CA1292554C - Automatic liquid level recording device - Google Patents
Automatic liquid level recording deviceInfo
- Publication number
- CA1292554C CA1292554C CA000513985A CA513985A CA1292554C CA 1292554 C CA1292554 C CA 1292554C CA 000513985 A CA000513985 A CA 000513985A CA 513985 A CA513985 A CA 513985A CA 1292554 C CA1292554 C CA 1292554C
- Authority
- CA
- Canada
- Prior art keywords
- well
- liquid surface
- milliamps
- reflections
- memory
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Abstract
AUTOMATIC LIQUID LEVEL RECORDING DEVICE
Abstract of the Invention Apparatus and method for obtaining from a well drilled into the subsurface of the earth the information necessary to determine the location of the liquid surface in same. A source of pressure pulses is coupled to the well surface casing in order that the pulses are transmitted downhole where they are reflected by all surfaces present therein such as, the liquid surface, tubing collars and tubing anchors. A transient pressure trans-ducer is provided which generates an electrical output in response to all reflections of the transmitted pulse. All of the re-flections occurring in the well are recorded for a sufficient amount of time to ensure the recording of the first reflection from the liquid surface present in the well, By processing all of the recorded reflections utilizing known values such as the spacing of the tubing collars in the well, a microprocessor in combination with ROM and RAM discriminates between the liquid surface reflection and other reflections in the well, determines the average pressure pulse velocity in the well and the travel time in the well of the liquid surface reflection.
All such information is stored in memory for further processing to accurately provide the location of the liquid surface in the well.
Abstract of the Invention Apparatus and method for obtaining from a well drilled into the subsurface of the earth the information necessary to determine the location of the liquid surface in same. A source of pressure pulses is coupled to the well surface casing in order that the pulses are transmitted downhole where they are reflected by all surfaces present therein such as, the liquid surface, tubing collars and tubing anchors. A transient pressure trans-ducer is provided which generates an electrical output in response to all reflections of the transmitted pulse. All of the re-flections occurring in the well are recorded for a sufficient amount of time to ensure the recording of the first reflection from the liquid surface present in the well, By processing all of the recorded reflections utilizing known values such as the spacing of the tubing collars in the well, a microprocessor in combination with ROM and RAM discriminates between the liquid surface reflection and other reflections in the well, determines the average pressure pulse velocity in the well and the travel time in the well of the liquid surface reflection.
All such information is stored in memory for further processing to accurately provide the location of the liquid surface in the well.
Description
AUTOMATIC LIQUID LEVEL RECORDING DEVICE
Background of the Invention This invention rela~es to the problem of accurately determining the location of the liquid surface in a well drilled into the sub-surface of the earth. More particularly, this invention relate~ to method and apparatus for economically obtaining the necessary infor-mation from a well which will enable one to accurately and effici-ently determine the location of the liquid surface therein. This accurate determination of the liquid surface enhances greatly the ability of one skilled in the art to analyze well problems and pro-vide curative measures therefor to increase a given well's production capability.
While the prior art has provided various devices and methods to determine the location of the liquid ~urface in a given well all have failed to provide one skilled in the art with an apparatus and technique which substantially eliminates the effects of human error, weather conditions and changing downhole conditions on such determi-nation. Representatives of the previous devices include the Sonolog*
instrument made by the Keystone Development Corporation of Houston, Texas, the Echometer~instrument made by the Echometer Company of Wichita Falls, Texas, and the device described in Mobil Oil Corpo-ration's U.S. Patent No. 4,318,278. Both the Echometer and the Sonolog instrument suffer from the dependence on a field operator to make frequent and multiple calculations and interpretations which provide the opportunity for gros~ error. The~e instruments require * Trade Marks ~k 12~2~;S~
an operator to trigger a pre~sure pulse source, record as a 5, function o~ time the amplitude of pulse reflections in the wellbore annulus on a constant speed chart recorder. These recorded re-flections are analyzed by the operator by counting tubing collars and attempting to choose the location on the chart of the liquid reflection. These devices clearly do not provide for frequent economic, efficient and accurate measurement o the liquid surface over any significant period of time and allow for a great deal of human error.
The device and method described in the aforementioned Mobil patent was an improvement over the Echometer and Sonolog devices but also suffers from many deficiencies which are remedied by the invention of the present application.
First of all, the prior device utilizes a gating means which is responsive to the output of a transient pressure transducer for starting and stopping a counting means. ~hen the gating means de-tects an initiating pressure pulse, it starts the counting meanswhich begins accumulal:ing clock pulses, one for each foot of depthO
The counting means acc~umulates clock pulses untIl stopped ~y the gating means. The gating means stops the counting means when an output from the transient pressure transducer is suffiently large.
~5 The nun~er o~ pulses accumulated in the counting means represents the depth of the liquid surface. Since the gating means is responsive to the amplitude o the output of the transient pressure transducer, ~ny out-put which i8 suiclently large will ~ause the gatlng me~ns to c~
stop the countiny means. There is no test provided to d~termine if the output from the transient pressure transducer is the reflection - ; ~ from the liquid surface. As ~he pressure increases in the well an-nulus, the acoustic ~ransmission properties improve and all the re-flections in the wellbore increase in amplitude. The reflection from a tubing anchor, a large collar or any anomaly may become large enough to prematurely activate the gating means and stop the counting means and cause the accumulated clock pulses to represent a depth other than that of the liquid surfaceO
A second deficiency in the prior device concerns the IlSe of a manually adjustable pulse counter for producing one pulse c~utput for an adjustable number of clock pulse inputs. This manual acljustment is employed to account ~or the pulse velocity in the wall annulus.
The value established by the field operator is one of tria~ and error interpretation. At the beginning of the test, the rate of the pulse counter is established by the field operator, such that the time between succeeding pulses is equal to the time required for sound to travel one foot in the annulus and return to the source Even if the operator does the calibration perfectly, the device will o~ten give erroneous depth information shortly after the well i~
shut-in due to a change in the pulse velocity in the well annulus caused Py i.e., change in pressure, change in gas cons~ituency or a temperature gradient through the annulus.
A third deficiency in the prior device concerns the use o~ a calibrated mute time for gating out the initiating pressure pulse ~29:~iS~
an~ re~lections, thexeby rendering the gating mean~ inoperative fox a known~ adjust~ble p~io~ of time beginning with the initiating ; pre~su~e pulse. If the li~uid level in the wel~ annulus rises to a point that the liquid surface re~lection time becomes less than the mute time, the ~evice may be disa~led for protracted periods o~ ti~ne~
A fourth deficiency in the prior device concerns the use of an adjus~able trigger level to activate the gatin~ means for stopping the counting means. Once the gating means has started the counting means, the counting means will accumulate clock pulses until stopped by the gating means. Since the gating means is responsive to any output from the ~ransient pressure transducer which is grc~ater in l'i amplitude than the adjusted trigger level, when an output from the transient pressu~re transducer is greater in amplitude than the trig- `' ger level the gating means will respond by stopping th~ counting means. In the event a field operator erroneously sets the trigger level, the gating means will fail to respond to the outpu1 o the 2tl transient pressure transducer and result in loss of data.
A fifth deficiency in the prior device concerns the use of digital readout therein which remains at the well site~ The use of digital readout and its attendant support circuitry and the instal-lation thereof in the device merely adds unnecessarily to the over-all cost of ~ame and its use, i.e., power cost and ~he reduction o~the time on the well between battery charges. Further, ~arge heavy-duty batteries are required to operate the device for a sufficient period of time to complete a well test. Safety problems present a _ 4 -~2~2~
concern when loading, unloading, connec~ing and/or charging ~uch 5, batteries as are required to power the device.
~ I A sixth deficiency in the prior device concerns the utili-`' - zation of a single pressure transducer therein. The appropriate pressure transducer is ,determined by the field operator based on 1) maximum surface pressure he expects the well to reach during the test, and 2) what pressure transducers he has available to him at the time. Thus, he must estimate such maximum sur~ace pressure. The transducer may be damaged if the surface pressure during the test exceeds the maximum pressure rating of the transducer the operator chooses to install. If, from his available stock, the field operator chooses an inappropriate transducer the pressure,reading will clearly be less than accurate. Since the surface pressure during a test can ;' ranga from low to high, in order to provide the necessary resolution, different transducers should be utilized as the pressure changes.
This is practically impossible with only one transducer in the device.
A seventh deficiency in the prior device concerns the recording of pressure as a digital count which i5 displayed andfor pr~nted as a digital count. This digital count must be converted to pressure by computation on the part of the field operator creatin~ a situ-ation for human error.
An eighth deficiency in the prior device concerns the necessity of an experienced, skilled field operator to correctly operate the device. The ~ield operator is required,to use judgment and experi~
ence to set up the device correctly and operate switche~ in the -- S ~
s~ :
cor-ect sequence or a large amount of data is lost.
A ninth deficiency in the prior device concerns the fact that the measurement of depth is affected by the energy in the initiating pressure pulse. The reflection of the pressure pulse from the liquid surface does not arrive at the transient pressure transducer as an instantaneous pulse. ~ispersion of the pressure pulse in the well :lO annulus and low pass filtering of the transient pressure transducer -output result in a signal which arises from 0 to its maximum value in fifty to one hundred milliseconds~ The use of a set trigger level in conjunction with the relatively slow rise time can result in re-flection arrival time variations of almost 100 milliseconds which re-presents between 30 to 70 feet. The operator normally attempts to set the adjustable trigger level and acoustic amplifier/gain such that ~ther re~lected pressure pulse from the liquid sur~ace is twic~e the voltage of the trigger level. When a well is shut-in tlle acous1:ic character-istics therein change, i.e., normally the gas becomes more conductive to acoustical energy. Thus, the acoustic energy reflecled by the liquid surface and received by the transient pressure transducer ~e-comes greater and as the transient pressure transducer output in-creases in amplitude, the time required for the signal to reach the trigger level decreases making the liquid surface appear ~hallower than it actually is. Conversely, in the event the aolenoid-operated valve which creates the pressure pulse is slow or sluggish (due to temperature or battery age) the ~esulting pulse can have relatively energy. In the event the reflected pressure pulse from the liquid i5~
i surface is just large enough to trigger the gating means~ the arrival time will be about 50 milliseconds later than it would be if the re-i flec~ed energy were twice as large resulting in the liquid sur~ace appearing deepex than it actually iso A tenth deficiency of the prior device concerns the necessity of having a field operator at the site at all times to adjust the de-vice for changing conditions in the well during a test. Fc~r example,in the absence of the field operator, if the 1) surface pressure in-creases su~ficiently some pressure data will be lost and t~le pressure transducer can be damaged, 2) if the surface pressure decreases suffi-ciently the pressure resolution will become very poort and 3) if acoustic properties change sufficiently all data from that point for-ward will be lost.
Summary of the Invention The above-set forth and other deficiencies of the prior art devices are remedied by the invention of the present application. I
have found that by recording, for a sufficient amount of time to en-sure the recording of liquid surface reflection, all reflections of the pressure pulse, the frequency of which are equal to or less ~han the maximum ex~ected reflected tubing collar frequency one can sub-sequently, from said recordings 1~ discriminate between liquid sur-face and other reflections, 2) determine the average pulse velocityin the well annulus, and 3) determine the travel time of the li~uid suxface reflection in the well, and thereby determine the actual location of the liquid surface in the well.
~Z9255~ j One object of the present invention i8 to provide a new and novel method and ap~aratus for enhancing one' 5 ability to locate the ~ level of the liquid surface in a well drilled through the substrata - , of the earth.
Another object of the present invention is to provide a new and novel method and apparatus for identifying which pressure pulse re-L0 ~lections are from the liquid surface in a well as opposed to theother reflections therein.
It is a further object of the present invention to provide a new and novel method and apparatus for determing the average pressure pulse velocity in a well.
`!5 It is an additional object of the present invention to provide a new and novel~method and apparatus for determining the travel time of liquid surface reflections in a well.
It is yet another object o~ the present invention to provide a new and novel method and apparatus for collecting and rel:aining in-a~o formation from a well necessary to dete~mine the locatioll of theliquid surface therein whereby the effects ~hereon of h~lan error, cnvironmental conditions, and power requirements are reduced to a minimum.
Still another object o~ the present invention is to provide a new and novel apparatus for collecting well data which can retain such and subsequently transmit same to larger and more sophisticated processing equipment ~or analysis.
I~ vet another object o~ the present invention to provide a . ~
`
~ .
lZ92~;5~
new a~d novel apparatus for collecting and retaining well d~t~ fro~
multiple wells which can segregate and identify such multiple well ! , data and transmit same to larger and more sophisticated processing equipment for analysis of all data or each individual well's data.
These and other objects of the present invention will become apparent to those skilled in the art upon the reading of the follow-1(~ ing description of the preferred embodiments hereof.
Description of the Drawin~s Fig. 1 is a block diagram of the apparatus of the present in-vention.
Fig. 2 is a block diagram of an additional aspect of the ap-1!~ paratus of the present invention.
In order for one to utilize the present invention as depicted -~in Fig. 1, there is obviously required a ~ource of pressure pulses for the generation thereof in a well. This invention may utilize the same or a substantially similar source of these pulses and a ~0 wellhead arrangement as depicted and descri~ed in Fig. 1 and Fig. 2 .of U.S. Patent No. 4,318,278. The electrical and mechanicai con-nections between the invention in Fi~. 1 and a suitable ~ellhead arrangement is depicted by lines A, B and C. Line A electrically connects the solenoid valve driver-80 with a solenoid-operated valve o~ the wellhead arrangement. Line B electrically con~ects ampli-fierJ~ilter-70 with the transient pressure transducer of the well-head arrangement. Line C mechanically connects pressure manifold-30 with the wellhead arrangement.
.
~L292~ii5~
Descri tion of the Preferred Emhodiments P ~
;5 In order to better unclerstand both the method and the apparatus : J of the present invention, it is necessary at this time to define . what will hereinafter be termed a "Shot" since ~he ~aking of a Shot in a given well is the basic mechanism which the present invention utilizes to perform its purposes and functionsO Therefore, in the context of the present invention, a Shot consists of the following.
steps:
l) Reading the real time of day, converti~g same to minutes and storing same in memory;
Background of the Invention This invention rela~es to the problem of accurately determining the location of the liquid surface in a well drilled into the sub-surface of the earth. More particularly, this invention relate~ to method and apparatus for economically obtaining the necessary infor-mation from a well which will enable one to accurately and effici-ently determine the location of the liquid surface therein. This accurate determination of the liquid surface enhances greatly the ability of one skilled in the art to analyze well problems and pro-vide curative measures therefor to increase a given well's production capability.
While the prior art has provided various devices and methods to determine the location of the liquid ~urface in a given well all have failed to provide one skilled in the art with an apparatus and technique which substantially eliminates the effects of human error, weather conditions and changing downhole conditions on such determi-nation. Representatives of the previous devices include the Sonolog*
instrument made by the Keystone Development Corporation of Houston, Texas, the Echometer~instrument made by the Echometer Company of Wichita Falls, Texas, and the device described in Mobil Oil Corpo-ration's U.S. Patent No. 4,318,278. Both the Echometer and the Sonolog instrument suffer from the dependence on a field operator to make frequent and multiple calculations and interpretations which provide the opportunity for gros~ error. The~e instruments require * Trade Marks ~k 12~2~;S~
an operator to trigger a pre~sure pulse source, record as a 5, function o~ time the amplitude of pulse reflections in the wellbore annulus on a constant speed chart recorder. These recorded re-flections are analyzed by the operator by counting tubing collars and attempting to choose the location on the chart of the liquid reflection. These devices clearly do not provide for frequent economic, efficient and accurate measurement o the liquid surface over any significant period of time and allow for a great deal of human error.
The device and method described in the aforementioned Mobil patent was an improvement over the Echometer and Sonolog devices but also suffers from many deficiencies which are remedied by the invention of the present application.
First of all, the prior device utilizes a gating means which is responsive to the output of a transient pressure transducer for starting and stopping a counting means. ~hen the gating means de-tects an initiating pressure pulse, it starts the counting meanswhich begins accumulal:ing clock pulses, one for each foot of depthO
The counting means acc~umulates clock pulses untIl stopped ~y the gating means. The gating means stops the counting means when an output from the transient pressure transducer is suffiently large.
~5 The nun~er o~ pulses accumulated in the counting means represents the depth of the liquid surface. Since the gating means is responsive to the amplitude o the output of the transient pressure transducer, ~ny out-put which i8 suiclently large will ~ause the gatlng me~ns to c~
stop the countiny means. There is no test provided to d~termine if the output from the transient pressure transducer is the reflection - ; ~ from the liquid surface. As ~he pressure increases in the well an-nulus, the acoustic ~ransmission properties improve and all the re-flections in the wellbore increase in amplitude. The reflection from a tubing anchor, a large collar or any anomaly may become large enough to prematurely activate the gating means and stop the counting means and cause the accumulated clock pulses to represent a depth other than that of the liquid surfaceO
A second deficiency in the prior device concerns the IlSe of a manually adjustable pulse counter for producing one pulse c~utput for an adjustable number of clock pulse inputs. This manual acljustment is employed to account ~or the pulse velocity in the wall annulus.
The value established by the field operator is one of tria~ and error interpretation. At the beginning of the test, the rate of the pulse counter is established by the field operator, such that the time between succeeding pulses is equal to the time required for sound to travel one foot in the annulus and return to the source Even if the operator does the calibration perfectly, the device will o~ten give erroneous depth information shortly after the well i~
shut-in due to a change in the pulse velocity in the well annulus caused Py i.e., change in pressure, change in gas cons~ituency or a temperature gradient through the annulus.
A third deficiency in the prior device concerns the use o~ a calibrated mute time for gating out the initiating pressure pulse ~29:~iS~
an~ re~lections, thexeby rendering the gating mean~ inoperative fox a known~ adjust~ble p~io~ of time beginning with the initiating ; pre~su~e pulse. If the li~uid level in the wel~ annulus rises to a point that the liquid surface re~lection time becomes less than the mute time, the ~evice may be disa~led for protracted periods o~ ti~ne~
A fourth deficiency in the prior device concerns the use of an adjus~able trigger level to activate the gatin~ means for stopping the counting means. Once the gating means has started the counting means, the counting means will accumulate clock pulses until stopped by the gating means. Since the gating means is responsive to any output from the ~ransient pressure transducer which is grc~ater in l'i amplitude than the adjusted trigger level, when an output from the transient pressu~re transducer is greater in amplitude than the trig- `' ger level the gating means will respond by stopping th~ counting means. In the event a field operator erroneously sets the trigger level, the gating means will fail to respond to the outpu1 o the 2tl transient pressure transducer and result in loss of data.
A fifth deficiency in the prior device concerns the use of digital readout therein which remains at the well site~ The use of digital readout and its attendant support circuitry and the instal-lation thereof in the device merely adds unnecessarily to the over-all cost of ~ame and its use, i.e., power cost and ~he reduction o~the time on the well between battery charges. Further, ~arge heavy-duty batteries are required to operate the device for a sufficient period of time to complete a well test. Safety problems present a _ 4 -~2~2~
concern when loading, unloading, connec~ing and/or charging ~uch 5, batteries as are required to power the device.
~ I A sixth deficiency in the prior device concerns the utili-`' - zation of a single pressure transducer therein. The appropriate pressure transducer is ,determined by the field operator based on 1) maximum surface pressure he expects the well to reach during the test, and 2) what pressure transducers he has available to him at the time. Thus, he must estimate such maximum sur~ace pressure. The transducer may be damaged if the surface pressure during the test exceeds the maximum pressure rating of the transducer the operator chooses to install. If, from his available stock, the field operator chooses an inappropriate transducer the pressure,reading will clearly be less than accurate. Since the surface pressure during a test can ;' ranga from low to high, in order to provide the necessary resolution, different transducers should be utilized as the pressure changes.
This is practically impossible with only one transducer in the device.
A seventh deficiency in the prior device concerns the recording of pressure as a digital count which i5 displayed andfor pr~nted as a digital count. This digital count must be converted to pressure by computation on the part of the field operator creatin~ a situ-ation for human error.
An eighth deficiency in the prior device concerns the necessity of an experienced, skilled field operator to correctly operate the device. The ~ield operator is required,to use judgment and experi~
ence to set up the device correctly and operate switche~ in the -- S ~
s~ :
cor-ect sequence or a large amount of data is lost.
A ninth deficiency in the prior device concerns the fact that the measurement of depth is affected by the energy in the initiating pressure pulse. The reflection of the pressure pulse from the liquid surface does not arrive at the transient pressure transducer as an instantaneous pulse. ~ispersion of the pressure pulse in the well :lO annulus and low pass filtering of the transient pressure transducer -output result in a signal which arises from 0 to its maximum value in fifty to one hundred milliseconds~ The use of a set trigger level in conjunction with the relatively slow rise time can result in re-flection arrival time variations of almost 100 milliseconds which re-presents between 30 to 70 feet. The operator normally attempts to set the adjustable trigger level and acoustic amplifier/gain such that ~ther re~lected pressure pulse from the liquid sur~ace is twic~e the voltage of the trigger level. When a well is shut-in tlle acous1:ic character-istics therein change, i.e., normally the gas becomes more conductive to acoustical energy. Thus, the acoustic energy reflecled by the liquid surface and received by the transient pressure transducer ~e-comes greater and as the transient pressure transducer output in-creases in amplitude, the time required for the signal to reach the trigger level decreases making the liquid surface appear ~hallower than it actually is. Conversely, in the event the aolenoid-operated valve which creates the pressure pulse is slow or sluggish (due to temperature or battery age) the ~esulting pulse can have relatively energy. In the event the reflected pressure pulse from the liquid i5~
i surface is just large enough to trigger the gating means~ the arrival time will be about 50 milliseconds later than it would be if the re-i flec~ed energy were twice as large resulting in the liquid sur~ace appearing deepex than it actually iso A tenth deficiency of the prior device concerns the necessity of having a field operator at the site at all times to adjust the de-vice for changing conditions in the well during a test. Fc~r example,in the absence of the field operator, if the 1) surface pressure in-creases su~ficiently some pressure data will be lost and t~le pressure transducer can be damaged, 2) if the surface pressure decreases suffi-ciently the pressure resolution will become very poort and 3) if acoustic properties change sufficiently all data from that point for-ward will be lost.
Summary of the Invention The above-set forth and other deficiencies of the prior art devices are remedied by the invention of the present application. I
have found that by recording, for a sufficient amount of time to en-sure the recording of liquid surface reflection, all reflections of the pressure pulse, the frequency of which are equal to or less ~han the maximum ex~ected reflected tubing collar frequency one can sub-sequently, from said recordings 1~ discriminate between liquid sur-face and other reflections, 2) determine the average pulse velocityin the well annulus, and 3) determine the travel time of the li~uid suxface reflection in the well, and thereby determine the actual location of the liquid surface in the well.
~Z9255~ j One object of the present invention i8 to provide a new and novel method and ap~aratus for enhancing one' 5 ability to locate the ~ level of the liquid surface in a well drilled through the substrata - , of the earth.
Another object of the present invention is to provide a new and novel method and apparatus for identifying which pressure pulse re-L0 ~lections are from the liquid surface in a well as opposed to theother reflections therein.
It is a further object of the present invention to provide a new and novel method and apparatus for determing the average pressure pulse velocity in a well.
`!5 It is an additional object of the present invention to provide a new and novel~method and apparatus for determining the travel time of liquid surface reflections in a well.
It is yet another object o~ the present invention to provide a new and novel method and apparatus for collecting and rel:aining in-a~o formation from a well necessary to dete~mine the locatioll of theliquid surface therein whereby the effects ~hereon of h~lan error, cnvironmental conditions, and power requirements are reduced to a minimum.
Still another object o~ the present invention is to provide a new and novel apparatus for collecting well data which can retain such and subsequently transmit same to larger and more sophisticated processing equipment ~or analysis.
I~ vet another object o~ the present invention to provide a . ~
`
~ .
lZ92~;5~
new a~d novel apparatus for collecting and retaining well d~t~ fro~
multiple wells which can segregate and identify such multiple well ! , data and transmit same to larger and more sophisticated processing equipment for analysis of all data or each individual well's data.
These and other objects of the present invention will become apparent to those skilled in the art upon the reading of the follow-1(~ ing description of the preferred embodiments hereof.
Description of the Drawin~s Fig. 1 is a block diagram of the apparatus of the present in-vention.
Fig. 2 is a block diagram of an additional aspect of the ap-1!~ paratus of the present invention.
In order for one to utilize the present invention as depicted -~in Fig. 1, there is obviously required a ~ource of pressure pulses for the generation thereof in a well. This invention may utilize the same or a substantially similar source of these pulses and a ~0 wellhead arrangement as depicted and descri~ed in Fig. 1 and Fig. 2 .of U.S. Patent No. 4,318,278. The electrical and mechanicai con-nections between the invention in Fi~. 1 and a suitable ~ellhead arrangement is depicted by lines A, B and C. Line A electrically connects the solenoid valve driver-80 with a solenoid-operated valve o~ the wellhead arrangement. Line B electrically con~ects ampli-fierJ~ilter-70 with the transient pressure transducer of the well-head arrangement. Line C mechanically connects pressure manifold-30 with the wellhead arrangement.
.
~L292~ii5~
Descri tion of the Preferred Emhodiments P ~
;5 In order to better unclerstand both the method and the apparatus : J of the present invention, it is necessary at this time to define . what will hereinafter be termed a "Shot" since ~he ~aking of a Shot in a given well is the basic mechanism which the present invention utilizes to perform its purposes and functionsO Therefore, in the context of the present invention, a Shot consists of the following.
steps:
l) Reading the real time of day, converti~g same to minutes and storing same in memory;
2) Reading surface pressure, determining 1:he ~5 range of pressure and storing same in me ry;
3~ Utilizing the gun arrangement, creatin~ a pressure pulse in the well, 4) Digitiæing and storing all re~lections in the well created by the pressure pulse;
5) Determining and storing in memory a nun~er which represents the frequency of collar re:-flections at about 2.0-second intervals for about 16.0 seconds; and 6) Determining and storing in memory a nu~er which represents the time required ~or the pressure pulse to travel down the well, rèflect off the liquid surface and return to the ~urface.
The present invention takes Shots either manually or auto , .
~2~2S5~
matically and ~oes ~hrough the same series of steps in ei~her mode to collect and retain information.
Referring now ~o Fig. 1 and the previously defined steps in a Shot, the present invention operates as follows:
Step 1: Microprocessor-10 as directed by program memory-22 reads the time of day from real time cloc~-20 and converts same to minutes and stores this time in ~ata memory-28.
Step 2: Microprocessor-10 as directed by memory-22 selects via voltage input multiplexer-60 an appropriate pressure transducer-32 from pressure manifold-30 in order that the voltage from the selected tranducer-32 is applied to analog to digital converter-50;
next, microprocessor-10 as direc~ed by memory-22 causes converter-50 to create a nu~er representing said applied voltage; nex~ micro- ~
processor-10 as directed by mem~ry-22 appends a number representing the pressure range of the selected transducer-32 to said created voltage number and stores same in memory-28.
Step 3: Microprocessor-10 as directed by memory-22 causes solenoid valve driver-80 to actuate the solenoid valve of tlie gun arrangment permitting entry of the pressure pulse into the well.
Step 4: Microprocessor-10 as directed by memory-22 selects Yia multip~exer-60, the voltage output of variable gain amplifier/filtex-70 for application to converter-50.
Next, ~icroprocessor-10 as directed by memory-22 configures clock-20 to create an interrupting pulse 1,024 time~ a second.
-~zs~
Next, micro~roces~or-10 a~ directed by memory-22 acc~pts external interrupts from clock-20.
! I Next, mi~roprocessor-10 as directe~ by memory-22 wait~
for an inter~upti~ pulse from clock-20 and upon the receipt of such an interrupting pulse microprocessor-10 as directed by memory-22 creates a number which represents the instantaneous voltage applied to the input of converter-50 from amplifier/filter-70 via multi-plexer-60.
Next, microproce;sor-10 as directed by memory-22 ~tores said instantaneous voltage numoer in echo memory-26. Subsequently-received interrupting pulses are digitized in the same manner and stored contiguously for a period of time which is sufficien~ to record the reflection from the liquid surface in the well~
Step 5: Microprocessor-10 as directed by memory-22 selects via multiplexer-60 the output of collar frequency processor-40 and directs same to convert:er-50.
Next, microprocessor-10 as directed by memory-22 con figures divide by N counter-90 to supply processor-40 with a fre-quency that processor-40 will process.
Next, microprocessor-10 as directed by memory-2~ re-trieves from memory-26 the instantaneous voltage numbers stored in Step 4 and provide~ said retrieved numbers to converter-50 Be-quentially beginning with the first of said numbers stored for 2,048 numbers, thereby reproducing at the input of processor-40 the in-sta~aneous voltages applied to the input o~ converter-50;in Step 4.
.. . ....
.
2~;i4 Processor-40 accumulates charge proportional ~o the energy at the 5 input of processor-40 only at the frequency supplied by counter-90.
~, Next, microprocessor-10 as directed by memory-22 con-verts the voltage at the input o~ converter-50 ~rom processor-40 via multiplexer-60 to a number representing the voltage and stores same in general purpose memory-24.
For a total of 256 times, Step 5 is repeated wherein each subsPquent time counter-90 supplies processor-40 with a fre-quency that is higher than the previously supplied frequency, there-by storing a total of 256 numbe:rs in memory-24.
Next, microprocess,or-10 as directed by memory-22 searches memory-24 for the location of the largest number out of the stored 256 and ~tores the locat:ion of said largest number in memory-28.
- All o~ the forego:ing in Step 5 is conducted sev~n mora . times~ each of said s~ven times utilizing the subsequent 2,048 numbe~s stored in memory-26 in ',tep 4.
Step 6: Uicroprocessor-10 as directed by memory-22 retrieves each o~ the largest numbers stored in memory-28 in Step S (t~iose numbers represent the collar ~requency of the instantaneous voltage echos stored as numbers in m~mory-26 in Step 4) and computes an ~5 average value o~ the largest numbers (this average value represent~
an average pressure pulse velocity throughout the wellbore)~
Next, microprocessor-10 as directed by memory-22 utilizing said average pressure pul~e velocity number computes the 9Z~S~
average collar frequency in the wellboreO The reciprocal of this computed freguency is the time between the collar reflection~ re-J corded in memory-26. Utilizing this time value, microprocessor 10 as directed by memory-22 computes the number of echo locations stored in memory-26 representing that time value by multiplying that time value by 1,024.
The present invention takes Shots either manually or auto , .
~2~2S5~
matically and ~oes ~hrough the same series of steps in ei~her mode to collect and retain information.
Referring now ~o Fig. 1 and the previously defined steps in a Shot, the present invention operates as follows:
Step 1: Microprocessor-10 as directed by program memory-22 reads the time of day from real time cloc~-20 and converts same to minutes and stores this time in ~ata memory-28.
Step 2: Microprocessor-10 as directed by memory-22 selects via voltage input multiplexer-60 an appropriate pressure transducer-32 from pressure manifold-30 in order that the voltage from the selected tranducer-32 is applied to analog to digital converter-50;
next, microprocessor-10 as direc~ed by memory-22 causes converter-50 to create a nu~er representing said applied voltage; nex~ micro- ~
processor-10 as directed by mem~ry-22 appends a number representing the pressure range of the selected transducer-32 to said created voltage number and stores same in memory-28.
Step 3: Microprocessor-10 as directed by memory-22 causes solenoid valve driver-80 to actuate the solenoid valve of tlie gun arrangment permitting entry of the pressure pulse into the well.
Step 4: Microprocessor-10 as directed by memory-22 selects Yia multip~exer-60, the voltage output of variable gain amplifier/filtex-70 for application to converter-50.
Next, ~icroprocessor-10 as directed by memory-22 configures clock-20 to create an interrupting pulse 1,024 time~ a second.
-~zs~
Next, micro~roces~or-10 a~ directed by memory-22 acc~pts external interrupts from clock-20.
! I Next, mi~roprocessor-10 as directe~ by memory-22 wait~
for an inter~upti~ pulse from clock-20 and upon the receipt of such an interrupting pulse microprocessor-10 as directed by memory-22 creates a number which represents the instantaneous voltage applied to the input of converter-50 from amplifier/filter-70 via multi-plexer-60.
Next, microproce;sor-10 as directed by memory-22 ~tores said instantaneous voltage numoer in echo memory-26. Subsequently-received interrupting pulses are digitized in the same manner and stored contiguously for a period of time which is sufficien~ to record the reflection from the liquid surface in the well~
Step 5: Microprocessor-10 as directed by memory-22 selects via multiplexer-60 the output of collar frequency processor-40 and directs same to convert:er-50.
Next, microprocessor-10 as directed by memory-22 con figures divide by N counter-90 to supply processor-40 with a fre-quency that processor-40 will process.
Next, microprocessor-10 as directed by memory-2~ re-trieves from memory-26 the instantaneous voltage numbers stored in Step 4 and provide~ said retrieved numbers to converter-50 Be-quentially beginning with the first of said numbers stored for 2,048 numbers, thereby reproducing at the input of processor-40 the in-sta~aneous voltages applied to the input o~ converter-50;in Step 4.
.. . ....
.
2~;i4 Processor-40 accumulates charge proportional ~o the energy at the 5 input of processor-40 only at the frequency supplied by counter-90.
~, Next, microprocessor-10 as directed by memory-22 con-verts the voltage at the input o~ converter-50 ~rom processor-40 via multiplexer-60 to a number representing the voltage and stores same in general purpose memory-24.
For a total of 256 times, Step 5 is repeated wherein each subsPquent time counter-90 supplies processor-40 with a fre-quency that is higher than the previously supplied frequency, there-by storing a total of 256 numbe:rs in memory-24.
Next, microprocess,or-10 as directed by memory-22 searches memory-24 for the location of the largest number out of the stored 256 and ~tores the locat:ion of said largest number in memory-28.
- All o~ the forego:ing in Step 5 is conducted sev~n mora . times~ each of said s~ven times utilizing the subsequent 2,048 numbe~s stored in memory-26 in ',tep 4.
Step 6: Uicroprocessor-10 as directed by memory-22 retrieves each o~ the largest numbers stored in memory-28 in Step S (t~iose numbers represent the collar ~requency of the instantaneous voltage echos stored as numbers in m~mory-26 in Step 4) and computes an ~5 average value o~ the largest numbers (this average value represent~
an average pressure pulse velocity throughout the wellbore)~
Next, microprocessor-10 as directed by memory-22 utilizing said average pressure pul~e velocity number computes the 9Z~S~
average collar frequency in the wellboreO The reciprocal of this computed freguency is the time between the collar reflection~ re-J corded in memory-26. Utilizing this time value, microprocessor 10 as directed by memory-22 computes the number of echo locations stored in memory-26 representing that time value by multiplying that time value by 1,024.
7 10 Next, microprocessor-10 as directed by memory-22 averages the previously computed number of echo locations in memory-26 and stores this average value in memory-24~ This process is repeated sequentially until all the average values obtainabl~ are stored in memory-24. These average values stored in memory-24 represent the energy content of all reflections from the wellbore caused by the pressure pulse at frequencies below the collar re-~lection frequency.
Next, microprocessor-10 as directed by memory-22 de-termines the location of the largest of the average values stored in memory-24 and multiplies said location by the number of locations avexaged to obtain the general location in memory-26 of the liquid level reflection.
Next, microprocessor-10 as directed by memory-22 retrieves from said general location in memory-26 the location of the large~t number with the correct polarity. Utilizing ~his re-trieved location as the ~tarting point, microprocessor-10 compute3 the location in memory-26 where the li~uid level reflection begin~
One way o~ performing thi~ computation compri~es ~tarting at~said 129~S54 retrieved location and reading values of decreasing depth until the first location containing a value of zero or opposite polarity to ! ~ that of said retrieved location is determinedO
Next, microprocessor-10 as directed by memory-22 stores in memory-28 the location in memory-26 where the liquid level reflection begins. This stored value represents the travel time from the earth's surface to the liquid surface in the well. By dividing this stored value by 2,048 ~he travel time dow~ to the liquid su~fac~ is con~erted to ~econd~.
If one desires to retrieve well inormation stored in the ap-paratus depicted in Fig. 1 without physically removing the apparatu~
from a well site, then one suitable way is to utilize the apparatus ..~
of Fig. 2 to retrieve same for further analysis. Referring now to Fig. 1 (Well Sounder unit hereinafter "WS") and Fig. 2 (Technician Interface Module unit hereina~ter "TIM'i), in order to transmit stored infoxmation from WS to TIM obviously microprocessors-10 in both TIM and WS must have established protocol. Physically TIM and WS are connected via WS serial port-12 and TIM serial port-30. Pre-ferably, both these ports have low power requirements. The basic interaction between the two units comprises the following steps;
Step 1: Communication is established between TIM microproce~-sor-10 and WS mlcroprocessor-10 via WS serial port-12 and $IM seria~
port-30, a~ directed by TIM program memory-22 and WS program memory-22.
Step 2: WS microprocessor-10 as directed by WS memory-22 a~k~
~IM microprocessor-10 as directed by TI~ memory-22, what data TIM
wan~s to re~ri~ve. TIM can obtain from WS all data present in WS
data memory-28 or specific da~a ~herein as identified by the time of day taken by WS. Whate~er data is requested it is ~ransmitted from WS memory-28 to TIM memory-28.
Step 3: TIM microprocessor-10 as directed by TIM memory-22 1 10 can transmit any or all data in T:~M memory-28 via TIM port-30 to other processing facilities.
It should be noted that the trIM unit is capable of being directed by a computer terminal to print or plot the data in TIM
memory-28 to allow an operator to obtain physical evidence of said data.
Referring again to Fig. 1, sllitable hardware for an emhodïment `. 3 of the present invention is as fol'lows:
1) WS Processor-10: consists of a microprocessor IC (integrated circuit) and associated memory ICs and IO (Input/Output) intexface ICs. The interface circuits consist of multiplexers, buffers, - latches, and decoding logi~ to a~]ow the microprocessor outputs to select a required memory o~ IO dç~ice and receive from the device ox send to the device, pertinent values. ~n particula~ the ~ultiplexer~
are (integrated circuit) l-of-8 Data Selector/Multiplexers. Any o~
~S the 8 outputs o~ the multiplexer used to select a memory will select one and only one memory IC, either RAM or ROM, except the memory in the highest memory address space will bç de-selected if the addres~
to be acces~ed is within 256 of the highest po~ible memory addres~.
l ~
~ ~2~2~;S~
I
tT~e la5t 256 addresses are reserved for th~ Real Time Clock-203.
S ~ny o~ the outputs of the multiplexer used to select an input device selects only one input device. Any of the outputs of the multiplexer used to select an ou~u~ device selects on~y oneou~ut device.
Buffers and latches are used to isolate the microprocessor's data ¦and IO busses from the memory and IO devices.
¦ 1 102) WS Program Memory-22: consists of industry standard Read Only Memory (ROM) or Erasable Programable Read Only Memory (EPROM)~
This memory contains the program ~dhich is executed by the WS Pro-cessor-10 during operation. It also contains all universal and n~chine dependent constants. This memory employs 64K EPROMs 15organized as 8192 words by 8 bits. Preferably, the generic type ~7C64 CM~S EPROMS are utilized for this memory.
, 3) WS General Purpo~e Memory-24: consists of industry standard ~andom Access Memory (RAM). This memory is used to hold numerical ~variables, temporary constants (those pertaining to only one well) 'and as common memory for passing values between routines in Memory-22.
This memory employs 64K R~Ms organized as 8192 words by 8 bits~ Pre-~rabl~, the generic type 6264LP CMOS RAMs are utilized for thi~
memory.
4) WS Echo Memory-26: consists of industry-standard ~andom ~S Access Memory (RAM). Thi~ memory is u~ed to store values which represent the instantaneous voltages which are generated by echos ~rom the well as a result of an initi~a~ ~ressure pulse. Thi~ memory employs 64K RAMs organized as 8192 words by 8 bits. Preferably, the generic type 6264LP CMOS RAMs are utilized for this memoryO
Z55~
6~ WS Real Time ~lock-20: consists of an IC clock and associ-! 5 ated components required to create a clock circuit with independent ! ~ Jtime-base and power supply. The real time clock keeps time in years, date, day of the week, hours, ~inutes and seconds. It contains a provision for setting the time of day when it will interrupt the WS Processor-10. It also has a provision for interrupting the WS
10Processor-10 at regular intervals of as li~tle as 122~07 microseconds This clock is interfaced to the WS Processor-10 such that ~t appears to occupy the last 256 addresses of the WS Processor-10 address space. Preferably, this clock is generic type 6818 Real Time Clock IC.
157) WS Serial Port-12: cQnsists o~ a serial communic~tion Ir (UART, U~ART or ACIA), baud rate ~ener~to~ c~xcuit, and ~S~232-C com-patible input/output circuits. The sexial communication IC ~ an IO
device wh~ch converts an output ~ro~ the microprocessor to a sexial commun~cation output and a ser~.~l communicat~on ~nput to micropro-cessor-compatible input. The baud rate generator is a ~requency div~der with a selectable div~s:~`on ~actor. The output ~s a fre-quency applied to the clock inpnt o~ the serial communication IC to allow rates of 75 to 9600 baud. The RS~232-C compatible input and output circuits are voltage leve~l translators. The ~erial communi-cation IC is of the gener;c type 6850 As~nchronous Com~unicationInterface Adapter (ACIA). This type IC is less versatile than a Universal Asynchronous Receiver Tr~nsm~tter (UART) or a Universal Synchronous/Asynchronous Recelver Transmitter (USART~ but an ~CIA
~2s~2s~
requires less circuit ~oard space, simpler interfacing, less soft-S ware and less power. Preferably, the serial comrnunication IC is a ; i, Hitachi type HD63A50 or HD63B50 ACIA. This is a CMOS device and ! ` thus re~uires less power t~an the generic e~uivalent 6850. The baud rate generator is implemented with ~wo divide by 16 counter ICs. One counter has a modified count such that its outpu~ frequency is usable as the clock inpu~ to the ACIA and second counter. The second count~r divides the output of ~he first by 2, 4, 8 and 16 each of which may also be applied to tpe ACIA clock input. The RS-232-C
compatible output circuit is a t~o-transistor circuit with an outpu~
which is inverted relative to it~ input and has voltage levels which are positive and negative while the input voltage levels are alway8 positive or 0. The RS-232-C input circuit employs a single inverter/
buffer, o~ a hex inverter/~uffer IC, and two resistors, one for current limiting and one as a 0 ~oltage reference.
~ 8) Solenoid Valve Drive-80: consists of transistor voltage level txanslators which drive the inputs of high current transistors or darlington connected transistor Elairs. A high current transistor or darlin~ton pair, when activated through its voltage level translator, ~upplys current, at the battery voltage, to the solenoid of a solenoid valve.
9) Variable Gain Amplifier/Filtex-70: consists of 4 subcircuit8 (1) an input preamp; (2) a 25HZ low pass filter; (3) an intermediate amplifier state; and (4) a digitally-controlled gain ~lock. The pre-amp is o~ the charge integrating type. It has input sur~e voltage ,J
~L~g~SS~
protection, and a logarithmic gain response~ Gain is supplied by an IC operation amplifier and associated dsscre~e componentsO The 25H~
; low pass filter is of the elliptic or inverse-hyperbolic type, im-plemented using an active-filter design. The design uses operational amplifier ICs, resistors and capacitors. The intermediate amplifier consists of an operational amplifier IC, 2 resistors and an output decoupling capacitor. The digitally control].ed gain block consists o a 10-bit digital to analog converter, and IC operational amplifier and the various resistors required to implement this proprietary design.
10) Voltage Input Multiplexer-60: a 1-of-8 analog multiplexer, such as an industry standard CD4051. It is one of the output devices . ~
controlled by the WS Processor-10. This device allows WS Processor- j 10 to select any of various voltage sources to be converted from a voltage to a representative digital value.
11) Pressure Manifold-30~ connected, through appropriate plumb-ing, to the surface of a well for the purpo;e o distxibuting thesurface pressure to several pressure transdllcers.
12) Pressure Transducers-32: devices which convert surface pressu~e to a voltage proportional to the pressure. ~ach of the transd~cexs operates over a limited range ~f pressuresO No two ~5 transducers have the same operating range. All pressure transducer~
are connected to the surface casing pressure of a well through a manifold arxangemen~O Individual pressure transducers ara ~elected by the Processor-100 as directed by Memory-22 ~ 29 ~ S S ~
13) Divide-by-N Counter-90: divides a fixea input frequancy by ;5 a divisor supplied by the WS Processor-10, as directed by Me~ory-22.
The output (frequency) of an extended range divide by N counter is applied to the input of an 8-stage binary coun~r with each of its 8 outputs available. The extended range Divide-by-N Counter is an output device of the WS Processor-10. W.S. Processor-10 supplies values from 0 to 255 to the extended range divide-by-N Counter which, in response, divides its input frequency by 128 to 383. The extended range divide-by-N Counter is implemented using two 4-bit divided-by-N Counter ICs, and associated gating and switching logic ICs as required.
14) Collar Frequency Processor-40: a set of digitally controlled, primaxily analog circuits. The circuits are: ta) a digitally con-trolled band pass filter; preferably the digitally controlled band pass filter is an N-path filter, with N=16. This filter employs 1 of 8 analog multiplexer ICs, and descrete components, resistors and capacitors; (b) a circuit which collects energy which passes',through the filter; a polarity independent charge integxating circuit, employing IC operational amplifiers, collects the charge on the N-path filter capacitors and converts the charge to a voltage pro-portional to the charge; (c) digitally controlled analog switching 2S circuits ~or applying a voltage, which represents the energy passe~
by the ~ilter to the Multiplexer-60. This voltage is then digitized by the WS Processor-10 through the Analog-to Digital Converter; the analog switching circuits, made of l-of-4 analog multiplexer~, .
~ ~9 ~ 55 ~ J
under the control of the WS Processor-10, selec~ively; discharge the filter capacitors, discharge ~he ch~rge-integrating capacitor, connec~s the charge-integrating capacitor to an operational ampli-; fier for charge to voltage conversion. ~his voltage is applied toMultiplexer-60 so it may be converted to a representative digital value and stored by the WS Processor-10 in Memory-~4. Inputs to this Processor are: ta) an analog representation of well echos supplied by the WS Processor-10, from Memory-26, thxough Converter-50; (b) comparison ~requencies supplied by t~e WS Processor-10 through Counter-90; and (c) digital inputs from the WS Processor-10 to control the analog switching circuits.
15) Digital to Analog/~nalog to Digital Converter-50: consist~
of a 10-bit digi~tal to analog converter (DACj IC, a buffer/ampli~ier employing an operational amplifier IC and a voltage comparator/level translator emp~oying an operational amplifiex ICo The digital in-puts to the DAC are supplied by WS Processor-10. The output of the DAC is applied to the input of the buffer/am~lifier. Inputs to the comparator/level translator are from the output of the buffer/ampli-fier and a volta~e (to be converted) source through Multipl~xer-60.
Analo~ to Digital conversion is accomplished by successive approximation as follows:
~S The WS Processor-10, as directed by Memory-22, supplies a 10-bi~ digital value to the 10-bit DAC. The resulting voltage output o the DACs buffer/amplifier is applied to one input of the comparator/level translator for ~z~s~
comparison with the voltage being a~plied through Multiplexer-60 to the other input of ths comparator/
', level translator. The WS Processor-10, as directed i by Memory-22, tests the output of the comparator/level translator each time it supplies a new value to the DAC.
A decision is made, based on the binary value out of the comparator/level translator, whether to use or disregard the last value supplied t~ the DAC. Used values are added together to yie~d a number which represents the voltage applied.
The above hardware and requisite software form an Analog to Digital Converter. Preferably, the 10-bit DAC is an Analog Device ~ype AD7533LN. Preferably, the operational ampli~iers are Analog Device type AD542LH.
Referring again to Fig. 2, suitable hardware for an embodiment of the present invention is as follows:
1) TIM Processor-10: consists of a microprocessor IC (integrated circuit) and associated memory ICs and IO (Input/Output) interface ICs. The interface circuits consist of multiplexers, buffers, latches, and decoding logic to allow the microproce~sor QUtpUt8 to seleat a required memory or IO device and receive from the device or send to the device pertinent values. In particular ~he multiplexers are (Integrated Circuit) 1-o~-8 Data Selector/Multiplexers. Any of the 8 outputs o~ the multiplexer used to select a memory will ~alect one and only one memory IC, either RAM or ROM. ~ny of the output~
:L292SS~
of the multiplexer used to select an input device seleots only one S input device. Any of ~he outputs of the multiplexer used to selec~
; an o~put device selects only one ou~ut device. Buffers and latches are used to isolate the microprocessor~s data and IO busses from the memory and IO devices.
2) TIM Program Memory-22: consis~s of in~ustry~standard Read Only Memory (ROM) or Erasable Programable Read Only Memory (EPROM).
This ~emo~y contains the program which is exe,_uted by the TIM Pro-cessor-10 during operation. It also contains all universal and machine-dependent constants. This memory empLoys 64K EPROMs organized as 8192 words by 8 bits. Preferablf the generic type 27C64 CMOS EPROMS are utilized for this memor~.
3) TIM Data~Memory-28: consists o~ industry-standard Random Access Memory (RAM). This memory is used to ;store data which are generated for each time-dependent measurement; i.e., time, transit time to the liquid, surace pressure value, pressure pulse velocity values, etc, This memory is used also to hold parameters of each well for which data is being stored. This memory is used also to hold temporary numerical and character valuesO This memory emplo~s 64K
RAMs organized as 8192 words by 8 bits. Prefera~ly, the generic type 6264LP CMOS RAMs are utilized for this memory.
4) TIM Serial Port-30: Consists o~ a serial communication ICs (UART, USART or ACIA), a baud rate generator circuit and RS-;232-C
¢ompatibl~ input/output aircuits. The ~erial aommu~ication IC is an IO device which converts an outpuk from the TIM Processor-10 to a - ~4 -s~ ~
- serial communica~ion output and a serial communication input to a 5 TIM Processor-10 compatible input. The baud rate generator is a ! frequency divider wi~h a selectable division factor. The output i~
a requency applied to the clock input of the serial communication IC to allow rates of 75 to 9600 baud. The RS-232-C com~atible in-put and outpUt circuits are voltage level translators, The serial communication ICs are of the generic type 6~50 Asynchronous Com-munication Interface Adaptor (~CI~). This type IC is less versa-tile than a Universal Asynchronous ~eceiver q'ransmitter (UART) or a Universal Synchronous/Asynchronous Receiver Transmitter (USART) but an ACIA requires less circuit boardspace, simpler interfacing, less so~tware and less power. Preferably, the serial communication IC
is Hitachi type HD63A50 or HD63B50 ~CIA. This is a CMOS device and thus requires less power than the ~eneri~: equivalent 6850. The baud rate generator is implemented with two ~livide by 16 counter ICs. One counter has a modified count such 1:hat i~s output fre-quency is usable as the clock input to the ACI~ and second counter.The second counter divides the output of the first by 2, 4, 8 and 16 each of which may also be applied to the i~CIA clo~k input. The RS-232-C compatible output circuit/s is a two-transistor circuit with an output which is inverted xelative to its input and ha~
voltage levels which are positive and negative while the input voltage levels are always positive and negative while the input voltage levels are always positive or 0. The RS-~32-C input circuit employs a single inverter/buffer, of a hex inverter/buffer IC, and ~ - 25 -lZ53'h~54 two .resistors, on~ for current limiting and one as a 0 voltage S refe~ence.
In another embodiment of ~he present invention, after a field technician establishes communication with the WS unit via a port,able computer terminal via the TIM unit and informs the WS unit a new test is beginning, the WS unit will operate automatically. In such an automatic operation the WS unit will repetitively 1) determine well surface pressure and store it in memory~
~) determine the e~apsed time since the test began and store it in memory, 3) initiate a pressure pulse in the well annulus, 4) "record all reflections from the well for a period of up to 32 seconds, 53 determine the pressiure pulse ve~ocity in the well at approximately 1000-foot intervals and store these pulse velocities in memory, 6) determine the transit time to the liquid surface and store the transit time in memory, 7) determine the transit time to a known feature, and store it in memory (which aids in accurate depth determination), and 8) set an alarm in its internal clock so that the well sounding unit can be informed when it is time to repeat the sequence o~ steps.
~9;2~
As a result of the utilization of this invention, the previ-S ously set forth de~iciencies o~ prior ar~ devices are substantially eliminated. Specifically, the present invention eliminates the need for a gating means the use of a manually-adjusted pulse counter, and the ef~ect on the depth measurement by the energy in initiating pulse. This is accomplished by having a recording means responsive 1~ to the output o~ transient pressure transducer, by recording all re~lections from the well annulus for a suffi~ient period of time to allow the liquid surface reflection to be recorded and by analyzing the recorded reflections with a compu~er and l~omputer program and/
or analog/digital hard~are; it is possible ~o discriminate between the liquid surface reflection and othel well anomalies as well as to determine the pulse velocity for each initiated pressure pulse and determine at what point in time the re~lected signal began to move from its zero or baseline value toward the peak which has been identi-fied as the li~uid surface reflection signal.
Further the present invention eliminates the use of calibrated mute time for gating out the initiating pressure pulse and reflection by employing an amplifier responsive to the cutput of transient pressure transducer having its gain controlled by a computer. The computer can set the gain to a predetermined low level prior to initiating the pressure pulse so that the initial impact o~ ~he pulse is no greater than the smaller reflected pulses.
In addition the present invention eliminates the use of an adjustable trigger level to activate gating means ~or stopping ~2~S~
countinq, by employiny an amplifier responsive to the output o~ a S transient pressure transducer having its gain controlled by a ! computer so that the effect of large repetitive reflections, ~uch as those from shallow collars, are compensated for.
Further, the present invention provides a readout unit which is capable o~ displaying numbers, letters and symbols in a separate unit which can su~port several WS units, theceby greatly reducing the cost per unit.
An additional feature of the present invention concerns the use of several pressure transducers which are selectable by the built-in computer, thereby enabling the appropriate pressure transducer for lS the existin~ surface pressure to be utilized.
Further, the present invention is capable of recording the pressure as a fraction of full scale pressure plus a pressure con-version factor, thereby converting the recorded value lnto pounds per square inch before being displayed or printed.
~0 A ~urther ~eature of the present invent:ion concerns the elimi-nation o~ the need ~or a skilled, experienced field operator. The present invention has no set-up/calibra~ion procedure, it requests information from the operator, has automatic gain control, automatic velocity measuring capability, it is not sensitive to trigger ampli-2S tude and does not require a fixed sequence of events that need to be remembered by the operator, thus allowing him to concentrate on efficiency rather than memory apout what to do next.
Power requirements in one embodiment of the present invention are significantly 1e~s than in known device~ of thi~ typc. In ordor to func~ion in it~ stand-by mode the microproce3sor u~ zed re-quires no more than 4 milliamps, in its operatin~ mode it require~
no mo~e than ~S milliamps. The Read Only Memory utilized herein re~ es no more than ~ millia~ps to function. The Ra~dom Access Memory utilized herein in its operatin~ mode requires ~o more than 40 milliamps and in its stand-by mode, no more than .002 milliamps.
These relatively low power requirements enable one to utilize a sn~t~
non-hazardous battery making charging very simple. By greatly re-ducing power requirements, both the WS and TIM units of the present inventiol~ can be F,ackaged in briefcase-size containers for ease i~
lS transportation to well sites.
While this invention has been set forth by a variety of embodt ments, it is not ~;o limited and many variations thereof will be ap-parent to one skilled in the art without departing from the true spirit and scope of this invention. It should ~e understood that 20. this invention is not necessarily limited to the above-set forth disoussion.
- 2g - .
Next, microprocessor-10 as directed by memory-22 de-termines the location of the largest of the average values stored in memory-24 and multiplies said location by the number of locations avexaged to obtain the general location in memory-26 of the liquid level reflection.
Next, microprocessor-10 as directed by memory-22 retrieves from said general location in memory-26 the location of the large~t number with the correct polarity. Utilizing ~his re-trieved location as the ~tarting point, microprocessor-10 compute3 the location in memory-26 where the li~uid level reflection begin~
One way o~ performing thi~ computation compri~es ~tarting at~said 129~S54 retrieved location and reading values of decreasing depth until the first location containing a value of zero or opposite polarity to ! ~ that of said retrieved location is determinedO
Next, microprocessor-10 as directed by memory-22 stores in memory-28 the location in memory-26 where the liquid level reflection begins. This stored value represents the travel time from the earth's surface to the liquid surface in the well. By dividing this stored value by 2,048 ~he travel time dow~ to the liquid su~fac~ is con~erted to ~econd~.
If one desires to retrieve well inormation stored in the ap-paratus depicted in Fig. 1 without physically removing the apparatu~
from a well site, then one suitable way is to utilize the apparatus ..~
of Fig. 2 to retrieve same for further analysis. Referring now to Fig. 1 (Well Sounder unit hereinafter "WS") and Fig. 2 (Technician Interface Module unit hereina~ter "TIM'i), in order to transmit stored infoxmation from WS to TIM obviously microprocessors-10 in both TIM and WS must have established protocol. Physically TIM and WS are connected via WS serial port-12 and TIM serial port-30. Pre-ferably, both these ports have low power requirements. The basic interaction between the two units comprises the following steps;
Step 1: Communication is established between TIM microproce~-sor-10 and WS mlcroprocessor-10 via WS serial port-12 and $IM seria~
port-30, a~ directed by TIM program memory-22 and WS program memory-22.
Step 2: WS microprocessor-10 as directed by WS memory-22 a~k~
~IM microprocessor-10 as directed by TI~ memory-22, what data TIM
wan~s to re~ri~ve. TIM can obtain from WS all data present in WS
data memory-28 or specific da~a ~herein as identified by the time of day taken by WS. Whate~er data is requested it is ~ransmitted from WS memory-28 to TIM memory-28.
Step 3: TIM microprocessor-10 as directed by TIM memory-22 1 10 can transmit any or all data in T:~M memory-28 via TIM port-30 to other processing facilities.
It should be noted that the trIM unit is capable of being directed by a computer terminal to print or plot the data in TIM
memory-28 to allow an operator to obtain physical evidence of said data.
Referring again to Fig. 1, sllitable hardware for an emhodïment `. 3 of the present invention is as fol'lows:
1) WS Processor-10: consists of a microprocessor IC (integrated circuit) and associated memory ICs and IO (Input/Output) intexface ICs. The interface circuits consist of multiplexers, buffers, - latches, and decoding logi~ to a~]ow the microprocessor outputs to select a required memory o~ IO dç~ice and receive from the device ox send to the device, pertinent values. ~n particula~ the ~ultiplexer~
are (integrated circuit) l-of-8 Data Selector/Multiplexers. Any o~
~S the 8 outputs o~ the multiplexer used to select a memory will select one and only one memory IC, either RAM or ROM, except the memory in the highest memory address space will bç de-selected if the addres~
to be acces~ed is within 256 of the highest po~ible memory addres~.
l ~
~ ~2~2~;S~
I
tT~e la5t 256 addresses are reserved for th~ Real Time Clock-203.
S ~ny o~ the outputs of the multiplexer used to select an input device selects only one input device. Any of the outputs of the multiplexer used to select an ou~u~ device selects on~y oneou~ut device.
Buffers and latches are used to isolate the microprocessor's data ¦and IO busses from the memory and IO devices.
¦ 1 102) WS Program Memory-22: consists of industry standard Read Only Memory (ROM) or Erasable Programable Read Only Memory (EPROM)~
This memory contains the program ~dhich is executed by the WS Pro-cessor-10 during operation. It also contains all universal and n~chine dependent constants. This memory employs 64K EPROMs 15organized as 8192 words by 8 bits. Preferably, the generic type ~7C64 CM~S EPROMS are utilized for this memory.
, 3) WS General Purpo~e Memory-24: consists of industry standard ~andom Access Memory (RAM). This memory is used to hold numerical ~variables, temporary constants (those pertaining to only one well) 'and as common memory for passing values between routines in Memory-22.
This memory employs 64K R~Ms organized as 8192 words by 8 bits~ Pre-~rabl~, the generic type 6264LP CMOS RAMs are utilized for thi~
memory.
4) WS Echo Memory-26: consists of industry-standard ~andom ~S Access Memory (RAM). Thi~ memory is u~ed to store values which represent the instantaneous voltages which are generated by echos ~rom the well as a result of an initi~a~ ~ressure pulse. Thi~ memory employs 64K RAMs organized as 8192 words by 8 bits. Preferably, the generic type 6264LP CMOS RAMs are utilized for this memoryO
Z55~
6~ WS Real Time ~lock-20: consists of an IC clock and associ-! 5 ated components required to create a clock circuit with independent ! ~ Jtime-base and power supply. The real time clock keeps time in years, date, day of the week, hours, ~inutes and seconds. It contains a provision for setting the time of day when it will interrupt the WS Processor-10. It also has a provision for interrupting the WS
10Processor-10 at regular intervals of as li~tle as 122~07 microseconds This clock is interfaced to the WS Processor-10 such that ~t appears to occupy the last 256 addresses of the WS Processor-10 address space. Preferably, this clock is generic type 6818 Real Time Clock IC.
157) WS Serial Port-12: cQnsists o~ a serial communic~tion Ir (UART, U~ART or ACIA), baud rate ~ener~to~ c~xcuit, and ~S~232-C com-patible input/output circuits. The sexial communication IC ~ an IO
device wh~ch converts an output ~ro~ the microprocessor to a sexial commun~cation output and a ser~.~l communicat~on ~nput to micropro-cessor-compatible input. The baud rate generator is a ~requency div~der with a selectable div~s:~`on ~actor. The output ~s a fre-quency applied to the clock inpnt o~ the serial communication IC to allow rates of 75 to 9600 baud. The RS~232-C compatible input and output circuits are voltage leve~l translators. The ~erial communi-cation IC is of the gener;c type 6850 As~nchronous Com~unicationInterface Adapter (ACIA). This type IC is less versatile than a Universal Asynchronous Receiver Tr~nsm~tter (UART) or a Universal Synchronous/Asynchronous Recelver Transmitter (USART~ but an ~CIA
~2s~2s~
requires less circuit ~oard space, simpler interfacing, less soft-S ware and less power. Preferably, the serial comrnunication IC is a ; i, Hitachi type HD63A50 or HD63B50 ACIA. This is a CMOS device and ! ` thus re~uires less power t~an the generic e~uivalent 6850. The baud rate generator is implemented with ~wo divide by 16 counter ICs. One counter has a modified count such that its outpu~ frequency is usable as the clock inpu~ to the ACIA and second counter. The second count~r divides the output of ~he first by 2, 4, 8 and 16 each of which may also be applied to tpe ACIA clock input. The RS-232-C
compatible output circuit is a t~o-transistor circuit with an outpu~
which is inverted relative to it~ input and has voltage levels which are positive and negative while the input voltage levels are alway8 positive or 0. The RS-232-C input circuit employs a single inverter/
buffer, o~ a hex inverter/~uffer IC, and two resistors, one for current limiting and one as a 0 ~oltage reference.
~ 8) Solenoid Valve Drive-80: consists of transistor voltage level txanslators which drive the inputs of high current transistors or darlington connected transistor Elairs. A high current transistor or darlin~ton pair, when activated through its voltage level translator, ~upplys current, at the battery voltage, to the solenoid of a solenoid valve.
9) Variable Gain Amplifier/Filtex-70: consists of 4 subcircuit8 (1) an input preamp; (2) a 25HZ low pass filter; (3) an intermediate amplifier state; and (4) a digitally-controlled gain ~lock. The pre-amp is o~ the charge integrating type. It has input sur~e voltage ,J
~L~g~SS~
protection, and a logarithmic gain response~ Gain is supplied by an IC operation amplifier and associated dsscre~e componentsO The 25H~
; low pass filter is of the elliptic or inverse-hyperbolic type, im-plemented using an active-filter design. The design uses operational amplifier ICs, resistors and capacitors. The intermediate amplifier consists of an operational amplifier IC, 2 resistors and an output decoupling capacitor. The digitally control].ed gain block consists o a 10-bit digital to analog converter, and IC operational amplifier and the various resistors required to implement this proprietary design.
10) Voltage Input Multiplexer-60: a 1-of-8 analog multiplexer, such as an industry standard CD4051. It is one of the output devices . ~
controlled by the WS Processor-10. This device allows WS Processor- j 10 to select any of various voltage sources to be converted from a voltage to a representative digital value.
11) Pressure Manifold-30~ connected, through appropriate plumb-ing, to the surface of a well for the purpo;e o distxibuting thesurface pressure to several pressure transdllcers.
12) Pressure Transducers-32: devices which convert surface pressu~e to a voltage proportional to the pressure. ~ach of the transd~cexs operates over a limited range ~f pressuresO No two ~5 transducers have the same operating range. All pressure transducer~
are connected to the surface casing pressure of a well through a manifold arxangemen~O Individual pressure transducers ara ~elected by the Processor-100 as directed by Memory-22 ~ 29 ~ S S ~
13) Divide-by-N Counter-90: divides a fixea input frequancy by ;5 a divisor supplied by the WS Processor-10, as directed by Me~ory-22.
The output (frequency) of an extended range divide by N counter is applied to the input of an 8-stage binary coun~r with each of its 8 outputs available. The extended range Divide-by-N Counter is an output device of the WS Processor-10. W.S. Processor-10 supplies values from 0 to 255 to the extended range divide-by-N Counter which, in response, divides its input frequency by 128 to 383. The extended range divide-by-N Counter is implemented using two 4-bit divided-by-N Counter ICs, and associated gating and switching logic ICs as required.
14) Collar Frequency Processor-40: a set of digitally controlled, primaxily analog circuits. The circuits are: ta) a digitally con-trolled band pass filter; preferably the digitally controlled band pass filter is an N-path filter, with N=16. This filter employs 1 of 8 analog multiplexer ICs, and descrete components, resistors and capacitors; (b) a circuit which collects energy which passes',through the filter; a polarity independent charge integxating circuit, employing IC operational amplifiers, collects the charge on the N-path filter capacitors and converts the charge to a voltage pro-portional to the charge; (c) digitally controlled analog switching 2S circuits ~or applying a voltage, which represents the energy passe~
by the ~ilter to the Multiplexer-60. This voltage is then digitized by the WS Processor-10 through the Analog-to Digital Converter; the analog switching circuits, made of l-of-4 analog multiplexer~, .
~ ~9 ~ 55 ~ J
under the control of the WS Processor-10, selec~ively; discharge the filter capacitors, discharge ~he ch~rge-integrating capacitor, connec~s the charge-integrating capacitor to an operational ampli-; fier for charge to voltage conversion. ~his voltage is applied toMultiplexer-60 so it may be converted to a representative digital value and stored by the WS Processor-10 in Memory-~4. Inputs to this Processor are: ta) an analog representation of well echos supplied by the WS Processor-10, from Memory-26, thxough Converter-50; (b) comparison ~requencies supplied by t~e WS Processor-10 through Counter-90; and (c) digital inputs from the WS Processor-10 to control the analog switching circuits.
15) Digital to Analog/~nalog to Digital Converter-50: consist~
of a 10-bit digi~tal to analog converter (DACj IC, a buffer/ampli~ier employing an operational amplifier IC and a voltage comparator/level translator emp~oying an operational amplifiex ICo The digital in-puts to the DAC are supplied by WS Processor-10. The output of the DAC is applied to the input of the buffer/am~lifier. Inputs to the comparator/level translator are from the output of the buffer/ampli-fier and a volta~e (to be converted) source through Multipl~xer-60.
Analo~ to Digital conversion is accomplished by successive approximation as follows:
~S The WS Processor-10, as directed by Memory-22, supplies a 10-bi~ digital value to the 10-bit DAC. The resulting voltage output o the DACs buffer/amplifier is applied to one input of the comparator/level translator for ~z~s~
comparison with the voltage being a~plied through Multiplexer-60 to the other input of ths comparator/
', level translator. The WS Processor-10, as directed i by Memory-22, tests the output of the comparator/level translator each time it supplies a new value to the DAC.
A decision is made, based on the binary value out of the comparator/level translator, whether to use or disregard the last value supplied t~ the DAC. Used values are added together to yie~d a number which represents the voltage applied.
The above hardware and requisite software form an Analog to Digital Converter. Preferably, the 10-bit DAC is an Analog Device ~ype AD7533LN. Preferably, the operational ampli~iers are Analog Device type AD542LH.
Referring again to Fig. 2, suitable hardware for an embodiment of the present invention is as follows:
1) TIM Processor-10: consists of a microprocessor IC (integrated circuit) and associated memory ICs and IO (Input/Output) interface ICs. The interface circuits consist of multiplexers, buffers, latches, and decoding logic to allow the microproce~sor QUtpUt8 to seleat a required memory or IO device and receive from the device or send to the device pertinent values. In particular ~he multiplexers are (Integrated Circuit) 1-o~-8 Data Selector/Multiplexers. Any of the 8 outputs o~ the multiplexer used to select a memory will ~alect one and only one memory IC, either RAM or ROM. ~ny of the output~
:L292SS~
of the multiplexer used to select an input device seleots only one S input device. Any of ~he outputs of the multiplexer used to selec~
; an o~put device selects only one ou~ut device. Buffers and latches are used to isolate the microprocessor~s data and IO busses from the memory and IO devices.
2) TIM Program Memory-22: consis~s of in~ustry~standard Read Only Memory (ROM) or Erasable Programable Read Only Memory (EPROM).
This ~emo~y contains the program which is exe,_uted by the TIM Pro-cessor-10 during operation. It also contains all universal and machine-dependent constants. This memory empLoys 64K EPROMs organized as 8192 words by 8 bits. Preferablf the generic type 27C64 CMOS EPROMS are utilized for this memor~.
3) TIM Data~Memory-28: consists o~ industry-standard Random Access Memory (RAM). This memory is used to ;store data which are generated for each time-dependent measurement; i.e., time, transit time to the liquid, surace pressure value, pressure pulse velocity values, etc, This memory is used also to hold parameters of each well for which data is being stored. This memory is used also to hold temporary numerical and character valuesO This memory emplo~s 64K
RAMs organized as 8192 words by 8 bits. Prefera~ly, the generic type 6264LP CMOS RAMs are utilized for this memory.
4) TIM Serial Port-30: Consists o~ a serial communication ICs (UART, USART or ACIA), a baud rate generator circuit and RS-;232-C
¢ompatibl~ input/output aircuits. The ~erial aommu~ication IC is an IO device which converts an outpuk from the TIM Processor-10 to a - ~4 -s~ ~
- serial communica~ion output and a serial communication input to a 5 TIM Processor-10 compatible input. The baud rate generator is a ! frequency divider wi~h a selectable division factor. The output i~
a requency applied to the clock input of the serial communication IC to allow rates of 75 to 9600 baud. The RS-232-C com~atible in-put and outpUt circuits are voltage level translators, The serial communication ICs are of the generic type 6~50 Asynchronous Com-munication Interface Adaptor (~CI~). This type IC is less versa-tile than a Universal Asynchronous ~eceiver q'ransmitter (UART) or a Universal Synchronous/Asynchronous Receiver Transmitter (USART) but an ACIA requires less circuit boardspace, simpler interfacing, less so~tware and less power. Preferably, the serial communication IC
is Hitachi type HD63A50 or HD63B50 ~CIA. This is a CMOS device and thus requires less power than the ~eneri~: equivalent 6850. The baud rate generator is implemented with two ~livide by 16 counter ICs. One counter has a modified count such 1:hat i~s output fre-quency is usable as the clock input to the ACI~ and second counter.The second counter divides the output of the first by 2, 4, 8 and 16 each of which may also be applied to the i~CIA clo~k input. The RS-232-C compatible output circuit/s is a two-transistor circuit with an output which is inverted xelative to its input and ha~
voltage levels which are positive and negative while the input voltage levels are always positive and negative while the input voltage levels are always positive or 0. The RS-~32-C input circuit employs a single inverter/buffer, of a hex inverter/buffer IC, and ~ - 25 -lZ53'h~54 two .resistors, on~ for current limiting and one as a 0 voltage S refe~ence.
In another embodiment of ~he present invention, after a field technician establishes communication with the WS unit via a port,able computer terminal via the TIM unit and informs the WS unit a new test is beginning, the WS unit will operate automatically. In such an automatic operation the WS unit will repetitively 1) determine well surface pressure and store it in memory~
~) determine the e~apsed time since the test began and store it in memory, 3) initiate a pressure pulse in the well annulus, 4) "record all reflections from the well for a period of up to 32 seconds, 53 determine the pressiure pulse ve~ocity in the well at approximately 1000-foot intervals and store these pulse velocities in memory, 6) determine the transit time to the liquid surface and store the transit time in memory, 7) determine the transit time to a known feature, and store it in memory (which aids in accurate depth determination), and 8) set an alarm in its internal clock so that the well sounding unit can be informed when it is time to repeat the sequence o~ steps.
~9;2~
As a result of the utilization of this invention, the previ-S ously set forth de~iciencies o~ prior ar~ devices are substantially eliminated. Specifically, the present invention eliminates the need for a gating means the use of a manually-adjusted pulse counter, and the ef~ect on the depth measurement by the energy in initiating pulse. This is accomplished by having a recording means responsive 1~ to the output o~ transient pressure transducer, by recording all re~lections from the well annulus for a suffi~ient period of time to allow the liquid surface reflection to be recorded and by analyzing the recorded reflections with a compu~er and l~omputer program and/
or analog/digital hard~are; it is possible ~o discriminate between the liquid surface reflection and othel well anomalies as well as to determine the pulse velocity for each initiated pressure pulse and determine at what point in time the re~lected signal began to move from its zero or baseline value toward the peak which has been identi-fied as the li~uid surface reflection signal.
Further the present invention eliminates the use of calibrated mute time for gating out the initiating pressure pulse and reflection by employing an amplifier responsive to the cutput of transient pressure transducer having its gain controlled by a computer. The computer can set the gain to a predetermined low level prior to initiating the pressure pulse so that the initial impact o~ ~he pulse is no greater than the smaller reflected pulses.
In addition the present invention eliminates the use of an adjustable trigger level to activate gating means ~or stopping ~2~S~
countinq, by employiny an amplifier responsive to the output o~ a S transient pressure transducer having its gain controlled by a ! computer so that the effect of large repetitive reflections, ~uch as those from shallow collars, are compensated for.
Further, the present invention provides a readout unit which is capable o~ displaying numbers, letters and symbols in a separate unit which can su~port several WS units, theceby greatly reducing the cost per unit.
An additional feature of the present invention concerns the use of several pressure transducers which are selectable by the built-in computer, thereby enabling the appropriate pressure transducer for lS the existin~ surface pressure to be utilized.
Further, the present invention is capable of recording the pressure as a fraction of full scale pressure plus a pressure con-version factor, thereby converting the recorded value lnto pounds per square inch before being displayed or printed.
~0 A ~urther ~eature of the present invent:ion concerns the elimi-nation o~ the need ~or a skilled, experienced field operator. The present invention has no set-up/calibra~ion procedure, it requests information from the operator, has automatic gain control, automatic velocity measuring capability, it is not sensitive to trigger ampli-2S tude and does not require a fixed sequence of events that need to be remembered by the operator, thus allowing him to concentrate on efficiency rather than memory apout what to do next.
Power requirements in one embodiment of the present invention are significantly 1e~s than in known device~ of thi~ typc. In ordor to func~ion in it~ stand-by mode the microproce3sor u~ zed re-quires no more than 4 milliamps, in its operatin~ mode it require~
no mo~e than ~S milliamps. The Read Only Memory utilized herein re~ es no more than ~ millia~ps to function. The Ra~dom Access Memory utilized herein in its operatin~ mode requires ~o more than 40 milliamps and in its stand-by mode, no more than .002 milliamps.
These relatively low power requirements enable one to utilize a sn~t~
non-hazardous battery making charging very simple. By greatly re-ducing power requirements, both the WS and TIM units of the present inventiol~ can be F,ackaged in briefcase-size containers for ease i~
lS transportation to well sites.
While this invention has been set forth by a variety of embodt ments, it is not ~;o limited and many variations thereof will be ap-parent to one skilled in the art without departing from the true spirit and scope of this invention. It should ~e understood that 20. this invention is not necessarily limited to the above-set forth disoussion.
- 2g - .
Claims (29)
1. Apparatus for collecting and retaining information from a well drilled through the substrata of the earth in order to determine the location of the liquid surface in said well which comprises:
a. a source of pressure pulses coupled to said well;
b. a transient pressure transducer coupled to said well which generates an electrical output in response to the downhole reflection of pressure pulses produced by said source;
c. means responsive to the output of said transducer for recording all of said reflections; which comprises a microprocessor in communication with ROM and RAM which by comparing the relative energy levels integrating the values of said recorded reflections in said RAM determines the set of recorded reflecting values with the largest relative, energy level which represents the liquid surface reflection;
d. means operably connected to said recording means for discriminating between liquid surface reflection and other reflections in said well;
e. further means operably connected to said discriminating means for determining the average pressure pulse velocity in said well;
f. an additional means operably connected to said discriminating means for determining the travel time in said well of said liquid surface reflections; and g. an additional means operably connected to said discriminating and determining means for retaining all of said information obtained by said means.
a. a source of pressure pulses coupled to said well;
b. a transient pressure transducer coupled to said well which generates an electrical output in response to the downhole reflection of pressure pulses produced by said source;
c. means responsive to the output of said transducer for recording all of said reflections; which comprises a microprocessor in communication with ROM and RAM which by comparing the relative energy levels integrating the values of said recorded reflections in said RAM determines the set of recorded reflecting values with the largest relative, energy level which represents the liquid surface reflection;
d. means operably connected to said recording means for discriminating between liquid surface reflection and other reflections in said well;
e. further means operably connected to said discriminating means for determining the average pressure pulse velocity in said well;
f. an additional means operably connected to said discriminating means for determining the travel time in said well of said liquid surface reflections; and g. an additional means operably connected to said discriminating and determining means for retaining all of said information obtained by said means.
2. Apparatus as in claim 1 which includes additional means operably connected to said retainage means which comprises:
a. means for collecting the information from said retainage means;
b. means for retaining said collected information; and c. means for transmitting said collected information to further means for the analysis of same.
a. means for collecting the information from said retainage means;
b. means for retaining said collected information; and c. means for transmitting said collected information to further means for the analysis of same.
3. Apparatus as in claim 2 which includes means for generating print-outs of said collected information.
4. Apparatus as in claim 1 wherein said recording means comprises:
a. an amplifier;
b. a filter operably connected to said amplifier;
c. an analog to digital convertor responsive to the output of said filter; and d. a microprocessor which reads the output of said converter and stores same in RAM.
a. an amplifier;
b. a filter operably connected to said amplifier;
c. an analog to digital convertor responsive to the output of said filter; and d. a microprocessor which reads the output of said converter and stores same in RAM.
5. Apparatus as in claim 4 which includes an analog switch responsive to the output of said filter.
6. Apparatus as in claim 1 wherein said micro-processor functions in its stand-by mode with no more than 4 milliamps.
7. Apparatus as in claim 1 wherein said micro-processor functions in its operating mode with no more than 15 milliamps.
8. Apparatus as in claim 1 wherein said ROM
functions with no more than 8 milliamps.
functions with no more than 8 milliamps.
9. Apparatus as in claim 1 wherein said RAM
functions in its operating mode with no more than 40 milliamps.
functions in its operating mode with no more than 40 milliamps.
10. Apparatus as in claim 1 wherin said RAM functions in its stand-by mode with no more than 0.002 milliamps.
11. Apparatus as in claim 1 wherein said velocity determination means comprises:
a. a microprocessor in communication with ROM
and RAM which computes the frequency of the recorded collar reflections utilizing values from said RAM by executing instructions from said ROM.
a. a microprocessor in communication with ROM
and RAM which computes the frequency of the recorded collar reflections utilizing values from said RAM by executing instructions from said ROM.
12. Apparatus as in claim 11 wherein said micro-processor functions in its operating mode with no more than 4 milliamps.
13. Apparatus as in claim 11 wherein said micro-processor functions in its operating mode with no more than 15 milliamps.
14. Apparatus as in claim 11 wherein said ROM
functions with no more than 8 milliamps.
functions with no more than 8 milliamps.
15. Apparatus as in claim 11 wherein said RAM
functions in its operating mode with no more than 40 milliamps.
functions in its operating mode with no more than 40 milliamps.
16. Apparatus as in claim 11 wherein said RAM
functions in its stand-by mode with no more than 0.002 milliamps.
functions in its stand-by mode with no more than 0.002 milliamps.
17. Apparatus as in claim 1 wherein said travel time determination means comprises:
a. a microprocessor in communication with ROM
and RAM which computes the time between a recorded star of a pressure pulse and the recorded reflection of said liquid surface utilizing values from said RAM by executing instructions from said ROM.
a. a microprocessor in communication with ROM
and RAM which computes the time between a recorded star of a pressure pulse and the recorded reflection of said liquid surface utilizing values from said RAM by executing instructions from said ROM.
18. Apparatus as in claim 17 wherein said micro-processor functions in its stand-by mode with no more than 4 milliamps.
19. Apparatus as in claim 17 wherein said micro-processor functions in its operating mode with no more than 15 milliamps.
20. Apparatus as in claim 17 wherein said ROM
functions with no more than 8 milliamps.
functions with no more than 8 milliamps.
21. Apparatus as in claim 17 wherein said RAM
functions in its operating mode with no more than 40 milliamps.
functions in its operating mode with no more than 40 milliamps.
22. Apparatus as in claim 17 wherein said RAM
functions in its stand-by mode with no more than 0.002 milliamps.
functions in its stand-by mode with no more than 0.002 milliamps.
23. A method for collecting and retaining information from a well drilled through a the substrata of the earth in order to determine the location of the liquid surface in said well comprising the steps of:
a. repetitively generating pressure pulses in said well to produce reflections thereof over a period of time;
b. recording all of said reflections for a sufficient amount of time to ensure the recording of liquid surface reflection; and c. processing said recorded reflection to (1) discriminate between the liquid surface reflection and other reflections; by digitizing and comparing the relative energy levels of all reflections to locate the recorded reflection with the largest relative energy level which represent the liquid surface reflection;
(2) determine the average pressure pulse velocity; and (3) determine travel time of said liquid surface reflection.
a. repetitively generating pressure pulses in said well to produce reflections thereof over a period of time;
b. recording all of said reflections for a sufficient amount of time to ensure the recording of liquid surface reflection; and c. processing said recorded reflection to (1) discriminate between the liquid surface reflection and other reflections; by digitizing and comparing the relative energy levels of all reflections to locate the recorded reflection with the largest relative energy level which represent the liquid surface reflection;
(2) determine the average pressure pulse velocity; and (3) determine travel time of said liquid surface reflection.
24. Method of claim 23 wherein said pulses are generated in an annulus between the casing and a tubing string of said well.
25. Method of claim 24 wherein said pulses are generated one every minute or less for a period of no less than 30 minutes from shut-in of said well.
26. Method of claim 23 wherein said sufficient time is amount necessary to record the first reflection from said liquid surface.
27. Method of claim 23 wherein said average pressure pulse velocity determination comprises computing the frequency of the recorded collar reflections and integrating said frequency with the known average tubing collar spacing in said well.
28. Method of claim 23 wherein said travel time determination comprises computing the time between the start of a recorded pressure pulse and its recorded reflection from said liquid surface.
29. Method of claim 23 wherein said processed recorded reflections have a frequency which is equal to or less than the maximum reflected tubing collar frequency.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US82994586A | 1986-02-18 | 1986-02-18 | |
| US829,945 | 1986-02-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1292554C true CA1292554C (en) | 1991-11-26 |
Family
ID=25255969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000513985A Expired - Lifetime CA1292554C (en) | 1986-02-18 | 1986-07-17 | Automatic liquid level recording device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1292554C (en) |
-
1986
- 1986-07-17 CA CA000513985A patent/CA1292554C/en not_active Expired - Lifetime
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