Res Sim CH1

Question 1

Uncertainties

Answer 1

1. Lack of knowledge. (reservoir size, thickness, areal extent and net-to-gross ratios.
2. Lack of data. I.e. Multiphase fluid properties (Krel, Pcapillary)
3. Reservoir architecture. i.e. sandbodies, shales, faults
4. Porosity & permeabilities in interwell regions
5. Fluid properties. Oil viscosity, formation volume factors (Bo, Bg, Bw), phase behaviour
6. Numerical errors in coarse grid block model.

Question 2

Appraisal

Answer 2

Recovery Plan
Facilities
Sub Facilities Capability
No., location and type of wells to be drilled
Sequence of drilling program and topside facilities

Question 3

Mature (producing for 2-20 years)

Access to some field production history - pressures, cumulative oil, watercuts, GOR’s for wells and field

Answer 3

H.M. of field production data to model future performance
H.M. to review FDP strategy.. i.e. add inj/prod, infill drilling
Decide between working on small projects Vs working on 2 or 3 existing wells
Review equity of partner companies
Review reservoir recovery mechanisms

Question 4

Late Field Development (closing years before abandonement)

Answer 4

Decide if field economically justifies simulation study

2 reasons to conduct res sim.

1. New development strategy - give field a new lease of life for a few years. I.e. stimiulation/IOR technique
2. Cost of field development may be so high anything we can do to extend field life may be termed economic

also some countries legislation require simulation as part of ongoing reservoir management

Question 5

Name three reservoir processes Black Oil Model models.

Answer 5

1. Primary depletion
2. Waterflooding
3. Immiscible gas injection

Most common. Treats o/w/g as mass components. Only gas dissolves in oil and water.

Rso an Rsw = gas solubility for oil and water

Question 6

Name three reservoir processes Compositional Model models.

Answer 6

Res Process Modelled:

1. Gas injection - near critical reservoirs
2. Gas injection - oil mobilisation with 1st contact
3. Gas recycling - condensate reservoirs

Based on fluid description on paraffin series up to C6 value. The rest are defined as C+ components.

Question 7

Contact angle

Answer 7

Contact angle is a petrophysical input.

Its the angle made by interface between wetting and non-wetting fluids, at the point both fluids reach the pore wall.

Question 8

Name three ways in which a Black Oil reservoir simulation differs from a Compositional simulation model.

Answer 8

1- black oil model treats a phase (o,w,g) as a “pseudo component”.

2- Compositional is based on the conservation of components (CH4, C10, H2O etc.) (more correctly). Black oil treats gas dissolution in oil through Rso - gas solubility

3- Compositional includes PVT description of the oil whereas black oil relies on simple Rso type treatment.