Replace string in the log file

Hello everyone,

I really suck with Powershell scripting. I'm trying to replace string in a log file, I was able to replace one part of the string that I want to replace with and the remaining part I just can't figure it out.

I have several string with &X-ARR-LOG-ID=xxxxxxxxxxxxxx (the xxx are 36 characters in length that including number, letter, and hyphen. It generates randomly  by IIS), I was able to replace &X-ARR-LOG-ID= but can't replace for part after =. 

I would really appreciate if anyone can help me with this.

Thanks in advance.

dtng