Dear Mr. Saidian,

how did you determined and measure your susceptibility data and what was the approach taken to precisely quantify the mineral composition of your rock samples? Both parts of the equation are crucial. Apart from that, the type of magnetic strength (e.g. ferro-magnetic...) should not be cast aside either.

Best regards

Harald G. Dill

Dear Mr. Dill

Thanks for the reply. I measured the bulk magnetic susceptibility of the cores using a KLY-4 Kappabridge instrument and the mineralogy using XRD experiment from a very reliable laboratory. The samples are from oil producing formation and there is no ferro magnetic mineral. The paramagnetic minerals are chlorite, illite and pyrite.

Milad

Dear Mr. Saidian,

the kappameter device seems to be o.k. , but the reliability of laboratory depends in this case on the method. This is especially true, when phyllosilicates are among the rock-forming minerals, where the Rietveld Method used to provide reliable results only. It seems to me that the aim is to correlate wireline data with laboratory data. The dataset, particularly with regard to the mineralogical part, is for me a bit too poor and the information too vague as to hand down a verdict in one or the other direction. It also depends on the accuracy of the results obtained or required. For a first-hand approximation it might work, but the chlorite s.s.s and illite are anything but easy to be described, as to their chemical composition. It will be a trial-and-error approach, expecting an assessment rather than a calculation. What was the mineral quantification like by the laboratory ?

Best regards

H.G.Dill

Hello Mr. Saidian,

It probably do not to go, as most magnetic minerals is accessory mineral, which You cannot detect by XRD (as magnetite and so on).

But You can use matrix calculation to calculate susceptilbility of each mineral. Try it, its easy way, and it can say something intersting for You.

Your

Viktor Goliáš

Mr. Dill,

I acquired the XRD data from a very reliable lab. There is no ferromagnetic mineral in my samples. I totally agree with you about uncertainty of illite and chlorite content measurement using XRD, but that is the best we can do. My main intention is to get a hold of the magnetic susceptibility of these parmagnetic minerlas for my sample set which are from the same formation. I can not rely on the very wide range reported in the literature for the same mineral.

So I have the constituents, I have the bulk MS and then I minimize the equations assuming linear system of equations. I was thinking of using a margin of error for each mineral based on the variation of reported values in literature.

Dear Viktor,

Thanks for your answer. As I mentioned in my answers to Mr. Dill I do not have minerlas with crazy high magnetic susceptibility. The highest are pyrite and chlorite. I will try to use a big sample set to increase the statistical accuracy of the minimization function.