Abstract:
A Production well (X well) in the Thal Area Riau, produce two types of crude oil; light oil and waxy oil.
These type oil is obtained from two different strata reservoir that is, A reserroar (1762, 6 m) and B
reservoir (1900,5 m). The double string production pipes distribute the crude oil from A reservoar (shortstring)
and B reservoar (long string). Two types of methods, ROF GC and biomarker have been used to
study reservoar geochemisry of X well. The study showed that there are mix between oil from reservoar A
and B. The mix is coused by corrotion in the pipe line. The mix increased from 4 % in 1979 to 95 % in
2001. The reservoar show that Goechemistry rservoar can be applied to prevent even to improve the
efficiency of production of X-Well in the future
