5 THE I RECORDS

The I data group is devoted basically to a definition of initial conditions for the global system. It supplements similar data read by subroutine READ1. Pressures are initialized within READ1 by assuming hydrostatic equilibrium with pressure PINIT at depth HINIT (READ R1-16). Temperatures are also initialized within that routine by linear interpolation from the table (ZT(I), TD(I)) (READ R1-11). The I records are read by subroutine INIT. The data obtained thereby may then be used to modify the initial pressure distribution to that appropriate for a natural flow within the reservoir. In this case, global boundary conditions prescribed in READ R1-28 for the up- and down-gradient faces of the system are respecified to their natural-flow values. In addition, both brine and radionuclide concentrations may be modified as desired from their default value of zero.

Reference: Reeves et al. [1986a], Section 5.1.

5.1 CONTROL PARAMETERS

If the initial concentrations are zero everywhere for both brine and radionuclides, and there is no natural flow, insert a blank record for READ I-1 and proceed to READ R1A-1.

 

READ I-1 (3I5)

LIST: ICOMP, INAT, IRD
  ICOMP Control parameter for initializing brine concentrations.
  0 - Initial concentrations in all the grid blocks are zero.   1 - The initial brine concentrations are not zero everywhere. Nonzero concentrations will be entered in READ I-2.
  INAT Control parameter for entering initial fluid velocity.
  0 - The reservoir fluid is static initially.   1 - The resident fluid velocity will be entered in READ I-3.   NOTE: While this will initialize a uniform flow field, the gradient will not necessarily be maintained during a transient flow simulation. To maintain a natural flow field, use perimeter wells (R2-4, 5, 6, 7) or prescribed pressures (R1-28).
  IRD Control parameter for initializing radioactive/ trace component concentrations.
  0 - Initial concentrations in all the grid blocks are zero.   1 - Nonzero concentrations for each component will be entered in READ I-4.
 

5.2 INITIAL BRINE CONCENTRATIONS

Skip the following READ if ICOMP = 0. If ICOMP = 1, read as many records as necessary following the last record with a blank record.

 
READ I-2 (6I5, E10.0)
 

I1, I2 Lower and upper limits, inclusive, on the I index of the region having a nonzero initial brine concentration.

J1, J2 (Similar definition for the J index).

K1, K2 (Similar definition for the K index).

CINIT Initial brine concentration in each of the blocks of the defined region, mass fraction.
 

5.3 INITIAL VELOCITY CONDITION

Reference: Reeves et al. [1986a], Section 5.1.1.

If INAT = 0, skip the following record.

READ I-3 (E10.0)

LIST: VEL
  VEL Initial velocity of the resident reservoir fluid in the x direction, ft/d (m/s). Initial velocities in the y and z directions are assumed to be zero. Under this option, boundary pressures corresponding to the initial velocity are calculated and fixed at their natural-flow values. This option is not intended to replace the steady-state pressure solution, rather, initial conditions for transient simulation.

5.4 INITIAL RADIONUCLIDE CONCENTRATIONS

If IRD = 0, skip this READ. If IRD = 1, read as many records as necessary following the last record with a blank record. A total of NCP such sets of data are required, in the order of increasing component number, with a blank record terminating each set.

READ I-4 (6I5,E10.0)

LIST: I1, I2, J1, J2, K1, K2, CINIT
  I1, I2 Lower and upper limits, inclusive, on the I index of the region having a nonzero initial radionuclide concentration.

J1, J2 (Similar definition for the J index).

K1, K2 (Similar definition for the K index).

CINIT Initial radionuclide concentration for the component being entered, mass fraction.