wellcat载荷介绍英文版.doc

Custom Load (Tube)Custom Load has tabs you use to specify density, pressure, and temperature profiles inside and outside the current string that are not available from any of the standard load types. Use the String tab to specify profiles inside the string and the Annulus tab to specify profiles outside.On the String tab, the Tubing Profile group box, located on the left, is used to define tubing density or tubing pressure profiles. On the Annulus tab, it is the Annulus Profile group box, and it is used to define annulus density or annulus pressure profiles.The Tubing and Annulus Temperature Profile group boxes are defaulted to undisturbed temperatures. Enter the temperature profile your want to model as final temperature for this load. Entries are assumed linear between the entered depths, and values should be entered at the top and base of the string.Fracture Screen-OutThis load case models the high injection pressure encountered at the end of a fracture operation. The prior load case (usually an injection case) is recalled for temperatures, internal densities, and external conditions (such as casing pressure).Fields and ControlsPump PressurePressure applied at the wellhead.Operation or LoadThis drop-down list box has the names of all loads or operations defined for the current string that can be linked to other loads. Selecting one of these items allows the code to use the temperature profile from the item as final temperature conditions for the current load case.Overpull (Tube)This load case models tension in the tubing string due to the air weight of the tubing (or buoyed weight in mud). An overpull force (usually applied to unseat a packer) can be specified to model additional surface tension applied to the tubing (usually to free stuck tubing). The temperatures specified on the Initial Conditions dialog are used as the temperature profile for the load case.Fields and ControlsOverpull ForceSpecify the overpull force.Running FluidDefine the fluid inside the well when the current string is run. This drop-down list box has the names of all fluid types for standard mud, compositional mud, brine, and air.Pressure Test (Tube)This load case models a tubing pressure test with pressure applied at the surface. An optional plug can be entered, and the axial force due to pressure acting on the plug will be included. The pressure below the plug is calculated based on the specified fluid density. The temperatures specified on the Initial Conditions dialog are used as the temperature profile for the load case.The following calculations are used: From the hanger to the plug depth,Pinternal = Ptest + g rmud TVD From the plug depth to the shoe,Pinternal = g rmud TVDFields and ControlsPump PressurePressure applied at the wellhead.Fluid Inside TubingFluid types available for specifying inside the tubing are Standard muds Standard hydrocarbons of gas type Compositional muds BrinesPlug PresentIf this check box is marked, a depth must be specified at which the plug will be placed. The default depth for the plug is defined as the base of the current string.Prod LinkThis load case is used to model the current string with the temperature profiles imported from a Prod operation.Fields and ControlsOperationContains initial conditions and the name of all Prod operations.Wellhead PressurePressure applied to the top of the fluid column in the current string.Fill from Annulus Contents Spreadsheet for Next StringIf marked, the density for the annulus fluid defined for the next string is used to define an internal density profile for the current string.FluidIf marked, you can specify a different fluid. Fluid types available are Standard muds Compositional muds BrinesPoint Axial LoadMarking this check box allows you to optionally apply an axial point load anywhere along the length of the current string.Axial ForceEnter the applied load value.Applied DepthSpecify the depth at which the axial force is applied.Pump-In to KillThis load case may result in worst-case burst loads at the surface for low permeability formations when a pump pressure significantly greater than the shut-in wellhead pressure is required to begin a bullhead kill operation.Temperature, internal density, and external conditions are recalled from the prior case (production or shut-in). It then applies the user-entered surface pressure.If you want to model thermal contraction loads during a kill operation, use the Transient Injection load as the prior operation or load.Fields and ControlsPump PressurePressure applied at the wellhead.Operation or LoadThis drop-down list box has the names of all loads or operations defined for the current string that can be linked to other loads. Selecting one of these items allows the code to use the temperature profile from the item as final temperature conditions for the current load case.Rod PumpThis load calculates tubing loads due to steady-state production in a well using a rod pump for artificial lift. WELLCAT uses the values you specify to perform a thermal simulation to calculate tubing temperatures and pressures based on the specified production conditions. These results are used to determine the forces acting on the tubing.The load calculation is based on data you specify to calculate the force acting on the tubing due to the differential pressure across the pump. This pressure acts on the cross-sectional area between the tubing ID and the pump bore diameter. A stress analysis can be performed for both an upstroke and downstroke. On an upstroke, the piston force due to the higher pressure above the pump is carried by the sucker rods and travelling valve, yet the pressure increase can cause buckling in the tubing. On a down stroke, this pressure force acts downward on the standing valve, and is carried by the tubing (that is, the valve is treated as a tubing plug).Fields and ControlsWellhead PressureFlowing pressure of the produced fluids at the top of the tubing string.Perforation DepthThis depth defines the location from which hydrocarbons are produced.Inlet TemperatureUndisturbed temperature at the perforation depth.Reservoir PressurePressure of the flowing fluid at the perforation depth.Produced FluidStandard hydrocarbon of type oil and gas as defined in the fluids inventory.Production RatesOilProduced oil flow rate from the well.WaterProduced water flow rate from the well.Rod Pump GeometryPump DepthDepth of the standing valve. The default value is the base of the production tubing.Pump Bore DiameterID of the pump bore.Sucker Rod DiameterThe diameter of the sucker rod.Shut-InThis load case models shut-in after production. Temperature, internal density, and external conditions are usually taken form the production case. Internal pressures are usually calculated based on the user-entered surface pressure and the fluid densities.If this is a long-term shut-in, temperatures are set to undisturbed. If gas is in the tubing during the shut-in, gas gravity can be entered and this will override the internal densities from the production case. Note that if gas gravity is not used, the calculated internal pressures may be slightly inaccurate for compressible fluids because the internal density is based on production temperatures and pressures.Fields and ControlsPressureThe pressure at the defined location.LocationThe location of either the wellhead or perforation. It defines the pressure location.Perforation DepthThe depth of the perforation. The default is the tubing base.Operation or LoadThis drop-down list box has the names of all loads or operations defined for the current string that can be linked to other loads. Selecting one of these items allows the code to use the temperature profile from the item as final temperature conditions for the current load case.Tubing Density From Operation of LoadMarking this option button imports the density from the Operation or Load field and uses it to calculate the densities inside the tubing. This option button is marked as the default setting inside this group box.Fluid Inside TubingMarking this option button allows you to specify a standard hydrocarbon or standard mud inside the tubing.Fluid Gradient Inside TubingMarking this option button allows you to specify a gradient inside the tubing rather than a density.Long Term Shut-In (Undisturbed Temperatures)Marking this check box sets the final temperatures to undisturbed.Steady-State InjectionThis load case models the injection of a water-base fluid into the tubing beginning with an undisturbed temperature profile. Injecting cool fluid will normally increase the tension in the tubing due to ballooning and thermal contraction. However, if there is a floating seal assembly at the packer, this load case can result in a reduction in tension due to the piston force acting on the seal assembly.Friction pressure drops are calculated using a power law rheological model. The rheological parameters (n prime and K prime) are determined by the program for user-entered fluid density.A temperature and pressure-dependent rheological fluid model is used, so the calculated pressure drop will not exactly equal the entered pressure drop for the entire tubing flow patch even with a single section tubing string.Fields and ControlsPump PressureDefines the injection pressure at the top of the tubing string.Inlet TemperatureDefines the temperature of the fluid as it is injected into the tubing.Injected FluidDefines the fluid being injected. The fluid type can be standard hydrocarbon, standard mud, or brine.Injection RateDefines the pump rate during the injection simulation.Perforation DepthThe depth at which injected fluids enter the formation.Steady-State ProductionThis load case models steady-state production of gas/oil/water fluids. Production usually results in a considerable amount of heat transfer to the tubing from the hotter produced fluid. This can result in a reduction in tension causing buckling due to thermal growth.The program uses a hybrid black oil model for the oil and dissolved gas, and a compositional model for the free gas. A composition using C1 C4 is determined based on the gas gravity. The Beggs and Brill model is used for two-phase flow pressure drops. The gas rate can be zero for water/oil production, and the liquid rates can be zero for gas production.Fields and ControlsPressureDefines the pressure of the flowing fluid at the specified location.LocationLocation of either the wellhead or perforations.Perforation DepthDefines the depth at which produced fluids enter the wellbore.Inlet TemperatureDefines the temperature at the perforation depth.Produced FluidDefines the fluid being produced up the well. It can be a standard hydrocarbon as defined in the fluids inventory.Production RatesInputThis drop down list box provides different criteria for entering production rate data. The options available are oil, gas, water oil, water, GOR gas, water, GORThe input option selected determines which three of the four input fields in the production rates group box are enabled.OilDefines the rate of oil production from the well.GasDefines the rate of gas production from the well.WaterDefines the rate of water production from the well.GORDefines the rate of GOR (gas-to-oil ratio) production from the well.Transient InjectionThis load case models steady state injection of natural gas. A compositional model for free gas is used. A composition using C1 C4 is determined based on the gas gravity.Gas pressures are based on the gas dynamic theories of Zucrow and Hoffman.Fields and ControlsPump PressureDefines the injection pressure at the top of the tubing string.Inlet TemperatureDefine the temperature of the fluid as it is injected into the tubing.I