It is not unusual for oaks and other hardwood trees to bleed foul smelling sap.  The condition is brought on by a bacterial disease called "slime flux" or "bacterial wetwood."  It is not normally harmful to mature trees.  

This is an excerpt from Virginia Tech's Pest Management Guide on the subject:

"The Precautions/Remarks: Bacterial wetwood is a condition that typically does not cause serious harm to the tree. Many tree species, including elm, oak, dogwood, and probably most other hardwood species, can be affected. Conifers are less commonly affected. Often a rancid or stinky odor emanates from affected tissue due to fatty acids produced by a complex of microorganisms. External signs on bark include vertical light or dark streaks with seeping liquids, wet or dry when observed. The word “wetwood” derives from the wet appearance of cross-sections of the wood. This disease has no real practical management. Fluxing in oak trees may become more severe in trees that have undergone high environmental stress situations and may disappear when stressors are gone. Stinging insects or other pests may be attracted to fluxing sites."

This publication from North Carolina State University gives additional information.  

You may wash away the existing sap with a spray from a garden hose but do not use any chemicals or soaps on it.  Since it is very attractive to insects, including bees, use caution around the area until the condition stops.  

In the unlikely event you feel the tree needs professional help, you can contact a certified arborist to take a look at it.  Arborists that work in Chesterfield County can be found on this list.

If you have additional questions on this subject, please use the reply feature within this email or contact the Chesterfield Cooperative Extension Office at<personal data hidden>.  Thanks for using Ask an Expert!