assignment 59

Solution:

A. Semi log analysis:

1. K (Permeability):

2. S (Skin factor):

3. To determine :

A plot of P versus radius should be performed to illustrate the increase in pressure from Pwf to reservoir pressure but here in this data we can use a plot of delta p (Pi-Pwf) versus time on a cartesian plot it will give the same indication:

Or it can be calculated using the formula:

4. Flow Efficiency

to calculate ks we must have rs (skin radius), according to the data it is possible to determine when the effect of the skin vanish which is @ time=50 hour approximately, but we can't exactly determine at what location this time is ,so based on the data we can't calculate the flow efficiency, but we can say it will be lower than 1 as the value of skin is positive which means that there is a damage and according to this damage the permeability will decrease so ks will be lower than k so FE will be lower than 1.

Based on Darcy law radial flow:

B. Log -Log analysis:

To determine the value of well bore storage or well bore storage effect it is clear that from log-log analysis, well bore storage will not appear as it is defined by unit slope line in the early time region and the data point in the early tome region is not giving straight line, so the effect of well bore storage is not clear. And based on this through cartesian analysis we cannot identify the well bore storage as there is no sign when it ends.