can oral sex be charged as statutory rape the same as actual intercourse?

Yes. In the state of Wisconsin under the legal definitions of terms used in the laws, the definition of "Sexual Intercourse" includes "cunnilingus" which is oral sex.

Wisconsin Criminal Code - Chapter 948 Crimes Against Children 948.01 Definitions:

"Sexual intercourse" means vulvar penetration as well as cunnilingus, fellatio or anal intercourse between persons or any other intrusion, however slight, of any part of a person's body or of any object into the genital or anal opening either by the defendant or upon the defendant's instruction. The emission of semen is not required.

948.09 Sexual Intercourse with a child age 16 or older.

Whoever has sexual intercourse with a child who is not the defendants spouse and who has attained the age of 16 years is guilty of a Class A Misdemeanor. This is the