Abstract: A technique involves collecting formation fluids through a single packer having at least one drain located within the single packer. The single packer is designed with an outer layer that expands to create a seal with a surrounding wellbore wall. The drain is located in the outer layer between its axial ends for collecting formation fluid which is routed from the drain to an axial end of the outer layer via a fluid flow passage. Mechanical fittings are mounted at the axial ends of the outer layer, and at least one of the mechanical fittings comprises one or more flow members coupled to the flow passage to direct the collected fluid from the packer. The one or more flow members are designed to move in a manner that freely allows radial expansion and contraction of the outer layer.

Abstract: A separator for downhole measuring during sampling in a subterranean formation. The separator allows for mixed fluid phases to be separated while flowing formation fluid therethrough.

Abstract: A technique involves collecting formation fluids through a single packer having at least one drain located within the single packer. The single packer is designed with an outer structural layer that expands across an expansion zone to facilitate creation of a seal with a surrounding wellbore wall. An inflatable bladder can be used within the outer structural layer to cause expansion, and a seal can be disposed for cooperation with the outer structural layer to facilitate sealing engagement with the surrounding wellbore wall. One or more drain features are used to improve the sampling process and/or to facilitate flow through the drain over the life of the single packer.

Abstract: Apparatus and methods to remove impurities at a sensor in a downhole tool are disclosed. During the testing and/or sampling of formation fluid in a borehole, the downhole tool creates a transient high rate of fluid flow of the formation fluid to remove impurities at the sensor.

Abstract: Subsea apparatus and a method for sampling and analysing fluid from a subsea fluid flowline proximate a subsea well is provided, wherein the apparatus comprises at least one housing located in close proximity to said subsea fluid flowline; at least one fluid sampling device located in the housing in fluid communication with a said subsea fluid flowline for obtaining a sample of fluid from the subsea fluid flowline; at least one fluid processing apparatus located in the housing in fluid communication with said subsea fluid flowline for receiving and processing a portion of the fluid flowing through said fluid flowline or in fluid communication with the fluid sampling device, for processing the sample of fluid obtained from the subsea fluid flowline for analysis, while keeping the sample of fluid at subsea conditions; a fluid analysis device located in the housing, the fluid analysis device being in fluid communication with the fluid processing device and/or with the fluid sampling device, the fluid analysis de

Abstract: Methods and apparatus for decreasing a density of a downhole fluid are described. An example apparatus to analyze a downhole fluid includes a chamber to decrease a density of at least a portion of a sample of a downhole fluid. Additionally, the example apparatus includes a sensor to measure a pressure of at least the portion of the sample in the chamber. Further, the example apparatus includes a fluid measurement unit to measure a characteristic of at least the portion of the sample based on a relationship between the pressure of at least the portion of the sample in the chamber and a predetermined pressure. Further yet, the example apparatus includes a control unit to determine a parameter of the downhole fluid based on the characteristic.

Abstract: An apparatus is provided that can be attached to a well to obtain samples of produced liquids. A vessel has an upper port, a lower port and a side port. Produced fluids enter the vessel through the side port. Natural gas associated with the produced fluids exits the vessel through the upper port, and is directed into a vapor recovery or other similar gas handling system and is not permitted to escape into the surrounding environment. Samples of produced liquids (and any accompanying solids) are obtained from the vessel through the lower port.

Abstract: Embodiments of the present invention provide systems and methods for downhole sampling or sensing of clean samples of component fluids of a multi-fluid mixture. More specifically, but not by way of limitation, embodiments of the present invention provide for, amongst other things, separating downhole multi-fluid mixtures into an oil-based fluid, a water-based fluid and/or the like and sampling and/or sensing of the clean separated fluids. Such sampling or sensing may be provided by a downhole tool in accordance with some embodiments of the present invention and the downhole tool may be used for production logging, formation testing and/or the like.

Abstract: A fluid sampling system retrieves a formation fluid sample from a formation surrounding a wellbore extending along a wellbore axis, wherein the formation has a virgin fluid and a contaminated fluid therein. The system includes a sample inlet, a first guard inlet positioned adjacent to the sample inlet and spaced from the sample inlet in a first direction along the wellbore axis, and a second guard inlet positioned adjacent to the sample inlet and spaced from the sample inlet in a second, opposite direction along the wellbore axis. At least one cleanup flowline is fluidly connected to the first and second guard inlets for passing contaminated fluid, and an evaluation flowline is fluidly connected to the sample inlet for collecting virgin fluid.

Abstract: A fluid sampling system retrieves a formation fluid sample from a formation surrounding a wellbore extending along a wellbore axis, wherein the formation has a virgin fluid and a contaminated fluid therein. The system includes a sample inlet, a first guard inlet positioned adjacent to the sample inlet and spaced from the sample inlet in a first direction along the wellbore axis, and a second guard inlet positioned adjacent to the sample inlet and spaced from the sample inlet in a second, opposite direction along the wellbore axis. At least one cleanup flowline is fluidly connected to the first and second guard inlets for passing contaminated fluid, and an evaluation flowline is fluidly connected to the sample inlet for collecting virgin fluid.

Abstract: Systems and methods for downhole formation testing based on the use of one or more elongated sealing pads capable of sealing off and collecting or injecting fluids from elongated portions along the surface of a borehole. The modified sealing pads increase the flow area by collecting fluids from an extended portion along the surface of a borehole, which is likely to straddle one or more layers in laminated or fractured formations. A tester device using the elongated sealing pads can be deployed and withdrawn using an extendible element pressing the pads to the borehole. Various designs and arrangements for use with a fluid tester, which may be part of a modular fluid tool, are disclosed in accordance with different embodiments.

Abstract: A fluid analysis tool, and related method, comprising means for selectively varying a temperature of fluid received in a tool from a subterranean formation, means for measuring a temperature and a thermophysical property of the fluid received in the tool, and means for determining a relationship between the measured temperature and the measured thermophysical property of the fluid received in the tool.

Abstract: A sample tank for receiving and storing sampled connate fluid from a subterranean geological formation. The sample tank includes a piston coaxially disposed within the tank. The piston can be disposed close to the end of the tank where the sampled fluid is introduced into the tank and urged along the length of the tank as sampled fluid is added to the tank. The piston includes an agitator for mixing the fluid and keeping particulates suspended within the fluid. The agitator includes a magnetic member, and is rotated by applying a varying electromagnetic field to the member.

Abstract: The evaluation and assessment of geologic formations comprising undersaturated coalbed methane reservoirs. In some embodiments, the present invention provides for inductively quantifying critical desorption pressure of the solid in an undersaturated coalbed methane reservoir from an unrelated substance, the formation water. By using these techniques, the characterization of undersaturated coalbed methane reservoirs may be more quickly and economically made based upon a methane content characteristic such as critical desorption pressure, gas content, and in some embodiments gas content as calculated from isotherm evaluation, estimates of dewatering for production, and ratios of critical desorption pressure to initial reservoir pressure, among other possible characteristics. The features of the invention may further have applicability in combination with conventional reservoir analysis, such as coring, logging, reservoir isotherm evaluation, or other techniques.

Abstract: A zone isolation assembly array (794) for a well (712) includes a first zone isolation assembly (722A) and a second zone isolation assembly (722B). The first zone isolation assembly (722A) selectively inhibits fluid communication between a first zone (726) and a second zone (728) of the well (712). The second zone isolation assembly (722B) can be positioned between the first zone isolation assembly (722A) and a surface region (32) of the well (712) in an in-line manner. The second zone isolation assembly (722B) selectively inhibits fluid communication between the second zone (728) and a third zone (796) of the well (712). In another embodiment, the zone isolation assembly array (794) includes a first docking receiver (748A), a second docking receiver (748B), a first docking apparatus (750A) and a second docking apparatus (750B). The docking receivers (748A, 748B) can be positioned in an in-line manner. The second docking apparatus (750B) is coupled to the first docking apparatus (750A).

Abstract: A pump system for testing an isolated zone in a borehole includes a testing pump and a testing device. The testing pump may be configured to at least assist in creating a formation fluid flow from the isolated zone in the borehole. The testing pump may be powered by a power fluid, where the power fluid may be delivered from a power fluid source. The power fluid source may be located at a location remote from the testing pump. The testing device may be configured to monitor the formation fluid flow. The testing device may further be configured to determine characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.

Abstract: An apparatus and method to perform measurements on fluid in a wellbore fluid sample tool in which at least a portion of the flowline of the sample tool is made of a non-magnetic and non-conductive material.

Abstract: A method and apparatus for maintaining the single phase integrity of a deep well formation sample that is removed to the surface comprises a vacuum jacket insulated single working cylinder divided by two free pistons into three variable volume chambers. The intermediate chamber is pre-charged with a fixed quantity of high pressure gas. Wellbore fluid freely admitted to one end chamber bears against one free piston to further compress the gas. The formation sample is pumped into the other end chamber to first, displace the wellbore fluid from the first end chamber and, sequentially, to further compress the gas to preserve the sample phase state upon removal to the surface.

Abstract: A formation testing apparatus and method are disclosed. In one aspect, a fluid is drawn from a formation, one or more sensors measure pressure of the fluid during the during drawing of the fluid, and a processor estimates an inflection point from the pressure measurements and controls the drawing of the fluid from the inflection point until the pressure of the fluid drops to a selected level.

Abstract: A method for acquiring a sample of a virgin fluid from a subsurface formation penetrated by a wellbore surrounded by a layer of contaminated fluid is disclosed. The method includes abutting a first packer against a wall of the wellbore, and extending at least a portion of a second packer beyond the first packer, wherein the second packer is at least partially disposed in the first packer. An inlet to a first flowline is at least partially defined by the first packer, and an inlet to a second flowline is defined by the second packer. The method further includes drawing one of virgin fluid, contaminated fluid and combinations thereof into the first flowline; and drawing virgin fluid into the second flowline.

Abstract: Apparatus and methods for collecting a downhole sample are provided. The method may include introducing a flowable sealant to a borehole wall portion, modifying a formation system mobility using the flowable sealant, and receiving the downhole sample using a sample receiving port positioned proximate the borehole wall portion. An apparatus includes a formation sampling member having a sample receiving port for receiving the downhole sample, and an inhibitor that includes one or more of an activator and an injector.

Abstract: An apparatus and method for collecting a fluid from a subterranean formation are disclosed. A fluid sample container has an elongated body. The elongated body includes an internal cavity, a first end having a first opening for receiving the downhole fluid into the internal cavity, a second end axially displaced from the first end, the second end having a second opening for expelling at least a portion of the downhole fluid from the internal cavity. Fluid collecting includes establishing fluid communication with a formation of interest and the fluid sample container receiving the downhole fluid into the internal cavity through the first opening and expelling at least a portion of the downhole fluid from the internal cavity through the second opening.

Abstract: The present invention relates to an apparatus and method for recovering a sample from a subterranean formation. The apparatus comprises a receptacle for receiving a sample and at least two seal assemblies disposed on an inner surface of the receptacle. The seal assemblies can be arranged to allow a portion of the sample therethrough during the sampling process and to retain fluids within the receptacle during recovery of the sample. The seal assemblies can comprise at least one seal. The at least one seal can be provided with at least one fluid pocket configured to change shape as the volume of fluid therein alters in response to a pressure differential. A plurality of pairs of seal assemblies can be spaced along the length of the inner surface of the receptacle.

Abstract: A method and apparatus for collecting a downhole fluid are disclosed. A method includes receiving a downhole fluid into a downhole sub from a first borehole wall portion adjacent a formation of interest and expelling at least a portion of the received downhole fluid from the downhole sub to a second borehole wall portion, wherein substantially all of the expelled downhole fluid enters the second borehole wall portion. An apparatus includes a downhole sub, a formation sampling member coupled to the downhole sub for collecting the downhole fluid from a first borehole wall portion adjacent a formation of interest, a sample expulsion member coupled to the downhole sub for expelling at least a portion of the collected downhole fluid from the downhole sub to a second borehole wall portion, wherein substantially all of the expelled downhole fluid enters the second borehole wall portion.

Abstract: Improved methods and systems of blending and analyzing well treatment fluids at a well site are disclosed. A first centrifugal pump pumps a first component of the well treatment fluid into a pipe and a first valve controls the flow of the first component into the pipe. A second centrifugal pump pumps a second component of the well treatment fluid into a pipe and a second valve controls the flow of the second component into the pipe. The pumps and the valves are then controlled in order to control the ratio of the first and second component of the well treatment fluid as they are delivered to the pipe and a sampling device is used to analyze the well treatment fluid.

Abstract: A method for acquiring a sample of a virgin fluid from a subsurface formation penetrated by a wellbore surrounded by a layer of contaminated fluid includes abutting a first packer against a wall of the wellbore, and extending at least a portion of a second packer beyond the first packer, wherein the second packer is at least partially disposed in the first packer. An inlet to a first flowline is at least partially defined by the first packer, and an inlet to a second flowline is defined by the second packer. The method further includes drawing one of virgin fluid, contaminated fluid and combinations thereof into the first flowline; and drawing virgin fluid into the second flowline.

Abstract: A replaceable DC electric motor and kit for a groundwater sampling and pumping device and system for withdrawing groundwater from a well. The motor is provided with means to align the motor with an alignment pin in the groundwater sampling device.

Abstract: A system for testing a subterranean formation penetrated by a well includes a downhole tool configured to be coupled to a work string that includes a tool body having a longitudinal bore for circulating a fluid and at least one aperture configured to receive at least one module. The system further includes a plurality of modules that are each configured to engage the at least one aperture and at least one cavity configured for receiving a probe, and a plurality of probes that each include at least one orifice configured for testing the formation, wherein a first of the plurality of probes has a first configuration and a second of the plurality of probes has a second configuration.

Abstract: A downhole tool for use in a well may comprise a vessel having a piston or a valve disposed therein and defining first and second volumes wherein the first volume is configured to receive formation fluid from an inlet port, and an actuator configured to extract formation fluid, the actuator being fluidly isolated from a fluid flow path extending between the inlet port and the first volume. The downhole tool may also comprise a flow-line configured to deliver formation fluid to the vessel, and an actuator configured to register an end of the flow-line with the inlet of the vessel.

Abstract: Methods and apparatuses for sampling fluid from a subterranean formation penetrated by a wellbore are provided. The subterranean formation has clean formation fluid therein, and the wellbore has a contaminated fluid therein extending into an invaded zone about the wellbore. A shaft is extended from a housing and positioned in a perforation in a sidewall of the wellbore. At least one flowline extends through the shaft and into the housing. The flowline(s) are adapted to receive downhole fluids through the perforation. At least one fluid restrictor, such as a packer, injection fluid or flow inhibitor, may be used to isolate at least a portion of the perforation whereby contaminated fluid is prevented from entering the isolated portion of the perforation. At least one pump selectively draws fluid into the flowline(s).

Abstract: A downhole fluid sample container includes a fluid sample container detachably coupled to a downhole sub, the fluid sample container having an internal chamber for receiving the downhole fluid. At least one semimetal (for example, silicon or germanium) window is coupled to the fluid sample container, the window being substantially transparent to electromagnetic energy wavelengths within a selected band. A method includes transmitting electromagnetic energy from an electromagnetic energy source to downhole fluid through at least one semimetal window in a container, receiving an electromagnetic energy response with a spectrometer, and estimating the downhole fluid property based at least in part on the electromagnetic energy response.

Abstract: A method of sampling fluid from a rock formation penetrated by a borehole includes positioning a downhole tool having a flow line in the borehole, establishing an inlet port through which fluid passes from a first point in the formation into the flow line, establishing an outlet port through which fluid passes from the flow line into a second point in the formation, and passing fluid between the formation and the flow line through the inlet and outlet ports.

Abstract: A docking receiver (48) for a subsurface well (12) having a fluid inlet structure (29), a riser pipe (30) and a docking apparatus (50) includes an upper section (372A) and a lower section (374A). The upper section (372A) is secured to the riser pipe (30). The lower section (374A) is secured to the fluid inlet structure (29). The lower section (374A) receives the docking apparatus (50) into an engaged position wherein fluid communication between a first zone (26) and a second zone (28) of the well (12) is inhibited. The lower section (374A) includes a contact surface (376A) and a distal region (377A). The contact surface (376A) contacts the docking apparatus (50) when the docking apparatus (50) is in the engaged position. The distal region (377A) is positioned more distally from a surface region (32) of the well (12) than the contact surface. The lower section (374A) can have a lower inner diameter (380UD, 380LD) that varies within the distal region (377A).

Abstract: Tools and methods for downhole sample analysis are provided. An apparatus for sampling a downhole fluid includes a tool having at least one surface element wetted by a downhole fluid such as drilling fluid, return fluid or production fluids such as asphaltenic hydrocarbons. At least one surface element disposed on the tool can include a fluid-repellent material disposed on a substrate for repelling at least a portion of the downhole fluid wetting the surface element.

Abstract: A technique involves collecting formation fluids through a single packer having at least one drain located within the single packer. The single packer comprises an outer seal layer, and the at least one drain is positioned in the outer seal layer. A viscosity system also is incorporated and enables the viscosity of a surrounding fluid to be selectively lowered for sampling.

Abstract: A method and system capable of economically removing a liquid from a liquid reservoir, such as oil from an oil reservoir, by withdrawing limited quantities of the liquid in discrete steps. The system includes a dipping unit sized to be received in a passage to the reservoir, such as a casing of an oil well, and a unit for lowering and raising the dipping unit within the passage. The dipping unit is configured and oriented to have an upper end portion and a lower end portion when within the passage. The dipping unit includes a chamber, a feature for enabling a liquid to enter the chamber when at least its lower end portion is submerged in the liquid within the reservoir, and a feature for releasing the liquid from the chamber.

Abstract: A downhole drilling tool positionable in a wellbore penetrating a subterranean formation is provided. The tool includes a formation evaluation tool having fixed and retrievable portions. The fixed portion is operatively connected to a drill collar of the downhole tool. The fixed portion is for establishing fluid communication with a subterranean formation. The retrievable portion is fluidly connected to the fixed portion and retrievable therefrom to a surface location. The retrievable portion is for receiving a formation fluid from the subterranean formation.

Abstract: A method of evaluating a fluid from a subterranean formation drawn into a downhole tool positioned in a wellbore penetrating the subterranean formation is provided. The method involves drawing fluid from a formation into an evaluation flowline, drawing fluid from a formation into a cleanup flowline, measuring a property of the fluid in the evaluation flowline and detecting stabilization of the property of the fluid in the evaluation flowline. Fluid properties in a combined flowline may be generated from the evaluation and cleanup flowlines. The fluid properties of the combined flowline may be used to project future evaluation flowline fluid properties. Contamination levels for a given fluid property of a given flowline may also be determined.

Abstract: A method for lowering the temperature of a portion of a subsurface formation is provided. Preferably, the formation is an oil shale formation. The method includes the step of injecting a cooling fluid under pressure into a wellbore, with the wellbore having been completed at or below a depth of the subsurface formation. In one embodiment the wellbore has an elongated tubular member for receiving the cooling fluid and for conveying it downhole to the subsurface formation. The wellbore also has an expansion valve in fluid communication with the tubular member through which the cooling fluid flows. The method then includes the steps of injecting a cooling fluid under pressure into the wellbore, and expanding the cooling fluid across the first expansion valve. In this way, the temperature of the cooling fluid is reduced. The temperature of the surrounding formation is likewise reduced through thermal conduction and convection. In another embodiment, a partially frozen slurry is used as the cooling fluid.

Abstract: In one embodiment an apparatus is disclosed that includes a tool in a wellbore. A probe is extendable from the tool to contact a wall of a formation surrounding the wellbore. A tube substantially surrounds the probe wherein the tube is extendable into the formation surrounding the wellbore. In another embodiment a method for reducing contamination of a sample of a formation fluid is disclosed that includes extending a probe to contact a wall of a formation. A barrier tube that substantially surrounds the probe is extended into the formation thereby restricting a flow of a contaminated reservoir fluid that would otherwise come from near-wellbore regions above and below the probe from going toward the probe.

Abstract: Systems and methods for installation and operation of a groundwater monitoring system in a borehole of any angle using a coaxial gas displacement pump with a unique O-ring assembly that serves as a two-position valve for groundwater purging and sampling and also as a housing and sealing mechanism for isolating an optical pressure sensor. The optical sensor measures in-situ hydraulic pressure directly subjacent and adjacent to the surrounding rock fractures and sediment pores without hydraulic interferences from potentiometric equilibration lag time from recovery fluid pressure inside a borehole, in a zone above the optical sensor, or on the inside of a riser pipe that rises to the ground surface.

Abstract: A method of evaluating a fluid from a subterranean formation drawn into a downhole tool positioned in a wellbore penetrating the subterranean formation is provided. The method involves drawing fluid from a formation into an evaluation flowline, drawing fluid from a formation into a cleanup flowline, measuring a property of the fluid in the evaluation flowline and detecting stabilization of the property of the fluid in the evaluation flowline. Fluid properties in a combined flowline may be generated from the evaluation and cleanup flowlines. The fluid properties of the combined flowline may be used to project future evaluation flowline fluid properties. Contamination levels for a given fluid property of a given flowline may also be determined.

Abstract: Apparatus and methods to perform downhole fluid analysis using an artificial neural network are disclosed. A disclosed example method involves obtaining a first formation fluid property value of a formation fluid sample from a downhole fluid analysis process. The first formation fluid property value is provided to an artificial neural network, and a second formation fluid property value of the formation fluid sample is generated by means of the artificial neural network.

Abstract: Methods that include a method of determining one or more approximate properties of a subterranean formation and/or a fracture therein comprising: obtaining fluid identity data for a plurality of flowback fluid samples; and using a reservoir model, with the fluid identity data and one or more subterranean formation properties as inputs thereto, to estimate one or more properties in a subterranean formation. Additional methods are provided.

Abstract: An apparatus and method for evaluating chemicals of interest in a subsurface bore hole, such as a groundwater sampling well. An absorbent member is attached it a flexible liner, and the liner is everted by fluid pressure down the borehole. The everted liner presses the absorbent member against the wall of the borehole. Any chemicals of interest are absorbed into the absorbent member from the media surrounding the borehole. The liner, with associated absorbent member thereon, is then extracted from the borehole. The absorbent member may then be subjected to any suitable laboratory analysis to evaluate the type, spatial distribution, and concentration of chemicals of interest, such as water contaminants occurring in the borehole.

Abstract: The invention relates to fluid sampling in a test that is used to determine physical and chemical characteristics of the fluids in a subterranean reservoir. The method reconstructs the entire pressure history of the fluid parcel that is captured in the fluid samplers during a test. Using this reconstructed pressure history of the samples, the quality of the samples, particularly, whether there is a phase change in the samples during the test, can be accurately quantified.

Abstract: Methods and apparatuses for sampling fluid from a subterranean formation penetrated by a wellbore are provided. The subterranean formation has clean formation fluid therein, and the wellbore has a contaminated fluid therein extending into an invaded zone about the wellbore. A shaft is extended from a housing and positioned in a perforation in a sidewall of the wellbore. At least one flowline extends through the shaft and into the housing. The flowline(s) are adapted to receive downhole fluids through the perforation. At least one fluid restrictor, such as a packer, injection fluid or flow inhibitor, may be used to isolate at least a portion of the perforation whereby contaminated fluid is prevented from entering the isolated portion of the perforation. At least one pump selectively draws fluid into the flowline(s).

Abstract: An extendable component for use in a downhole tool for traversing subsurface formations includes a drive element that defines an axis and has a distal end, and an abutment that is spaced radially from a distal end of the drive element. A driven element defines a driven element axis, is flexibly coupled to the drive element, and includes a proximal end disposed adjacent to the drive element and a distal end. A tilt arm is coupled to the driven element, is disposed at an angle with respect to the driven element axis, and is configured to engage the abutment. The driven element is moveable between a normal position and a tilted position. A contact head is coupled to the driven element distal end and is adapted to engage the wellbore wall.

Abstract: Methods and systems and are described for isolating or manipulating a sample of a heavy oil composition from a hydrocarbon reservoir. One method embodiment of the invention comprises circulating a heated fluid in a first region of a reservoir where a heavy oil composition is present or believed present using a surface pump and a well completion comprising a downhole pump for a time and flow rate sufficient to produce flowable heavy oil composition, the well completion comprising a sampling tool; and sampling the flowable heavy oil composition using the sampling tool. This abstract complies with rules requiring an abstract. It should not be used to limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A method of sampling fluid from a subterranean formation includes positioning a first tool having a heater in a borehole so that the heater is adjacent a portion of the subterranean formation: heating with the heater the portion of the subterranean formation; removing the first tool from the borehole; orienting a second tool having a sampling probe in the borehole so that the sampling probe is to contact a portion of the subterranean formation heater by the heater; and obtaining via the sampling probe a fluid sample from the portion of the subterranean formation heater by the heater.