Abstract: | The activities of deep
fluid are regionalized in the Tarim Basin. By analyzing the REE in core samples and crude
oil, carbon isotope of carbon dioxide and inclusion temperature measurement in the west of
the Tazhong Uplift in the western Tarim Basin, all the evidence confirms the existence of
deep fluid. The deep fluid below the basin floor moved up into the basin through
discordogenic fauit and volcanicity to cause corrosion and metaaomatosis of carbonate rock
by exchange of matter and energy. The pore structure and permeability of the carbonate
reservoirs were improved, making the carbonate reservoirs an excellent type of deeply
buried modification. The fluorite ore belts discovered along the large fault and the
volcanic area in the west of the Tazhong Uplift are the outcome of deep fluid action. Such
carbonate reservoirs are the main type of reservoirs in the Tazhong 45 oilfield. The
carbonate reservoirs in well YM 7 are improved obviously by thermal fluid dolomitization.
The origin and territory of deep fluid are associated with the discordogenic fault and
volcanicity in the basin. The discordogenic fault and volcanic area may be the pointer of
looking for the deep fluid modified reservoirs. The primary characteristics of hydrocarbon
accumulation in deep fluid reconstructed carbonate rock are summarized as accumulation
near the large fault and volcano passage, late-period hydrocarbon accumulation after
volcanic activity, and subtle trap reservoirs controlled by lithology. |