Skin Factor is usually defined to account for additional pressure drop due to damage or stimulation around the wellbore in an oil / gas formation. The positive skin may be caused by such phenomena as mud and cement infiltration, wax/asphaltene deposition, connate water vaporization, etc. On the other side, such processes as acidizing, solvent injection, hydraulic fracturing may cause negative skin. In my question, I am looking for maximum allowable skin values for each of the above causes.
This discussion might help.
https://www.researchgate.net/post/How_high_can_skin_factor_be
Does the case include turbulent flow? (non-Darcy skin factor?). Non-Darcy skin? what flow rates and D are you talking about?
If he/she is including that, then the number can go high more than normal skin factors due to damage. Also, what are the other conditions: partial penetration, two phase flow ... etc
Here are other good links:
2.http://www.fekete.com/san/webhelp/welltest/webhelp/Content/HTML_Files/Reference_Materials/Skin.htm
3. http://petrowiki.org/Flow_equations_for_gas_and_multiphase_flow
Good luck.
Dear Khaldoon
Thanks a lot for your detailed answer. The problem is that the reservoir under study is producing less than expected, and we are studying to explore the reason. In doing this, he examined many possibilities, and the one reason was a high skin as I mentioned in my question.
But we are not sure how great the skin could be for our case
High values of skin are not uncommon, even though after certain value (perhaps S > 20) it becomes just an academic exercise as the FE is almost 0%. But I have worked on projects where S>80 were common. I would suggest that the important thing when investigating skin is to determine which is the mechanism generating that skin, out of 57 types of skin then we can concentrate on specific actions to remove them or prevent them. I hope it helps
I agree with Juan, it is important to determine what is the mechanism that generates that skin factor. So it can determine if the value found is consistent.
FE is flow efficiency. Waiting for the anwer regarding 57 types.
This is an answer that has taken sometime to come along, apologies for the delay. i would start with the Civan's book (Formation Damage by Civan F.), it is so wide and describes the physics and chemistry of many types of skin. I hope it helps
typical values for the skin factor range from -6 for an infinite - conductivity massive hydraulic fracture to more than 100 for a poorly executed gravel pack
- Badges
- Science topic
- Similar topics
- Engineering
- Petroleum Engineering
- Gas