Need help with Quantification and evaluation of crude oil reserves!

[Gitta]

Hello members,

I am new to the petroleum engineering industry and I would request your help on information regard the quantification(estimation) and evaluation of crude oil reserves using Petrel software. I will be grateful for any help extended my way.

cheers

Gitta

[vinomarky]

Gitta,

The evaluation of reserves can be an extraordinarily complex task - it is the culmination of many different disciplines of knowledge so don't feel bad if no-one has answered with the simple solution you may be hoping for

I suggest that you visit first the basics of volumetric reserves calculations to help understand the main variables (ie GRV, Porosity, Saturation & RF). Once you start understanding the main drivers to the uncertainty, then you'll be better placed to intelligently predict under your situation which of those are the key one(s) - this will guide to what level of detail you need to understand/model the system

Once you understand this, then you may want to build an appropriately detailed/complex model in Petrel before (perhaps) taking it to a reservoir simulator.

The above is a long winded way of saying that to learn how to build a simple Petrel model and calculate reserves given simplistic assumptions is very easy. To do a complex model and incorporate robust dynamically determined recoveries is quite complex.

[Gitta]

Thanks vinomarky,

You reply was very helpful. However I still need help. I have been furnished with the following information;

1. Petrel model
2. Density
3. Volume factor
4. Viscosity
5. Surface vsicosity
6. GOR
7. The relative density of gas
8. Surface density
9. Formation water viscosity
10. Formation volume factor of water
11. Oil compressibility
12. Formation water compressibility

I am supposed to use the above given information plus Petrel to estimate the crude oil reserves. If anyone has an idea about how I can go about the process please share. You can either share here or send to my email at gilo_38k@yahoo.com.

Thanks

Gilbert

[vinomarky]

With the Petrel model (and I'm assuming hydrocarbon column height info or pre-populated hydrocarbon saturations) then calculating the hydrocarbon in place is a matter of using the Petrel Volume Calculation process (under Utilities), and dropping in the NTG (if present), porosity, oil and gas saturations and it will spit out HC in place. To work out reserves is another matter altogether as you need to come up with the magical recovery factor, and if you don't have any idea as what to use then (sorry to be blunt) you should not have been asked to calculate the reserves

[Chee Koh Peh]

Gilbert, Vinomarky is right.

All you can do with the above data is calculate the in place volumes known as the Original Oil in Place OOIP.

This is not the same as reserves. Be warned!

Reserves by definition (SPE PRMS) are "Reserves are those quantities of petroleum anticipated to be commercially recoverable by application of development projects to known accumulations from a given date forward under defined conditions. Reserves must further satisfy four criteria: They must be discovered, recoverable, commercial, and remaining (as of a given date) based on the development project(s) applied"

Therefore unless you have wells drilled in the field, and welltest data, a company approved development plan, capital committed, foretasted production, Opex and Capex profiles, so you can perform what is known as an Economic Limit Test (ELT) you do not have any reserves.

If you do not have this data, to identify the recoverable resources (not reserves) you will need to find an analogue field with the same reservoir, fluid and geological properties and look at the recovery factor and use a similar recovery factor (RF). Thus a OOIP x RF = recoverable resources. (Not reserves)

Estimating reserves is a difficult task requiring much experience and involves geologists, reservoir engineers and economists.

Rgrds

Chee Koh Peh

[Shakespear]

Look here for some free stuff

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Plenty of reading in my opinion. Ryder stuff would be most interesting.

[Gitta]

Thanks alot guyz. My assignment is infact about calculation of OOIP and not evaluation of reserves. I had misunderstood. Thanks for the correction and enlightenment. However, I have another question to pose. Is it possible to combine two methods when calculating OOIP? If yes, how can it be done.

cheers

[vinomarky]

Combining and contrasting the results from different methods is not only possible, but recommended. The more different ways you can calculate an answer the better, since taken togeather they will tend to yield more insight into the likely ranges and uncertainty along with where the numbers broadly agree vs diverge.

THERE WILL BE NO SINGLE CORRECT NUMBER that you'll be able to come up with..... so expect differences - the key is to try to understand what is driving those differences.

[gazhali]

....

[Gitta]

Thanks vinomarky,

But how does on go about the combination? If anyone has any information on how to go about this combination please paste it here or send in to my email gilo_38k@yahoo.com.
Regards

Gitta

[Gitta]

Ooooop! I shouldn't have underline the email. Again my email is gilo_38k@yahoo.com

cheers

Gitta

[Gitta]

Dear gazhali,

I am sorry I can not see your reply. I don't know why.