well spacing

[chap]

hello

is it we must construct bubble map to know the well spacing and the location of the well we want to drill?

ty.

[596kunal]

Yes this is one factor that can be taken into consideration.

[Shakespear]

construct bubble map

Something tells me you might be using OFM but I can not be sure.

The key here is to understand what happens as you START producing a well from t=0. As the well flows the pressure drops in the reservoir DRAINAGE AREA as that is the driving force to move the fluid toward the well. Where there is no pressure drop, there is no movement of fluid. That might sound so obvious but that is the key to this term.

[link Point to another website Only the registered members can access]
Also, as long as the pressure transient moving away from the well does not hit any boundaries you are in Infinite Flow regime.

[link Point to another website Only the registered members can access]
A well test could help you to estimate the drainage area.

Another way to estimate it is through Material Balance Calculations. The produced fluid came from the Drainage Area, hence some average drainage radius. Here you are making the assumption of producing from a tank (circular drainage). Something along these lines you will find in this presentation

[link Point to another website Only the registered members can access]
Another more powerful option is reservoir simulation.

[link Point to another website Only the registered members can access] Here we see the drainage area clearly.

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]

[596kunal]

OK, in that case there is a relation between drainage area and well spacing (but obvious)
so wat is the relation between ultimate recovery and well spacing ?

[Shakespear]

OK, in that case there is a relation between drainage area and well spacing (but obvious)
so wat is the relation between ultimate recovery and well spacing ?

I hope you understand that a single well can not drain a reservoir in a REASONABLE amount of time. The best way to see this would be to do a single well simulation in a large reservoir.

The oil company needs to recover their sunk cost AS SOON AS is reasonable possible, this will vary with each project. In a risky place you want to do it at maximum rate.

Now if the wells are TOO CLOSE they will produce oil that the other well could by itself. So one needs to find this balance.

This is BEST done by reservoir simulation as you have another fluid always present, water. So as you produce eventually the water will start to come in and that will be the determining factor what is you so called Drainage Area. Not So Simple to deal with this without simulation.

what is the relation between ultimate recovery and well spacing ?

None that I know as ultimate recovery depends on more than just well spacing. Look up the definition and you will understand what I mean.

See this but remember the assumptions in these types of calculations as what is under the ground is not regular and homogeneous

[link Point to another website Only the registered members can access]

[596kunal]

Whenever i try to analyse the behavior of field with well-spacing(well density), i always come to conclusion with: the closer well spacing does play imp. role only in case of certain specific parameters (all those which you mention).
But when it comes to relation betn these 2 quantities (well-density & ultimate recovery), ther is no such effect (not considering those reservoirs which has heterogeneity i.e. major faults,uplifts etc.)
i hope i m rite.

[Shakespear]

Someone did a lot of work for you here,

[link Point to another website Only the registered members can access]

[596kunal]

hahaha...
thats my paper only sir.

[Shakespear]

hahaha...
thats my paper only sir.

Good to hear

You did a good job of studing the situation.

[596kunal]

thank u sir
At present i m in a critical situation in my project. My objective is to discuss the effect of well spacing on ultimate recovery, and we are using petrel & eclipse simulators in order to achieve it. I have gone thru the reservoir concepts of well spacing under some scenarios. As it is my final year B.tech project so there is a bit of time constraint associated with it (6-12 months).
I am looking for a secondary type depletion drive reservoir (Pi < bubble pt. pressure) so that we can obtain a significant difference in ultimate recovery under various cases. Is this approach right ?
or can you suggest a good idea/theme if the project title is "A comprehensive study of effect of well spacing on ultimate recovery"

[Shakespear]

I am looking for a secondary type depletion drive reservoir (Pi < bubble pt. pressure) so that we can obtain a significant difference in ultimate recovery under various cases. Is this approach right ? or can you suggest a good idea/theme if the project title is "A comprehensive study of effect of well spacing on ultimate recovery"

I guess I am not quite sure where you are going with this. As your first work showed, there is no general relationship to find the optimum spacing as there is simply too many variables which changed from field to field. The methodology is clear enough as to how to find it, trial and error with surface and economic constraints.

If the company is small and the field the approach will be equally simple to answer the question. If the company is Statoil the approach will be very sophisticated, simulations to find the optimal well distribution. The variable driving everything will be economics.

[chap]

Thank you all..but if i'm provided well test data,how i can estimate the drainage area?