Seismic Wave Field Anomaly Identification of Ultra-Deep Heterogeneous Fractured-Vuggy Reservoirs: A Case Study in Tarim Basin, China

Abstract

Ultra-deep (7500–9000 m) Ordovician tight limestone heterogeneous fractured-vuggy reservoir is an important target of FuMan Oilfield in Tarim Basin. The strike-slip fault controlled reservoir is related to formation fracture and dissolution caused by geological stress. The seismic wave-field anomaly characteristics with different energy and irregular waveform are displayed in the seismic profile. Accurate identification of fractured-vuggy reservoirs wrapped in tight limestone is the direct scheme to improve production efficiency. Therefore, a new combination method flow of seismic wave-field anomaly recognition is proposed. In this process, the seismic data must be preprocessed initially, and on this basis, robust formation dip scanning is carried out. Secondly, the dip data is applied to the transverse smoothing filter to obtain the formation background data. Eventually, the seismic wave-field anomaly data is the residual between background data and original seismic data. This method has been applied in blocks with different structural characteristics and can effectively improve the resolution of strike-slip fault controlled reservoirs. Based on the results, the drilling success rate is increased to more than 95%, and the high-yield rate of oil tests is increased to 75% in 2021. Multiple applications indicate that the method is robust and can be popularized.

The Advances and Challenges of the Ediacaran Fractured Reservoir Development in the Central Sichuan Basin, China

“…In this way, the "sweet spot" of fractured reservoirs is the favorable target for economic production along the strike-slip fault damage zone. The fractured reservoir has been studied by geological, geophysical and engineering methods, of which the seismic technology plays an important role in the reservoir description [32,33,[36][37][38]. Owing to the intense heterogeneity of fractured reservoirs and low-resolution seismic data, there is still a big challenge in the description of fractured reservoirs in the deep subsurface.…”

“…Furthermore, new methods of development are expected to quantitatively or semiquantitatively evaluate the fracture network along the fault zone. With high-resolution 3D seismic data, most "bead shape" reflections have been successfully identified with fracture-cave reservoirs in the Tarim Basin [38][39][40]. The seismic description of small-scale vug and fracture reservoirs is still a big challenge in the exploitation of oil/gas in the deep subsurface.…”