Well drainage! Help !

[jikzo]

Hi all ..

Am currently working on a project for my internship ... and i have a challenge .. which is :

to determine the drainage of a specific well .. we dont have the model of it .. and most of the data needed to calculate the drainage area are not available .. "and this is making me suffer Big Time ! "
we have a seismic model which shows the well trajectory only .. am not supposed to give the exact area of the drainage ..
we just need to know from where it's draining .. the location in general only ..
So, please tell me what data should I check that might help me ??
any thoughts you have anything .. might be useful ... so please share it with me ..

Additional info. :
The formation has many faults that are believed to be Sealing .


Thank you very much ..

[kochichiro]

You need well test data (build-up or drawdown) or production data if it available.

[ahmedm]

since the faults are sealing you might assume the closure to be the drainage area
but usually the drainage area of a well can be calculated by finding you EUR then that will by the well OIIP
then use the equation of OIIP to estimate your drainage area

N = A*h*NTG*por*(1-Swi)/Bo

hope this gives some insight
good luck
you can ask your mentor
or any sr. res engineer there

[jikzo]

You need well test data (build-up or drawdown) or production data if it available.

I have the well test data but they're not enough .. only for one year !

I have the production data .. but how can these data help me ? plz explain more ..


Thank you !

[jikzo]

since the faults are sealing you might assume the closure to be the drainage area
but usually the drainage area of a well can be calculated by finding you EUR then that will by the well OIIP
then use the equation of OIIP to estimate your drainage area

N = A*h*NTG*por*(1-Swi)/Bo

hope this gives some insight
good luck
you can ask your mentor
or any sr. res engineer there

How Can I calculate the EUR ? :/
and after calculating ooip how is it helpful ?

my mentor doesnt know either .. me and him are working on this project .. and the lack of data is the Problem !

but plz explain more .. sry ..

[vinomarky]

Take your seismic model, complete with sealing faults and create a simple geologic model - assume constant perms/poro unless you know otherwise such that you get the appropriate level of drawdown for your known production rates

Make your simple simulation model and see what it tells you - It will inevitably be that you are withdrawing most fluid from the areas that have the most kh (ie most height with constant k assumption)

Edit: if you are next going to tell us that for whatever reason you cant build a simple model from the seismic model, then the best recommendation I can give is to find a crystal ball. There is always a certain baseline of information you require to be able to (gu)estimate with an accuracy that beats flipping a coin, and it sounds like you are pretty close to that limit.

[ahmedm]

if you have the production data just plot 1/q vs Np/q it will be about straight line
the 1/slope will by your EUR , or estimated ultimate recovery
assuming EUR = N then calculate the A based on the equation above

the idea of using model to purpose as mensioned is very worthy to try

hope this helps

[ahmedm]

guys

please your inputs to help our friend here
i know alot of reservoir engineers are in the forum



thanks

[jikzo]

Take your seismic model, complete with sealing faults and create a simple geologic model - assume constant perms/poro unless you know otherwise such that you get the appropriate level of drawdown for your known production rates

Make your simple simulation model and see what it tells you - It will inevitably be that you are withdrawing most fluid from the areas that have the most kh (ie most height with constant k assumption)

Edit: if you are next going to tell us that for whatever reason you cant build a simple model from the seismic model, then the best recommendation I can give is to find a crystal ball. There is always a certain baseline of information you require to be able to (gu)estimate with an accuracy that beats flipping a coin, and it sounds like you are pretty close to that limit.

ok , i'll see if I can do that .! The geologic model i mean , I liked the crystal ball method though :P

Thanks alot =)

[jikzo]

if you have the production data just plot 1/q vs Np/q it will be about straight line
the 1/slope will by your EUR , or estimated ultimate recovery
assuming EUR = N then calculate the A based on the equation above

the idea of using model to purpose as mensioned is very worthy to try

hope this helps

Ok, i have daily data for q and Np .. should it be yearly? or its ok ?


Thank you very very very much !

[vinomarky]

The plot method, while useful, wont actually answer the question you had which was ;

just need to know from where it's draining .. the location in general only ..

[kochichiro]

Well if you have well test data, for example build-up, try to interpret it. If the time of build-up was enough, you probably see some faults or maybe all of them. Moreover, there is a method to estimate well drainage area from build-up when time wasn’t sufficient to see any boundaries -

[link Point to another website Only the registered members can access] The results would be the same as for simplified geological model, during interpretation of build-up you also assume constant k and h and you receive drainage area as a radial or linear (in case of faults) distance from the well.