petroleum formation evaluation -3

7/31/2019 Petroleum Formation Evaluation -3

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PANDIT DEENDAYAL PETROLEUM UNIVERSITYSCHOOL OF PETROLEUM TECHNOLOGY

B.TECH. SEMESTER - VIASSIGNMENT - 3

Course: Petroleum Formation evaluation (PE 308)

Problem 1:


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iv


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Problem 2:


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Problem 3: The following information are known for Zone-A and B.Calculate Sw using Humble Formation Factor formula with n =2


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Problem 4: Explain the following SP system with representative circuit,when mud filtrate is dilute (a) and concentrated (b).

(a) (b)


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Problem 6 :

In the log example given below, indicate the shale baseline and zone the loginto three major units: label the shale and the two reservoir units. Assuming

that the lower reservoir is water filled, answer the following questions;(a) Is the mud filtrate more or less saline than the formation water?(b) Is the average porosity of the upper reservoir greater or less than that of

the lower reservoir?(c) Is the upper reservoir, which curve(s) indicate(s) why the neutron

porosity is greater than the density porosity?(d) On the basis of resistivity curve alone, the upper reservoir may be split

into two portions. Do they both contain hydrocarbon? Why?

(e) Which of the two zones do you expect to be more permeable?


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Using the corrected deflection of the SP from the above, estimate the waterresistivity using the relation:

Rmf

SSP = - 70.7 log10 --------------

Rw

What is the value of Rw if you use the uncorrected value of SP?


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Problem 8:

A 9 inch borehole is filled with mud at a constant temperature of 100 0F. Theresistivity of the mud is 0.9 ohm-m at 100 0F.

a) What is the resistance of the mud column from surface to 7000 ft?b) What is the resistance if the temperature is raised to 2000F?c) In the latter case, what would be the resistance if the diameter of the

borehole was increased to 1 m?

Problem 9 :

The log of figure below shows a measurement of the mud resistivity (in ohm-m) as a function of depth. Ignore the SP curve since it was measured 9 monthsprior to the mud measurements.

a) Assuming constant mud salinity for the bottom 300 ft of log, whattemperature variation would be required to produce such a resistivitychange? Sketch a log of it in track 3

b) What salinity variation could produce a similar change in resistivity inaccordance with the temperature over this zone? Plot a few points of theconcentration of NaCl as a function of depth in track 3.

c) What is good explanation for the resistivity behavior in this example?


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Log chart of SP, borehole mud resistivity, and temperature


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Problem 10:

From the data of the following figure verify the expected exponentialdependence of resistivity on the inverse of temperature (0K). Taking pointsfrom the curve for a concentration of 4000 kppm, how far does the resistivityat 350 0F deviate from the model equation

= 0eC/T , c is the characteristics of a given liquid

A nomogram for determining the resistivity of an NaCl solution as a functionof the NaCl concentration and temperature. G/G is grain per gallon


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Problem 11: The following log responses (along with auxiliary data) arethrough a consolidated sandstone with porosity about 0.27 fraction bulkvolume. Comment and interpret the SP log response within the depth from11050 ft t0 11160 ft.

petroleum formation evaluation -3

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