Sensitivity study of fracture parameters in a carbonate oil reservoir

2011 ◽  
Author(s):  
Mohammed Alhussain ◽  
Kyle T. Spikes ◽  
Mrinal K. Sen
Keyword(s):  
Sensitivity Study ◽  
Oil Reservoir ◽  
Fracture Parameters

Sensitivity of Steamflood Model Results to Grid and Timestep Sizes

1984 ◽  
Vol 24 (01) ◽  
pp. 65-74 ◽  
Author(s):  
Jamal Hussein Abou-Kassem ◽  
Khalid Aziz
Keyword(s):  
Heavy Oil ◽  
Size Effects ◽  
Truncation Error ◽  
Injection Pressure ◽  
Steam Injection ◽  
Sensitivity Study ◽  
Grid Size ◽  
Oil Reservoir ◽  
Fully Implicit ◽  
Heavy Oil Reservoir

Abstract Numerical simulation of complex processes in oil reservoirs has become a standard tool. The grid size and timestep sensitivity of a simulator are of prime concern in reaching the correct conclusions in any study. This paper presents an analysis of the sensitivity to timestep and grid size of a one-dimensional (1D) and two-dimensional (2D) compositional multiphase steamflood model used to simulate a heavy-oil reservoir. The behavior of primary variables before breakthrough in the 1D and 2D cases is presented for clearer understanding of steamflooding heavy-oil reservoirs. The peculiar features exhibited by primary variables of the production and injection blocks for the 1D reservoir plus timestep and grid-size effects on primary variables for 2D cases studied are discussed. Sensitivity studies of grid and timestep size are meaningful only if each is carried out while the other variable has minimum truncation error. The recovery performance parameters are less sensitive to timestep size than to grid size. They are also less sensitive in the 2D runs than in the 1D runs. The time/pore-volume-injected (PVI) relationship is very sensitive to grid size, and to a lesser extent, to timestep size. Introduction Numerical dispersion is particularly important in simulating multiphase flow, miscible displacement, and compositional phenomena. Settari recommends that detailed study be carried out on grid- and timestep-size effects. A grid-size sensitivity study is recommended when a reservoir is simulated to define the necessary grid size used. Such a study requires a series of simulation runs with increasing or decreasing grid definition. When simulators with fully implicit formulation are used, where large time steps are possible, the time truncation error also can become important. Therefore, a timestep sensitivity study for these simulators is also necessary."Sensitivity analysis" refers to the sensitivity of the primary variables and recovery performances to grid and timestep size. A review of recent literature reveals that grid and timestep effects have not been studied on all primary variables for 1D simulations and are lacking for 2- or 3D simulations. Sensitivity analyses for both 1- and 2D simulation of a heavy-oil reservoir along with a study of the behavior of primary variables in steamflooding are presented. Simulator and Data Used The simulator used in this study was developed by Abou-Kassem. A brief description of the simulator is given in Ref. 9. It is a fully implicit, compositional, three-phase steamflood model. The model employs a sophisticated well model and a nine-point finite-difference scheme in two dimensions only. It can be operated in 1- and 2D modes with the choice of block-centered or point-distributed grid. In this paper only results of a block-centered grid with gas hysteresis and with no heat loss to surrounding formations are presented. The reservoir is represented by a one-fourth five-spot flood pattern with dimensions of 137 × 137 × 63 ft [41.76 × 41.76 × 19.2 m]. The permeability and porosity are 4 darcies and 0.38, respectively. The reservoir is initially saturated with 18 % water and 82 % heavy oil composed of 70 % nonvolatile oil component and 30 % methane. The nominal mobility ratio is 285,000, which corresponds to an effective mobility ratio of about 10,000. The Appendix provides more detailed data. Steam of 0.70 quality at an injection pressure of 1,000 psia [6.9 MPa] was injected into the reservoir having an initial pressure and temperature of 554 psia [3.9 MPa] and 60F [288.7K], respectively. The maximum steam injection rate was 883 cu ft/D [25 m3/d] cold water equivalent (CWE). The production well was put on "deliverability" control with a bottomhole pressure (BHP) of 400 psk [2.8 MPa]. The reservoir is simulated with a uniform grid (with square block for 2D). Results and Discussion Results of the simulator used in this study were compared with results obtained from a commercial steam model in 1D and 2D modes. Excellent agreement was obtained when the simulator was run with the five-point finite-difference formulation. The 2D results presented next are for a diagonal grid with the nine-point difference scheme. Behavior of Primary Variables in Steamflood Simulation. Primary Variables of Injection Well Block (1-D Simulation). The behavior of the primary variables associated with the injection block as a function of PVI is shown in Fig. 1. As steam injection begins, the pressure increases first moderately then very rapidly because the system has been compressed and all fluids are almost immobile. The pressure of the injection block is slightly less than the maximum injection pressure. SPEJ P. 65^

scholarly journals Sensitivity Study to Evaluate the Impact of Critical Parameters for Feasibility of Air-Injection in Light-Oil Reservoir

2018 ◽  
Vol 11 (31) ◽  
pp. 1-7
Author(s):  
Tunio Abdul Haque ◽  
Majeed Shar Abdul ◽  
Qureshi Muhammad Furqan ◽  
Mahesar Aftab Ahmed ◽  
◽  
...  
Keyword(s):  
Sensitivity Study ◽  
Air Injection ◽  
Critical Parameters ◽  
Oil Reservoir ◽  
Light Oil ◽  
The Impact

Race Difference in Auditory Sensitivity

1964 ◽  
Vol 7 (4) ◽  
pp. 389-393 ◽  
Author(s):  
David C. Shepherd ◽  
Robert Goldstein ◽  
Benjamin Rosenblüt
Keyword(s):  
White Women ◽  
White Men ◽  
Sensitivity Study ◽  
Auditory Sensitivity ◽  
Race Difference ◽  
Men And Women ◽  
Auditory Thresholds ◽  
Békésy Audiometry ◽  
Method Of Adjustment ◽  
Better Than

Two separate studies investigated race and sex differences in normal auditory sensitivity. Study I measured thresholds at 500, 1000, and 2000 cps of 23 white men, 26 white women, 21 negro men, and 24 negro women using the method of limits. In Study II thresholds of 10 white men, 10 white women, 10 negro men, and 10 negro women were measured at 1000 cps using four different stimulus conditions and the method of adjustment by means of Bekesy audiometry. Results indicated that the white men and women in Study I heard significantly better than their negro counterparts at 1000 and 2000 cps. There were no significant differences between the average thresholds measured at 1000 cps of the white and negro men in Study II. White women produced better auditory thresholds with three stimulus conditions and significantly more sensitive thresholds with the slow pulsed stimulus than did the negro women in Study II.

A Sensitivity Study on Low Salinity Waterflooding

2017 ◽  
Vol 04 (03) ◽  
pp. 231-236 ◽  
Author(s):  
Barham S. Mahmood ◽  
Jagar Ali ◽  
Shirzad B. Nazhat ◽  
David Devlin
Keyword(s):  
Sensitivity Study ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Sensitivity study of precision pressurized membrane reflector deformations

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 308-314
Author(s):  
G. Greschik ◽  
M. Mikulas ◽  
A. Palisoc ◽  
C. Cassapakis ◽  
G. Veal
Keyword(s):  
Sensitivity Study
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