In this chapter we will consider an example of visual expert system written on the Actor Prolog language. ... There are a lot of methods of oil field bed stimulation that increase output of the oil production: thermal, physical-chemical, gas, microbiological, and others. ... Fig. ... The Top-Most diagram consists of three blocks: the "Describe parameters of hydrocarbon field" block, the "Check adaptability of existed methods of oil production" block, and the "Display solution" block. ... Gas methods. ...