A method for producing a crude product is disclosed. Formation fluid is
produced from a subsurface in situ heat treatment process. The formation
fluid is separated to produce a liquid stream and a first gas stream. The
first gas stream includes olefins. The liquid stream is fractionated to
produce one or more crude products. At least one of the crude products
has a boiling range distribution from 38.degree. C. and 343.degree. C. as
determined by ASTM Method D5307. The crude product having the boiling
range distribution from 38.degree. C. and 343.degree. C. is catalytically
cracked to produce one or more additional crude products. At least one of
the additional crude products is a second gas stream. The second gas
stream has a boiling point of at most 38.degree. C. at 0.101 MPa.