peripheral and pattern flooding

1. Peripheral and Pattern Flooding
By
SYED NAWAZ
M.Tech Petroleum Exploration and Production
Delta Studies Institute
Andhra University

2. Content
• Introduction
• Technical terms
• Classification
• Pilot testing
• Peripheral testing
• References

3. Introduction
• Can also be said as injection pattern, the particular arrangement
of production and injection wells.
• For every field or for a section of a field, the injection pattern are
designed separately
• The pattern of flooding can be change during the life of a
reservoir, in order to change the direction of flow in a reservoir
with the intent of contacting unswept oil.

4. Important terms for understanding
• Sweeping efficiency : the percentage of original oil in place displaced from a formation by a
flooding fluid
• Over all displacement efficiency(E): the proportion by volume of oil swept out of the pore
space of a reservoir by the encroachment of another fluid. The displacing fluid may be
reservoir water, gas or an injected fluid
• Microscopic displacement efficiency(Ed): is a measure of the effectiveness of the displacing
fluid in moving the oil at those places in the rock where the displacing fluid contacts the oil or
at a pore scale
• Macroscopic displacement efficiency(Ev): is a measure of how effectively the displacing fluid
sweeps out the volume of a reservoir, both areally and vertically and as well as how
effectively

5. Factors affecting types of efficiencies

7. Mobility and Mobility Ratio

9. Classification of pattern
• Direct line drive,
• Staggered line drive,
• (2 spot
• 3 spot
• 4 spot
• 5 spot
• 7 spot
• 9 spot) and inverted pattern with each of them
• Normally the 2-3 spot pattern are used for pilot testing purposes.

10. Pilot testing in EOR
• The primary purpose is to validate the performance of a particular EOR
process in the field. Eg: laboratory tests and simulation studies indicate
that a highest recovery and best overall economic value among recovery
process considered. Before making a huge investment required for a
large scale application, a Pilot is conducted at a well spacing scalable to
that expected for full scale application
• Pilot testing is classified into 4 types:
• Non Producing Pilot,
• Small Scale Unconfined Pilot,
• Small Scale confined Pilot,
• Multi Pattern Producing Pilot

11. Non producing pilot
• Aim to determine the ease at which the gas can be injected into
the formation and to evaluate injectivity losses resulting from
water alteration by gas processes
• The vertical sweep and local displacement efficiency of the gas at
injected area can be determined.

12. Producing Pilot
• Also known as oil in the tank pilot.
• Direct determination of oil recovery, dynamic fluid properties,
Pressuer drop between injectors and producers.

13. Confined small scale pilot
• Used for closure well spacing
• At cheaper cost then other pilot methods it can determine the
vertical sweep efficiency.
• In addition to this detailed information on pressure gradient, fluid
mobility.

14. Unconfined small scale
• It can provide production history quickly at low cost, but swept
volume estimation is difficult
• They are sensitive to fluid drift (body of a fluid permanently
displaced)

15. Pattern flooding types

21. Selection is based on
• Converting existing wells into projector
• Drilling infill injection wells
• Reservoir heterogeneity
• Directional permeability

23. Peripheral flooding

24. General well spacing distances and rate of
wells

25. Cased study at Kube Field
Note: normal flood pattern perform better than their inverted
equivalent because inverted pattern have less injectors which
decreases the sweeping efficiency of oil.

26. References
• Dr.Hareram Sir (Guest faculty, Andhra University)
• Evaluation of various water flooding pattern in KUBE field (Research
Paper)
• Petrowiki
• One petro
• Enhanced oil recovery pilot testing best practices (Research Paper)
• SPE
• Rigzone
• Syed Nawaz (Student of Andhra University)
• Youtube

27. Any Queries
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