Some embodiments include transistors having a channel region under a gate, having a source/drain region laterally spaced from the channel region by an active region, and having one or more dielectric features extending through the active region in a configuration which precludes any straight-line lateral conductive path from the channel region to the source/drain region. The dielectric features may be spaced-apart islands in some configurations. The dielectric features may be multi-branched interlocking structures in some configurations.

A microelectronic assembly includes a first component with first conductive elements; a second component with second conductive elements; a bond metal; and an underfill layer. The posts have a height above the respective surface from which the posts project. A bond metal can be disposed between respective pairs of conductive elements, each pair including at least one of the posts and at least one of the first or second conductive elements confronting the at least one post. The bond metal can contact edges of the posts along at least one half the height of the posts. An underfill layer contacts and bonds the first and second surfaces of the first and second components. A residue of the underfill layer may be present at at least one interfacial surfaces between at least some of the posts and the bond metal or may be present within the bond metal.

The silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH4) and ammonia (NH3) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354, and the silicon nitride layer 910 is provided over the oxide semiconductor layer 906 used for the thin film transistor 355 with the silicon oxide layer 909 serving as a barrier layer interposed therebetween. Therefore, a higher concentration of hydrogen is introduced into the oxide semiconductor layer 905 than into the oxide semiconductor layer 906. As a result, the resistance of the oxide semiconductor layer 905 used for the resistor 354 is made lower than that of the oxide semiconductor layer 906 used for the thin film transistor 355.

To provide a semiconductor device which has transistor characteristics with little variation and includes an oxide semiconductor. The semiconductor device includes an insulating film over a conductive film and an oxide semiconductor film over the insulating film. The oxide semiconductor film includes a first oxide semiconductor layer, a second oxide semiconductor layer over the first oxide semiconductor layer, and a third oxide semiconductor layer over the second oxide semiconductor layer. The energy level of a bottom of a conduction band of the second oxide semiconductor layer is lower than those of the first and third oxide semiconductor layers. An end portion of the second oxide semiconductor layer is positioned on an inner side than an end portion of the first oxide semiconductor layer.

It is an object to provide a highly reliable semiconductor device with good electrical characteristics and a display device including the semiconductor device as a switching element. In a transistor including an oxide semiconductor layer, a needle crystal group provided on at least one surface side of the oxide semiconductor layer grows in a c-axis direction perpendicular to the surface and includes an a-b plane parallel to the surface, and a portion except for the needle crystal group is an amorphous region or a region in which amorphousness and microcrystals are mixed. Accordingly, a highly reliable semiconductor device with good electrical characteristics can be formed.

A semiconductor device including a circuit which does not easily deteriorate is provided. The semiconductor device includes a first transistor, a second transistor, a first switch, a second switch, and a third switch. A first terminal of the first transistor is connected to a first wiring. A second terminal of the first transistor is connected to a second wiring. A gate and a first terminal of the second transistor are connected to the first wiring. A second terminal of the second transistor is connected to a gate of the first transistor. The first switch is connected between the second wiring and a third wiring. The second switch is connected between the second wiring and the third wiring. The third switch is connected between the gate of the first transistor and the third wiring.

By applying an AC pulse to a gate of a transistor which easily deteriorates, a shift in threshold voltage of the transistor is suppressed. However, in a case where amorphous silicon is used for a semiconductor layer of a transistor, the occurrence of a shift in threshold voltage naturally becomes a problem for a transistor which constitutes a part of circuit that generates an AC pulse. A shift in threshold voltage of a transistor which easily deteriorates and a shift in threshold voltage of a turned-on transistor are suppressed by signal input to a gate electrode of the transistor which easily deteriorates through the turned-on transistor. In other words, a structure for applying an AC pulse to a gate electrode of a transistor which easily deteriorates through a transistor to a gate electrode of which a high potential (VDD) is applied, is included.

A low resistivity interface material is provided between a self-aligned vertical heater element and a contact region of a selection device. A phase change chalcogenide material is deposited directly on the vertical heater element. In an embodiment, the vertical heater element in L-shaped, having a curved vertical wall along the wordline direction and a horizontal base. In an embodiment, the low resistivity interface material is deposited into a trench with a negative profile using a PVD technique. An upper surface of the low resistivity interface material may have a tapered bird-beak extension.

An amorphous oxide thin film containing amorphous oxide is exposed to an oxygen plasma generated by exciting an oxygen-containing gas in high frequency. The oxygen plasma is preferably generated under the condition that applied frequency is 1 kHz or more and 300 MHz or less and pressure is 5 Pa or more. The amorphous oxide thin film is preferably exposed by a sputtering method, ion-plating method, vacuum deposition method, sol-gel method or fine particle application method.

An embodiment of the present invention provides a TFT array substrate including: a base substrate (1) and thin film transistors. The thin film transistor includes a gate electrode (2), a semiconductor layer (5), a semiconductor protective layer, a source electrode (8) and a drain electrode (9). The semiconductor protective layer is disposed adjacent to the semiconductor layer (5) and includes a composite lamination structure, which includes a protective layer formed of an insulating material capable of preventing de-oxygen of the semiconductor layer (5) and an insulating layer formed of an insulating material to be etched more easily.

An object is to manufacture and provide a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which a semiconductor layer including a channel formation region serves as an oxide semiconductor film, heat treatment for reducing impurities such as moisture (heat treatment for dehydration or dehydrogenation) is performed after an oxide insulating film serving as a protective film is formed in contact with an oxide semiconductor layer. Then, the impurities such as moisture, which exist not only in a source electrode layer, in a drain electrode layer, in a gate insulating layer, and in the oxide semiconductor layer but also at interfaces between the oxide semiconductor film and upper and lower films which are in contact with the oxide semiconductor layer, are reduced.

Provided is a novel coated phosphor capable of effectively suppressing the adverse effects of hydrogen sulfide gas generated by the reaction between a sulfur-containing phosphor and moisture in the air. Provided is a sulfur-containing phosphor having a configuration in which ZnO compound containing Zn and O is present on the surface of a sulfur-containing phosphor having a host material which includes sulfur.

A transistor device includes a compound semiconductor body having a first surface and a two-dimensional charge carrier gas disposed below the first surface in the compound semiconductor body. The transistor device further includes a source in contact with the two-dimensional charge carrier gas and a drain spaced apart from the source and in contact with the two-dimensional charge carrier gas. A first passivation layer is in contact with the first surface of the compound semiconductor body, and a second passivation layer is disposed on the first passivation layer. The second passivation layer has a different etch rate selectivity than the first passivation layer. A gate extends through the second passivation layer into the first passivation layer.

Blast absorbing structures and system for use in absorbing blast forces exerted on a floor of a personnel cabin of a vehicle, are disclosed. The blast absorbing flexing structure comprises a bottom section forming a floor of the cabin, a first side section and opposing second side section, each side section extending from the bottom section and including a plurality of steps along a length of the second side section. The steps flex in response to a blast force. In another embodiment, the blast absorbing expanding structure comprises a force abatement device forming a floor of the cabin, a cover plate having a plurality of slots arranged around a perimeter of the plate. The cover plate is movable between a neutral position and a blast force position to diminish the blast forces prior to the blast forces to reaching an occupant of the cabin.

In the specification and drawings an accessory cart is described and shown with a base, a housing element that is connected to the base and extends upward from the base, and a platform, which is connected to the housing element with the height of the platform being automatically adjustable.

A four-wheel independent suspension system for an electric wheelchair includes a chassis, two front wheels each fixed to a front rod respectively, and two rear wheels each fixed to a rear rod respectively. The chassis includes a rail extending in a width direction of the chassis, each of the front and rear rods has one end connected to a square first connecting sleeve, in the first connecting sleeve is disposed a first shock absorber which includes a rectangular outer pipe, and a rectangular inner pipe disposed in and rotated degrees with respect to the outer pipe, the edges of the inner pipe are abutted against the inner surface of the outer pipe, between each of the edges of the inner pipe and the inner space of the outer pipe is disposed an elastic rubber, the inner pipe of each of the first shock absorbers is sleeved on the rail.

A control arrangement for a hydropneumatic suspension system and a hydropneumatic suspension system are provided. The control arrangement has a pressure supply connection, a return connection, a piston chamber connection adapted to be connected to the piston chamber of a suspension cylinder of the hydropneumatic suspension system, an annular chamber connection adapted to be connected to the annular chamber of the suspension cylinder, and at least one controllable valve arrangement comprising a plurality of switch positions via which the pressure supply connection and the return connection are connectable to the piston chamber connection and the annular chamber connection. The annular chamber connection is in flow connection with the return connection via a pressure-limiting line having a hydraulically controllable pressure-limiting element. The pressure-limiting element has a control input adapted to be acted upon via a control line by a control pressure which is limitable to a predefinable pressure limit.

A reconfigurable fixed position suspension and support structure attached to the trailer body using a locking device consisting of pins, bolts and/or other fastening devices. The support structure has a removable locking device that when attached to the support structure locks the support structure and suspension into a fixed position relative to the trailer body. When the trailer is not in operation, the locking device can be removed allowing the suspension group to be reconfigured, and each suspension to be repositioned relative to the trailer body. The removable locking device is then reattached to the suspension support structure locking the support structure and suspension into a new fixed position relative to the trailer body.

In an outer tube for a front fork, a metal upper collar to which an upper vehicle body attaching bracket is connected is fitted and attached to an upper end portion of the plastic pipe, a metal sleeve is fitted and attached between an intermediate portion and a lower end portion of the plastic pipe, and the sleeve is provided with a lower collar to which a lower vehicle body attaching bracket is connected, and a seal case for inserting and supporting the inner tube.

A system and method for adjusting the arms of an over-sized trailer is described herein. In one embodiment, the system can comprise a center support, a plurality of swing arms, and a plurality of stabilizer rods. The swing arms can be mounted to the left side and the right side of the center support. The swing arms can each comprise an arm and an arm hinge. The swing arms can be capable of rotating about the arm hinge. Furthermore, a dolly can be capable of being mounted to each swing arms. Each of the stabilizer rods can comprise a first rod portion and a second rod portion. The first rod portion can be connected to the center support and the second rod portion connected to one of the swing arms.

A gliding apparatus includes a gliding board, a first front boot-retaining device for ascending a slope and a second front boot-retaining device for the descent. The first front retaining device comprises a first boot-fastening mechanism, defining a boot pivot axis during the ascent. The second front retaining device comprises a second boot-fastening mechanism, including a movable element incorporating an interface surface capable of contacting a front portion of the boot, the movable element being separate from the first fastening mechanism. The second front retaining device is configurable in a first “inactive” configuration for which the interface surface is away from the boot front portion, and a second “active” configuration for which the interface surface contacts the boot front portion. The first boot-fastening mechanism is capable of cooperating with the movable element of the second front retaining device so as to maintain the second front retaining device in its active configuration.

An airbag system for protecting rear seat occupants in dynamic side impacts using an improved packaging arrangement is provided. The system includes seat base and seat back frames. The seat back frame is movable between an upright position and a reclined position. The system further includes a unified airbag having a pelvic portion and a thoracic portion. The pelvic portion is positioned adjacent to the seat base frame. The thoracic portion is positioned adjacent to the seat back frame. The unified airbag is attached to the seat base frame by fixed anchors and to the seat back frame by a movable anchor. A grooved track is provided for attachment of the movable anchor. The airbag may be a strip shape or a triangular shape. One or more tethers may be attached to the unified airbag.

Interior panels having integrated airbag doors for motor vehicles and methods for making such interior panels are provided herein. In one example, an interior panel comprises a substrate having outer and inner surfaces and an opening extending therethrough. A multi-shot injection molded airbag chute-door assembly is mounted to the substrate and comprises a chute wall that at least partially surrounds an interior space. A door flap portion is pivotally connected to the chute wall and at least partially covers the opening. A perimeter flange extends from the chute wall and has a flange section that overlies the outer surface of the substrate. A molded-in lip feature extends from the flange section and contacts the outer surface to form a seal between the flange section and the substrate. A skin covering extends over the substrate and a foam is disposed between the skin covering and the substrate.

In an inflated and expanded state of a side airbag, a forwardly extending portion, provided at an upper portion of a rear side bag portion, extends from a side of a shoulder portion of a seated passenger toward a vehicle front side and is disposed above a front side bag portion. A dimension in a vehicle transverse direction of this forwardly extending portion is set to be smaller than that of the front side bag portion, and a vehicle transverse direction inner side surface at an upper end side of the front side bag portion is inclined or curved so as to rise-up while heading toward a vehicle transverse direction outer side. An upper arm portion is pushed-up due to sliding contact with this surface. Even when the seated passenger inertially toward an oblique front of a vehicle, the shoulder portion can be restrained by the forwardly extending portion.

Airbag inflator system includes an inflatable airbag, e.g., a side curtain airbag, a housing, a gas generating system arranged apart from the housing for generating gas, and a conduit leading from the gas generating system to the housing to provide gas to the housing, e.g., to a lateral end of the housing. A filter may be arranged between the gas generating system and the housing, possibly in the conduit. A nozzle may be arranged between the gas generating system and an interior of the airbag, which nozzle is varied as a function of temperature. The housing may be movably arranged relative to a fixed base and mounted to vary its relation to the base as a function of temperature, e.g., via elastic or deformable supports which support the housing on the base.

There is provided a behavior control device for the prevention of a jackknife phenomenon of a combination vehicle including a tractor and a trailer pivotably coupled with the tractor, taking into account that the relative pivoting action of the trailer and tractor varies according to the magnitudes of a vehicle speed or a deceleration. The inventive behavior control device comprises a braking-driving force control portion which controls a braking-driving force of the tractor or the trailer to reduce a difference between a yaw rate of the tractor and a yaw rate of the trailer and a judgment portion which judges whether or not a braking-driving force control of the tractor or the trailer by the braking-driving force control portion is necessary; wherein the judgment portion changes based on a vehicle speed or a deceleration of the vehicle the judgment of whether or not the braking-driving force control is necessary.

A lightweight folding motorized chair with mechanical traction steering and braking. A folding frame supports the traction wheels and the drive system with hinged frame members configured to mechanically fold the control levers, wheels and periphery components into a substantially flat configuration for easy storage in small spaces. A mix of weight saving choices including: structural materials; mechanical traction control system; lithium ion battery; and overall lightweight design keeps the folding motorized chair at a size and weight that a person can lift into the trunk of a car.

A pre-weakened cover of an airbag module is provided including a layer having an outer show surface and an opposing inner surface. A plurality of first cuts is arranged at a first angle on the inner surface. A plurality of second cuts is arranged at a second angle on the inner surface. Each of the second cuts intersects two adjacent first cuts to form a generally V-shaped pattern.

A pre-weakened cover of an airbag module is provided including a layer having an outer show surface and an opposing inner surface. A plurality of first cuts is arranged at a first angle on the inner surface. A plurality of second cuts is arranged at a second angle on the inner surface. Each of the second cuts intersects two adjacent first cuts to form a generally V-shaped pattern.

A tool comprising a tool body having an opening defined by interior walls extending into the tool body and a casing disposed within the opening. The tool further includes a scintillator material disposed within the casing and a first compressive member disposed within the tool body at a first axial location. The first axial location extends for a fraction of a total axial length of the casing and exerts a first radially compressive force at the first axial location.

A tubular string is advanced with a bottom hole assembly as the hole is drilled and reamed in a desired direction with the aid of directional drilling equipment adjacent the bit. When the advanced tubular forms the desired lap to the existing tubular, the assembly can be configured to cement the tubular and expansion can then be accomplished to fill the annular space and enhance the cement bonding. The expansion equipment can create a bottom bell on the expanded tubular and expand the top end into a bell of the existing tubular so that a monobore is created as the process is repeated with each added string. Numerous variations are contemplated for each single trip including but not limited to the direction of expansion, whether cementing or expansion occurs first, reforming folded tubing in the hole as well as the nature of the expansion tool and pressure control when drilling.

A drilling apparatus for drilling boreholes in an underground formation includes a tool body that can be positioned in a borehole where drilling is to take place. The apparatus further includes a gas cutting torch having a nozzle, a supply of a cutting gas connected to the gas cutting torch. In some embodiments, the gas cutting torch and supply of cutting gas may be connected by an umbilical link. The tool body may be advanced through the borehole as drilling takes place. In some embodiments, the tool body may be advanced via a tractor device that forms part of the tool body or attached to the tool body.

Methods and systems are described for improved drilling operations through the use of real-time drilling data to predict bit wear, lithology, pore pressure, a rotating friction coefficient, permeability, and cost in real-time and to adjust drilling parameters in real-time based on the predictions. The real-time lithology prediction is made by processing the real-time drilling data through a multilayer neural network. The real-time bit wear prediction is made by using the real-time drilling data to predict a bit efficiency factor and to detect changes in the bit efficiency factor over time. These predictions may be used to adjust drilling parameters in the drilling operation in real-time, subject to override by the operator. The methods and systems may also include determining various downhole hydraulics parameters and a rotary friction factor. Historical data may be used in combination with real-time data to provide expert system assistance and to identify safety concerns.

The invention relates to a method and apparatus for opening threaded joints of drilling equipment (6) by striking the drilling equipment (6) with the percussion device of a rock drilling rig (1) and by measuring vibration originating from the drilling equipment (6) during striking. In addition to vibration, measuring means (9) measure a parameter defining at least one additional condition, on the basis of which the decision to stop striking is made.

Described herein is a wear indicator (100) for use in a drill bit or a core head. The wear indicator (100) comprises an elongate element that forms part of the drill bit. The elongate element has a plurality of numbers (110, 120, 130, 140, 150, 160, 170, 180) formed along its length, each number (110, 120, 130, 140, 150, 160, 170, 180) being formed as a void and corresponds to a level of wear in accordance with the IADC dull grading system. As the drill becomes worn, the wear indicator (100) wears at the same rate to reveal one of the numbers (110, 120, 130, 140, 150, 160, 170, 180). The numbers range from “1” to “8” where the number “1” illustrates the least wear and the number “8” indicates the most wear. When unworn, none of the numbers are visible.

A drill bit assembly for measuring reservoir formation properties comprises a bit head and a pin body, and an electrically insulated gap joint between two conductive parts of the drill bit assembly. The bit head has a cutting end and an opposite connecting end with an engagement section. The pin body comprises a connecting end with an engagement section. The pin connecting end is connected to the bit head connecting end such that the engagement sections overlap. The electrically insulating gap joint can fill a gap between the bit head and pin body engagement sections such that the bit head and pin body are mechanically connected together at the connecting ends but electrically separated. Alternatively or additionally, the pin body can have two pieces which are separated by an electrically insulating gap joint. An electrical conductor is electrically connected at a first end to the bit head and is communicable at a second end with an alternating current signal to transmit an alternating current into the bit head, thereby inducing an electric current into a reservoir formation adjacent the bit head. Electronic equipment includes measurement circuitry configured to determine the alternating current at the bit head, the alternating current being inversely proportional to a bit resistivity of the formation.

In some example embodiments, a system includes a drill string having a drill bit. The drill string extends through at least part of a well bore. The system also includes a first vibrational sensor, positioned on the drill bit to measure, at a first location on the drill string, an amplitude of one or more of an axial vibration and a lateral vibration. The system also includes a second vibrational sensor, positioned above the drill bit and on the drill string. The second vibration sensor is to measure, at a second location on the drill string, one or more of an axial vibration and a lateral vibration. The system includes a processor unit to determine a type of vibration based on a comparison of the amplitude at the first location to the amplitude at the second location, wherein the type of vibration is at least one of bit whirl of the drill bit and a while of a bottom hole assembly that is part of the drill string.

A cutting element for an earth-boring tool. The cutting element comprises a substrate base, and a volume of polycrystalline diamond material on an end of the substrate base. The volume of polycrystalline diamond material comprises a generally conical surface, an apex centered about a longitudinal axis extending through a center of the substrate base, a flat cutting surface extending from a first point at least substantially proximate the apex to a second point on the cutting element more proximate a lateral side surface of the substrate base. Another cutting element is disclosed, as are a method of manufacturing and a method of using such cutting elements.

An arrangement having a piston configured to move along an axial pathway a rotating seal configured to seal an inside environment from an outside environment, the rotating seal configured to be acted upon by a pressure exerted from the piston, a differential pressure sensor measuring a pressure difference between a first fluid from the outside environment and a second fluid on the inside environment, a motor connected to the piston, the motor configured to actuate the piston to a position along an axial pathway and an electronic feedback control system connected to the motor, the electronic feedback system configured to interface with the differential pressure sensor and maintain a pressure generated by the piston onto the rotating seal to a desired pressure.

Systems and methods for processing drilling data. One embodiment provides a method comprising building user-designed contexts (which can be designated as built-in contexts) for drilling structures. The method also comprises orchestrating module execution within the user-designed contexts. The method further comprises providing data from the user-designed contexts to such modules via an interface. Some methods include monitoring drilling data to detect events (for instance departure from a pseudolog) and orchestrating module execution responsive thereto. The method can include exposing the orchestration of the execution of the module instances as a service. Moreover, some embodiments provide extra-contextual application program interfaces. In addition, or in the alternative, some embodiments schedule the orchestration of the modules based on declarations related to the inputs and/or outputs of the modules.

Mobile drilling devices and systems, methods, and computer-readable media for controlling such devices are provided. One method includes receiving user input from a user of a mobile computing device. The method further includes transmitting data based on the user input from the mobile computing device to a control circuit of a mobile drilling device via a wireless network connection. The method further includes generating a plurality of control signals based on the data received from the mobile computing device. Each of the plurality of control signals is configured to control movement of a separate one of a plurality of movement devices of the mobile drilling device. The plurality of movement devices are configured to move the mobile drilling device between locations.

This invention provides a structure for gunpowder charge for charging gunpowders of different rates in combined fracturing perforation devices. The structure for gunpowder charge is convenient to mount and transport. In one embodiment, said structure for gunpowder charge comprises an inner gunpowder box located between adjacent perforating charges in the charge frame of a perforation device, and an outer gunpowder box attached to the outer wall of the charge frame, wherein said outer gunpowder box comprises one or two box units (2 or 4) with at least one claw at the inner side of said box unit, said claw can be locked into a groove or installation hole of the charge frame, and wherein said inner gunpowder box and said outer gunpowder box are charged with gunpowders of different burning rates.

A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

In at least some embodiments, a pulsed-electric drilling system includes a bit that extends a borehole by detaching formation material with pulses of electric current, and a drillstring that defines at least one path for a fluid flow to the bit to flush detached formation material from the borehole. A feed pipe transports at least a part of said fluid flow to said path, and the feed pipe is equipped with a cooling mechanism to cool the fluid flow. The use of a cooled fluid flow may enhance the performance of the pulsed-electric drilling process.

A method for managing a drilling operation, including generating, by a first sensor and a second sensor of a bottom hole assembly (BHA), a first time based data log and a second time based data log, respectively, representing a borehole parameter along a drilling trajectory, determining, by a computer processor of the BHA and during the drilling operation, a time shift by comparing the first time based data log and the second time based data log, where offsetting the first and second time based data logs by the time shift maximizes a correlation factor of the first and second time based data logs, and determining, within a pre-determined time period from generating the first and second time based data logs, a drilling speed based on the time shift and a pre-determined distance between the first sensor and the second sensor.

Apparatus and method for automated drilling of a borehole in a subsurface formation. In one embodiment, a method includes selecting at least one control variable. A drilling performance objective having a value that is influenced by drilling of the borehole using the at least one control variable is defined. A first interval of the borehole is drilled maintaining the at least one control variable at a first value. A second interval of the borehole is drilled maintaining the at least one control variable at a second value. A third interval of the borehole is drilled maintaining the at least one control variable at a third value. The third value is selected based on a comparison of the values of the drilling performance objective while drilling the first interval and second interval to a predetermined optimal value of the drilling performance objective.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) comprising a polycrystalline diamond (“PCD”) table including at least a portion having aluminum carbide disposed interstitially between bonded-together diamond grains thereof, and methods of fabricating such PDCs. In an embodiment, a PDC includes a substrate, and a PCD table bonded to the substrate. The PCD table includes a plurality of bonded-together diamond grains defining a plurality of interstitial regions. The PCD table further includes aluminum carbide disposed in at least a portion of the plurality of interstitial regions.

Disclosed herein is a method of delineating a second wellbore from a first wellbore. The method includes, emitting acoustic waves from a tool in the first wellbore, receiving acoustic waves at the tool reflected from the second wellbore, and determining orientation and distance of at least a portion of the second wellbore relative to the tool.

A method of monitoring a well for unwanted formation fluid influx is disclosed. Measurements of well outflow are acquired during a period in which drilling operations are performed for the well. Occurrences of stagnant flow events during the period are determined. An outflow signature is generated from the well outflow measurements for each stagnant flow event. The outflow signatures are displayed sequentially in time of occurrence. Each outflow signature is analyzed for an anomaly.

Method and apparatus for controlling rock drilling with a percussion device belonging to a rock drill to deliver stress waves to rock through a tool by pushing the tool against the rock by means of a feed motor and rotating simultaneously the tool by means of a rotation motor, whereby the maximum feed force is determined, pressure medium is supplied to the feed motor and to the rotation motor and the feed force is controlled according to the drilling conditions. The feed force is controlled on the basis of the feed speed and the rotation torque. The apparatus has a load control valve which controls the feed.