Production sharing agreement language

I received an new Production Sharing Agreement for section 18 Block C-8 Section 9,10 Block C-8, Section 9 block C-8. Supposedly they are drilling 4 new wells. I am from Ohio and don’t understand much. In the agreement it says " Each Interest Owner further agrees that this Agreement affects only production of Horizontal Wells and in no way affects ownership under any vertical wells drilled or to be drilled on Subject Lands.

Is this normal? Other wells that we have include vertical wells.

Thanks for your help,

Tina