could you help me ,please?

[amin_2710]

hello dear members,
i have two questions that really confused me and i am asking your help and ill be so gratefull.
q-1:
in condensate gas reservoirs calculations, the total number of moles of the fluid in the reservoir is not equal to the total number of moles in the surface for the same fluid neglecting pressure and temprature,why??

q-2:
also in condensate gas reservoir calculations, we have three ways to calculate "initial oil in place",
the first way is by using the law of "R" which is initial surface gas oil ratio of the production ,as you know."

the second way is by using the law of "Ge" the volume of equivlent condensate gas produced

Ge=133000*sp.gravity/molecular weight of the fluid

so what is the third way?

thankyou so much

[amin_2710]

any one respond to me please? its VERY IMPORTANT !

[Shakespear]

The 3) I believe would be Material Balance.

As the fluid flows to the top through the tubing it continuously sees pressure dropping. As the pressure drops at some point this pressure will enter the 2-Phase region of the fluid and condensate will be seen in the tubing at some depth on the way up. If the velocity of the fluid is lower than the drop out velocity, then you will see the condensate (liquid) drop down into the well and not make its way up to the surface. This will have a lot of heavy components of the GC which if not accounted for will cause errors. If this is happening then your surface measurements (PVT data) will not reflect what is really in your reservoir. The calculations will be wrong.


Look here

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

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

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

[vinomarky]

q-1 - You are certainly confused. The total number of moles of hydrocarbons will be identical between downhole and surface conditions. What will change is the number of moles in the gaseous and fluid phase.... ie in condensate gas reservoir (with 100 vapour phase downhole), you will have 100% of your moles vapur downhole, and something less than 100% vapour moles at surface, with the difference being the condensate yield.

q-2 - Not sure what 'three methods' you are referring to. As with all problems, there are many ways to solve this, and they are dependent upon the situation and the data you have to hand. One additional 'simple' way that immediately comes to mind is really just a variation of your first method, that is often gas PVT analysis quotes a CGR (Condensate Gas Ratio - stb/Mscf) which you then simply multiply by the OGIP. On the other end of the spectrum, you can always fit an EOS to the PVT data and simulate compositionally. For all of these cases though, the actual condensate volumes will be affected by your separator conditions.

hello dear members,
i have two questions that really confused me and i am asking your help and ill be so gratefull.
q-1:
in condensate gas reservoirs calculations, the total number of moles of the fluid in the reservoir is not equal to the total number of moles in the surface for the same fluid neglecting pressure and temprature,why??

q-2:
also in condensate gas reservoir calculations, we have three ways to calculate "initial oil in place",
the first way is by using the law of "R" which is initial surface gas oil ratio of the production ,as you know."

the second way is by using the law of "Ge" the volume of equivlent condensate gas produced

Ge=133000*sp.gravity/molecular weight of the fluid

so what is the third way?

thankyou so much

[Shakespear]

Please do not take this wrong but if understanding mole composition bottom vs. uphole is a problem then trying to do q2 suggestion as per vinomarky will be next to impossible.

The Whitson Video course that is found here

[link Point to another website Only the registered members can access]
will discuss exactly what you are asking and what vinomarky is talking about.

It is not easy and requires good data. Take the time to watch this video and you will learn a lot about Near Critical Reservoir PVT studies.

Simpler (need to be careful with this word) methods are found here

[link Point to another website Only the registered members can access]
The above 4share account has a lot of GOOD STUFF !!!!! Look

[amin_2710]

Thankyou very very much,you have been most helpful to me,both replays were helpful.thankyou again

[Shakespear]

Near Critical reservoirs are tricky "animals". Whitson in his lecture stresses this a lot. He keeps talking about getting GOOD data (PVT) to be able to deal with these types of reservoirs.

Good Luck !!!

[amin_2710]

thankyou so much .