CA1255780A - Well production controller system - Google Patents

Abstract

WELL PRODUCTION CONTROLLER SYSTEM

ABSTRACT OF THE DISCLOSURE

A fully programmable system for controlling the operation of one or more gas or oil production wells by controlling the inter-mittent operation of the wells in response to either programmed information or monitored and measured criteria related to the wells themselves. The system includes battery powered solid state circuitry comprising a keyboard, a programmable memory, a microprocessor, control circuitry, means for inputting measured parameters from a plurality of transducers and a liquid crystal display system for displaying information contained within the memory, or one of the measured parameters. In one embodiment, the system monitors pressure, flow, and other parameters of a plurality of wells drawing petroleum products from a common reservoir to control the intermittent operation of either gas injection to the well, outflow of fluids from the well, or shutting in of the well to maximize the overall output of the entire array of wells drawing from the common reservoir.

Description

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1 This application is a division of application serial number 464,290 filed September 28, 1984.
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to a system for electronically controlling one or more petroleum production wells, and more particularly, to a system for controlling wells in order to optimize the production efficiency of formation fluids.
History of the Prior Art Each underground hydrocarbon producing formation, known as a reservoir, has its own characteristics with respect to permeability, porosity, pressure, temperature, hydrocarbon density and relative mixture of gas, oil and water within 1~ the formation. In addition, various subterranean formations comprising a reservoir are interconnected with one another in an individual and distinct fashion so that the production of hydrocarbon fluids at a certain rate from one area of one ~ formation will affect the pressures and flows from a different area of an adjacent formation.
Certain general characteristics are, however, common to most oil and gas wells. For example, during the life of any producing well, the natural reservoir pressure decreases as gases and liquids are removed from the formation. As the natural downhole pressure of a gas well decreases, the well bore tends to fill up ~s~
with liquid~, ~uch a~ oil and water, which block the flow of the formation gas into the borehole and reduce the output production of the well. In such ga~ well~, it i8 conventlonal to periodi-cally remove the accummulated liquia~ by artificial lift tech nique~ which include plunger. lift device~, gas lift devices and downhole pump~. In the case of oil well~ within which the natural pre~ure ha~ decreased to the point that oil does not ~pontaneou~ly flow to the surface, fluid production i8 maintained by ar~i1cial lift methods such a~ downhole pump and by g~8 in~ection l~ft techniques. In addition, certain well~ are fre-quently .~timulated into in~reased production by secondary reco-~ery technique~ such as the injection sf water and/or ga3 into the formation to maintain reservoir pressure and to cause a flow of fluids from the ormation into the wellbore.
In oil and gas wells where~n the ambient re~ervoir pres~ure ha~ been substantially depleted, two general technlques are com-monly used: (l) plunger lift and ~21 ga~ lift.
Plunger lift production system3 include the u3e of a small cylindrical plunger which travels through tubing extending from a ~ location adjacent the producing formation down in the borehole to surface equipment located at the open end of the borehole. In general, fluid~ which collect in the borehole and inhibit the flow of fluidq out of the formation and into the wellbore, are collected in the tubing. Perlodically the end of the tub1ng i~

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opened at the surface and the accumulated reservoir pre~sure ~s ~ufficient to force the plunger up ~he tubing. The plunger carrie~ with it to the surface a load of accummulated fluids which are ejected out the top of the well thereby allowing ga-q to flow more freely from the formation into the wellbore and be delivered to a distribution system at the surface. After the flow of gas has again become restricted due to th~ further accum-mulation of fluids downhole, a v~lve in the tubing at the surface of the well i9 cloqed SO that the plunger then fAlls b~ck down the tubing and i~ ready to lift another load of fluids to the surface upon the reopening of the valve.
A gas lift production system includes ~ valve sy~tem for controlling the injection of pressurized gas from a source exter-nal to the well, such a~ another ga~ well or a compressor, into the borehole. The increased pressure from the injec~ed ga~ for-ce~ accumulated formation fluid3 up a central tubing extending along the borehole to remove the fluids and restore the free flow of gas and/or oil from the formation into the well. In wells where liguid fall back is a problem during gas lift, plunger lift may be combined with ga~ lift to improve efficiency. Such a system is ~hown in U. S. Patent No. 4,211,279 issued July 8, 1980 to Xenneth ~. Isaak~.
In either case, there i5 a requirement for the periodic operation of a motor valve at the surface of the wellhead to control either the flow of fluids from the well or the flow of injection gas into the well to a~sist in the production of gas and liquid~ from the well. The~e motor valves are convantionally controlled by-timing mechanism~ and are proqrammed in accordanc~

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with prlnciple~ of re~ervoir engineering which determined the length of time that a well ~hould be either ~shut in a and restricted from flowing ga~ or liquid~ to the ~urface and the time the well should be ~opened" to freely produce. Generally, the criteria used for operation of the motor valve i8 ~trictly one of the elapse of a pre-~elected time period. In mo~t ca3es, measured well parameters, such as pre~sure, temperature, etc. are used only to override the timing cycle in ~pecial conditions.
For example, U. S. Patent No. 4,354,524 discloRes a pneumatic timing system which improve~ the efficiency of using injected ga~
to artifically lift liquid~ to a well surface by means of the plunger lift technique. U. S. Patent No. 3,336,945 to aO~tock et al discloses a pneumatic timing device for timing the intermit-tent operation and/or injection of wells to increase the produc-lS tion. U. S. Patent No. 4,355,365 to McCracken et al discloses a system for electronically intermitting the operation of a well in ac~ordance wlth prior art timing technique~ wherein the well i~
allowed to flow for a first pre-selected period and then shut in for a second pre-selected period to increase the production from the well. The differential control system manufactured by Plunqer Lift Systems, Inc. of Marietta, Ohio serves to operate a plunger lift completion in accordance with a gating system in which measured values of pressure and fluid levels are compared with pre-set values. UO S. Patent No. 4,150,721 to Norwood discloses a similar gas well controller sy~tem which al~o utili-zes digital logic circui ry gating to operate a well in responseto a timing counter and certain mea~ured well parameters.

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Under certain circumstanceR, however, the mere timed inter-mittent operation of a single motor valve to control either outflow from the well or gas injection to the well will not effect maximum production nor will operation based upon a mecha-nical comparison of well parameters with preset maximum andminimu~ values. It i8 inefficient and costly to inject ga~ into a wellbore which does not contain liquids which require artifi-cial lift or when the well i~ flowing naturally with a satisfac-tory production rate. Further, it i~ inefficient to in~ect either too small or too large a volume of gas as compared to the volume of liquid contained within the borehole which doe~, ln fact, need artiflcial lift. For example, it may be desirable to open a well flow valve and a gas inject valve simultaneously and then close the ga~ inject valve after a fir~t time period wheD
~ufficient pressure is developed in the well to produce continued flow from the well for a second time period. In addition, ~equential operation of a pair of motor valves may be desirable such as when two valves are connected to the well output and a fir~t is opened to allow fluid expul~ion and then clo~ed while a second valve i~ ~imultaneously opened for a time perlod to allow gas production after the fluid has been cleared. Moreover, it may also be useful to utilize a cingle controller to sequentially intermit the operation of individual ones of a plurality of well~; each for different selected time period~.

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As re~ervoir engineerlng technology become~ more sophlsti-cated, more i~ learned abo~t the various parameters which affect the optimum production of a well, and even the manner ln whlch production from ad~acent wells affect each oth~r. It i8 cle~r S that a SyBtem by which a plu~allty of well~ could be controlled for periodic operation to maximize and optimi~e the production from all wells would be of value. In addltion, it would be an advantage to utilize other parameter~ a~Yociated wlth a produc~ng well, ~uch as casing pressure, tubing pressure, flow rate and pressure and oil/water mix, upon which to base the criteria o when to intermittently open or close a well or when to intermit-tently inject fluid~ into the well to stimulate the productlon of gas and/or liquids therefrom. For example, it would be desirable to open a flowing well when the tubing pressure i9 greater than lS an ideal value determined from casing pres~ure, flowinq pre~sure and ga~/liguid ratio.
Moreover, it would be highly de~irable to be able to provide a fully programmable controller for the operation of a plurality of motor valves within an array of producing wells whereby various measured par~meters from each of the wells could be used ~o control the intermittent operation of each of those wells in order to optimize the production from all of the wells. The system of the present invention provides 3uch a fully program-mable controller for the optimization of well production.

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The ~y~tem of the present invention can be used in multiple applications of producing w~lls, for example, ln gas lift comple-tions, plunger lift completions, well~ having fluctuating bottom hole pressures and production flow rate and, in addition~ to unload gas wells. In parti.cular, the present invention i8 espe-cially u~eful in any type of artificial lift completion which involves the intermittent injection of gas in order to lift liquid~ to the surface and may al~o be used to control ga3 injec-tion into one or more well~ in order to optimize the total pro-duction of formation fluid~ from ~he well~.

SUMMARY OF THE INVENTION

An ob~ect of the pre~ent inventlon 1~ to provide an electro-nic controller which measures various well parameter~, analy%es those mea~urement~ based upon pre-programmed con~ideration~, and controls the intermittent injection of gas into one or more well~
to provide for optimum ga~/liquid ratio and optimum production rate~ from the well or wells.
Another object of thP pre~ent invention is to provide sy~tem which include~ motor valves, parameter sen~ing equipment, and a programmable electronic controller which continually ad~usts the opening and clo~ing of the motor valve~ for optimu~
formation fluid production rates. In addition, another ob~ect includes providing a system which monitors injection supply gas 5'7&~

pres~ure, motor valve position, wellhead production fluid pressure, wellhead productioo fluid ~emperature, wellhead produc-tion flow rate, gas to liquid ratio, ~ales flow l~ne pressure, sale~ flow line temperature, ~ales line flow rate, and plunger S po~ition for all well~ producing within a sy~tem and whlch controls the gas in~ection and/or productio~ flow from each of the wells to optimize production from all of the wells.
A still further object of the present invention i~ to provide a Rystem in a gas injection lift production syRtem which mea~ure~
the results of each injection of q~s such a8 the ~rrival of a plunger at the well surface, the increa9e ~n liquid produc~lon, and the increase in casing pressure and modifies the in~ection interval~ to maximize production from the well. AnothPr object i~ to provide a system which will terminate ga~ injection into a well if gas supply pressure drops too low, lf ca~ing pres~ure increases to too high a value, if plunger arrival doe~ not occur within a calculated maximum time interval~ or if production flow line pressure increase~ to too high.a value.
A further object of the present invention i~ to provide an electronic controller for a oil/ga~ production system which iB
fully programmable and has a display panel which allow~ periodic re-programming thereof.
One further embodiment of the pre~ent invention include~ a production controlling system having provision for monitoring ~S 7~

tubing, casing, and production flow line pre~ure~ for optimum control of production from plunger l$ft well~. An additional ob~ect i8 to prov~de ~n electronic controller which monitor~
tubing, casing and production line flow pressures to adjust the on~Qff time for production from the well based upon a comparison o~ actual tubing pres~ure with a calculated ideal tubing pressure and to qhut in the well upon arrival of the plunger at the well surface, or ca~ing pres~ure dipping below a pre-3elected limit or exceeding a pre-selected maximum time limit for production from the well.
A further ob~ect of the invention i9 to sequantially intermit the operation of individual ones of a plurality of different wells, each for different time periods~
An additionàl object of the invention i~ to sjmu].taneou~ly open a pair of motor valve~ and then clo~e them ~equentially after different time period to increa~e production for a given quantity of injection gas. A further ob ject i~ to 3equentially open a first motor valve to allow liquid expulqion and cloqe it thereafter while simultaneou~ly open.ing a second valve to allow gas production for a selected time period.

BRIEF DESCRIPTION O~ THE DRAWING

For understanding of the present invention and for further objects and advantage~ thereof, reference may now be had to -the _ g _ ~ ~ ~ 5'~

following description ta~en in con~unction with the accompanylng drawing in whichs FIG. 1 i~ a schematic drawing of a gas injection plunger lift well completion having two motor valves and including a program-S mable electronic controller constructed in accordance with theteaching3 of the present invention;
FIG. 2 i~ a schematlc drawing of a plunger lift well comple-tion having two motor valves and including a programmable electronic controller con~tructed in accordance with the eeachings of the present invention FIG. 3 i8 a schematic drawing of a plurality of sequentially operated production wells each havinq a single motor valve and including a programmable electronic controller constructed in accordance with the teachings of the invention;
FIG. 4 is a schematic drawing of a plunger lift well comple-tion wherein the well i~ operated in accordance with ~ariou~
mea~ured parameter~ and includin~ a programmable electronic controller constructed in accordance with the invention~
FIG. 5 is a block diagram of an electronic controller u~ed in con~unction with the ~ystems ~hown in FIGS. 3 and 4~
FIG. 6 is a block diagram of an electronic controller used in con~unction with the ~ystem~ ~hown in FIGS. 1 and 2;
FIGS. 7A, 7B and 7C are each portion~ of a schematic diagram of an electronic controller constructed in accordance with the ~ ~ ~ 5t~

invention and -~hown in FIGo 57 and F~GS. 8A, 8B, ac and 8D are each portion~ of a ~chematic diagram of an electronic controller con~tructed in accordance with the pre~ent invention and shown in FIG. 6.

DESCRIPTION OF THE PREFERRED E:MBODIMENT

Dual ~ontroller OPeration The well completions ~hown in FIGS. 1 and 2 operate with the controller of the present invention in a fir~t mode to ~imulta-neou~ly open a pair of motor valves and ~equentlally close them 1~ in pre-selected time frame~ and in a second mode to ~equentially open a pair of motor valves, simultaneously opening the ~econd and closing the first in accordance with detection of the occurrence of an event and pre-selected time periods.
Mode A
Referring ~irst to FIG. 1, there i8 shown an illustrative ~chematic of a ga~ well equipped as a plunqer lift completion with ~upplementary ga~ injection. The well includes a borehole 12 extending from the surface of the earth 1~ which is lined with a tubular casing 14 which extends from the ~urface down to the producing geological strata. The casing 14 includes perforation~
15 in the region of the producing ~trata to permit th0 flow of ga~ from the formation into the ca~ing lining the borehole~ The producing strata into which the borehole and the ca~ing extend~

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~8 formed of coar~e rock and 8erve~ a~ a pre~surized re~ervoir containing ~ mixture of ga~, oil and water. The casing 14 i~
prefer~bly perforated along the region of the borehole containing the producing strata in area 15 in order to allow fluid com-munication between the strata and the well. A ~tring of tubinglS extends axially down the casing 1~.
Both the tubing and the casing extend into the borehole from a wellhead 18 located at the surface above the well which provi-des support for ~he str~ng of tublng extendlng $nto the cas~ng ~nd closes the open end of the ca~ing~ The casing i8 connected to a line 22 which supplies high pressure gas from an external ~ource such a~ a compressor tnot ~hown) through a fir~t motor valve 25 into the ca~ing 14. The first motor valve 25 i~
operated between the open and close conditlon by a programmable well production intermitter/controller 26 con~tructed in accor-dance with the teachings of the pre~ent invention~
The tubing 16 is connected to a production flow line 27, through a ~econd motor valve 32 and to a separator 28. The out-put 10w of the tubinq 16 into the production flow line 27 is generally a mixture of both liquid3, such a~ oil, water, and con-densate, and gases and is direeted through the separator 2a which effects the physical separation of the liquids from the ga` es and passes the gas into a sales line 3~ for delivery to a ga~
gathering sy~tem. The liquids output from the separator 28 are ~ 5'7~3 directed into a liquid storage re~ervoir 36 for ~ubse~uent dispo-sal by well known methods. Pxes3urized ga~ i8 also ~upplied through a filter 17 and a regulator 19 for use in pneumatically operating the motor valves 25 and 32 by mean~ of ~olenoids 31.
The ~tring of tubing 16 extends axially down the casing and is terminated by a tubinq 9~0p 23 and bumper ~pring 24. A
reciprocating plunger 20 i8 positioned within the tubing 16 and i8 prev~nted pas~ing out the lower end of the tubing by the bumper spring 24 and tubing stop 23. The upper end of the tubing 16 i~ closed by a lubricator 29 which receive~ the plunger 20 wh~n it i~ in its uppermost po~ition. The lubricator 29 also includes a sensor 30 which detects when the plunger has arrived at its uppermo~t position.
In a gas inject system of the type shown in FIG. 1, it is desirable to conserve gas and inject only as much gas through the first motor valve 25 as i8 required to move the plunger 20 up the tubing 16 and eject the accumulated fluid~ from the well through the second motor valve 32. Thereafter, the fir~t valve i8 closed and the second allowed to remain open for a pre-selected time ~ perlod of production flow from the cleared well. When the well has been closed'for a sufficient period of time to develop a for-mation pres~ure, liquids will also have accumulated within the casing 14, in the region of the perforations 15 ad~acent the pro-ducing formation. The~e formation fluids restrict the flow of ~ 13 -a~s~7~

~ase~ from the formation into the ca~ing ~o they are removed at the beginning of the production cycle when both the first and second motor valves 25 and 32 are opened simultaneou31y. ~he first mo~or valve 25 i5 opened by mean~ of ~on~ ~olenoid 31 to in~ect a flow of high pressure ga~ from the external source into the ca~ing 14 and raise the pre~ure. The second motor valve 32 i9 opened also by mean~ of an ~on~ solenoid 31 to open the upper end of the tubing production flow line 27 and cau~e the plunger 20 to move upwardly within the tubing and bring along with it a quantity of formation fluid~ which have accumulated within the cas~ng in the region of the produc~ng formation. The liquid~
brouqht to the ~urface by the plunger 20 flow out through the second motor valve 32 and the production flow line 27 into the ~eparator 28 in a conventional fa~hionO The plunger arrival ~en-lS sor 30 detect~ when the plunger 20 has reached the top of thetubing and i~ lodged in the lubricator 29 and produce~ a plunger arrival output ~ignal to the controller 26. In re~pon~e to the plunger arrival signal, or the passage of a pre-programmed time, whichever happens first, the controller 26 operate~ the ~off~

2~ solenoid 31 of the first motor valve 25 to close the valve and stop ga~ injection. The ~econd motor valve 32 i~ allowed to remain open for a pre-programmed time period to permit the flow of production gas from he formation. APter the set time period, the second motor valve 32 i~ closed to permit the plunger 20 to fall back dowm the tubing ~tring 16 and reposition it~elf at the bumper sprin~ 24 for a ~ubsequent trip to the ~urfaca to again empty accumulated formation fluid~ from the well. Thus, in the aystem of FIG. l, a pair of motor valves are ~imultaneou~ly opened and sequentially close~ to maximize production flo~ while minimizing the consumption of ~n~ection gas.
Mo~e B
Referring now to FIG. 2, there is shown an illustrative sche-matic of a plunqer lift completion ga~ well, similar to the well of FIG. l, but wherein the formation pressure i~ sufficient that no supplementary in~ection gas i8 nece~sary in order to clear the well of accumulated fluids. The well includes a borehole 12 extending rom the earth surface 13 down to the producing geolo-gical strata and which is lined with a tubul~r ca~ing 14. The ca~ing 14 al~o includes perforations 15 in the reglon of the pro-ducing ~trata to permit the flow of gas from the formatlon into the casing. A ~tring of tubing 16 extend~ axially down the casing 14.
~oth the tubin~ 16 and the casing 14 extend into the borehole from a wellhead 18 located at the surface and which provide~ ~up-port for the string of tubing and closes the open end o~ the ca~ing. A reciprocating plunger 20 is positioned within the tubing 16 and is prevented from pas~ing out the lower end of the tubing by a bumper spring 24 and tubing stop 23. The upper end ~5 J ~

of the tubing 16 1~ enclosed by a ~ubricator 29 wh~ch receivea the plunger 2Q when it i~ in it8 Uppermogt pO8 ~ tion. ~he lubri-cator 29 also include~ a ~en~or 30 which measures when the plungar has arrived at its uppermo~t po~itlon.
The upper end of the tubing 16 i8 connected to a first flow ~T~ ~1 and a first motor valve 42 into A low pressure fluid deli-very line 43 leading to a separator 28. The first motor valve 42 is actuated by a pair of ~on~ and ~off n solenoid~ 44 under control of a well production controller 2S constructed in accor-10 dance with the teachings of the invention. The solenoids control the flow of pres~urized air or gas supplied via line 43 by means not shown. The upper end of the tub~ng 16 i~ also connected to a ~econd flow aT~ 45 through a second motor valve 46 to a h~gh pressure gas sales line 47. The ~econd mo~or valve 46 i~
15 ~ctuated by on" and ~off R solenoids 48 under control of controller 26.
In operation, the plunger lift completion of FIG. 2 i3 closed in for a pre-selected time period during which sufficient for-mation and gas pressure is developed to move the plunger 20 along 20 with fluids accumulated in the casing 14 to the surface. After passage of the selected time period, the cycle is begun by opening motor valve 42. ~8 the plunger 20 ri~e~ to the surface, the accumulated fluids carried by the plunger pass out through the first flow ~T~ 41, through the low pressure fluid line 43 ~ ~ ~ 5'l~

into the sepaxator 28. When the plunger arrival sensor 30 detect~ that the plunger i~ pO8 ~ tioned ~n the lubricator 29, tho controller 26 close3 the first motor valve 42 and slmult~neously opens the second motor valve 46 to allow the high pressure for-~ation gase~ to pa88 through the ~econd flow ~T" 45 and out thehigh pressure gas sale~ line 47. After a pre-~elec~ed time period of high pressure production gas flow through the line 47, the second motor valve 46 i8 again closed to ~hut ln the well and ~llow the plunger 2D to drop back down the tubing 16 and the for-mation ga8 pressure to re-accumulate for a subsequent cycle.
Thu8, in the system of FIG. 2, a pair of motor valves are operated so that a first valve i8 opened for a time to clear the well and then closed while a second valve 18 ~imultaneously opened for a second time period to allow production flow from the cleared well and then clo~ed. Thus, th;s mode of plur~l vnlve operation effectively separate~ the low pressure fluids from the high pressure production qa~
Referring now to FIG. S, there i8 ~hown a block diagram of the well production controller 26 which effects the oper~tion o~
the well complet10ns illu~trated ln PIGS. 1 ~nd 2. The clr-cuitry include~ ~ micro-proce~sor 51 drlven by ~ clock driver 52 and connected via a multiplexed data/addres~ bu 53 to a memory 54 and a demultiplexing latch 55. The proces~or 51, as well as all other processors referred to herein/ i8 preferably of the ~ ~ ~ 5'~

CMOS type and, by way of example only, a national ~em~-conductor model NSC 800N-1 CMOS micrq-proce~or has perormed satisfac-torily. The mlcro-processor 51 is ~180 connected through an address bu~ 56 and a memory decoder 57 to the memory 54 and to a perpheral decoder 58 and z real time clock 59. Pinally, ~he micro-proceQ80r 51 i8 connected over the bu3 53 to a peripheral interface adapter (PIA) 61.
The peripheral interface adapter 61 iQ connected to receive input from a plunger arrival sensor through ~n operatlonal ~mplifier 62 and an air presQure fall sen~ox through ~n a~80-ciated amplifier 63. A high tubing pres~ure limit ~ensor provi-de3 a signal through ampiifier 64 in the event the tubing pre~ure exceeds a pre-~elected valua while a low tubing pres~ure sen~or provides a Qignal through amplifier 65 in the event the tubing pressure drops helow a pre-selected v~lue. In addition, since only battery power is available in the remote area~ where quch systems are most often located, the system is provided with a low battery voltage detector and a battery voltage failure detector 66 which provide~ information through the p~rlpher~l interface adapter 61 to the re~t of the system.
The peripheral interace adapter 61 i8 connected to actuate pa~r of motor valves by means of two pairs of solenoid~, one for ~ona and one for "off~ in each of the 301enoid pairs 67 and 68.
An address from the peripheral interface adapter 61 i~ pa~sed ~5~

through a decoder 71 ~o one or the other of a pair of solenoid driver~ 72 and 73 for respectlve ones of the motor valve ~olenoid pair~ 67 and 680 A one shot multi-vibrator 74 select~ the time period during which a signal i8 3upplied to the solenoid driver~.
The well controller ~ystem o~ FIG. 5 also include~ a keyboard 75 for the entry of multiple programming data into the memory 54 through a keyboard encoder 7~ and the bus system 77.
A multi-character optical display 78, preferably of the liquid crystal display ~LCD) type, i~ provided for operator observation of infoxmation as it i~ programmed into the ~ystem as well as various parameters and item~ of dat~ which can be moni-tored during the operation of the ~yQtem. In addition, thQ
display provide~ a visual alarm upon malfunction a8 well as visual indication3 of low battery voltage and a battery failure lS condition. The di~play 78 is driven through a pair of display driver~ 81 and 82 in conventional fashion. In one embodiment of the di~play 78, each character can be either the numerals 0-9 or the letters ~, E, L, or P. A loss of ~oleno~d air ~upply pressure effect~ closure of all motor valves and is visually indicated by the indication HELP l; a low battery alarm is indl-cated by a display which alternately fla~he~ HELP 2 and the time at which the condition began; a dead battery effects clo~ure of all motor valves and i8 ~hown by HELP 3. The ~tatus portion of the display 78a indicates the condition of the cycle of oper~tlon 7~

of the clrcuit a~ either ON TIME-P; OFF TIME-E; or ExaAusT TIM~-L
while the remaining time i~ 3hown and decremented in hour~, minu-tes and ~econds in display ~ections 78b, 78c, and 78d, re3pec-tively. The mode of operation of the controller i-~ shown in Section 78e: 1 for mode A and 2 for mode B.
To prov1de maximum battery life in remote loca~ion~, the ~y~te~ in~lude3 a power ~ave circuit 83 which operates to power down all proce~sor function.~ except those neces~ary to maintain memory until the occurrence of either the pa~sage of a ~elected time period or the receipt of an input signal from the keybo~rd 75.
In the operation of the ~ystem of FIG. 5 ~n mode A, as described above in connection with FIG. 1~ programming entries are made by fir~t depressing the MOD~ key 75b and thereafter either the numeral 1 to select MOD~ A and the numeral 2 to select MODE B. For example, to program a MODE A operation, the PRO&RAM
key 75a is then depre~ed followed by the ON TIME key 75c and then numeral key~ to program in~o the memory 54 a time indicative of the time period within which ga~ is to be injected ioto the well with both motor valves open. Next, the PROGRA~ REY 75a i~
pre~ed again followed by the EX~AUST TIM2 key 75d and numer~l keys to enter into memory the time during which the ~econd motor valve i~ to remain open after the fir t valve i~ clo~ed ~o that pro~uc.tion flow from the well may continueO Finally, the PROGRAM

~s~ v 1 key 75a, OFF TIME key 75e and numeral keys are sequentially activated and a third time is entered into memory which is indicative of the time within which both motor valves should be closed and the well shut-in. Each of the programming parameters are displaced in the LCD display 78 as they are entered into memory through keyboard 75. A mode B operation is similarly programmed with ON TIME to open the first motor valve (a "maximum time" in -the event the plunger does not arrive by then), EXHAUST TIME to close the first motor valve and open the second and OFF TIME to close the second motor valve and shut-in the well.
Once the system is started by depressing RUN key 75f, the micro-processor 51 controls operation of the system to provide signals to the peripheral interface adapter 61, decoder 71, and one-shot multi-vibrator 74 to energize both the solenoid drivers 72 and 73 and open both motor valves 67 and 68. After the first "on" time period has elapsed, the first motor valve 67 is closed to stop the injection of lift gas into the well while the second motor valve 68 remains open to allow production flow from the well for an additional "exhaust time" after which a signal is provided to the peripheral interface adapter 61 to effect the closure of the second motor valve 68. Thereafter, both valves remain closed for a third pre-selected "off time" period until the cycle is begun again.
In the operation of the circuitry of FIG.5 in mode B, in ~s~l ~o ~onnection with the operation of the completion shown in FIG. 2, the keybQard 75 iB used to select PROGRA~, MODE and the numeral 2 and, thereafter, program the "on~ time period within which high pre~sure ga~ produc~ion flow i8 to occur following clearing of the well a~ well as the time within which the well i~ to be fully ~hut in to allow formation pressure to accumulate. Upon inl-tiation of the cycle by depression of the ~UN key 75f, the micro-proce sor delivers a ~ignal through the peripheral interface adapter 61, the one-~hot multi-vibrator 74, and the decoder 71 to open the first motor valve 67~ When a ~ignal i8 received over the plunger arrival sensor through the operational amplifier 62~
the flip-flop 60 and the peripheral interface adapter 61, the micro-proces~or again ~auses the first motor valve 67 to clo~e and, ~imultaneouRly, the second motor valve 68 to open for a pre-nelected ~exhaust time~ period of high pressure production flow~Thereafter, both motor valves 67 and 68 are closed for a pre-programmed ~off time~ period and the cycle is again repeated.
The system also includes a "pressure override ~eature in both modes A and B so the pres~ure tran~ducer~ are conne~ted through operational amplifiers 6~ and 65 so that after an on time ha~ expired and the tubing pres~ure i~ still above a pre-~et high limit, the well will remain open until the pre~sure falls below that value. Similarly, if after an off time ha~ explred, the tub~ng pressure i8 ~till below ~ lower limlt the well atAys closed Referring next to the schematic diagram shown in FIGS. 7A, 7 and 7C, arranged for viewing as ~hown therein, the micro-prOCe38Qr 51 i8 connected to be driven by a 500 ~ clock driv~r 52 comprising an oscillator gl connected through a flip-flop c~r-cuit 92. The 03cillator 91 include~ a 1 MHz crystal 91a acro~
which i3 connected 8 re~i3tor 91b, a pair of ~eries-connected capacitors 91c and 91d and an inverting ampllEier 91e. The micro-processor 51 is connected to the memory decoder 57 by leads comprisin~ the address bus 56. The output oE the memory decoder 57 l8 connected to the memory 54 by addresq lead~ 93 and con-nected to the peripheral decoder 58 by a single lead 93a. The output of the micro-proce~sor 51 is also connected by means of a data and address bu3 53 to a number of other componen~s including the memory 54, the real tlme clock 59, the di~pl~y driver~ 81 and 82 (FIG. 5), a~ well a~ the keyboard encoder 76 and the peripheral interface adapter 61. A memory decoding latch 57 is provided to demultiplex the data and addre~ bu~es from the out-put of the micro-processor 51. The memory 54 ~ncludes a RAM
~0 memory 94 for the storage of measured parameters and keyboard selectable programmed data, as well a~ a plurality of ~PRO~'S 95, 96, and 97 for the ~torage of program control for the micro-proce~sor 51. The keyboard encoder 76 i~ connected to the keyboard 75 ~FIG. 5) to input data from the keyboard into both ~ ~ ~ 5 ~

the ~emory 54 ~ well as the optical d~play 83 for observAtion by the operator. The outpUt of the peripheral interface adapter 61 i8 connected to both a ~olenoid decoder 71 as well a~ through a one-~hot multi-vibrator 74 to energize the ~olenoid~ for a pre-selected time period. A pair of solenoid driver c~rcuits 72 and73 are connected to ~ona and ~off~ ~olenoid~ for each of the two motor valves.
A plurality of external input~ are connected to the input of the peripheral interface adapter 61. A signal from a plunger arrival switch is connected through an inverter 62 and a ~lip-flop and 60 to provide a plunger arrival ~ignal when the plungerhas reached the top position in the tubing. An ~on time~ ~8 pre-programmed into the controller ~o that i f the plunger doe~ no~
arrive to cau~e a plunger arrival ~ignal by the t1me the ~on lS time~ has expired, the controller will au~omatically cycle and clo~e the first valve and simultaneou~ly open the second valve.
A~ter the pas~age of a pre-selected time period following a plunger arrival, a signal i8 placed on the plunger re-set lead PR
which resets the flip-flop 60 and enables it to recelve a new plunger arrival signal on the next cycle. An air pres~ure fail signal i8 al~o coupled through an inverter 63 to an input of the PIA 61 while high pressure and low presqure transducer~ are con-nected a~ input~ to the PIA and, respectively, provide indica-tion~ that the tubing pressure i~ either above or below ~S5'7~10 pre-~elected values. In addition, a battery fall 3iqnal is coupled through an operational amplifier 98a and connected to the peripheral interfacs adapter as the BF lead while ~ battery low ~ignal of a ~omewhat greater voltage than the f ail 1~ connected S to the PIA through operational amplifier 98b as the ~L leadO
As cAn be seen, the circuitry of FIGSo 7A, 7B and 7C serve to route ~ignals to and from the micro-proce~30r and the varlou~
peripheral components through the peripheral interface adapter to effect operation as set forth above in connection with FIGS. l and 2.
The power sav~ circuit 83 consis~ of a pair of intercon-nected flip-flops 83a and 83b having OR gates connected to each of thelr reset leads. An output from the keyboard encoder 76 through OR gate 99a is coupled to the fir~t flip-flop ~3R. An output from the resl time clock is al80 connected via th~ CL~
lead to the other input of OR gate 99~. An output from the set lead of flip-flop ~3a 18 connected through another OR gate 99b back to the micro-processor as the WK leadO Output from the flip-flops 83a and 83b are connected through a pair of EXCLUSIV~
2~ OR gates lOOa and lOOb which are connected to drive the displayO
One of the qate~ lOOa is connected to drive the time colon which flashe3 on and off while the unit is in operation while the other qate lOOb is connected to a ~power save~ colon which burn~ ~te~dy when the system i~ in power save mode and indicates that minimum o 1 power is being consumed. In power save mode, all processor and analog functions are powered down except those necessary to maintain memory and essential digital operations to conserve power. In the event of a signal from either the keyboard decoder 76 or the real time clock 59, which produces a signal on the CLK lead every five seconds, is received through gate 99a, the power sa~e circuit is switched out of power save mode and power is delivered to all of the components for operation and evaluation of the status of the system.
Multi-Controller Operation Referring now to FIG, 3, there is shown a schematic drawing of a plurality of plunger lift well completions 101-106 similar to that shown in FIG. 2 and which are all controlled by a well production controller 26 constructed in accordance with the teachings of the present invention. Each of these wells may illustratively include a borehole 12 extending from the surface of the earth down to a producing geological formation which is lined with a tubular casing 14 which is perforated in a region adjacent the producing formation.
The well also includes a string of tubing 16 connected from the region adjacent the perforations to the surface and which extends out through the top of the casing through a flow "T" 107 and a lubricator 29. The lower end of the tubing is terminated by a tubing stop and a bumper spring and a plunger 20 is mounted for reciprocation within the - 26 ~

~ ~';g5~

tubing. Each o the well~ completion~ 101-106 may be essentially identical for illu~tr~ive purposes, and the output of each Plow ~T~ 107 is connected, re~pectively, through a one of a plurallty of motor valves 111-116 to a common manifold 117 connected to a eparator 28 and a gaq ~ale~ line 32. Each of the motor valves 111-116 are actuated by a pair of solenoids 121-126, respec-tively, which are connected for operation to the well production controller 26.
Due to the expen~e of providing supply gas and/or compre~or capacity i~ remote locations, it i~ frequently de~irable to operate only one of a plurality of wells at a particular time period. The controller of the present invention 26 ~erves to sequence a multiple of wells between an ~onR and an nof~A state, ea~h for a pre-~elected time period of ~on~ time and ~off~ time in an orderly fashion. That i~, by entering the hon~ tim~ ~nd ~offa time for each of the plurallty of wells in th~ array, the controller will perform an orderly ~queing~ function to turn the wells on in sequence in accordance with the ~equential order in which the well~ each reach an expiration of their ~off~ time.
2~ Referring to FIG. 6, the LCD di~play i8 similar to the display 78 of FIG. 5, with alphabetical characters Bo Eg L and P
to lndicate both alarm condition~ and circuit statu~, and numeral characters to indicate time~. The qtatus portion 78a indicates the condition of the cycle of operation of the circuit a~ either ~ 7 ~

0~ TIMX - P or OFF TIME - ~ while the remaining time i9 decremented ln hours, minutes and second~ in display sectlons 78c, 78d and 78e, reapectively. The well number being operated by the contxoller ~8 shown in sectio~ 78b.
The system is programme~ in ~he multi-well configuration a~
followR. First, the PAUS~ key 236e i8 pressed to ~top the opera-tion of the circuit in whatever atate it i8 in. Next, the PROGRAM key 236a i~ pressed followed by the WELL NUM~ER key 236b and a numeral to indicate the p~rticular well. There~t~r, ~
time key such as ON TIME key 236c i8 depre~sed followed ~y numeral keya to program the time into the memory. Each time period programmed requires the ull ~equence to be repeated, namely, PROGRAM, WELL NUMBER, numerals to select the well, ON
TIME or OFF TIME ~eys and numeral~ to select the time. The ~equence i3 repeated until all on tlmes and off times for all wella haa been entered into the memory.
The operation of the controller 26 in conjunction with the multiple well configuration of FIG. 3 will be explained in further detail below.
Optimizinq Controller Operation Referring now to FIG. 4; there i~ shown an illu~tr~tive sche~
matlc drawing of a plunger lift oil well completion similar to thoae of FIGS. 2 and 3, wherein the well i8 operated ln ~ccor-dance with various mea~ured parameter~ by a well production controller 26. The well includes a borehole 12 extending from the surfaca of the earth and havlng ~ tubular casing 14 ex~ending from the surface down to ~he producing formation at which per-fQrations 15 are formed to allow the pa~sage of fluids and ga~ea from the formation into the c~sing 14. The well al80 include~ a string of tubing 16 which i~ terminated at the lower end by tubing stop 23 and a bumper ~pring 24. A reciprocating plunger 20 i8 mounted for movement in a vertical direction up and down the tubing 16. The upper end of the casing i8 closed at a wellhead 18 and has protruding therefrom a ~ection of the tub-~ng which includes a lubricator 23 to receive the plunger 20 when it i8 in its uppermost positionO In addition, a plunger arrival sensor 30 is provided to indicate when the plunger i8 in itB
uppermost position. ~he upper end of the tubing include~ a flow ~T~ 130, the output of which i8 connected through a motor valve 131 operated through solenoid3 132 by the well production controller 26.
The output flow line from the motor valve 131 passes through temperature flow and pres~ure sensors 133 and 134 intc ~
separator 135~ Actual tubing pressure and temperature are moni-tored through tran~ducer~ 139 and 140 while tran~ducer~ 145 and 146 monitor ca ing pre~sure and temperature. The liquid flow from the separator al~o has temperature, pressure and flow rate monitored by sensors 136-138, re~pectively, into a storage tank - 29 ~

~5'7~(~

1 36. The gas flow from the separator 135 flows through tem-perature, pressure, and flow rate sensors 141, 142, and 143, into the gas sales line 32. The output of each of the temperature, pressure, and flow rate sensors are connected to the well production controller 26 and each supplies a measured value thereto when the transducer is energi2ed by the controller. It should be clear that in other aspects of the invention, the well parameter monitoring transducers 133, 134, and 136-146 could be selected to measure other desired parameters, e.g., oil/water ratio and supply that information to the controller 26 for use operating the well or wells.
Based upon established principles of reservoir engineering, there are certain pressure/flow relationships in a well completion which relate to optimum production from the well. For example, it has been determined that by calculation of the Ideal Tubing Pressure from established relationships for a well, an operator can compare the Actual Tubing Pressure of that well just before the well is opened and adjust a conventional intermitted timing cycle to achieve optimum production from the well. That i5, by flowing the well for a longer period (or shutting it in for a shorter periodl, if the actual tubing pressure is greater than the calculated ideal pressure and by flowing the well for a ~ 30 -~35'~'~0 ~horter period ~or ~hutting it in for a longer period~, produc-tion level~ near optimum can be achieved.
Rowever, the pressure/flow relationship~ in a well change with time and mny vary ~ubstant~ally for a particular well bet-ween visit~ by an operator to adjust the timing cycles. The controller of the present invention includes the capability of regularly, cyclically measuring the various flow/pressure/tem-perature parameter of one or more wells and controlling the operation based directly upon the use of the monitored values in algorithms pre-programmed into the processor and the result o~
the processor's calcula~ions and decisions. This enables dlrect, continuous operation of a well to achieYe optimum production from an individual well or an entire field of wells ~ased upon actu~l operating conditions.
Purely, by way of example, in ~llu~trating the u~e of the well controller of the present invention shown ln FIG. 4, a NET
PRESSUR~ can be determined for a particular well by mean~ of the followlng relationship:
CASING AVERAGE FLOWING NET
PRESSURE S~P M A~OR PRESSURE P~ESSURE
For each well there are numerous factors which determine the rate at which a plunger completion will cycle, such as depth of the well, gas/fluid ratio, qas gradiant, fluid gradiant and casing and tubing sizes. That i8, a particular well will build ~s~

up pressure from the reservoir ~ufficient to move the plunger to the surfa~e and remove a lo~d of fluld at a characteri~tic rate and there i8 ~ome percentage of the net pressure at which the well will cycle over without a risk of the plunger getting stuck in the middle. A ~ACTOR a~ ~ome two digit fraction of the N~T
PRESSUR~ is experimentally determined and programmed into the 8y9~em .
A M~XIMUM FLUID PRESSURE i~ next determined:
NET PACTOR MAXIMUM FLUID
x PRESSURF PRESSURE
and IDEAL TU13ING CASING M~XIMUM FLI)ID
PRESSURE PRESSURE PRESSUR~
Thu~, the controller periodically energizes transducers to mea~ure the various parameter3 nece~ary to determine an IDEAL
TUBING PRESSUR~ and the SALES LINE PRESSURE.
I~ the sale~ line pressure is le3~ than the ideal tubing pre~sure, then the well should be opened for flow, if not the well should be shut-in. The well production controller 26 of the invention in the embodiment ~hown in FIG. 4 moni~ors the ca3inq pre~ure by means of tranqducer 145, the flowing separator pre~ure by means of tran.~ducer 142, and the tubing pressure through transducer 139. The factor i8 e~tabllshed for A p~r-ticular well based upon the ability of the well to llft ~ colum~

5~

1 of fluid and as a function of the gas/liqu.id ratio and programmed into the controller memory. The well production controller 26 calculates the ideal tubing pressure in accordance with the aforesaid algorithms and compares it to the sales line pressure measured at transducer 142 and, in the event the ideal pressure rises above the sales line value, the motor valve 131 is actuated through solenoids 132 to open the well and permit production flow therefrom.
Referring now to FI~. 6, there is shown a block diagram of a system constructed in accordance with the invention for the operation of the well control system shown in FIGS. 3 and 4. In particular, the system includes a micro-processor 151 driven by a clock driver 152 which is connected to a line driver 157 by means of an address bus 156. The micro-processor 151 is also connected by means of a data and address bus 153 through a line driver 150 to a memory 154. In addition, the micro-processor 151 is connected to a demultiplexing latch 158, the output of which is connected to the memory 154 via the bus 177 as well as to the real time clock 159 and a system decoder 200. A bus system 201 connects the system decoder and the real time clock to a peripheral interface adapter 202, having a plurality of inputs.
A low voltage detecting network is connected to the input of 7~

an operational amplifier 203 which provides a low analog battery voltage signAl to the lnput of the peripheral lnterfnce ad~pt~r 202 whlle a low voltage condition from the digital battery ia connected throu~h ~n operation~l ampllfier 20~ to provldo ~n indication to the peripheral.interface.adapter.
An output from a casing pre~ure tran~ducer 18 connected from terminals 205 through an operational amplifier 206 and an analog digital converter 207 to the peripheral interface adapter 202.
Similarly, an input from terminal~ 208 from which i8 connected a flow line pres~ure tran~ducer i8 connected through ~n operational amplifier 209 and the A to D converter to the input of the peripheral interface adapter 202. In addition, the output of a tubing pressure transducer i~ connected from terminal~ 210 through the operational ampllfier 211, and the A to D converter to the input of the peripheral interace adapter 202, provide substantive measurements of the preci~e value~ of ca~ng, flow line, and tubing pressures any time these transducers are energized. The ca~ing preq~ure, flowing line pre~sure, and tubing pre~xure transducer3 connected to terminals 205~ 208, 210 and 214 may be tranqducer3 145, 134 and 139, respectively, of FIG. 4. An output from the peripheral interface adapter 202 i~
connected through a switching tran~l~tor 212, a field effect transistor 213 and an analog battery regulator 216 to supply voltage to the transducers over terminals 214 to power the trans-S 1 ~0 ducers and produce an output reading indicative of the re~pectiYe pressures. Input from ~ ~digitalU battery i~ pxovided to leAds 215 which are connected to a digital battery regul~tor 217, the output of which powers all of tha digital components neces3ary to retaln memory and continue regul~r operation. A separate analog battery i~ provided for powering the analog components such as the pre~sure transducer~ and i8 operated through a power ~ave circuit which will be more fully explained below.
A second peripheral interface adapter 219 i~ provided and the output of which i9 connected through a bus 237 to a solenoid decoder 238 connected to actuate one of a plurality of ~olanoid drivers 22Q-226 which control the plurality of motor valves ln the multiple well embodiment of FIG. 3. A low digital battery voltaqe detection network 231 is connected through an operational amplifier 232 to the input of the peripheral interface adapter 219 while a dead battery detection network 233 i~ connected through an operational amplifier 234 to another input of the peripheral interface adapter 219. A plunger arrival terminal 235 i9 connected to a pl~nger arrival detector (FIG. 4) and provide~
~ a si~nal throuqh flip-flop 239 to indicate the arrival of a plunger at the upper portion of the tubinq to the peripheral interface adapter 21~. An air pres~ure failure detector i8 con-nected to terminal 236f and provideq a ~ignal to the peripheral interface adapter 219 i~ the event of a failure of the compres~ed - 35 o ~ ~ S ~78 air ~upply used to operate the motor valve~q A multi-character liquid crystal display 241 1~ provided wlth a pair of display driver~ 242 and 2~3. A bus ~y~tem 201 inter-connects the di-~play drivers 242 and 243 to a keyboard ancoder 245 which decode~ a keyboard 236 to display information encoded by the keyboard into the memory 15~. Further, the optical display 241 may be utilized to observe various item~ of memory such a~ previou~ly programmed times as well as v~rious values of meaqured parameter~ within the systeM and the current operating ~tatus of the controller. The components within the power save circuit 250 which are adapted to reduce the power consumption of the controller during mo~t of the time operation of the ~y~temO
That iB, the power save circuitry 250 operate~ to power down all of the non-essential function~ which consume power until a ~ignal i~ received either from the real time clock on a periodic ba~is or from a keyboard entry indicative that the sy~tem i8 being programmed or queried for information. Either of these two events serve to power up the sy~tem to make mea~urement~ and see lf any action need~ to be ta~en.
It can be readily seen how the controller ~y~te~ of PIG~ 6 serves to ope~ate the multiple well production control 8y~tem of FIG. 3. The pau8e key 236e i3 actuated to ~top operation of the controller. Next, a code i8 entered via keyboard 236 to indicate that the controller is to be used in the multiple well control ~ ~ ~ 5 78 0 configurat~on ~nd then the PROGRAM ~ey 236a pre~ed to prepara the controller to receive lnformatlon. A WELL NUMBER key 236b ~nd tben numeral keys to select the well and an ON TIME key 236c or OFF TIM~ key 236d are used to a~ign a well number and aon~ or ~off~ times for that well. The entire cycle i3 repeated for each time on each well. A location within memory 15~ ~ B allotted to provide or the reception of keyed in number and time information for each of the motor valves 111-116 of the slx well~ 101-106 controlled by solenoid drivers 220 -226. Each well i~ given a number designation and, thereafter, an ~on~ time and an ~offn time i~ keyed into the memory to be associated ~ith each well.
In addition, a location within the memory 154 is allotted for storage of which particular wells have timed down to complete their ~off time~ and in what ~equence they timed down and were then ready to be intermitted into the aon~ ~tate~ Thu~, only one of the well motor valves 111-116 i8 actuated at a time but each time that one of the wells 101-106 ~off timea has expired, it will be then placed in a sequential que with the other wall~
ready to flow in the order in which their noff times~ were over.
Motor valves 111-116 are sequentially driven to the ~on~ state to open a well in accordance with the well ~8 po8it~0n in the que as determined by the micro-proce~or 151.
It can al80 be readily seen how the controller ~ystem of FIG.
6 serveR to operate the optimizing production control system of 8~

FIG. 4. Ca~ing, flowing line and tubing pre~sures are measured by transducer~ which are periqdically energized by mean~ of power on terminals 214 to produce mea~ured v~lue indi~ations on ter-minals 205t 20~, and 210 which are pas~ed through the operational amplifiers 206~ 20~, and 21L, the analog to digital converter 207, and the peripheral interface adapter 202 to the micropro-cQ~sor 151. With each measurement, the microproce~ or 151 deter-mine~ an ideal tublng pres~ure in accordance with ~e exemplàry algorithm set forth above. In the event that the calculations based upon these measured values exceeds the measured tubing sale~ line preRsure, the ~olenoid driver 220 of motor valve 131 lFIG. 4) is driven to the ~off~ state. If the ~ales line pre~sure i8 qreater than the ideal pres~ure, a ~ignal i8 given by the microproceAsor 151 to open the motor valve 131 by meanR of ~5 solenoid drlver 220.
It can be ~een how from the lllu~tration on optimi~lng well completion of FI~. 4 and the circuitry of FIG. 5, that as the ~ophi~tication of reservoir engineering increaaes to be able to quantify the relationship between one or more of variou~ wells, ~ algorithm~ can be written with which data can be evaluated ~nd ~
decision made ac to which of one or more wells should be placed in what state in order to achieve optimum production from the plurality of wells.
Referring now to FIGS. 8A-8D, there i8 shown a 3chematlc

- 3~ -7~0 dia~ram of the system illuatrated in block form ~n FIG. 6. As can be seen, a clock driver 152 drives a microproce~sor 151 pre-ferably of the CMOS type. Output from the microprocessor 151 on the address bus 156 is provided to the line driver 157 and multlplexed data both into ~nd out of the microproces~or 151 flow~ over the data bus 153. A line driver i9 provided at 150 to move information into and out of the memory 154 which consist~ of a RAM together with a plurality of EPOM storage units. A
demultiplexing latch 158 i~ provided on the data bus to demultiplex the output from the microproce~or 151. The latch 158 is connected to the real time clock 159 vla bus 177 as well as the me~ory 154 and the total ~ystem decoder 200. OUtpUt8 from the system decoder 200 go both the memory 154 as well as to each of the peripherals. The multiplex da~a bus 201 carries data addres~ and control infor~ation among each of the periphe~al unlts such as the real time clock 159, the keyboar~ incoder 245 as well as the fir~t and second peripheral interfac~ adapters 202 and 219.
The analog circuit for use in connection with the measuring o~ actual data in the configuration of FIG. 4 i~ contained in the analog circuit 320. Thi~ comprises terminals 205, 208, and 210 to receive signals from the ca~ing line and tubing pre~sure transducer~ through the operational amplifier~ 206~ 209, ~nd 211 whlch pa~s through an analog to digit~l convexter 207 into tho '78~

per$pheral interface adapter 202. An lnput from th~ battary on term~nals 215 i8 periodically pa~sed through a fleld effect tran-sistor 213 and an analog battery regulator 216 to energize ter-minal 214 and power each of the pres~ure tran~ducer~ to receive value reading therefrom.
A fir~t operational amplifier 203 i~ connected to a voltage dividing network to mea~ure low analog battery condition while a ~econd operational amplifier 204 i~ connected to measure a dead analog battery condition and provide an indication through the analog/digital converter 207 to the peripheral interface adapter 202. Digit~l battery condition i8 mea~ured by network 231 and di~ferential amplifier 232 while dead digital battery condition is detected by network 233 and operational ampli~ier 234 into the peripheral interface adapter 219.
Solenoid driver circuit~ 350 are connected to the perlpheral interface adapter 219 which drives through a one-shot mult~vibra-tor 251 and a solenoid decoder 238 to power a plurality of motor valve sole~oid drivers 221-226. An air pressure failure signal on lead 236a provides an indicat$on to the peripheral interface adapter 219 whlle a plunger arrival signal on terminal 235 provi-des an indication through the flip-flop 236 t~ the peripheral interface adapter 219. In particular~ the circuitry operate~ to provide ~y~tematic operation of the well configuration shown in FIGS. 3 and ~.

~s~

In another aspect, the concept~ of the pre~ent invention can be used to monitor well parameter~ and only allow productlon flow in the event the quality and quantity of output ~ustifiea tho quantity of in~ection ga3 required to produce that flow. For exampla, in an offshore field where a compressor of a given capa-city iq being used to sequentially supply in~ect gas to a plura-lity of ga~ in~ection completions, such as those ~hown in FIG. 1, it is de~irable to utilize the compressor capacity in the most efficient manner. Thus, the broad concept of the present inven-tion includes a controller for linking a plurality of wellR andmeans for monitoring the volume oE in~ection ~as supplied to a well, the volume of production gas obtained, the volume and pro-duction fluid obtained and the percentage of oil/water mlxture of production fluid and determlning over a sample period whether or lS not the production flow obtained ~ustified the quantity of inject gas necessary to obtain that flow. If not, the well i8 shut ~n and the inject gas capacity utilized to produce a different well where a qreater production efficiency i~ pre~ent. The shu~-in well is re-activated periodically and sampled again to re-2~ evaluate whether or not it~ production efficiency has increa~edto a point which would justify resumption of production. Thls approach optimizes the utilization of available production resources to obtain maximum return from a production field.
While particular embodiment~ of the invention have been ~ ~ ~ 5 ~O

described, it i8 obvious that changes and modif ications may be made therein an~ ~till remain with the scope and spirit o the invention. It i8 the intent that the appended claims cover all such change~ and modif ications .

Claims (28)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A system for controlling the cyclic operation of a petroleum producing well having a first motor valve connected between a supply of pressurized gas and the well casing and a second motor valve connected between the tubing of the well and a flow sales line comprising:
selectively programmable memory means;
means for storing in said memory signals indicative of a first time period during which pressurized gas is to be injected into the well casing to clear the well of fluids, a second time period during which flow is to be allowed from the well after the fluids are cleared, and a third time period during which the well is to be shut in;
means responsive to the beginning of a cycle for opening both the first and second motor valves simultaneously and beginning said first time period;
means responsive to the expiration of said first time period for closing said first motor valve and beginning said second time period;
means responsive to expiration of said second time period for closing said second motor valve and beginning said third time period; and
1. Claim 1 continued...
   
   means responsive to expiration of said third time period for re-opening said first and second motor valves simultaneously and beginning said first time period.
2. 2. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 1 wherein said means for storing includes:
   a keyboard connected to said memory and an optical display for selectively programming said memory with said time period values.
3. 3. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 1 wherein the well is a plunger lift completion and includes:
   a plunger mounted for reciprocating movement in the tubing of the well;
   means for sensing when the plunger arrives at its uppermost position in the well tubing; and means responsive to detection of plunger arrival by said plunger sensing means for closing said first motor valve if said first time period has not expired.
4. 4. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 1 which also includes:
   means for measuring the tubing pressure of said well;
   means responsive to the tubing pressure being greater than a pre-selected value during said second time period for extending the length thereof for production flow from the well; and means responsive to the tubing pressure being less than a pre-selected value during said third time period for extending the length thereof and keep the well shut-in,
5. 5. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 2 wherein each of said motor values are operated by a supply of pressurized gas and which includes:
   means responsive to the pressure of said supply gas being below a pre-selected value for closing all motor valves and providing a visual alarm in said optical display.
   
   6. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 1
6. Claim 6 continued....
   
   wherein each of said means for opening and closing motor valves includes:
   processor means;
   peripheral interface adapter means;
   a pair of solenoids connected to operate each motor valve;
   a solenoid decoder connected between said peripheral interface adapter and said solenoids; and data bus means interconnecting the processor with said memory and said peripheral interface adaptor to permit data flow therebetween and enable the processor to control the solenoids based upon time period information stored in the memory.
   
   7. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 1 wherein the system is battery powered and which also includes:
   power save gating circuitry to power down all analog circuit and all digital functions other than timing and memory to conserve power;
   a real time clock; and
7. Claim 7 continued....
   
   means responsive to regular periodic signals from the real time clock or a signal from said keyboard to disable said power save gating circuitry and supply full operating power to the system.
8. 8. A system for controlling the cyclic operation of a gas producing well having a first motor valve connected between the tubing and a fluid reservoir and a second motor valve connected between the tubing and a gas sales line, comprising:
   selectively programmable memory means;
   means for storing in said memory signals indicative of a first time period during which fluids are to be cleared from the well, a second time period within which gas flow is to be allowed from the well after the fluids are cleared from the well and a third time period within which the well is to be shut-in;
   means responsive to the beginning of a cycle for opening said first motor valve and beginning the first time period;
   means responsive to the expiration of said first time period for simultaneously opening said second motor valve and closing said first motor valve and beginning the second time period;
   means responsive to the expiration of said second time period for closing said second motor valve and beginning the third time period; and means responsive to the expiration of said third time period for re-opening said first motor valve and beginning the first time period.
9. 9. A system for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 8 which also includes:
   means responsive to the arrival of a plunger at the uppermost position in the tubing prior to the expiration of said first time period for simultaneously opening said second motor valve and closing said first motor valve and beginning the second time period.
10. 10. A system for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 8 wherein said means for storing includes:
    a keyboard connected to said memory and an optical display for selectively programming said memory with said time period values.
11. 11. A system for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 8 which also includes:
    means for measuring the tubing pressure of said well;
    means responsive to the tubing pressure being greater than a pre-selected value during said second time period for extending the length thereof for producing flow from the well; and means responsive to the tubing pressure being less than a pre-selected value during said third time period for extending the length thereof and keeping the well shut-in.
12. 12. A system for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 10 wherein each of said motor valves are operated by a supply of pressurized gas and which includes:
    means responsive to the pressure of said supply gas being below a pre-selected value for closing all motor valves and providing a visual alarm in said optical display.
13. 13. A system for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 8 wherein each of said means for opening and closing motor valves includes:
    processor means;
    peripheral interface adapter means;
    a pair of solenoids connected to operate each motor valve;
    a solenoid decoder connected between said peripheral interface adaptor and said solenoids; and data bus means interconnecting the processor with said memory and said peripheral interface adaptor to permit data flow therebetween and enable the processor to control the solenoids based upon time period information stored in the memory.
    
    14. A system for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 8 wherein the system is battery powered and which also includes:
    power save gating circuitry to power down analog circuits and all digital functions other than timing and memory to conserve power;
    a real time clock, means responsive to regular periodic signals
14. Claim 14 continued....
    
    from the real time clock or a signal from said keyboard for disabling said power save gating circuitry and supplying full operating power to the system.
    
    15. A method for controlling the cyclic operation of a petroleum producing well having a first motor valve connected between a supply of pressurized gas and the well casing and a second motor valve connected between the tubing of the well and a flow sales line comprising:
    storing in a selectively programmable memory signals indicative of a first time period during which pressurized gas is to be injected into the well casing to clear the well of fluids, a second time period during which flow is to be allowed to flow from the well after the fluids are cleared, and a third time period during which the well is to be shut in;
    simultaneously opening both the first and second motor valves and beginning said first time period in response to the beginning of a cycle;
    closing said first motor valve and beginning said second time period in response to the expiration of said first time period;
15. Claim 15 continued....
    
    closing said second motor valve and beginning said third time period in response to expiration of said second time period; and re-opening said first and second motor valves simultaneously and beginning said first time period in response to expiration of said third time period.
16. 16. A method for controlling the cyclic operation of a petroleum producing well as set forth in claim 15 wherein said storing step includes:
    connecting a keyboard to said memory and to an optical display for selective programming of said memory with said time period values.
    
    17. A method for controlling the cyclic operation of a petroleum producing well as set forth in claim 15 wherein the well is a plunger lift completion and the method includes:
    reciprocating a plunger mounted for movement in the tubing of the well;
    sensing when the plunger arrives at its uppermost position in the well tubing; and
17. Claim 17 continued....
    
    closing said first motor valve in response to sensing plunger arrival if said first time period has not expired.
18. 18. A method for controlling the cyclic operation of a petroleum producing well as set forth in claim 15 which also includes:
    measuring the tubing pressure of said well;
    extending the length of said second time period for production flow from the well in response to the tubing pressure being greater than a pre-selected value during said second time period; and extending the length of said third time period and keeping the well shut-in and in response to the tubing pressure being less than a pre-selected value during said third time period.
    
    19. A method for controlling the cyclic operation of a petroleum producing well as set forth in claim 16 wherein each of said motor valves are operated by a supply of pressurized gas and which includes:
    closing all motor valves and providing visual alarm in said optical display in response to the
19. Claim 19 continued....
    
    pressure of said supply gas being below a pre-selected value.
20. 20. A system for controlling the cyclic operation of a petroleum producing well as set forth in claim 15 wherein each of said steps of opening and closing motor valves includes:
    providing a processor means;
    providing a peripheral interface adaptor means;
    providing a pair of solenoids connected to operate each motor valve;
    providing a solenoid decoder connected between said peripheral interface adaptor and said solenoids;
    and interconnecting the processor with said memory and said peripheral interface adaptor with data bus means causing data flow therebetween and enabling the processor to control the solenoids based upon time period information stored in the memory.
    
    21. A method for controlling the cyclic operation of a petroleum producing well as set forth in claim 16 wherein battery power is used to perform the steps and which method also includes:
21. Claim 21 continued....
    
    providing power save gating circuitry to power down all analog circuits and all digital functions other than timing and memory to conserve power;
    providing a real time clock; and disabling said power save gating circuitry and supplying full operating power to the system in response to regular periodic signals from the real time clock or a signal from said keyboard.
    
    22. A method for controlling the cyclic operation of a plunger lift completion gas producing well having a first motor valve connected between the tubing and a fluid reservoir and a second motor valve connected between the tubing and a gas sales line, comprising:
    storing in a selectively programmable memory signal indicative of a first time period during which fluids are to be cleared from the well, a second time period within which gas flow is to be allowed from the well after the fluids are cleared from the well and a third time period within which the well is to be shut-in;
    opening said first motor valve and beginning the first time period in response to the beginning of a cycle;
22. Claim 22 continued....
    
    simultaneously opening said second motor valve and closing said first motor valve and beginning the second time period in response to the arrival of the plunger at the uppermost position in the tubing;
    closing said second motor valve and beginning the third time period in response to the expiration of second time period; and re-opening said first motor valve and beginning the first time period in response to the expiration of said third time period.
23. 23. A method for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 22 which also includes:
    simultaneously opening said second motor valve and closing said first motor valve and beginning the second time period in response to the expiration of said first time period prior to the arrival of the plunger at the uppermost position in the tubing.
24. 24. A method for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 22 wherein said storing step includes:
    
    Claim 23 continued....
    
    selectively programming said memory with said time period values by connecting a keyboard to said memory and an optical display.
25. 25. A method for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 22 which also includes:
    measuring the tubing pressure of said well;
    extending the length of the second time period for production flow from the well in response to the tubing pressure being greater than a pre-selected value during said second time period; and extending the length of the third time period and keep the well shut-in in response to the tubing pressure being less than a pre-selected value during said third time period.
    
    26. A method for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 24 wherein each of said motor valves are operated by a supply of pressurized gas and which includes:
26. Claim 26 continued....
    
    closing all motor valves and providing a visual alarm in said optical display in response to the pressure of said supply gas being below a pre-selected value.
27. 27. A method for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 22 wherein each of said steps of opening and closing motor valves includes:
    providing a processor means;
    providing a peripheral interface adaptor means;
    providing a pair of solenoids connected to operate each motor valve;
    providing a solenoid decoder connected between said peripheral interface adaptor and said solenoids;
    and interconnecting the processor with said memory and said peripheral interface adaptor by data bus means and causing data flow therebetween to enable the processor to control the solenoids based upon time period information stored in the memory.
28. 28. A method for controlling the cyclic operation of a plunger lift completion gas producing well as set forth in claim 22 wherein the battery power is used to perform the steps and which method also includes:
    providing power save gating circuitry to power down analog circuits and all digital functions other than timing and memory to conserve power;
    providing a real time clock;
    disabling said power save gating circuitry and supplying full operating power to the system in response to regular periodic signals from the real time clock or a signal from said keyboard.