The Ultra Deep Volcanic Intrusive Rocks Seismic Identification and Its Potential of Oil and Gas Exploration,in the Northern Tahe Oilfield

In the northern part of Tahe Oilfield, influenced by the magmatic activity at the end of Cambrian, many sets of complex magma intruded into Sinian-Lower Cambrian and formed.Based on this, the integrated drilling and seismic data were used to identify and predict Late Cambrian intrusions into the Sinian-Cambrian strata in the northern part of the Tarim Oilfield, and to analyze the hydrocarbon exploration potential of these intrusions. The results show that the Sinian-Cambrian ultra-deep intrusive rocks are developed in Tahe Oilfield, and the buried depth is more than 8.0 × 103 m. The intrusive rocks on the seismic section are irregular in seismic shape, which is obviously different from the wave impedance of carbonate rocks. According to the seismic reflection shape, the intrusive rock structures such as rock strains, rock caps and rock beds can be identified. The intrusive rocks are mainly distributed along the deep faults in the plane, which are oval and sub-circular, with an area of 0 ~ 4.0 × 106 m2 and different sizes. The intrusive rocks formed by magmatic intrusions into the Lower Cambrian strata during the Late Cambrian period intersect and adjoin high-quality hydrocarbon source rocks in a vertical direction. Furthermore, due to the influence of multiple phases of faulting, microfractures have developed and interconnected along the periphery of the intrusions, thereby forming large-scale reservoir complexes. At the same time, the tectonic uplifts resulting from these intrusions provide favorable settings for hydrocarbon accumulation. Therefore, the hydrocarbon accumulation complexes formed by intrusive rocks in the Lower Cambrian exhibit a well-defined reservoir-seal configuration and possess significant exploration potential.