XPath selector for nodes that its ancestors are not a specific node

I'm writing an XPath selector to select all the node name o:OLEObject providing that its ancestor is not w:del. but the nodes in w:del are included in the result. Can you help me to clear it?
Here is my script:

   publicList<String> getAllOleObjectId(XmlObject wobj) {
		List<String> lstOfOleObjIds = new ArrayList<String>();
		XmlCursor cursorForOle = wobj.newCursor();
		if(cursorForOle != null) {
			cursorForOle.selectPath(
				"declare namespace w='http://schemas.openxmlformats.org/wordprocessingml/2006/main' " + 
				"declare namespace o='urn:schemas-microsoft-com:office:office' " +
				".//*/o:OLEObject[ancestor::*[not(self::w:del)]]"
			);
			while (cursorForOle.hasNextSelection()) {

				 cursorForOle.toNextSelection();
				 XmlObject oleObj = cursorForOle.getObject();
				 Node oleDomNode = oleObj.getDomNode();
				 NamedNodeMap domAttrObj = oleDomNode.getAttributes();
				 lstOfOleObjIds.add(domAttrObj.getNamedItem("r:id").getNodeValue());
		   }
		}
		cursorForOle.dispose();
		return lstOfOleObjIds;
	}

You should replace your XPath with :

//*/o:OLEObject[not(ancestor::w:del)]

Select OLEObject element, child of any (*) element, and which has no ancestor element named del.