If you are referring to the large round plugs (almost look like pipe plugs, about 1.5" diameter) with the large hex shaped hole in the center, those are coolant plugs, there should be 3 in a row, (one will be a reducer with a temp sensor in it). They like to rust into place, but you might get lucky, they take a 17mm hex socket. They are a straight thread plug with a sealing washer (like the ones used on banjo bolts) Not sure how oil could leak from it though, sure it's not thickened coolant oozing?
Those are the only plugs I know of in the block by the pump. There might be some oil gallery taps down below the pump, if there are they will be centered in the "raised hump" that runs the length of the block casting to the oil filter.