关键词: 柴达木盆地, 英东油田, 晚期构造成藏模式, 山地三维地震, 断块油藏, 高效开发

Abstract:

Yingdong oilfield is located in the eastern part of Yingxiongling tectonic belt, Qaidam Basin, characterized by very complex surface topography, which was previously considered to have no favorable geological conditions for hydrocarbon accumulation, so that there has been no major discovery. With continuous improvement in 3D mountain seismic technology and logging evaluation during recent years, a great breakthrough was achieved in 2010, proving that Qaidam Basin is a single monolithic oil and gas field with the largest reservoir reserves, the highest abundance, the best physical properties and development benefit, and the production capacity of 50 million tons. In this study, Yingdong oilfield was precisely analyzed to investigate the reservoir formation characteristics and technological problems, so as to obtain the following understandings. Yingxiongling area is characterized by late hydrocarbon generation and continuous charging, where Neogene lacustrine facies sand bodies are widely distributed with good reservoir-cap assemblage; the faults have favorable lateral sealing performance, easy to form fault block traps in mid-shallow layers. In Yingdong area, Eocene high-quality source rocks are connected by large detachment faults, resulting in the adjustment of early accumulated hydrocarbon reservoirs and the late continuous hydrocarbon migration and accumulation. The shallow and deep faults were combined to form the relay transport mode, thus leading to hydrocarbon accumulation in the tectonic traps of shallow layers during the late period, characterized by the late compound reservoir accumulation. Aiming at the complicated topography and reservoir characteristics of Yingdong area, the integrated technology of complex 3D mountainous seismic acquisition, processing and interpretation was created to lay the foundation for the implementation of oil and gas exploration target. To solve the problems such as long oil-bearing gas well member and difficult fluid identification in Yingdong oilfield, the long-well-member oil-gas-water reservoir multiple development mode was established as well as the multi-constraint complex fault-block geological modeling technology. Through this study, the reservoir accumulation mechanism of Yingdong oilfield was identified, and the complex key engineering technology was achieved, which provide geological theory and technical support for the efficient development and rapid production of Yingdong oilfield.

Key words: Qaidam Basin, Yingdong oilfield, late tectonic accumulation model, 3D mountain seismic, fault block reservoir, efficient development