Summary A simplified discrete-fracture model suitable for use with general-purpose reservoir simulators is presented. The handles both 2- and 3D systems includes fracture-fracture, matrix-fracture, matrix-matrix connections. formulation applies an unstructured control volume finite-difference technique a two-point flux approximation. implementation generally compatible any simulator that represents grid connections by connectivity list. specialized treatment based on "star-delta"...

ABSTRACT A simple, mechanistically based scheme for the calculation of pressuredrop in wells producing oil and gas single-phase liquid, bubble slugflow patterns is described checked with independent field data. The schemeis on an identification flow pattern through a modification theflow map Govier, Radford Dunn application themechanical energy balance form appropriate assuggested by Govier Aziz. Predictions some 48 are compared withfield data predictions Orkiszewski, Duns Ros, Hagedornand...

Summary The determination of the optimal type, location, and trajectory a nonconventional well is extremely challenging. problem more complicated than other optimization problems because wide variety possible types (i.e., number, orientation laterals) that must be considered. In this paper, general methodology for wells presented. procedure entails Genetic Algorithm (GA) applied in conjunction with several acceleration routines include an artificial neural network, hill climber, near-well...

Summary Drift-flux modeling techniques are commonly used to represent two- and three-phase flow in pipes wellbores. Unlike mechanistic models, drift-flux models continuous, differentiable, relatively fast compute, so they well suited for use wellbore within reservoir simulators. require a number of empirical parameters. Most the parameters current simulators were determined from experiments small-diameter (2 in. or less) pipes. These may not be directly applicable wellbores surface...

Abstract Mechanistic models for multiphase flow calculations can improve our ability to predict pressure drop and holdup in pipes, especially situations that cannot easily be modeled a laboratory which reliable empirical correlations are not available. In this paper, new mechanistic model, applicable all pipe geometries fluid properties, is presented. New proposed liquid/wall liquid/gas interfacial friction stratified flow, the liquid fraction entrained annular-mist distribution coefficient...

Abstract A semi‐mechanistic model for two phase gas‐liquid slug flow proposed recently by Dukler and Hubbard has been modified extended to apply the entire intermittent regime. Flow predictions of in this paper are compared with detailed experimental data obtained an air‐oil system. The requires use empirical correlations velocity situ liquid volume fraction slug. In addition, either frequencies or length corresponding given design conditions must be known. However, calculated values average...

A method is presented for numerical finite difference solution of the equations motion in three dimensions. The complete Navier-Stokes are transformed and expressed terms vorticity a vector potential. solved using an alternating direction parabolic portion problem, successive over-relaxation elliptic portion. classical problem convection fluid layers bounded by solid walls heated from below both two Comparison with other methods prior work dimensions shows that new here has important...

Abstract Practical production optimization problems typically involve large, highly complex reservoir models, thousands of unknowns and many nonlinear constraints, which makes the numerical calculation gradients for process impractical. This work explores a new algorithm using optimal control theory. The approach is to use underlying simulator as forward model its adjoint gradients. Direct coding is, however, time consuming, code dependent on in sense that it must be updated whenever...

ABSTRACT The commonly used Cartesian and hybrid local grid refinements have the disadvantage that base is always Cartesian, which makes it difficult to align along reservoir heterogeneities. Also, locally orthogonal Voronoi A;-orthogonal perpendicular bisector (PEBI) grids are only useful for isotropic or limited anisotropic permeability distributions. finite-difference approach proposed in this paper overcomes limitations of existing flexible gridding schemes modeling full, asymmetric...

Summary The general petroleum-production optimization problem falls into the category of optimal control problems with nonlinear control-state path inequality constraints (i.e., that must be satisfied at every time step), and it is acknowledged such involving state variables can difficult to handle. Currently, one methods implicitly incorporates forward adjoint equations address this issue. However, these either are impractical for production or require complicated modifications...

Abstract A simplified discrete fracture model suitable for use with general purpose reservoir simulators is presented. The handles both two and three-dimensional systems includes fracture-fracture, matrix-fracture matrix-matrix connections. formulation applies an unstructured control volume finite difference technique a two-point flux approximation. implementation generally compatible any simulator that represents grid connections via connectivity list. specialized treatment based on...

Summary. Three related stream injection problems are presented along with simulation results for them obtained from six organizations. The problem selected comparison were intended to exercise many of the features thermal models that practical and theoretical interest. first deals three cycles cyclic steam other two deal displacement in an inverted nine-spot pattern. "black-oil" type third compositional type. Complete data these problems. solutions indicates good agreement most importance...

Summary A technique is presented to improve the treatment of wells in reservoir simulators by use an orthogonal curvilinear grid (cylindrical or elliptical) well regions and a rectangular elsewhere reservoir. Special methods are developed handle irregular blocks connecting two types regions. The nonlinear equations for Regions solved with different levels implicitness; simultaneous solution (implicit) method applied regions, while implicit pressure, explicit saturation (IMPES) used region....

Abstract This paper describes an implicit-pressure explicit-composition and explicit-saturation compositional model. The model uses equation of state (Peng-Robinson) for phase equilibrium density calculations. Interfacial tension effects are considered also. formulation the pressure yields a symmetric diagonally dominant matrix that allows use iterative conjugate gradient method large systems. Simulation laboratory CO2 displacements shows good agreement between calculated experimental...

Summary In this paper, a single-phase wellbore-flow model is presented that incorporates not only frictional, accelerational, and gravitational pressure drops, but also the drop caused by inflow. The new readily applicable to different wellbore-perforation patterns well completions, can be easily incorporated into reservoir simulators or analytical, reservoir-inflow models. It found influence of either inflow outflow depends on flow regime present in wellbore. For laminar wellbore flow, wall...