ENERGY SCIENCE AND TECHNOLOGY SOFTWARE CENTER
U.S. Department of Energy
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# SOFTWARE ABSTRACT

PACKAGE ID 000375MNFRM00 HORIZ/SLNTD/WELL/MOD Oil Production Ming-Ming Chang UNL/UNL 07/01/1989 07/01/1989 A horizontal and slanted well model was developed and incorporated into BOAST, a black oil simulator, to predict the potential production rates for such wells. The HORIZONTAL/SLANTED WELL MODEL can be used to calculate the productivity index, based on the length and location of the wellbore within the block, for each reservoir grid block penetrated by the horizontal/slanted wellbore. The well model can be run under either pressure or rate constraints in which wellbore pressures can be calculated as an option of infinite-conductivity. The model can simulate the performance of multiple horizontal/slanted wells in any geometric combination within reservoirs. ESTSC Note; Software Abstract; NIPER-326;\ 1 CD Rom Y 1 Technically, the HORIZONTEL/SLANTED WELL MODEL is a finite-difference, implicit pressure-explicit saturation (IMPES) numerical simulator. It contains both direct and iterative solution techniques for solving systems of algebraic equations. Implementation of no-flow boundary conditions is acheived by setting transmissibilities at boundary interfaces to zero. Based on the location of the horizontal (or vertical/slant) well defined in the reservoir grids, the well model first determines reservoir grid blocks penetrated by the wellbore. It then calculates the productivity index (PID) for the wellbore within each penetrated grid block. The PID value of each wellbore block is computed from the wellbore length and geometric location of the wellbore within the block. Since the wellbore may not be parallel to the boundaries of its rectangular reservoir block, the horizontal/slanted wellbore located anywhere in a rectangular block is first broken down into three vector components. The PID of the wellbore block is then calculated separately for the three components, assuming that the well was located in the middle of the wellbore contained in the rectangular block. The calculated PIDS are then combined as the PID of the horizontal/slanted wellbore for that block. The HORIZONTAL/SLANTED WELL MODEL can be used to calculate the wellbore productivity for both nonboundary and boundary blocks which contain up to four reservoir boundaries. MAINFRAMES Machine Dependent BOAST is a three-dimensional, three-phase black oil simulator for solving reservoir engineering and production problems. BOAST simulates isothermal, Darcy flow in three dimensions. It can simulate oil and/or gas recovery by fluid expansion, displacement, gravity drainage, and capillary inhibition mechanisms. The model was checked against the analytical formulas of transient wellbore pressure in an infinite slab reservoir. A close match having an average deviation of only plus or minus 4% was found between the analytical formula and the fully penetrating slanted well model after a production period of early radial flow. A good agreement was also obtained between the simulation results of the horizontal model and published analytical curves. Ming-Ming Chang, Simulation of Production from Wells with Horizontal/Slanted Laterals, NIPER-326, March 1989; Ming-Ming Chang, User''s Guide to the Computer Simulation Program Accompanying DOE Report: NIPER-326, June 1989. One megabyte or more of memory. HORIZONTAL/SLANTED WELL MODEL submitted July 1989. DOE/FE National Petroleum Technology Office