The largest ultra-deep (>6000 m) strike-slip fault-controlled oilfield in the world is found in the Tarim Basin of Northwestern China. The localized fractured reservoirs are the major production targets along the strike-slip fault zones. Different from its use in the primary porous-type reservoirs, however, the conventional technology is not favorable for use in oil/gas development in Ordovician carbonate reservoirs. For this reason, high-density seismic acquisition and high-resolution seismic processing were carried out to provide high-precision data for fault and fractured reservoir identification. In addition, the multi-filtering process and the maximum likelihood method are typically used to identify small faults and fault segments along a strike-slip fault zone. Further, seismic facies-constrained inversion and amplitude attributes are favorable for large fracture-cave reservoir description. With the advancements in seismic technology, the high and stable production well ratio has been doubled in the “sweet spots” of fractured reservoir optimization, and the first ultra-deep strike-slip fault-controlled oilfield with an annual oil production of over 1 million tons has been realized, achieving economic development in the ultra-deep fractured reservoirs. However, unstable production and high rates of production decline are still significant challenges in the economic exploitation of the ultra-deep fractured reservoirs. Seismic technology requires further improvement for the description of small fractured reservoirs and matrix reservoirs, as well as reservoir connectivity prediction and hydrocarbon detection in the deep subsurface.

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The early Cambrian shale is of an important petroleum source rock on the Earth. Due to few drilling data and poor seismic data, the organic matter enrichment of the Lower Cambrian shale is still an enigma in the Tarim Basin. Total organic carbon (TOC), major and trace element data of shale samples from five boreholes were experimented to decipher the mechanism of the organic matter enrichment in the early Cambrian shales. The results show that the shales deposited in the western restricted intraplatform have much higher TOC contents (3.2%–19.8%, on average 11.0%) than those from the eastern basin (2.2%–10.2%, on average 4.5%). The paleoproductivity proxies (Ba, Ba/Al, P/Al) in the western restricted platform are much higher than those in the eastern basin. The trace element indicators such as V/Cr, Ni/Co, Mo‐TOC and MoEF‐UEF suggest an anoxic environment across the basin, but a more restricted environment in the western intraplatform. It is concluded that the paleoproductivity rather than anoxic condition and hydrothermal activity have resulted in the differentiation of the organic matter enrichment from the western intraplatform to eastern basin in the early Cambrian shales, and restricted environment is favorable for paleoproductivity and preservation of organic matter.