GENER

GENER introduces sinks and/or sources

Record GENER.1

Free format for 11 parameters.

ELNE, SLNS, LTAB, TYPE, ITAB, GX, EX, HX, LOT12, LOT13, LOT14

or Format (A3, I2, A3, I2, 4I5, 5X, A4, A1, 6E10.4) (for 5 -character element name only).

EL, NE, SL, NS, NSEQ, NADD, NADS, LTAB, TYPE, ITAB, GX, EX, HX, LOT12, LOT13, LOT14

ELNE name of the element containing the sink/source.

SLNS name of the sink/source.

EL, NE code name of the element containing the sink/source.

SL, NS code name of the sink/source. The first three characters are arbitrary, the last two characters must be numbers.

NSEQ number of additional sinks/sources with the same injection/production rate (not applicable for TYPE = DELV, used for formatted input only).

NADD increment between the code numbers of two successive elements with identical sink/source (used for formatted input only).

NADS increment between the code numbers of two successive sinks/sources (used for formatted input only).

LTAB number of points in table of generation rate versus time. Set 0 or 1 for constant generation rate. For wells on deliverability, LTAB denotes the number of open layers, to be specified only for the bottommost layer.

TYPE specifies different options for fluid or heat production and injection. For example, different fluid components may be injected, the nature of which depends on the EOS module being used. Different options for considering wellbore flow effects may also be specified.

HEAT	Introduces a heat sink/source
COM1	component 1 (water)
WATE	Water
COM2	component 2
COM3	component 3
∙∙∙
COMn	component n
MASS	mass production rate specified
DELV	well on deliverability against specified bottomhole pressure.
F--- or f---	well on deliverability against specified wellhead pressure

For DELV, if a well is completed in more than one layer, bottommost layer must be specified first, with number of layers given in LTAB. Subsequent layers must be given sequentially for a total number of LTAB layers.

For F--- or f--- type, by convention, when the first letter of a type specification is F or f, TOUGH4 will perform flowing wellbore pressure corrections using tabular data of flowing bottomhole pressure vs. flow rate and flowing enthalpy. The tabular data used for flowing wellbore correction must be generated by means of a wellbore simulator ahead of a TOUGH4 run as ASCII data of 80 characters per record, according to the format specifications below.

The first record is an arbitrary title. The second record holds the number of flow rate and flowing enthalpy data (table points), NG and NH, respectively, in Format 2I5; in Table 17 we have NG = 11, NH = 9. This is followed by NG flow rate data in format 8E10.4, and NH enthalpy data also in format 8E10.4. After this come NG sets of NH flowing bottomhole pressure data in format 8E10.4. The data in Table 17 were generated with the HOLA wellbore simulator (Aunzo et al., 1991) for a 0.2 m (≈ 8 inch) inside diameter well of 1,000 m feed zone depth with 7 bars wellhead pressure. Formation temperature for the conductive heat loss calculation in HOLA was assumed to increase linearly from 25 ˚C at the land surface to 275.5 ˚C at 750 m depth. Flow rates cover the range from 0.5 to 90.5 kg/s, and flowing enthalpies cover the range from 1,000 to 1,400 kJ/kg. A data record with very large bottomhole pressures of 55.55 MPa was added by hand for a very large hypothetical rate of 1,000 kg/s. This was done to avoid rates going out of table range during Newton-Raphson iteration in a TOUGH4 flow simulation.

Table 17. Flowing bottomhole pressures (in Pa) at 1000 m feed zone depth for a well of 20 cm (≈ 8 inch) inside diameter producing at 7 bar wellhead pressure (calculated from HOLA; Aunzo et al., 1991).

*f725d* - (q,h) from ( .5000E+00, .1000E+07) to ( .9050E+02, .1400E+07) 11 9 .5000E+00 .1050E+02 .2050E+02 .3050E+02 .4050E+02 .5050E+02 .6050E+02 .7050E+02 .8050E+02 .9050E+02 1.e3 .1000E+07 .1050E+07 .1100E+07 .1150E+07 .1200E+07 .1250E+07 .1300E+07 .1350E+07 .1400E+07 .1351E+07 .1238E+07 .1162E+07 .1106E+07 .1063E+07 .1028E+07 .9987E+06 .9740E+06 .9527E+06 .1482E+07 .1377E+07 .1327E+07 .1299E+07 .1284E+07 .1279E+07 .1279E+07 .1286E+07 .1292E+07 .2454E+07 .1826E+07 .1798E+07 .1807E+07 .1835E+07 .1871E+07 .1911E+07 .1954E+07 .1998E+07 .4330E+07 .3199E+07 .2677E+07 .2280E+07 .2322E+07 .2376E+07 .2434E+07 .2497E+07 .2559E+07 .5680E+07 .4772E+07 .3936E+07 .3452E+07 .2995E+07 .2808E+07 .2884E+07 .2967E+07 .3049E+07 .6658E+07 .5909E+07 .5206E+07 .4557E+07 .4158E+07 .3746E+07 .3391E+07 .3402E+07 .3511E+07 .7331E+07 .6850E+07 .6171E+07 .5627E+07 .5199E+07 .4814E+07 .4465E+07 .4208E+07 .3957E+07 .7986E+07 .7548E+07 .7140E+07 .6616E+07 .6256E+07 .5908E+07 .5634E+07 .5399E+07 .5128E+07 .8621E+07 .8177E+07 .7820E+07 .7560E+07 .7234E+07 .6814E+07 .6624E+07 .6385E+07 .6254E+07 .8998E+07 .8732E+07 .8453E+07 .8124E+07 .7925E+07 .7671E+07 .7529E+07 .7397E+07 .7269E+07 .5555e+08 .5555e+08 .5555e+08 .5555e+08 .5555e+08 .5555e+08 .5555e+08 .5555e+08 .5555e+08

The data must be provided by means of a disk file, whose name consists of the four characters of the TYPE specification, and the one character of the following ITAB parameter. For example, to use wellbore pressure data in a disk file called f725d, specify TYPE as ‘f725’, and specify ITAB as ‘d’. Different wellbore tables, representing e.g. wells with different diameter, feed zone depth, and flowing wellhead pressure, may be used simultaneously in a TOUGH4 simulation. Also, several wells completed in different grid blocks may reference the same wellbore table.

The capability for flowing wellbore pressure correction is presently only available for wells with a single feed zone.

TOUGH4 introduces additional options for the TYPE including:

GAPP Produce mass of gas phase with given buttonhole pressure, GX is for

productivity index PI ( $m^3$), EX is for the bottomhole pressure.

AQPP Produce mass of aqueous phase with given buttonhole pressure, GX is for

productivity index PI ( $m^3$), EX is for the bottomhole pressure.

OIPP Produce mass of non-aqueous phase with given buttonhole pressure,

GX is for productivity index ( $m^3$), EX is for the bottomhole pressure.

GAPR Produce mass of gas phase with given production rate.

AQPR Produce mass of aqueous phase with given production rate.

OIPR Produce mass of non-aqueous phase with given production rate.

GAIP Injection mixing gas with given bottomhole pressure. GX is the

bottomhole pressure, HX, LOT12, LOT13, and LOT14 are the mass

fractions of each component (see below for formatting).

AQIP Injection mixing aqueous fluid with given bottomhole pressure. GX is the

bottomhole pressure, HX, LOT12, LOT13, and LOT14 are the mass

fractions of each component (see below for formatting).

OIIP Injection mixing non-aqueous fluid at given bottomhole pressure. GX is

the bottomhole pressure, HX, LOT12, LOT13, and LOT14 are the

mass fractions of each component (see below for formatting)

(Comp. name) production (negative) or injection (positive) of the component.

Inputs of mass fractions through HX, LOT12, LOT13, and LOT14 for injection fluids with given bottomhole pressure require a special format as n0.x, which consists of two portions, one (n) for the component number, the other (x) for the mass fraction, e.g. “20.22, 10.28, 40.5” represents injection fluid consisting of three components, including component2 with mass fraction of 0,22, component1 with mass fraction 0,28, and component4 with mass fraction of 0.5. The sum of the mass fractions must be equal to 1.0 and the component number must correspond to the component list of the model. Maximum 4 components are allowed for the injection with GAIP, AQIP, and OIIP. The type GAPP, AQPP, OIPP, GAPR, AQPR, QIPR, GAIP, AQIO, and QIIP are implemented using the virtual node well treatment method. Coordinate z of the well elements and elements connected to them must be provided in the mesh input if virtual node method is used.

The component name can also be an option of the TYPE. This option specifies the injection or production of the component. For example, TYPE “CO2” represents the injection or production CO2 to/from the model element. A negative GX indicates production and positive GX indicates injection.

ITAB unless left blank, table of specific enthalpies will be read (LTAB > 1 only). When time-dependent injection is used, ITAB must be specified non-blank, and specific enthalpy data must be given. If LTAB =0 or 1 and ITAB is non-blank (excluding ITAB ="V" or "M"), user provided enthalpy will be used for the calculation, not matter injection or production. In addition, if ITAB is "M", "N", “V” or “T”, it has special meanings:

“V” or “v” production or injection rate is in volume per second, no time series of

specific enthalpy data will be read (may need additional inputs with IE(55),

FE(66)-FE(79)).

“T” or “t” production or injection rate is in volume per second, the time series of

specific enthalpy data will be read (may need additional inputs with IE(55),

FE(66)- FE(79)).

“M” or “m” production or injection rate is in mole per second, enthalpy is in J/mole,

no time series of specific enthalpy data will be read.

“N” or “n” production or injection rate is in mole per second, enthalpy is in J/mole,

the time series of specific enthalpy data will be read.

GX constant generation rate; positive for injection, negative for production; GX is mass rate (kg/sec) for generation types COMl, COM2, COM3, etc., and MASS; it is energy rate (J/s) for a HEAT sink/source. For wells on deliverability, type GAPP, AQPP, and QIPP, GX is productivity index PI ( $m^3$), see Eq. (4-15). For type GAIP, AQIP, and OIIP, GX is bottomhole pressure,

EX fixed specific enthalpy (J/kg) of the fluid for mass injection (GX>0). For wells on deliverability against fixed bottomhole pressure, with type of GAPP, AQPP, and OIPP, EX is bottomhole pressure Pwb (Pa), at the center of the topmost producing layer in which the well is open.

HG thickness of layer (m; wells on deliverability with specified bottomhole pressure only). It is masse fraction for type GAIP, AQIP, and OIIP.

LOT12-14 (optional) Additional data lot for the input. They could be used for mass fractions input for TYPE option GAIP, AQIP, and OIIP, or other well control parameters.

Record GENER.l.l (optional, LTAB > l only)

Free format for as more as 15 parameters per line, or Format (15E14.7)

Fl(L), L=l, LTAB

F1 generation times

Record GENER.1.2 (optional, LTAB > 1 only)

Free format for as more as 15 parameters per line, Format (15E14.7)

F2(L), L=1, LTAB

The number of data for input at each line must be identical with the F1 input.

F2 generation rates.

Record GENER.1.3 (optional, LTAB > 1 and ITAB non-blank only; this data must be provided for injection at time-dependent rates)

Free format for as more as 15 parameters per line, or Format (15E14.7)

F3(L), L=1, LTAB

The number of data for input at each line must be identical with the F1 input.

F3 specific enthalpy of produced or injected fluid.

Repeat records GENER.1, 1.1, 1.2, and 1.3 for the number of sinks/sources desired.

We provide an alternative input for Record GENER.l.l (optional, LTAB < -1 only)

Free format for 4 parameters per line, or Format (3E14.7, 1A10)

GTime, GRate, GEnthalpy, GType

GTime generation time.

GRate injection or production rate at the time GTime. As special cases, it is production

index for well type (GType ) DELV, GAPP, AQPP and OIPP, and it is bottom hole

pressure for well type GAIP, AQIP, and QIIP.

GEnthalpy specific enthalpy of produced or injected fluid. As a special case, it is bottom hole

pressure for well type DELV, GAPP, AQPP and OIPP.

GType Well production or injection type.

GTime can be in different time unit and in time series or time section based on well "TYPE" inputted by Record GENER.1 (We borrow variable "TYPE" for this purpose as it is not used for well with such alternative input). The "TYPE" can be:

"SECS" Time unit is in second, time series (default).

"HOUS" Time unit is in day, time series.

"DAYS" Time unit is in day, time series..

"SECP" Time unit is in second, time period.

"HOUP" Time unit is in day, time period.

"DAYP" Time unit is in day, time period.

GType can be any types that are allowed for the "TYPE" in the Record GENER.1 . An additional type "CLOS" is defined for indicating close of a well.

Repeat input GENER.1.1 for abs(LTAB) times.

Record GENER.2 A blank record closes the GENER data block.

Alternatively, generation information may terminate on a record with ‘+++’ typed in the first three columns, followed by element cross-referencing information.

Used in: All EOS modules

Example:

GENER // in main input file

A3A 1, injH2, , , , , COM3, , 5.0E+00, 5.356e4 //ELNE, SLNS, , , , , TYPE, , GX, EX

In GENER file with free format, TOUGH4 does not allow including NSEQ, NADD, and NADS (which will not be used) in the input line. The formatted input remains the same parameters which is for compatible with TOUGH3 input.

GENER

A3A 1, injH2, , COM3, , 5.0E+00, 5.356e4 //ELNE, SLNS, LTAB, TYPE, ITAB, GX, EX

We may use the alternative input for a complex well operation. For example, a well for H2 storage has following operation history:

(1) Produce water to reduce reservoir pressure at a rate of 10kg/s for 2 days.

(2) Inject cushion gas CO2 at 1kg/s for 5 days

(3) Close well for 3 days.

(4) Inject H2 for 0.2 day at a rate 2kg/s.

(5) close well for 0.7 day.

(6) produce H2 for o.1 day at a rate 4kg/s.

(7) repeat step (4-6) for additional two days.

The input will be:

GENER

A3A 1, injH2, , , , -12, DAYP,

2.0, -10.0, , WATE //produce water

5.0, 1.0, .526684E+06, CO2 //inject CO2, 5.356e4 enthalpy of injected CO2

3.0, , ,CLOS //close well

0.2, 2.0, 5.356e4 , H2 // inject H2

0.7, , ,CLOS

0.1, -4.0, , H2 //produce H2

0.2, 2.0, 5.356e4 , H2 // inject H2

0.7, , ,CLOS

0.1, -4.0, , H2

0.2, 2.0, 5.356e4 , H2 // inject H2

0.7, , ,CLOS

0.1, -4.0, , H2

If "TYPE" is "DAYS" , the input will be like:

GENER

A3A 1, injH2, , , , -12, DAYS,

0.0, -10.0, , WATE //produce water

2.0, 1.0, .526684E+06, CO2 //inject CO2, 5.356e4 enthalpy of injected CO2

7.0, , ,CLOS //close well

10.0, 2.0, 5.356e4 , H2 // inject H2

10.2, , ,CLOS

10.9, -4.0, , H2

11.0, 2.0, 5.356e4 , H2 // inject H2

11.2, , ,CLOS

11.9, -4.0, , H2

12.0, 2.0, 5.356e4 , H2 // inject H2

12.2, , ,CLOS

12.9, -4.0, , H2

MOP(12) must be 2 for this input.