Injection Patterns query

[soman703]

Hello Everyone,

I have few questions regarding Injections wells please:

1- When do we use which type of Injection pattern? Two or three spots patterns are usually used in Pilot phase but what about other well patterns such as four spot, inverted four spot , five spot, Inverted five spot , Seven spot, Inverted seven spot, nine spot & Inverted nine spot etc..

I have been told that its associated with depth of injection wells and amount of oil needed to be swept. And mostly in reservoirs that are not deep enough such wells are drilled.Can anyone comment on this please?? What are operational rule of thumbs regarding this?

2- When do we drill vertical injectors and when do we prefer horizontal or deviated injectors with respect to geological formations and reservoir types?

Normally when we drill a vertical Injector in a high permeability reservoir, we experience Injectivity loss due to water hammering. Can anyone comment on its solution?

In different scenarios how do we counter Injectivity loss?


Thanking you all,
Soman Ahmed

[soman703]

232 views and no replies? come on guys. anyone ??

[kader_007]

Hi soman,
1.
Actually the type of injection scheme is also related to the development plan you adopt.
In the past a "good practice" had been to go for peripheral injection rather than pattern for early life of the field then leave the patterns for late life to avoid early breakthrough especially if you have limitations and constraints in terms of water handling.
Another point to consider is that for compartmented and small reservoirs a one to one pattern can be considered as there is no justification to Ho for high count patterns.
In any case the patterns had to be assessed by a robust and history matched model not on lying for recovery comparison but also for water breakthrough and wc general trend in order to find the balance between the two i.e. recovery versus wc with your existing or planned facilities.
2.
Then vertical or deviated or event horizontal depends mainly on the formation you have whether it is a high height sand body or thin layers. Vertical is the most common for heterogeneous reservoirs but it doesn't mean the best choice, thin reservoirs with high areal extent need a better distributed injection hence horizontal profiles.

I am not familiar with water hammering in reservoir level this is usually a facility and or pipeline issue nevertheless injection loss is a "natural" phenomenon, you can't pretend injecting even a "clean" water without losing injection performance with time because of fines and formation reaction with water and the solution usually is to plan rigless activities (coil tubing) formation wash, acid jobs sometimes and as a way of enhancing the Injectivity at near well bore also hydraulic frac can be considered (for clastic sandstone) or acid jobs in carbonates of course here again a proper knowledge of the meneralogy of your formation is a must for a proper section of the treatment.

Hope this answers your questions.

Regards,
Kader

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[soman703]

Dear Kader 007,

Thankyou so much for detailed reply.

It cleared my doubts.

I really appreciate your kindness and willingness to share your knowledge.

Thanking you,
Soman Ahmed

[kader_007]

Dear Kader 007,

Thankyou so much for detailed reply.

It cleared my doubts.

I really appreciate your kindness and willingness to share your knowledge.

Thanking you,
Soman Ahmed

You're welcome we are all here to learn from each other.
Kader

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