METHOD FOR CONDUCTING WELL TESTING OPERATIONS WITH NITROGEN LIFTING, PRODUCTION LOGGING, AND BUILDUP TESTING ON SINGLE COILED TUBING RUN

A method for performing a pressure buildup test in an evaluation zone of a well includes the steps of perforating the well in the evaluation zone to allow the flow of hydrocarbon fluids from the reservoir, deploying a pressure buildup test system into the evaluation zone, supplying the lift fluid via the coiled tubing to lift the hydrostatic pressure to lift the hydrocarbon fluids from the evaluation zone toward the surface, moving the packer to the set position, monitoring the pressure data in the evaluation zone, closing the shut-in valve when the stable state of the pressure data is reached, and measuring a buildup pressure in the evaluation zone using the pressure monitoring device. The pressure buildup test system includes a packer, a sub port, a coiled tubing, a shut-in valve, a pressure monitoring device, and a PLT.

TECHNICAL FIELD

Described are methods and apparatus for performing pressure buildup testing in a well. More specifically, provided are methods and apparatus for performing pressure buildup testing in a well using a nitrogen lift.

BACKGROUND

Currently three coiled tubing runs are required to perform one well test operation during the exploration phase. The first coiled tubing run is to run coiled tubing into the wellbore to lift the well with nitrogen (N2) prior to installing pressure gauges on the wireline. The second coiled tubing (“CT”) run again lifts the well with N2just before the well shut-in period for the pressure buildup test. The third coiled tubing run is for the purpose of pumping a heavy kill fluid into the well after the well test operation is complete.

Coiled tubing insertions are generally required for the purpose of evaluating unconventional and tight gas zones. Unconventional and tight gas zones are typically quite deep so, if there is heavy fluid in the well, they do not flow unless the hydrostatic pressure is “lifted” by pumping nitrogen into the well. With a lower hydrostatic pressure, the zones can flow and the flow can be measured and tested.

When a zone of interest is found, it is required to do a pressure buildup test. The current practice is to lift a zone of interest with nitrogen, then stop to pull the coiled tubing out of the well to deploy pressure gauges and the shut-in valve into the well, then run coiled tubing to lift the well again to apply the drawdown needed for the pressure buildup test, then at the conclusion of the test the gauges must be retrieved from the well. Important pressure data is lost between the well's flowing state and the time when pressure gauges are installed up to 24 hours later. A technical solution is needed to allow for the recording of the early pressure buildup data of the zone to better understand the reservoir quality.

Zones of interest in unconventional and tight gas zones generally require nitrogen lifting before they can be logged and evaluated. Currently, when a zone of interest is identified in a well, the buildup test equipment has to be run downhole separately after a coiled tubing run to lift the well with nitrogen. The buildup test equipment includes pressure gauges and a shut-in tool run by slickline to the surface. The well needs to be lifted for a second time after installing gauges and a shut-in (SI) tool on the slickline. The pressure gauges record pressure over time. The SI tool closes after a set period of time expires allowing the pressure in the well to build up. The SI can be activated on a timer or from the surface. The pressure gauges then record the pressure buildup. The buildup rate can be used to evaluate the productivity of a zone of interest.

SUMMARY

Described are methods and apparatus for performing pressure buildup testing in a well. More specifically, provided are methods and apparatus for performing pressure buildup testing in a well using multiple well nitrogen lifting steps and zonal isolations of areas of interest in one CT run.

In one aspect, a method for performing a pressure buildup test in an evaluation zone of a well is provided. The method includes the steps of perforating a casing of the well in the evaluation zone, where perforating the casing is operable to allow the flow of hydrocarbon fluids from the reservoir to the evaluation zone, deploying a pressure buildup test system into the evaluation zone of the well. The pressure buildup test system is configured to measure pressure in the evaluation zone. The pressure buildup test system includes a packer configured to isolate the evaluation zone when in a set position and configured to create an annulus between the casing of the well and the pressure buildup test system in a retracted position, a sub port configured to deliver a lift fluid to the evaluation zone, a coiled tubing configured to deliver the lift fluid from the surface to the sub port, where the pressure buildup test system is deployed by the coiled tubing. The coiled tubing includes a cable configured to transmit electronic signals to a surface control system from the pressure buildup test system. The pressure buildup test system further includes a shut-in valve configured to control the flow of hydrocarbon fluids from the evaluation zone to a well space at a distance above the packer, a pressure monitoring device configured to measure pressure data in the evaluation zone and transmit the pressure data to the surface control system through the cable, and a PLT configured to measure flow from the evaluation zone through the shut-in valve to the well space above the packer. The method further includes the steps of supplying the lift fluid via the coiled tubing to lift the hydrostatic pressure of the evaluation zone, where lifting the hydrostatic pressure is operable to lift the hydrocarbon fluids in the evaluation zone through the annulus between the packer and the casing toward the surface, moving the packer to the set position, where in the set position the packer contacts the casing of the well such that the hydrocarbon fluids in the evaluation zone flow through the shut-in valve to the well space, monitoring the pressure data of the evaluation zone to determine a stable state of the pressure data, closing the shut-in valve when the stable state of the pressure data is reached to prevent the flow of the hydrocarbon fluids from the evaluation zone, and measuring a buildup pressure in the evaluation zone using the pressure monitoring device.

In certain aspects, the lift fluid is nitrogen. In certain aspects, the method further includes the step of returning the packer to the retracted position after the buildup pressure is measured. In certain aspects, the method further includes the step of re-positioning the pressure buildup test system to a second evaluation zone, moving the packer to the set position, monitoring the pressure data of the hydrocarbon fluids flowing through the shut-in valve to determine the stable state of the pressure data in the second evaluation zone, closing the shut-in valve when the stable state of the pressure data is reached to prevent the flow of the hydrocarbon fluids from the second evaluation zone, and measuring the buildup pressure in the second evaluation zone using the pressure monitoring device. In certain aspects, the method further includes the step of filling the well with a completion fluid. In certain aspects, the completion fluid is brine. In certain aspects, the coiled tubing includes a valve configured to shut-off the flow of the lift fluid. In certain aspects, the method further includes the steps of drilling the well for production of hydrocarbon fluids and preparing the well by installing the casing in the well.

In a second aspect, an apparatus for pressure buildup testing in an evaluation zone of a well is provided. The apparatus includes a packer configured to isolate the evaluation zone when in a set position and configured to create an annulus between a wall of the well and the apparatus in a retracted position, a sub port configured to deliver a lift fluid to the evaluation zone, a coiled tubing configured to deliver the lift fluid from a surface to the sub port, where the apparatus is deployed by the coiled tubing. The coiled tubing includes a cable configured to transmit electronic signals to a surface control system from the apparatus. The apparatus further includes a shut-in valve configured to control the flow of hydrocarbon fluids from the evaluation zone to a well space at a distance above the packer, a pressure monitoring device configured to measure pressure data in the evaluation zone and transmit the pressure data to the surface control system through the cable, and a PLT configured to measure flow from the evaluation zone through the shut-in valve to the well space above the packer.

In certain aspects, the surface control system is configured to send and receive electronic signals to the shut-in valve. In certain aspects, the surface control system is configured to send and receive electronic signals to the pressure monitoring device. In certain aspects, the surface control system is configured to send and receive electronic signals to the PLT. In certain aspects, the surface control system is configured to display the electronic signals transmitted by the cable and is further configured to store the electronic signals transmitted by the cable.

In a third aspect, a method for performing a pressure buildup test is provided. The method includes drilling a well for production of hydrocarbons and preparing the well by casing the well. A coiled tubing is then inserted into the well. Nitrogen is supplied via the coiled tubing to lift the hydrostatic pressure of the evaluation zone. The pressure of the evaluation zone is also measured using at least one pressure monitoring device.

In another aspect, an apparatus for pressure buildup testing in a well is provided. The apparatus includes at least one downhole pressure monitoring device operable to detect pressure in an evaluation zone. The apparatus further includes a packer for isolating a zone of interest. The apparatus also includes at least one data transmission device in communication with the at least one downhole pressure monitoring device for transmitting data to a surface of a well. The apparatus further includes a coiled tubing operable to allow the flow of nitrogen, as well as a valve for controlling the flow of nitrogen through the coiled tubing. The apparatus also includes a production logging tool for measuring and characterizing hydrocarbon flow.

DETAILED DESCRIPTION

Although the following detailed description contains many specific details for purposes of illustration, it is understood that one of ordinary skill in the art will appreciate that many examples, variations and alterations to the following details are within the inventive scope and spirit. Accordingly, the exemplary embodiments described and provided in the appended figures are set forth without any loss of generality, and without imposing limitations, on the scope.

The method and apparatus provided allow a pressure buildup test to be performed in one or more evaluation zones of a zones of interest in a well, using only one coiled tubing run. As used, “zone of interest” refers to a promising zone of a reservoir for hydrocarbon production. “Promising” as used throughout means a zone that is likely or substantially likely to produce hydrocarbon fluids. A zone of interest can be physically defined by the geophysical data recorded by wireline or drilling logs performed as part of the initial preparation of a well, such prior to casing a well. A given well can have multiple zones of interest and a given zone of interest can have multiple evaluation zones.

Advantageously, the methods and apparatus provide more accurate well test data because the nitrogen lifting and well-testing operations are combined into a single apparatus and process.

Referring toFIG. 1, an embodiment of the apparatus of pressure buildup test system10is shown. Pressure buildup test system10includes coiled tubing20. Coiled tubing20can be any coiled tubing containing cable22operable to be inserted into well80. Cable22transmits electronic signals or data from surface100to equipment downhole. Cable22provides electronic communication with the downhole devices, allowing both sending and receiving of real-time data and information to and from the surface. In at least one embodiment, cable22provides the means to actuate downhole devices. Examples of downhole devices include flow control devices, sample devices, perforating tools, packers, downhole recorder devices. Cable22can be any data transmission device that allows for communication between surface control system70and the downhole devices, alternately cable22can be any transmission device that allows for power delivery between surface control system70and the downhole devices, and alternately cable22can be any transmission device that allows for simultaneous communication and power delivery between surface control system70and the downhole devices. Examples of cables that can be used as cable22include electrical cable and fiber optic cable. Coiled tubing20, including cable22, can be a coiled tubing appropriate for transmission of nitrogen, transmission of fluids into the well, logging and perforating. In at least one embodiment, pressure buildup test system10is conveyed into well80using an electric line, such as a wireline. In at least one embodiment, well80is cased with casing82. In at least on embodiment, pressure buildup test system10and the pressure buildup test employ a single coiled tubing, in a single coil tubing run.

Coiled tubing20delivers a lift fluid from surface100to sub port30. The lift fluid provides the “lifting” of the hydrostatic pressure of the hydrocarbon fluid in the well to achieve well initiation. As used here, “well initiation,” refers to when the density of the hydrostatic column in the well is reduced to have a positive pressure drawdown (for example, when the sand face pressure is higher than the hydrostatic bottomhole pressure), such that the hydrocarbon fluid from the formation flows into the well and to the surface. The lifting of the hydrostatic pressure prompts the fluid in well80to flow toward surface100around coiled tubing20in well space84. The lift fluid is any fluid capable of lifting the hydrocarbon fluid in well80. In at least one embodiment, the lift fluid is nitrogen. This is also known as nitrogen kick-off. Nitrogen is inert and inexpensive. In at least one embodiment, well initiation is employed using nitrogen fed through coiled tubing20from surface100to sub port30. In at least one embodiment, the hydrocarbon fluid is lifted from well80in the absence of any mechanical equipment, such as a jet pump. In at least one embodiment, the coiled tubing is in the absence of hydrocarbon fluid flowing within it.

Coiled tubing20is connected to surface control system70. Surface control system70includes the equipment necessary to transmit the lift fluid from surface100to sub port30. In at least one embodiment, surface control system70includes a blower. In one embodiment, surface control system70includes a pump. Surface control system70also includes the readout system necessary to display the electronic signals and data transmitted through cable22of coiled tubing20, including, for example, monitors, computer processors, and other control equipment. Surface control system70includes equipment known in the art necessary to operate and control the system in well80.

Referring toFIG. 2, an embodiment is shown, in which well initiation is employed using well initiation pump120. Well initiation pump120connects to surface control system70by cable22. Well initiation pump120connects to packer40, such that well initiation pump120is located between surface100and packer40. Well initiation pump120provides the motive force to lift the hydrocarbon fluid in well80. Well initiation with a pump operates under the same principle as well lifting using gas, where the hydrostatic back-pressure of the well is reduced to encourage flow. Well initiation pump120can be any type of pump capable of producing a motive force to induce the hydrostatic back-pressure of the well to flow. The selection of pump for well initiation pump120can depend on the fluids that are expected to flow and the presence of gases in the fluids. Examples of pumps that can be used as well initiation pump120include reciprocating pumps, progressive cavity pumps, electrical submersible pumps, and jet pumps. In at least one embodiment, well initiation pump120is an electric submersible pump. In an embodiment with well initiation pump120, pressure buildup test system10is in the absence of sub port30and coiled tubing20.

Referring again toFIG. 1, in some embodiments, sub port30connects to packer40. Packer40isolates evaluation zone90in well80. Isolating well80at or near the zone of interest can prevent “wellbore storage effects” and thus reduce the risk of corrupted well test data. As used here, “wellbore storage effects” refers to a phenomena that is observed in well testing, Wellbore storage effect occurs when the shut-off test pressure is being measured at the surface, the initial pressure values are not a direct representation of the reservoir data but rather are affected by the wellbore column (in other words, the pressure changes will be cushioned by the wellbore column). In the embodiments described, the wellbore storage effect is minimized or avoided altogether by sealing evaluation zone90with packer40and measuring pressure data as close as possible to evaluation zone90. In some embodiments, packer40is set above evaluation zone90. In some embodiments, packer40is set below evaluation zone90. In some embodiments, packer40is set in the midst of evaluation zone90.

Packer40has a retracted position and a set position. In the retracted position, as shown inFIG. 1, annulus50forms between the walls of well80and the outside surface of packer40around which hydrocarbon fluid in evaluation zone90can flow. In the set position, as shown with reference toFIG. 1a,packer40contacts the walls of well80preventing hydrocarbon fluid in evaluation zone90from moving around packer40. In the set position, hydrocarbon fluid can only move from evaluation zone90toward surface100by passing through shut-in valve52to subport30. Shut-in valve52redirects hydrocarbon fluid from evaluation zone90to well space84between coiled tubing20and casing82in well80. In some embodiments, packer40is a straddle packer. In some embodiments, packer40is a temporary packer.

Cable22of coiled tubing20connects to shut-in valve52, pressure monitoring device54, and PLT60. In at least one embodiment, shut-in valve52is physically connected to packer40. Shut-in valve52is a downhole shut-in valve (DHSI valve). As used herein, a “downhole shut-in valve” refers to a valve designed to close in less than three seconds so that the initial transient pressure behavior can be recorded. Shut-in valve52when closed provides a downhole shut-in which minimizes wellbore effects that distort well transient pressure data. In at least one embodiment, as shown inFIG. 1, pressure monitoring device54is physically connected to shut-in valve52, such that shut-in valve52is situated between packer40and pressure monitoring device54. In at least one embodiment, as shown with reference toFIG. 3, pressure monitoring device54is physically connected to packer40adjacent to shut-in valve52. Pressure monitoring device54operates independently from shut-in valve52. In embodiments where shut-in valve52is not used, pressure monitoring device54can still be used.

Pressure monitoring device54is a pressure gauge to measure and record pressure data. Pressure monitoring device54measures the pressure in well80. In at least one embodiment, pressure monitoring device54measures pressure in evaluation zone90. Pressure monitoring device54includes any known pressure monitoring device that can measure and record transient pressure data and steady-state pressure data can be used. Examples of pressure gauges that can be used as pressure monitoring devices54include pressure recorders, such as pressure bombs and quartz gauges. Pressure monitoring device54is capable of capturing pressure data beginning at the moment shut-in valve52is closed in order to record the critical early transient pressure behavior. In at least one embodiment, pressure monitoring device54transmits pressure data in real-time to surface control system70through cable22.

PLT60is a production logging tool (PLT) capable of measuring and characterizing flow. PLT60uses cable22of coiled tubing20to communicate to surface control system70in real time. In at least one embodiment, PLT60measures and records in real-time for assessment of evaluation zone90. In at least one embodiment, PLT60includes a spinner and sensors to measure and characterize flow.

In some embodiments, the pressure data is recorded in memory. In at least one embodiment, the pressure data is stored in memory of pressure monitoring device54. In at least one embodiment, the pressure data is stored in memory of PLT60. Recording the data in memory acts as a data back-up. In some embodiments, the pressure data is transmitted to surface control system70at surface100in real time. In some embodiments, the pressure data is recorded in memory and transmitted to surface control system70in real time. In some embodiments, the data is transmitted via cable22in coiled tubing20to surface control system70. In some embodiments, the pressure data is transmitted by wireless downhole gauges.

In one aspect, a method for performing a pressure buildup test is provided. The method is described with reference toFIGS. 1 and 1a,however it is understood that the method could be performed with any of the embodiments or combinations of embodiments as described. The method includes the step of drilling well80for production of hydrocarbon fluids. Drilling well80also includes the step of casing well80with casing82. The steps of drilling well80for production of hydrocarbon fluids and preparing well80by casing well80with casing82are standard procedures performed in the preparation of wells for production. Known methods can be used for drilling of well80for production and of casing well80with casing82.

Casing82is perforated at evaluation zone90. Perforating casing82and allowing flow provides the means to fully evaluate the production potential of a zone of interest. “Perforation” or “perforating” refers to a procedure to generate holes in the casing, thus allowing fluids, such as hydrocarbon fluids to flow from the reservoir into the interior of a well. The hydrocarbon fluid can be any fluid in a reservoir capable of being produced through well80. Hydrocarbon fluids can include oil, natural gas, brine, water, and combinations thereof In at least one embodiment, the hydrocarbon fluid is oil. In at least one embodiment, the hydrocarbon fluid is natural gas. Evaluation zone90is at a predetermined depth of a zone of interest. In at least one embodiment, casing82is perforated at the predetermined depth of the zone of interest at the furthest distance from the surface.

Once casing82of well80is perforated at evaluation zone90, pressure buildup test system10is deployed downhole in well80, such that packer40is proximate to evaluation zone90by coiled tubing20. As used, “proximate to evaluation zone” means the packer can be below the evaluation zone, alternately the packer can be in the midst of the evaluation zone, and alternately the packer can be above the evaluation zone. In at least one embodiment, pressure buildup test system10is deployed downhole in well80prior to casing82being perforated. In at least one embodiment, pressure buildup test system10is deployed downhole by wireline.

Once pressure buildup test system10is in position proximate to evaluation zone90, the lift fluid is supplied via coiled tubing20and sub port30to lift the hydrostatic pressure of evaluation zone90. Packer40is in retracted position, as shown inFIG. 1. Shut-in valve52is open. The hydrocarbon fluid in well80is lifted from evaluation zone90toward surface100. Hydrocarbon fluid flow is measured real time via PLT60. When the hydrocarbon fluid has been lifted from evaluation zone90, a pressure buildup test can be performed. In at least one embodiment, the hydrocarbon fluid in well90is lifted toward the surface in the annulus, well space84, between well80and coiled tubing20, such that coiled tubing20supplies the lift fluid and is in the absence of hydrocarbon fluid.

To begin the pressure buildup test, packer40is placed in the set position, as shown in FIG. la, at the required depth of isolation at or near evaluation zone90to prevent wellbore storage effects from corrupting the well test data. After packer40is in the set position, the hydrocarbon fluid in evaluation zone90flows through shut-in valve52to sub port30and out to well space84and up to surface100. The hydrocarbon fluid continues to flow until stable state is reached as indicated in surface control system70from readings transmitted by pressure monitoring device54and PLT60. “Stable state” or “stable conditions” means a stable pressure and a stable flow rate through shut-in valve52as measured by pressure monitoring device54and PLT60. As used throughout, “stable” means a steady-state or substantially steady-state in which the pressure or flow rate are constant and unchanging for a time period.

When stable state is reached shut-in valve52is shut, which begins the buildup of pressure for transient analysis. Shut-in valve52is closed and pressure measurements using pressure monitoring device54are recorded as pressure data. Pressure monitoring device54measures the pressure as it builds up in evaluation zone90. In some embodiments, the pressure measurements begin during hydrocarbon fluid flow. In some embodiments, the pressure measurements begin at the moment shut-in valve52is closed. The pressure measurements are recorded over time to determine the pressure buildup rate. The pressure buildup rate is indicative of a well's production potential.

Shut-in valve52is closed quickly or suddenly, so that it closes in a small amount of time to record the instantaneous transient pressure data. Shut-in valve52is closed and the pressure monitoring device54records the pressure data for buildup analysis and measures the buildup pressure. As used herein, “pressure buildup” refers to the increase in the pressure values after the closure of the shut-in valve. The pressure buildup data are analyzed (for example, the pressure values, the derivate of the pressure values, and the second derivative of the pressure values) and characteristics of the formation can be inferred from the analyzed data set. Characteristics can include, for example, permeability, skin factor, and nearby faults. The duration of the pressure buildup test depends on characteristics the pressure buildup test data seeks to evaluate. For example, determination of faults at a distance from the wellbore requires more time than analysis of faults near the wellbore. There can be two ways to determine if the pressure buildup test is complete. In an instance where surface control system70is capable of real time monitoring of downhole conditions, then the real time surface readings can indicate the boundary of the test, in other words, surface control system can indicate when complete pressure buildup has been achieved. In an instance where surface control system70is not capable of real time monitoring of downhole conditions, then memory gauges can be used to collect the pressure data and the time can be estimated based on previous trials in the well and the reservoir. As a rule of thumb, the pressure buildup test can be expected to last1.5times the flow.

After the buildup test is complete, packer40is returned to the retracted position, such that packer40is unset or released, and pressure buildup test system10can be retrieved from within well80. In at least one embodiment, after the buildup test is complete, packer40is returned to the retracted position and repositioned to another zone of interest in well80or another evaluation zone90.

In some embodiments, the method further includes perforating casing82before performing the testing procedure. In some embodiments, multiple evaluation zones can be assessed without the need to remove the pressure buildup test system apparatus from well80. In such embodiments, pressure buildup system10is positioned with packer40at a second evaluation zone and nitrogen is supplied via coiled tubing20to lift the hydrostatic pressure of the second evaluation zone and then pressure build test system10is used to measure an in-flow of hydrocarbons in a pressure buildup test. This can be repeated in any number of evaluation zones without removal of pressure buildup testing10from well80.

In at least one embodiment, the casing is perforated in a first evaluation zone, the pressure buildup test system is lowered proximate the first evaluation zone and the pressure buildup test is completed. The pressure build up test system is then removed from the first evaluation zone and the first evaluation zone is then sealed off from connection with the well above the first evaluation zone. The first evaluation zone can be sealed by cementing or bridge block. At a second evaluation zone, at a predetermined depth that is closer to the surface than the first evaluation zone, the casing is again perforated. The pressure buildup test system is placed in the second evaluation zone and a second pressure buildup test is performed. This can be repeated in additional evaluation zones that progressively move closer to the surface. Perforating one evaluation zone at a time ensures that only the evaluation zone currently being evaluated contributes to the pressure data received by the pressure buildup system. It is understood that a high degree of accuracy is desired when conducting pressure buildup tests and small pressure perturbations can lead to well testing errors.

In further embodiments, well80is filled with a completion fluid. The completion fluid, or kill fluid, can be a fluid that can control the pressure of well80. In some embodiments, brine is used as the completion fluid. Brine is salty water that has a higher density than fresh water. The brine can come from any source of brine that would be capable of controlling the pressure of well80. In alternate embodiments, the kill fluid is a heavy fluid sufficient to stop the flow of hydrocarbons from the reservoir into well80.

Benefits to the various embodiments disclosed in the present application include reducing the number of coiled tubing insertions for the purpose of evaluating unconventional and tight gas zones. Reducing the number of coiled tubing runs will also result in reducing the rigging up and down of coiled tubing surface equipment. Reductions in coiled tubing runs reduces the operational cost associated with such operations. Additionally, embodiments allow evaluation zones to be lifted and energized to flowing conditions by circulating nitrogen through coiled tubing to the evaluation zone. Various embodiments also allow for the evaluation and measurement of flow from the evaluation zone with production logging tools. PLT can be used to measure and characterize the well's production while it is flowing. PLT can be used to evaluate a zone during the lifting phase, prior to the pressure buildup test. Various embodiments further allow for performance of an instantaneous shut-in of the flowing zone to record a pressure buildup test using downhole pressure monitoring devices. Embodiments are in the absence of memory gauges or pre-set shut-in valves that close after a set time has lapsed. Various embodiments also allow for observation of pressure data in real-time via an electrical or fiber-optical data transmission cable to surface. Another benefit of embodiments is the ability to repeat the test method at multiple evaluation zones in a well without the need of retrieving coiled tubing to the surface.

In at least one embodiment, the downhole devices are in the absence of production tubing.

Although the methods and apparatus have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the inventive principle and scope. Accordingly, the scope should be determined by the following claims and their appropriate legal equivalents.

Ranges may be expressed here as from about one particular value to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value to the other particular value, along with all combinations within said range.