow from sub-groups of wells such as

sub-groups

15, 16, 17, and 27. This connection is made by main production flow lines which include central flow line 11 and

group flow lines

12, 13, 14, and 26. Each of the subgroups of wells may comprise a selected number of wells, the number depending upon the frequency with which a given well is to be placed on test and the capacity of the test and control equipment at the location of each subgroup. The maximum number of wells in a given subgroup is dependent upon testing requirements prescribed by governmental or industrial regulatory bodies concerned with a given producing area or unit. Further, engineering requirements as to the operation of a given field or unit may require tests more frequently than prescribed by regulatory bodies and thus fewer wells than the number permissible under regulation may be employed. For example, in group 17, six

wells

20, 21, 22, 23, 24, and 25 are connected by separate flow lines to a flow control unit or valve 28. Valve 28 is adapted to connect well 20, for example, to a gas-liquid separator 29. During the period that well 20 is connected to the separator 29, the remainder of the wells 21-25 are connected through valve 28 to group flow line 14 so that production therefrom is commingled for flow through the line 14 to the central flow line 11. Gas from separator 29 is measured as in a unit 30 and recorded. Liquid from the separator 29 is measured as by unit 31 and recorded. Basic sediments and water from the separator 29 are measured or sampled by unit 32. Thereafter, the gas and liquid from separator 29 are combined and travel through channel 33 and flow line 14 to the central flow line 11.

Operation of valve 28 is so controlled that fluid from well 20 is routed through valve 28 to the test separator 29 for a predetermined period of time. Thereafter, well 21 will be connected through valve 28 to the separator 29 while wells 20 and 22-25 are connected to the line 14. The remaining wells 2225 on subsequent days or for subsequent periods may be connected through the separator 29 with the production from each of the wells measured as by units 30-62. In the foregoing cycle is based on a test of one well per day, each well may be tested about four times per month.

In a similar manner, the wells in

sub-groups

15 and 16 as well as others connected to the central flow line 11 may be sequentially tested at locations remote from the central gathering and treating station with but a minimum of equipment and pipe lines necessary to operate the entire producing area. By this means considerable savings in operating costs and initial installation is achieved. At the same time a complete and accurate record of production is maintained.

It will be noted, as indicated in FIG. 1, that the wells in sub-groups are connected to flow lines leading to a header house 18 in which all testing and control equipment may be enclosed. Protection from the weather is thus provided. A test unit thus housed may be readily prefabricated and mounted on skids or similar devices for ready transport to a desired location. At the same time the equipment may readily be connected to a subgroup of producing wells. Group flow line 12 carries production from the sub-group 15 to the central flow line 11.

Referring now to FIG. 2, there is illustrated in more detail the system employed for automatic testing of production from wells such as in the group 17. The wells are connected by way of gathering lines Zita-25a to the control unit 28. Motor-driven valves, such as valves b-25b, driven by motors 200-250, are connected in each of the flow lines Mia-a respectively to provide on-otf control of production from Wells 2045. Normally the valves, such as valves 20b25b, will be maintained open when it is desired to produce the wells 20- 25 continuously. Valve 23, in the form illustrated, is a multi-port rotary selector valve. This valve has a plurality of inlet ports and a large outlet port located around the periphery of the valve body. There is also provided a rotating L 28a inside the valve body which is utilized selectively to connect inlet ports to a single outlet port at the bottom of the valve body. The large outlet port of the valve 28 is connected by way of a check valve to the flow line 14.

The single outlet port leading from the bottom of the valve 28 is connected by way of check valve 41 to the input flow line to the separator 29. With the rotating L 28a in the valve 23 interconnecting line 25a and the separator 29, all of the flow lines Mia-24a are connected through check valve 40 to the line 14.

Fluid entering separator 29 is separated into liquid and gas components as Well understood by those skilled in the art. Gas flows from the separator 29 by way of a gas back pressure control valve 43 and the gas metering unit 30. The gas meter 30 measures the amount of gas flowing through an orifice represented by the unit 30a during the period that a given well is on test. "Meter orifice unit 30a is connected by way of conduit 44 and check valve 45 to the flow line 14.

The gas back pressure valve 43 is adapted automatically to maintain the minimum pressure differential between the separator 29 and the fiow line 14 to maintain liquid flow through the test separator. Thus, pressure differential will vary depending upon the producing conditions and may be of the order of 5 p.s.i. With the pressure in the separator 29 thus maintained above the pressure in the flow line 14 both gas and liquids issuing from the separator 29 may be injected into the flow line 14 for flow to the central gathering and treating station. Liquid from the separator 29 passes through the meter 31 and thence by way of Water test unit 32,

an oil dump valve 46, line 47, check valve 48, and thence to the flow line 14.

In order that the production from a given well may accurately be measured, it has been found necessary to maintain liquids as they are measured at the pressure in the separator 29. With this in mind, it will be noted that the liquid meter 31, preferably of the positive displacement type, is installed between the separator 29 and the oil dump valve 45 so that the metering element is always flooded to prevent the introduction and accumulation of gas therein which would render measurements erroneous.

In the system shown in FIG. 2, the gas back pressure valve 43 leading from the test separator 29, hereinafter identified more fully, is lever-operated and linked to a liquid level float 29a inside the separator 29. When the liquid level in the separator 29 rises above a working level, the back pressure valve 43 begins to close causing pressure inside the separator to increase the rate of movement of liquid through the separator to regain the proper working level. When the system is operating normally, and pressure in the group flow line 14 varies, there will be maintained just enough back pressure on the separator to move the test production into the group flow line 14.

I To aid in this action, the oil dump valve 46 is also levercally indicated by the dotted line 50.

The system of FIG. 2 also includes

lines

51, 52, 53, and 54 each equipped with suitable manually operable control valves.

Lines

51, 52, 53, and 54 lead to a pit, a flair unit, a test tank, and a drain, respectively (none of which are shown), to permit such non-automatic operations as may be desirable in initiating and maintaining operation of a given unit.

From the foregoing description, the measurement of production from a given group of wells may be understood. However, it is desirable not only that the measurements be made but that a permanent record of the production from each well be provided. In Order to provide such a record and to control the operation of each satellite unit, a timing control unit 62 is provided which may include means to preset a production program and a recording program. For example, to control the production program, power from a source 63 is transmitted through the control unit 62 to motor 60 at predetermined time intervals to move the rotating L in the valve 28 successively from one inlet port to another so that the wells associated with a given satellite unit sequentially will be routed through the separator and gauging system. At the same time, the automatic control unit 62 serves to energize a recording unit 64 to indicate, as a function of time, the operations in the gauging system. More particularly, the recorder 64 in the form illustrated is a strip chart recorder, hereinafter more fully identified, having twelve recording pens and twelve input channels. The recorder 64 is thus adapted to produce twelve parallel lines along the length of a strip chart 65. Each of the traces or lines may be moved from a quiescent point to an offset point to indicate either of two conditions. Connections between the controller 62 and the recorder 64 as by cables 66 permit application of D.C. signals to recorder 64. Controller 62 produces such signals in correlation with the position of the rotating L 28a in valve 28 so that there may be assigned to each of the lower six traces on chart 65 an indication of the position of the rotating L. Thus, the upper five traces in their quiescent positions indicate that for the time interval represented by chart 65 wells -24 were flowing through the valve 28 to the group flow line 114. The lower trace, displaced from its quiescent position, indicates that production from well was routed through valve 28 to the separator 29.

Further, the top two traces on chart 65, FIG. 2, serve to provide a record of the amount of basic sediment and water metered by the unit 32.

In one form, unit 32 was a capacitance product analyzer in which liquid from meter 31 flows through a capacitance cell. The electrical capacitance measured by this unit is dependent upon the dimensions of the cell and the dielectric constant of the material between the electrodes. With all other parameters fixed, the capacitance of the cell is directly proportional to the dielectric constant and, within limits, to the water content of the liquid. An electrical signal representative of the water content of flow through unit 32 is thus provided at the output terminals of the unit 32 and is applied to an electromechanical integrator 32b by way of channel 32a. In order to provide a quantitative measure of water flowing through unit 32, a flexible coupling 32c is provided to interconnect meter 31 and integrator 32b. By means of the coupling 32c, rotational motionis applied to. integrator 32b which is proportional to and thus representative of the rate of flow of liquid from separator 29. The water measuring system thus embodied in the present system may be of the type illustrated and described in United States Patent 2,720,624.

In the present system, electrical impulses are applied from the integrator 32b by way of channel 32d to the input terminal of a decade divider 3Ze. More particularly, the decade divider 32e includes a ten terminal stepping switch 32 the armature of which is actuated and thus moved from one terminal to another upon each application of a pulse from unit 32b to the solenoid 32g. Channel 32d is connected not only to solenoid 32g but also to one of the terminals of switch 32 and to the second terminal 64b of the recorder 64. The armature of switch 32 is connected to the first terminal 64a of recorder 64. By suitable calibration of integrator 32b as it responds to the flow function from cable 320 and to the output from the unit 32, a pulse is recorded on the top trace of record 65 for every ten barrels of water produced and a pulse is recorded on the second trace of record 65 for each barrel of water produced.

In a similar manner, the positive displacement meter 31 is provided with a transducer 31a which applies to channel 31b a pulse for each barrel of liquid passing through meter 31. Channel 3112 is connected to a second decade divider 31c, the outputs of which are connected to the third terminal 640 and the fourth terminal 64d, respectively, of recorder 64. By this means, a pulse is recorded on the third trace of record 65 for every ten barrels of liquid produced and a pulse is recon-(led on the fourth trace of record 65 for each barrel of liquid produced.

Gas meter 30 is provided with a transducer 3% which applies to output channel 3th: a pulse for every ten cubic feet of gas passing through orifice 30a. Channel 300 is connected to the input of a decade divider 30d whose outputs are connected to the fifth terminal 64a and the sixth terminal 64 of recorder 64. With meter 36 and transducer 3% suitably calibrated there is thus recorded on the fifth trace of record 65 a pulse for every cubic feet of gas produced. A pulse is also recorded on the sixth trace of record 65 for every ten cubic feet of gas produced. It will be recognized that the calibration for each of the parameters, water, liquid, and gas may be varied to meet the conditions in areas of interest.

For safety purposes, a high pressure switch 2% on separator 29 is connected by way of channel 29c to the control input terminal of control unit 62. Pressures in separator 29 in excess of a preset limit close a circuit in control unit 62 to energize motor 66 from source 63 so that the rotating L in valve 28 is rnoved to a zero position 281) and is not connected to receive fiow from any of the fiow lines 2061-2561. By this means, flow to the separator 29 is automatically terminated upon build-up of unduly high pressures should such pressures occur when the gas back pressure valve 43 is fully closed and oil dump valve 46 is completely open. High pressures under such conditions indicate malfunctioning of the system and the necessity of removal of the test unit from the flow channel. The control unit 62 is so set that, when the pressure in separator 29 reaches a level within the normal operating range, fiow through the separator will be resumed by returning the rotating L 28a in valve 28 to the flow line to which it was previously connected or to which it is otherwise scheduled.

As a further safety measure, a high-low pressure switch 67 is provided in the group flow line 14. Either an unduly high pressure or an unduly low pressure in line 14 will close switch 67. Closure of switch 67 energizes solenoid 68 by completing a circuit through solenoid 68 and volt age source 69. Solenoid 68, as an element of the control unit 62, serves to control motor-operated valves 20b-25b. More particularly, motors 200-250 are coupled in driving relation to valves 2611-2512, respectively. Electrical conductors 62a extend from control unit 62 as separate energizing circuits for each of the motors 2tlc-25c. By this means, actuation of switch 67 either in response to high or low pressure outside a predetermined range will shut in all wells connected to valve 28 until the pressure in line 14 returns to within a normal range. Control system 62 preferably operates to return all wells to production upon return to operating range from high pressure. However, if low pressure is encountered, manual operation is required to return wells to production. Further, in one embodiment of this system, manually-operated switches were provided between each of the lines 62a and an energy source to permit manual closure of each of valves 20b-25b so that any given well could be removed from production while the remainder of the wells connected to the test unit could be produced.

The functions of the various units embodied in the system of FIG. 2 have been set forth in order to provide an indication of one mode of operating an automatic satellite producing system. It is to be understood, however, that the components may be varied as to specific type or manufacturer while retaining the functions above de- 7 scribed. In one system it was found satisfactory to employ the following components.

The test separator 29 was of the type supplied by National Tank Company of Tulsa, Oklahoma, United States of America, and identified as Nationals COG Separator, having lever-operated oil dump valves and gas back pressure valves with fioat control.

Valve 28 was of the type manufactured and sold by Win-Well Manufacturing Company, Tulsa, Oklahoma, United States of America, and identified as a 7-Way Multi- Port Rotary Selector Valve (ASA 300-lb. Class B with llO-volt A.C. Electric Operator).

Meter 31 was a positive displacement type liquid meter manufactured and sold by the A. O. Smith Company, Los Angeles, California, United States of America, identified as model W-l2 and was calibrated from zero to three gallons per minute fiow rate with a large numeral re-set counter graduated in barrels, 10ths and 100ths, and provided with an impulse transmitter 31a.

The gas meter 30 was an Integrating Orifice Type Flow Meter manufactured by Fisher & Porter of Hatboro, Pennsylvania, United States of America, and identified by Catalog No. 199-1620, with an integrator and an impulse transmitter 30b.

The control unit 62 was a Paragon Timer Control manufactured and sold by Paragon Electric Co. of Two Rivers, Wisconsin, United States of America, and identified as Paragon Series 9624 with a day omission feature.

Recorder 64 was of the type manufactured and sold by Esterline Angus and identified as Esterline-Angus Model AW with -motor-wound spring chart drive having a chart speed of one and one-half inches per hour. This particular recorder included electromagnetic to accommodate twenty pens but was employed with twelve pens as indicated in FIG. 2. The number of pens in each case will be dependent upon the number of wells in a given satellite production unit.

In one installation of the type above described, the pressure in the flow line 14 varied between about 25 and 80 p.s.i. By operation of the gas back pressure valve 43 and the oil dump valve 46, the pressure on the separator 29 was maintained within the limits of about 30-90 p.s.i. and at all times about p.s.i. above the pressure in the flow line 14 to maintain the meter 31 at all times flooded.

A plan view and an elevation view of one embodiment of the system illustrated diagrammatically in FIG. 2 is shown in FIGS. 3 and 4. In this embodiment it was found desirable to leave at least one of the seven input ports to the valve 28 plugged and thus not connected to any well in order that flow through the test separator could be terminated by rotating the L to the closed port. In this condition all wells flow through the valve 28 directly to the flow line 14. With such limitation, only six wells were associated with the test unit of FIGS. 3 and 4.

The outline of the header house 18 is indicated by the dotted enclosure 70 of FIG. 3 in which there is shown a plan view of the header system. Valves such as valve 20b are located inside the housing with flow lines extending therefrom to the valve 28. The test flow line 71 leading to separator 29 is connected into the bottom of the valve 28 as best seen in FIG. 4. Flow line 14 is connected onto the side of the valve 28 (FIG. 3) to receive flow from all wells not connected to the test line 71. Lines 20a25a and 14 thus provide fluid inlets and an outlet, respectively, for the system within enclosure 7 0.. Liquid from the separator 29 passes through normally open valve 72 to the positive displacement liquid meter 31, the product analyzer 32, and thence by way of the oil dump valve 46 to the group flow line 14. Gas from separator 29 flows through gas back pressure valve 43, the metering orifice 30a, and thence into the group flow line 14. Valve 55 is a manually operable control valve to permit such non-automatic operations as may be desirable ininitiating and maintaining operation of a given unit.

In FIG. 3, the oil dump valve 46 has been illustrated as spaced from gas back pressure valve 43 although actually they are in vertical alignment in the COG Separator in order to be linked to float 29a. In order to permit the location of the meter 30 ahead of valve 46, it was necessary to move the oil outlet about peripherally from the gas outlet. The lever linkages between the float 29a and the

valves

43 and 46 are indicated by the dotted lines 50 in FIG. 3.

While the gas metering orifice 30a may be suitably calibrated to operate any place in the system where there is single phase flow, it is essential that the meter 31 be located ahead of the oil dump valve 46. It may be preferable to locate the gas metering orifice 30a ahead of the gas back pressure valve 43 where pressure may be more readily controlled and subject to less variation than may be found in the flow line 14.

The foregoing description relates to a system in which a rotary type selector valve such as the valve 28 is can ployed. Valve 28 broadly may be considered to be a. flow control or production routing means of which there are other types wholly suitable for operating in accordance with the present invention. Su-cha system is shown in FIGS. 5 and 6 and is based upon a different type of fiow control means employing diaphragm-operated, three-way valves in each flow line leading to the satellite unit. More particularly, in FIGS. 5 and 6, ten producing wells are embodied in a satellite producing unit wherein production from the wells one at a time is diverted through a separator for metering the gas and liquid components. The production from the remainder of the wells is commingled for flow in a main production flow line leading to a central gathering and treating station. In FIG. 5, flow lines -109 are connected to manually operable valves 100a- 109a positioned outside and immediately adjacent the wall of an enclosure 18a. Production flowing in lines 100-109 through the interconnecting valves 100a-109a then flows directly to a valve-manifold system in which the threeway, three-positioned pneumatic valves automatically control flow between production wells, a separator 110, and a group flow line 111 and at the same time provide for onoti control for each well. Diaphragm type pneumatic valves 120429 are of the type in which application of pressure above or below the operating diaphragm will selectively seat valves to route flow therethrough. More particularly, in a neutral position, with the pressure equal on both sides of the diaphragm, the valve is closed preventing flow therethrough. However, if -a valve such as valve has pressure applied to one side of the diaphragm therein, fluid may flow from line 100 to the test manifold 130. When this is the case, pressure applied to the other side of the diaphragms in the remaining valves 121-129 will route flow therefrom directly to the group flow line 111.

Production introduced into the test manifold 130, then flows into the separator 110. Liquid issues from the separator 110 by way of the channel 131 and then through a capacitance probe 132 and a positive displacement meter 133. A flow line 134 is connected at the output of meter 133 to an oil dump valve 135 which in turn is connected through check valve 135a to the group flow line 111. The valve 135 is operated pneumatically under the control of a liquid level-sensitive controller 136 hereinafter more fully identified.

Gas separated in unit 110 issues from unit 110 by Way of channel 137. It flows through a metering orifice in section 137a whereby the gas flow is measured by a meter or flow computer 138 which senses the pressure drop across the orifice in section 137a. The output from the gas orifice then passes through a back pressure valve 139 and thence, by way of check valve 140a, to the group flow line 111. The back pressure valve 139 is designed automatically to maintain a pressure in the separator 110 five to ten pounds above any pressure in the group flow line 111.

While not shown, it is to be understood that in FIGS. and 6 there will be provided auxiliary piping selectively to vent by manual operation various points in the system in order to the place unit in operation and to permit selective maintenance operations without the interruption of production. The system, such as shown in FIGS. 5 and 6, is supported on a skid-mounted platform suitably housed for protection from the weather to assure reliable operation while at the same time providing ready connections at valves $a1l)9a for flow lines leading from individual wells.

In the pneumatic system illustrated in FIGS. 5 and 6, control of the diaphragm valves 120-129 wa from a compressed air source (not shown) but fed through an air supply line 150, FIG. 6, and applied to the diaphragm valve, such as valve 124, by way of solenoid-operated

valves

151 and 152, respectively.

Valves

151 and 152 are actuated under the control of a test programmer unit 153 operable to apply an actuating voltage by way of circuit 154 to the solenoid 151a associated with valve 151 when production through line 1534 and valve 124 is to be routed through the test separator. When this is the case, air pressure is applied above the diaphragm in valve 151 to route production therethrough to the separator 111 At the same time all valves corresponding with valve 152 are actuated as through application of an actuating voltage applied to circuits such as circuit 155 to solenoids such as solenoid 1520 to apply air pressure under the diaphragm of the associated valves to route production from all remaining flow lines 1110-193 and 105409 to the group flow line 111.

Details of the programmer and the pneumatic control system have not been further shown since they are generally well understood by those skilled in the art.

In both the systems of FIGS. 3 and 4 and of FIGS. 5 and 6 various protective features were included. For example, separator 11%, FIG. 5, is provided with a high level and a low level control unit 160. If the oil level in separator 11d exceeds predetermined limits, high or low, control action is effected to switch any well then con ected to the separator 11% to the group flow line 111. A high fluid level in separator 118 actuates a switch which closes a diaphragm type motor valve 149 and as a result pressure builds up in the separator 1 1d, causing it to dump more fluid. A high pressure switch 161 on separator 11% serves to switch any well connected to the separator to the group flow line 111. As emergency conditions correct themselves, a well scheduled for test is returned automatically back to flow through the test separator. Further, pressure in line 111 is monitored by a high and low pressure switch (not shown in FIG. 5 but corresponding with switch 67 of PEG. 2). In the event high pressure is present on the line 111, actuation of the switch will shut in all Wells by returning diaphragm valves 120- 129 to their normal position. The wells will be returned to production when the pressure returns to within a normal range. When the switch in line 111 is actuated by low pressure as may be caused by a break in a line leading to the testing station, it must be manually reset before production can be restored.

In the system illustrated in FIGS. 5 and 6, the following components were employed:

Valves 1251429 were diaphragm valves manufactured and sold by Garrett Oil Tool Division of U.S. Industries, Longview, Texas, United States of America, and identified as 'Z-Type CPC Motor Valve.

The production and test programmer 153 was of the type manufactured and sold by Garrett Oil Tool Division of US. Industries, Longview, Texas, United States of America, and identified as Type C Programmer.

The capacitance probe 132 was of the same type as analyzer 32, FIGS. 3 and 4, above described.

The meter 133 was of the type manufactured and sold by A. O. Smith Corporation of Los Anegles, California,

10 United States of America, and identified as Model No. W-12.

The gas flow computer 138 was of the same type as unit 30, FIGS. 3 and 4, identified above.

The valve 14% and the gas back pressure valve 139 were of the type manufactured and sold by Fisher Governor Company of Marshalltown, Louisiana, United States of America, and identified as Model l25P Diaphragm Valve and Type 445 Governor Valve, respectively.

The dump control unit 136 was of the type manufactured by Black, Sivalls & Eryson of Tulsa, Oklahoma, United States of America, and identified as 15 DRT Valve with Type 887 Torsion Tube Level Controller and Type 1450 Pilot.

While in the foregoing description reference has been made to a capacitance-type probe unit for determining the water content of the liquid issuing from the separator, it has been found acceptable for water determination to use a liquid sampler unit in which a proportionate sample of liquid flowing from each well is collected in a test jar for analysis. Units of this nature found to be satisfactory are of the type manufactured and sold by Engineered Oil Controls, Ltd, Edmonton, Alberta, Canada, and identified as Type S-l Automatic Proportioning Sampler. Such units (not shown) may be suitably connected to the liquid flow line leading from the test separator by Way of valves operated in conjunction with the flow programmer so that production from each well successively flowing through the separator will be sampled.

The foregoing description has pertained principally to a system in which most, if not all, operations may .be performed automatically as under the control of unit 62 and the safety devices included in the system. It will be recognized that features of the present invention may be utilized to advantage in those cases where fully automatic operation may not be feasible. For example, 'with reference to FIG. 2, the valve '28, which has been earlier de scribed as operable along with an electric operator, may be adapted for manual operation. Valves Ztlb-ZSb similarly may be manually operated for routing flow from a selected well through the valve 28 and the separator 29. In the system shown in FIGS. 5 and 6, the pneumatically operated valves 120429 may be replaced with manually operable valves with flow being controlled by manual setting thereof. In either case, it will be desirable to provide measurements and records of gas, liquid, and water flow from the separator 29 in the manner described herein.

Having described the invention in connection with certain specific modifications thereof, it is understood that further modifications may now suggest themselves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims.

What is claimed is:

1. The method of operating oil and gas wells which comprise-s sequentially flowing fluids from each of a plurality of wells to a gas liquid separating zone, during the period of flow from a given well through said zone commingling fluid from the remainder of said wells for group flow in a separate flow path by-passing said zone, at said zone separating the flow from said given well into gas and liquid, and measuring said gas and said liquid issuing from said zone while at least said liquid being measured is maintained at the pressure in said zone, commingiing the liquid issuing from said Zone with said fluids in said separate flow path, and maintaining the pressure in said zone at a predetermined relatively low differential above the pressure in said separate flow path.

2. The method of controlling production of oil and gas in a plurality of sub-groups of wells for flow to a central gathering and treating station which comprises, in each of said sub-groups sequentially and periodically flowing fluids from each of a plurality of Wells to a gasliquid separating zone, during the period of flow from a given well through said zone commingling fluids from the remainder of said wells for group How in a separate flow path :by-passing said zone and leading to said central gathering and treating station, at said zone separating the flow from said given well into gas and liquids, measuring said gas and said liquids issuing from said zone while maintaining the zone and the liquids being measured at a predetermined minimum pressure differential above the pressure in said separate flow path, and commingling the gas and liquids issuing from said zone with the flow from the remainder of the wells at said separate flow path.

3. A system for operating oil and gas wells which comprises a gas-liquid separator having an inlet and separate outlets for gas and liquids, flow control means for sequentially directing the flow of fluids from each of a plurality of wells to said inlet of said gas-liquid separator and for commingling fluid from the remainder of said wells, a group flow line located close to said liquid outlet of said separator and extending from said flow control means separate from said separator for receiving said commingled fluid, separate flow lines extending from said outlets for gas and liquids issuing from said separator and leading to said group flow line, said liquid flow line leading to said group flow line at a point close to said separator, means in each said gas and said liquid flow lines respectively for measuring the gas and liquid issuing from said separator while at least said liquids are maintained at the pressure in said separator, and means for maintaining the pressure in said separator and the pressure in said liquid flow line at said liquid measuring means at a predetermined relatively low differential above the pressure in said group flow line.

4. A system for controlling and selectively testing crude oil production from a plurality of oil wells comprising a main production flow line leading to a central gathering and treating station, a gas-oil separator located close to said main production flow line and having an inlet, a gas outlet, and a liquid outlet, a test line leading to said outlet of said gas oil separator, a gas flow line leading from said gas outlet of said gas-oil separator to said main production flow line and including means for measuring the volume of gas flow therethrough, an oil flow line leading from said liquid outlet of said gas-oil separator to said main flow line at a point close to said separator and including a flow control means, a positive displacement meter means in said oil flow line between said separator and said control means for continuously measuring the volume of liquid from the separator flowing through said flow line, means for maintaining the pressure in said separator and the pressure in said oil flow line at said positive displacement meter means at a predetermined low diflerential above the pressure in said main production flow line whereby oil will flow from said separator into said oil flow line and thence to said main production flow line without separation of gas during measurement therein, gathering lines leading from each of said plurality of oil wells, production routing means interconnecting said gathering lines, said main flow line, and said test line for selectively connecting any one of said gathering lines to said separator and for commingling the flow of oil in the remainder of said gathering lines for flow into said main production flow line, and means for selectively operating said production routing means for sequentially routing flow from each of said gathering lines through said separator for predetermined test periods.

5. A system for controlling and selectively testing crude oil production from a plurality of oil wells comprising a main production flow line leading to a central gathering and treating station, a gas-oil separator located close to said main production flow line and having an inlet, a gas outlet, and a liquid outlet, a test line leading to said inlet of said gas-oil separator, a gas flow line leading from said gas outlet of said gas-oil separator to said main production flow line and including means for measuring the volume of gas flow therethrough, an oil flow line leading from said liquid outlet of said gas-oil separator to said 12. main flow line at a point close to said separator and including a flow control means, means for measuring the quantity of water in the liquids flowing through said oil flow line, a positive displacement meter means in said oil flow line between said separator and said control means for continuously measuring the volume of liquid from the separator flowing through said flow line, means for maintaining the pressure in said separator and the pressure in said oil flow line at said oil measuring means at a predetermined low differential above the pressure in said main production flow line whereby oil will flow from said separator into said oil flow line and thence to said main production flow line 'without separation of gas during measurement therein, gathering lines leading from each of said plurality of oil wells, production routing means interconnecting said gathering lines, said main flow line, and said test line for selectively connecting any one of said gathering lines to said separator and for commingling the flow of oil in the remainder of said gathering lines for flow into said main production flow line, and

means for selectively operating said production routing means for sequentially routing flow from each of said gathering lines through said separator for predetermined test periods.

6. A system for controlling and selectively testing crude oil production from a plurality of oil wells comprising a main production flow line leading to a central gathering and treating station, a gas-oil separator located close to said main production flow line and having an inlet, a gas outlet, and a liquid outlet, 21 test line leading .to said inlet of said gas-oil separator, a gas flow line leading from said gas outlet of said gas-oil separator to said main production flow line and including means for measuring the volume of gas flow therethrough, an oil flow line leading from said liquid outlet of said gas-oil separator to said main flow line at a point close to said separator and including a flow control means, a positive displacement meter means in said oil flow line between said separator and said control means for continuously measuring the volume of liquid from the separator flowing through said flow line, means for maintaining the pressure in said separator and the pressure in said oil flow line at said positive displacement meter means at a predetermined low differential above the pressure in said main production flow line whereby oil will flow from said separator into said oil flow line and thence to said main production flow line without separation of gas during measurement therein, gathering lines leading from each of said plurality of oil wells, production routing means interconnecting said gathering lines, said main flow line, and said test line for selectively connecting any one of said gathering lines to said separator and for commingling the flow of oil in the remainder of said gathering lines for flow into said main production flow line, means for collecting samples of liquid in said oil flow line, and means for selectively operating said production routing means and said means for collecting samples for sequentially routing flow from each of said gathering lines through said separator for predetermined test periods and for collecting a sample of production from each well.

7. A production system for oil wells which comprises a plurality of local stations and a central gathering and treating station, flow lines for connecting each of said local stations to a plurality of said oil wells, an enclosure at each said local station into which said flow lines extend, a gas-liquid separator in each said enclosure, :1 gas flow channel and a liquid flow channel in each said enclosure extending from said separator for gas and liquids issuing therefrom, gas measuring means in each said gas flow channel and liquid analyzing means in each said liquid flow channel, flow control means in each said enclosure interconnecting the fiow lines and said separator for selectively routing fluid from said flow lines through said separator, a main production flow line interconnecting said central station and each said local station and extending into each said enclosure to a point close to each said separator and interconnecting said flow control means, said flow lines, and each said gas and liquid flow channels at said local station for receiving combined fluid fiow from said flow lines and from said gas liquid separator and for delivering to said central station combined fluid fiow from all said wells, and means for maintaining the pressure in each said separator and the pressure in each said liquid flow channel at said analyzing means at a predetermined relatively low differential above the pressure in each said main production flow line.

8. A manufacture for an oil production system which comprises a portable enclosure, means \for mounting said enclosure for ready movement from one location to another, a gas-oil separator in said enclosure having gas and liquid flow lines extending therefrom for gas and liquids issuing from said separator, means associated with said gas and liquid flow lines to measure and separately to record the respective quantities of gas, liquid, and water which may issue from said separator, a plurality of inlets adapted to extend out of said enclosure and an outlet located close to said separator and adapted to extend out of said enclosure, flow control means in said enclosure interconnecting said inlets, said outlet and said separator and adapted selectively to connect any one of said inlets to said separator and the remainder of said inlets to said outlet, flow channels interconnecting said gas and liquid flow lines and said outlet for delivering gas and liquid from said measuring means to said outlet and means for maintaining the pressure in said separator and the pressure of the liquid in said liquid flow line for measurement by said measuring means at a predetermined relatively low differential above the pressure in said outlet.

9. A manufacture for an oil production system which comprises a header house, mounting means supporting said header house for ready movement thereof from one location to another, a gas-oil separator in said house having at least two outlets, gas and liquid flow channels extending from said outlets of said separator and including means in said flow channels for measuring the respective quantities of gas, liquid, and water which may issue from said separator, recording means electrically connected to said measuring means for providing a record of said quantities, a plurality of inlet lines adapted to extend out of said house, an outlet line located close to said separator and adapted to extend out of said house, flow control means mechanically interconnecting said inlet lines, said outlet line, and said separator and adapted selectively to provide a single flow channel from any one of said inlet lines to said separator and to provide a common flow line from the remainder of said inlet lines to said outlet line, flow lines interconnecting said channels and said outlet line, and means for maintaining the pressure in said separator and the pressure of the liquid in said liquid flow channel for measurement by said measuring means at a predetermined relatively low differential above the pressure in said outlet line.

10. A system for controlling and selectively testing crude oil production from oil Wells which comprises a main production fiow line leading to a central crude oil gathering and treating station,

a test line leading to a gas-oil separator located close to said main production flow line,

a gas flow line leading from said gas-oil separator to said main production flow line and including means for measuring and recording the volume of gas flowing therethrough,

an oil flow line leading from said gas-oil separator to said main flow line at a point close to said separator and including,

means for continuously measuring the water content of the crude oil and recording a function 14 responsive thereto, positive displacement meter means for continuously measuring and recording the volume of liquid from the separator flowing through the oil flow line,

means for controlling the pressure in said gas-oil separator and the pressure in said oil flow line at said positive displacement meter means to a predetermined low ditierential above the pressure in the main production flow line whereby crude oil from said separator will flow through said oil flow line to said main production flow line without further separation of gas during measurement therein,

a central valve control station for interconnecting the gathering lines leading from each oil well, the main production flow line, and the test line, and

means for selectively operating said valve control station so that the desired well is connected to the test line for the desired test period and all other wells are connected to said main production line.

11. A system for controlling production of oil and gas from a plurality of wells which comprises gathering lines leading from each of a first group of said Wells to a first station, gathering lines leading from each of a second group of said wells to a second station, a central flow line for both said stations leading to a central gathering station, a first flow control means connected to all of said gathering lines leading to said first station, a second flow control means connected to all of said gathering lines leading to said second station, each said flow control means including means for directly commingling flow from all but one of the lines connected thereto, means coupled to each said flow control means for sequentially selecting said one of the lines from all of the gathering lines of each said group, a group flow line extending from each said flow control means to said central flow line, a line pressure control means in each said group flow line for establishing a pressure level in said group flow line, an oil and gas separator located close to said group flow line at each said station, a test flow line extending .from each said flow control means to each said oil and gas separator for directing flow in each said one of said gathering lines through said separator, liquid and gas output flow lines extending from each said separator for separate gas and liquid flow upon issue from each said separator and connecting with said group fio-w line extending from each said flow control means, said liquid output line of each said separator connecting with said group flow line at a point close to said separator, liquid measuring means in each said liquid output line, gas measuring means in each said gas output line, and pressure control means for maintaining the pressure in each said separator and said liquid measuring means at a predetermined low diiferential above said pressure level in said group flow line.

12. A system for controlling production of oil and gas from a plurality of wells which comprises gathering lines leading from a first group of said wells to a first station, gathering lines leading from a second group of said wells to a second station, a central flow line for both said stations leading to a central gathering station, a first flow control means connected to all of said gathering lines leading to said first station, a second flow control means connected to all of said gathering lines leading to said second station, each said flow control means including means for directly commingling flow from all but one of the lines connected thereto, means coupled to each said flow control means for sequentially selecting said one of the lines from all of the gathering lines of each said group, means including a group flow line having a line pressure control means therein extending from each said flow control means and leading to said central flow line, an oil and gas separator located close to said group flow line at each said station, a test flow line extending from each said flow control means to each said oil and gas separator for directing flow from each said one of said gathering lines through said separator, liquid and gas output flow lines extending from each said separator for separate gas and liquid flow upon issue from each said separator and connecting with said group flow line extending from each said flow control means, said liquid output line of each said separator connecting with said group tiow line at a point close to said separator, liquid measuring means in each said liquid output line, gas measuring means in each said gas output line, and separator pressure control means for maintaining the pressure in each said separator and in each said liquid measuring means at a predetermined low difierential above the pressure in said group flow line, said pressure control means being operable upon the occurrence in each said group flow lme of pressures of predetermined low and predetermlncd high levels for shutting in all wells of each said groups.

13. A system for operating a plurality of oil and gas wells which comprises a gas-liquid separator having a productron inlet, a gas outlet and a liquid outlet, means including flow lines leading from each of said Wells and flow control means for sequentially directing the fiow of fluids from each of said Wells to said production inlet and for concomitantly commingling fluid from the remainder of sald Wells, a group flow line located close to said liquid outlet of said separator and extending from said flow control means for receiving the commingled fluid, a gas flow line extending from said gas outlet to said group flow line, a liquid flow line extending from said liquid outlet to said group flow line at a point close to said separator, means in said gas and liquid fiow lines for measuring the gas and liquids respectively issuing from said separator, and means in said gas and liquid flow lines for maintaining the pressure in said separator and the pressure in said liquid flow line at said measuring means at a predetermined low ditferential above the pressure in said group flow line.

14. A system for operating a plurality of oil and gas Wells which comprises a gas-liquid separator having a production inlet, a gas outlet and a liquid outlet, means lncluding flow lines leading from each of said wells and flow control means for sequentially directing the flow of fluids from each of said Wells to said production inlet and for concomitantly commingling fluid from the remainder of said wells, a group flow line located close to said liquid outlet of said separator and extending from said flow control means for receiving the commingled fluid, a gas flow line extending from said gas outlet to said group flow line, a liquid flow line extending from said liquid outlet to said group flow line at a point close to said separator, means in said gas and liquid flow lines for measuring the gas and liquids respectively issuing from said separator, means in said gas and liquid flow lines for maintaining the pressure in said separator andthe pressure in said liquid flow line at said measuring means at a predetermined relatively low difierential above the pressure in said group flow line, and a means responsive to a predetermined high pressure and a predetermined low pressure within said group flow line to shut in all said wells.

15. A system for operating oil wells which comprises a plurality of local stations and a central gathering and treating station, gathering lines connecting each of said local stations to a plurality of said oil Wells, a gas-liquid separator at each of said local stations, a gas flow channel and a liquid flow channel extending from each of said separators for gas and liquids issuing therefrom, gas measuring means in each said gas flow channel and liquid analyzing means in each said liquid flow channel, flow control rneans at each said local station interconnecting the gathering lines and each said separator for selectively routing the flow of fluid from each of said gathering lines through said separator and for commingling fluid from the remainder of said wells, a group flow line at each said local station interconnected with said flow control means,

said gathering lines, and said gas and liquid flow channels for receiving combined fluid flow from said gathering lines and from said gas-liquid separator, a central flow line interconnected with said group lines and extending to said central gathering station for receiving the combined flow from said group flow lines, and a central gas-liquid separator at said central gathering station interconnected with said central flow line for separating the combined flow into gas and liquid.

' 16. A system for operating oil Wells which comprises a plurality of local stations and a central gathering and treating station, gathering lines connecting each of said local stations to a plurality of said oil wells, a gas-liquid separator at each of said local stations, a gas flow channel and a liquid flow channel extending from each of said separators for gas and liquids issuing therefrom, flow control means at each said local station interconnecting the gathering lines and each said separator for selectively routing the flow of fluid from each of said gathering lines through said separator and for commingling the fluid from the remainder of said Wells, a group flow line at each said local station located close to each said separator and interconnected with each said flow control means, said gathering lines, and said gas and liquid flow channels for receiving combined fluid flow from said gathering lines and from said gas-liquid separator, said group flow line at each said local station being interconnected with each said liquid fiow channel at a point close to each said separator, means in each said gas and said liquid flow channels respectively for measuring the gas and liquid issuing from each said separator while at least said liquids are maintained at the pressure in each said separator, and means for maintaining the pressure in each said separator and the pressure in said liquid flow channels at said measuring means at a predetermined relatively low difierential above the pressure in each said group flow line, a central flow line interconnected with said group flow lines and extending to said central gathering station for receiving the combined flow from said group flow lines, and a central gas-liquid separator at said central gathering station interconnected with said central flow line for separating the combined flow into gas and liquid.

17. A system for operating oil and gas wells which comprises a gas-liquid separator having an inlet and separate outlets for gas and liquids, flow control means for sequentially directing the flow of fluids from each of a plurality of Wells to said inlet of said gas-liquid separator and commingling fluid from the remainder of said wells, a group flow'line located close to said liquid outlet of said separator and extending from said flow control means for receiving said commingled fluid, separate flow lines extending from said outlets for gas and liquids issuing from said separator and leading to said group flow line, said liquid flow line leading to said group flow line at a point close'to said separator, means in each said gas and said liquid flow line respectively for measuring the gas and liquids issuing from said separator, and means for maintaining the liquid in said liquid flow line substantially at the pressure in said separator during measurement therein.

18. A production system for oil wells which comprises a plurality of local stations and a central gathering and treating station, flow lines for connecting each of said local stations to a plurality of said oil Wells, a gas-liquid separator at each said local station, a gas flow channel and a liquid flow'channel extending from each said separator for gas and liquids issuing therefrom, gas measuring means in each said gas flow channel and liquid measuring means in each said liquid flow channel, flow control means interconnecting the fiow lines and said separator at each said local station for selectively routing fluid from said flow flow from said flow lines and from the gas-liquid separator at each said local station for delivering to said central station combined fluid flow from all said wells, and means at each said local station for maintaining the pressure of the liquid in the liquid flow channel extending from each said separator substantially at the pressure in said separator during measurement thereof.

References Cited in the file of this patent UNITED STATES PATENTS 46,794 Green Mar. 14, 1865 18 Ballard Jan. 13, 1920 Raymond Feb. 14, 1933 Bennett Dec. 14, 1940 Kimmel May 22, 1945 Sharaf Mar. 3, 1953 Malir June 30, 1953 Ohlsen et al Feb. 28, 1956 Peters et a1 July 23, 1957 Truman July 29, 1958 Jackson Oct. 7, 1958 Wiley et al. Apr. 21, 1959

Claims

1. THE METHOD OF OPERATING OIL AND GAS WELLS WHICH COMPRISES SEQUENTIALLY FLOWING FLUIDS FROM EACH OF A PLURALITY OF WELLS TO A GAS-LIQUID SEPARATING ZONE, DURING THE PERIOD OF FLOW FROM A GIVEN WELL THROUGH SAID ZONE COMMINGLING FLUID FROM THE REMAINDER OF SAID WELLS FOR GROUP FLOW IN A SEPARATE FLOW PATH BY-PASSING SAID ZONE, AT SAID ZONE SEPARATING THE FLOW FROM SAID GIVEN WELL INTO GAS AND LIQUID, AND MEASURING SAID GAS AND SAID LIQUID ISSUING