Chesapeake are drilling SE to NW (as did COP and Hilcorp at...

Chesapeake are drilling SE to NW (as did COP and Hilcorp at right-angles to the trend in Live Oak and Karnes) whereas the others to the east are drilling N to S. Coincidentally, there seems to be a corresponding change in the boundary orientations. Is the direction of the drilling influenced by the boundaries or by a localised change in direction of the EFS trend? McMullen is SW of Karnes and, from maps I have seen, the trend direction is unchanged NE:SW.