how to calculate formation water resistivity (rw)

necataltin72 · Post by **necataltin72** » Mon Dec 01, 2008 3:04 am

Hi, need equations to calculate formation water resistivity Help!!!!

skroy · Post by **skroy** » Mon Dec 01, 2008 10:43 am

This is available in any standard well logging book. From your profile it is not clear what is your specialization or still you are studying. If you do not want to go thru any book or any specific doubt or you want to start discustosion (not a bad idea-here most of are asking for ebooks and software) that is most welcome for a change. By tomorrow I will give a reply to your question if by that time your query is left unanswered. I invite well loggers to join and discuss. I suggest we discuss topics on this board itself and not by pm. This will help everybody.

asadiqbal · Post by **asadiqbal** » Mon Dec 01, 2008 3:27 pm

FORMATION RESISTIVITY CAN BE CALCULATED FROM SP LOG EASILY...............

skroy · Post by **skroy** » Mon Dec 01, 2008 6:35 pm

asadiqbal, anything is easy when you know it.

necataltin72, I have made a small note for you.
There are several ways to calculate Rw :
If clean water-bearing formation can be identified from the logs, several approaches can be used to estimate formation water resistivity(Rw):
1.Assuming Sw=100 and values for

sankar.halder · Post by **sankar.halder** » Mon Dec 01, 2008 7:55 pm

I have newly registered for this site . My decision was partly influenced by my dear friend Mr S K Roy who highly recommended this site for an effective portal for sharing/acquiring knowledge regarding aspects of Petroleum Geology .
I have a query regarding estimation of production capacity of low resistivity HC pays .

jabbar · Post by **jabbar** » Mon Dec 01, 2008 11:12 pm

Dear Friend
We recommanded this 4shared website for more books on Logging tools and Logging petrophysics calculation , one of the calculation you will find a methods on how to calculate the Rw .
http://www.4shared.com/dir/1817499/5999 ... aring.html
And many thanks to the owner of the Forum and the website .
Best regards to all

skroy · Post by **skroy** » Mon Dec 01, 2008 11:30 pm

Everybody knows everything is available in books. I have also used some books for replying. If we don't reply or discuss this type of topic, this portal will be reduced to a bartering site; people looking for ebooks and softwares only will visit. Discussions will freshen up our knowledge too who already know the subject. Friends, do you agree?

necataltin72 · Post by **necataltin72** » Tue Dec 02, 2008 2:25 am

Thanks for your reply, I tried to use resistivity ratio to calculate rw, as you mentioned the equation Rw=Rmf*Rt/Rxo. I used Rmf value in the log header with the temperature it has been measured; but as temperature has increased, Rw values got decreased and as a result, Sw values got higher and higher as depth increase. So it did not make a lot of sense to me. I thought maybe it was because of I was using Rxoz data so I tried by Ro-HILT instead of Rxoz; but it did not change. Another equation I used was Rw= Rt*(power (Ptotal,2)) This equation looked like more reliable than the other one at shallow depths down to 600-700 m. But then formation porosities were got nearly %10 to %0 because of tight sandstone reservoir. So calculated Rw values was so small that all sandstone reservoir seemed as full of bound water; no hydrocarbon but I mudlogging data did not tell the same thing; there was strong mud gas shows below 1000 m. So I thought this was not the right equation. Sp values are so changeable from field to field that I do not want to rely on that much changeable data to Rw. I will try the equation you wrote: Rwa=Rt*

skroy · Post by **skroy** » Tue Dec 02, 2008 2:48 am

Topic is becoming interesting as you are telling your observation. Experience and observation are more important than what is written in books. Something we read in books and feel it is so easy. But it is different when we work in field. I will discuss your observation with my more knowledgeable friends and try to come with a solution soon. Why our other friends here are not joining? Plz join. Let us continue discussion.

jabbar · Post by **jabbar** » Tue Dec 02, 2008 6:02 am

I think as we working with well logging tools and measurements is to take a first look on the books in this topics and then if you feel that you are good or better than these books , this is very good thing if you over understand the calculation .
I think the Fourm not only for bartering as you intend , I think if you have a small part of information better is let the other know about , If any engineer or geologist do not have any back ground for the subject better is for looking inside these books and then you are free.

Best regards to all person

arturo82 · Post by **arturo82** » Tue Dec 02, 2008 8:23 am

skroy wrote:Everybody knows everything is available in books. I have also used some books for replying. If we don't reply or discuss this type of topic, this portal will be reduced to a bartering site; people looking for ebooks and softwares only will visit. Discussions will freshen up our knowledge too who already know the subject. Friends, do you agree?

totally agree

Post by **FANARCO** » Tue Dec 02, 2008 6:29 pm

If any body post the chart here for risistevity Vs salinity and temp. it will be good

Ebdowy · Post by **Ebdowy** » Wed Dec 03, 2008 10:06 am

These files will help

skroy · Post by **skroy** » Sun Dec 07, 2008 5:14 pm

I expected others to join and reply before I try to do. Now that I am busy with some urgent project I will be able to reply only after fnishing current job. Hope by this time somebody will come up with a solution to your query. Thanks.

.::FANARCO::.

how to calculate formation water resistivity (rw)

how to calculate formation water resistivity (rw)

Low resistivity pays

Rw