Showing papers on "Annulus (oil well) published in 1994"

Aspects of Wellbore Heat Transfer During Two-Phase Flow (includes associated papers 30226 and 30970 )

Abstract: Wellbore fluid temperature is governed by the rate of heat loss from the wellbore to the surrounding formation, which in turn is a function of depth and production/injection time The authors present an approach to estimate wellbore fluid temperature during steady-state two-phase flow The method incorporates a new solution of the thermal diffusivity equation and the effect of both conductive and convective heat transport for the wellbore/formation system For the multiphase flow in the wellbore, the Hasan-Kabir model has been adapted, although other mechanistic models may be used A field example is used to illustrate the fluid temperature calculation procedure and shows the importance of accounting for convection in the tubing/casing annulus A sensitivity study shows that significant differences exist between the predicted wellhead temperature and the formation surface temperature and that the fluid temperature gradient is nonlinear This study further shows that increased free gas lowers the wellhead temperature as a result of the Joule-Thompson effect In such cases, the expression for fluid temperature developed earlier for single-phase flow should not be applied when multiphase flow is encountered An appropriate expression is presented in this work for wellbores producing multiphase fluids

Gas-liquid separator for well pumps

Abstract: A gas-liquid separator for a well pump includes a stationary helical baffle disposed in a tubular housing for separating gas from liquid and conducting gas through a center conduit disposed in the housing to a tubing string in communication with the separator or into the well annulus for flow to the surface. The baffle may be interposed in a conventional downhole submersible pump between the motor section and the pump section and the pump section may be modified to have a hollow impeller drive shaft for conducting gas separated by the separator through the pump section and out of gas discharge ports in the pump section housing. In an alternate embodiment gas is discharged from the hollow drive shaft into the tubing string and liquid separated from the gas is pumped through the pump section and out into the wellbore annulus. The baffle may have at least two stages, one of which causes some of the liquid being conducted through the separator to bypass the second separator stage and flow directly to the pump inlet so that more effective separation of gas from liquid occurs in the second stage and all of the liquid entering the pump inlet has minimal gas content.

Frac pack flow sub

Abstract: Gravel slurry is pumped through the longitudinal service bore of a tubular service tool which is extended through a packer mandrel and into the seal bore of a tubular cross-over tool which is disposed in the annulus between the service tool and a well casing. Slurry flow is directed from the service bore through a cross-over flow port of the cross-over tool into the annulus between the cross-over tool and the well casing. The gravel-laden slurry is injected through casing perforations into the surrounding earth formation at a high flow rate. After the fracture operation has been completed, the slurry flow rate is reduced substantially and a gravel pack is accumulated in the annulus between the well screen and the well casing. Slurry liquid is circulated through the well screen into a return flow bore of the service tool. The slurry liquid is then conducted through a longitudinal cross-over flow passage formed through the cross-over tool into a return annulus defined between the service tool and the packer mandrel. The slurry liquid is then conducted through the annulus between the service tool and the well casing to the surface.

Apparatus for increasing productivity by cutting openings through casing, cement and the formation rock

Abstract: A perforator to increase conductivity of a deposit bearing region of oil, gas, and/or water saturating a rock formation having a wellbore hole therethrough and, thus, increase production by cutting elongated openings (slots) through casing, cement bond and formation rock. The perforator is attached to the bottom end of a string of drill pipes. The string of drill pipes are connected to a surface raising and lowering device for raising and lowering the string of drill pipes into a wellbore hole. A pump pumps an abrasive liquid into the perforator through the string of drill pipes. The perforator has telescoping nozzles and double jet nozzles. The abrasive liquid is jetted at a high velocity out of the telescoping jet nozzles and the double jet nozzles. By shifting the perforator with the raising and lowering device while pumping the abrasive liquid into the perforator, slots are cut in the casing, cement bond and formation rock along wellbore axis. A stream of abrasive liquid ejected from the telescopic jet nozzle penetrates and deepens the slot made by a stream of abrasive liquid ejected from double jet nozzles. The abrasive liquid returns to the surface of the well in the annulus between the casing and the string of drill pipes to the wellhead and exits the annulus through the side outlet.

Method and apparatus for drilling with high-pressure, reduced solid content liquid

Abstract: A drillstring terminating in a drill bit is run into a borehole. A reduced solid content drilling fluid is pumped through the drillstring and out the bit, wherein the drilling fluid impinges upon and disintegrates formation material in cooperation with the bit. An annulus fluid having a density greater than that of the drilling fluid is continuously pumped into the annulus between the borehole and drillstring, wherein the annulus fluid extends substantially from the surface to the bottom of the drillstring. Drilling fluid and cuttings resulting from disintegration of formation material are returned to the surface through a substantially unobstructed tubular passage in the drillstring. The annulus fluid is maintained under a selected and controlled pressure in the annulus, wherein an interface is formed at the drill bit at which annulus fluid mixes with the drilling fluid and is returned along with the drilling fluid and cuttings and drilling fluid is substantially prevented from entering the annulus.

Exhaust fan apparatus

Abstract: An exhaust fan to be mounted on a roof and for exhausting spent gases from a building, including a centrifugal fan scroll casing with a centrifugal fan impeller mounted on an axle within the casing and having an axis of rotation at right angles to the side members of the scroll casing. A bifurcated stack including two generally parallel passageways is connected to the scroll casing so that the stack is upright and communicates with the outlet port of the scroll casing. A ring defining an annulus may be provided at the outlet end of the stack to induce ambient air to mix with the spent air exhausting from the bifurcated tubular member.

Anchor system for pipe cutting apparatus

Abstract: An apparatus for cutting pipe disposed in a string down a borehole of an oil or gas well, including an elongated body for lowering into the bore of the string and defining an annulus between the body and the pipe wall, a quantity of combustible material supported within the elongated body, for providing a cutting flame when the material is ignited, a nozzle to direct the cutting flame radially outward from the body against the wall of the pipe to be cut, and an anchor supported along the lower end of the body, of a desired length and diameter defining an annulus below the cutting nozzle, so that upon the ignition of the material, the pressure of the gases produced by the ignition which collect in the annulus formed by the anchor below the nozzle is substantially equal to the gas pressure in the annulus formed by the body, and the cutting nozzle is maintained at a stable point within the hole to produce an even cut. The cutting device used in the method of the present invention may also include a chemical cutting device.

Gas well tubing flow rate control

Abstract: Gas in association with liquids is produced from a wellbore by disposing a first tubing string having a first fluid communication path into the wellbore to near or below the bottom of a producing zone, disposing within the annulus between the first tubing string and the outer surface of the wellbore a second fluid communication path from near or below the bottom of the producing zone to an offtake line at the surface, disposing a choke means in at least one of the fluid communication paths, and producing gas while controlling the choke means to establish sufficient gas flow up the first fluid communication path so as to unload liquids from near or below the bottom of the producing zone and produce the liquids up the first tubing string in association with gas flow In accordance with a preferred embodiment, the first tubing string has a sufficiently small diameter that liquids can be unloaded from the well over life of the production Preferably, the choke means is a valve automatically controlled by differential pressure controller measuring pressure differential across an orifice plate in the first fluid communication path

Viscid oil well completion

Abstract: A horizontal well completion apparatus and method for heavy, viscous oil in a producing zone (114) are disclosed using a single well Hot injection fluid is injected into an injection string (120), and emitted through steam distribution holes (133) in the lower portion (120) of the injection string into the casing (116) near perforations (118) A packer (126) separates the upper well annulus (140) from the lower well annulus (142) Insulation (121) surrounds injection tubing string (120) between the packer (126) and the well head (111) Perforations (118) in the horizontal portion (112) of the well allow heated oil to flow into the lower annulus 42 in the horizontal portion (112) of the well where is picked up by the injected fluid and lifted to the surface of the well by a jet pump (128) Temperature and pressure in the lower well annulus (142) are controlled by the temperature and pressure of the injection fluid, and the pumping rate of the produced fluids

Core-annular flow of liquid membrane emulsion

Abstract: A modeling and experimental study of the core-annular flow (CAF) was carried out with a viscous liquid membrane emulsion as the core and an aqueous solution as the annulus. A hydrodynamic model has been developed for stable CAF with a centered, nondeformable core surrounded by a turbulent aqueous annulus with or without a drag reducer. This model has been verified with data from flow tests with viscous emulsions in a horizontal flow loop of 3/4-in. (19-mm) tubing and a fullscale, down-hole well tubing of 2-7/8 in. (73 mm). By the use of this model along with the data, the effects of annular size on total and core flow rates and pressure drop are investigated for annuli with and without a drag reducer.

Double tilting pad journal bearing

Abstract: A double tilting pad journal bearing includes a substantially cylindrical, open ended beating casing having a longitudinal axis extending therethrough, an interior surface of which supports a plurality of beating liner pads for circumferential and axial tilting movement relative to the casing and to the longitudinal axis. The casing is formed with a pair of annular oil feed grooves in the exterior surface thereof communicating with the interior of the bearing casing by a plurality of radially directed feed passages. The interior surface is also formed with at least one oil drain annulus in communication with at least one radially oriented drain port. Annular seals are fitted within grooves at opposite ends of the bearing casing. The bearing liner pads are secured within the casing by a sliding tongue and groove fit which nevertheless permits tilting of the pads both circumferentially and axially. Locking pins are used to hold the bearing liner pads in proper circumferential orientation within the bearing casing.

Method of selective treatment of open hole intervals in vertical and deviated wellbores

Abstract: A method for repairing damaged sections of an oil well includes the use of a combination of two fluids, pumped simultaneously to allow treatment of a specific part of a portion of an oil producing zone. A first fluid is pumped down a coiled tubing and a second fluid is pumped down the annulus formed by the coiled tubing and the production tubing. Because of density differences in the two fluids, diversion is facilitated, treating the lower part of the pay zone with the first fluid and the second fluid to keep the first fluid away from the upper section of the open hole. The coiled tubing could be raised or lowered during this procedure to help ensure desired zone coverage.

Adjustable surface well head casing hanger

Abstract: A surface wellhead system for a subsea well utilizes a two-piece casing hanger. The casing hanger has an inner member that secures to a string of casing that extends from the sea floor to a surface casing head. The outer member of the casing hanger is axially adjustable relative to the inner member and will hold tension in the casing. The outer member lands on a load shoulder in the casing head. An annulus outer seal seals between the exterior of the outer member and the bore of the casing head. An inner seal seals between the inner member and the bore of the outer member.

Well fluid isolation and sample apparatus and method

Abstract: The present invention specifically permits purging and/or sampling of a well but only removing, at most, about 25% of the fluid volume compared to conventional methods and, at a minimum, removing none of the fluid volume from the well. The invention is an isolation assembly that is inserted into the well. The isolation assembly is designed so that only a volume of fluid between the outside diameter of the isolation assembly and the inside diameter of the well over a fluid column height from the bottom of the well to the top of the active portion (lower annulus) is removed. A seal may be positioned above the active portion thereby sealing the well and preventing any mixing or contamination of inlet fluid with fluid above the packer. Purged well fluid is stored in a riser above the packer. Ports in the wall of the isolation assembly permit purging and sampling of the lower annulus along the height of the active portion.

Method for accessing bypassed production zones

Abstract: A method for establishing production of oil or gas from a secondary production zone which is above a primary production zone in a well in which a settable material is placed in the annulus between the casing and the tubing above the secondary production zone and allowed to set up, and the secondary zone is then perforated with a through-tubing perforating gun.

Heat controlled oil production system and method

Abstract: The heat control production system and method for an oil well utilizes a noncorrosive gas compatible with crude oil fire hazards to provide an insulating annulus between the production tubing string of an oil well and the bore hole or casing or other tubing string surrounding the production tubing string by pressurizing the insulating annulus from the source of gas such that crude oil from the oil reservoir enters the insulating annulus and interfaces with the gas intermediate the surface and the oil reservoir whereby the insulating annulus provides minimal heat transfer to allow the crude oil produced through the production tubing string to reach the surface at a preselected temperature up to the oil reservoir temperature which avoids undesirable precipitation or gelling of paraffinic hydrocarbons from heat loss to the overburden of the oil well.

Method for measuring the velocity of water flow through nested conduits

Abstract: This disclosure provides a method for measuring the velocities of water volumes flowing co-directionally in separate conduits nested such as in injection or production well-bores. The method allows an oxygen activation measurement of thevelocity of the water flow in the tubing-casing annulus in the presence of waterflowing in the tubing string in the same direction. The method allows continuouslogging at variable or constant cable velocities or stationary logging. Based on the method of velocity gauging, the method isolates the signal from the annular flow and can produce a continuous log of linear and volumetric annular flow rates with depth.

Method for enhanced cleanup of horizontal wells

Abstract: A method for improving the efficiency of horizontal wellbore cleanout of a horizontal wellbore drilled from a vertical wellbore, having a perforated liner cemented across the horizontal wellbore. The method includes running a coiled tubing into the horizontal wellbore. A first cleanup fluid is injected down the coiled tubing and a second cleanup fluid is injected down an annulus formed by the coiled tubing and the wellbore. The injection rates of the cleanup fluids in the coiled tubing and the annulus are balanced. The coiled tubing is moved back and forth over the horizontal wellbore.

Sand washing with coiled tubing

Abstract: The paper discusses the procedure of washing sand or other deposits from wells by means of coiled tubing and Newtonian fluids. Factors affecting the operation also are discussed. In order to execute the operation properly the pump capacity must be estimated to secure the required fluid flow velocity in the annulus as well as the pressure drop for so defined fluid flow capacity.

A method of measuring the velocity of liquid flow

Abstract: A method of measuring the velocities of water volumes flowing co-directionally in separate conduits (14, 18) nested such as in injection or production well-bores allows an oxygen activation measurement of the velocity of the water flow in the tubing-casing annulus (20) in the presence of water flowing in the tubing string in the same direction. The method provides continuous logging at variable or constant cable velocities or stationary logging. Based on the method of velocity gauging, the method isolates the signal from the annular flow and can produce a continuous log of linear and volumetric annular flow rates with depth.

Three-dimensional nonlinear analysis of drill string structure in annulus

Abstract: Three-dimensional nonlinear analysis of drill string structure in annulus of curved wellbore is done by using the theory of finite element and Newton-Raphson method. According to the characteristics of its deformation, a method of the description and computation of taking different forms of elements for different parameters is advanced. The penalty function method is applied for finding the unknown boundary. The nonlinear effects of curvature of wellbore on the side forces on bit are shown by the computation.

Variable delivery vane pump.

Abstract: A primary vane pump suitable for an aircraft jet engine fuel pump has a rotor with vanes, and an intermediate casing, which is also rotatable, both mounted in a fixed housing. The rotor vanes are enclosed in the casing and provide a primary pumping stage. The intermediate casing has outer vanes enclosed with the fixed housing, which provide a governor stage vane pump when the casing rotates. An inlet annulus supplies fuel to passages in the rotatable casing leading to the primary pumping stage and other passages in the rotatable casing conduct pumped fluid out to a discharge annulus. A closed fluid loop is established from discharge annulus to the governor stage vane pump, out through a valve and back to the discharge annulus. The reaction on the casing caused by the primary pump rotor tends to rotate the intermediate casing, while pressure drop through the valve in the closed fluid loop resists rotation. Adjustment of the valve adjusts rotational speed of the intermediate casing and varies the delivery rate of fuel by the primary vane pump.