Stimulated reservoir volume (SRV) fracturing has become the most efficient technology in the treatment of unconventional hydrocarbon reservoir formations. This process aims to optimize well productivity by establishing an intricate network of fractures that integrate hydraulic and natural fractures, distal to the wellbore, thereby amplifying the contact area with the subterranean formations and fracture systems. This study introduces a quantitative framework designed to characterize the fracturing effects within naturally fractured unconventional hydrocarbon reservoirs. Leveraging existing fracturing treatment designs and production performance data, the study formulates a mathematical model of the complex fracture network, predicated on the principle of material balance. The model comprehensively accounts for the development degree of natural fractures, the morphological impact of stress differentials on the fracture network, and the imbibition displacement effects of the fracturing fluids. The model’s accuracy is verified through an integration with microseismic monitoring data and an enhanced understanding of reservoir development. Building upon this foundation, the study quantitatively dissects the impact of various engineering parameters on the efficacy of SRV fracturing. The proposed quantitative characterization method is adept for widespread application across multiple wells in oil and gas fields, offering a distinct advantage for the swift and precise assessment of SRV fracturing outcomes in naturally fractured unconventional hydrocarbon reservoirs. The research method, which is based on readily accessible fracturing construction data and is more convenient, can to a certain extent improve the efficiency of hydraulic fracturing evaluation work.

The global climate and environmental variability can induce fish adaptive strategy change and form a corresponding complementary mechanism subsequently. Because of climate fluctuation, human activities, and water conservancy projects, it has been reported that natural fish resources of the silver carp have been declining in a wavy trend from 1950. However, few studies have explored the potential effects of determining the relationship between the adult fish and fish larvae. Using the field survey method, this study analyzed the fisheries resource status of the adult silver carp and its early life stage in the Yangtze River. Results indicated that different geographic populations showed significant habitat dependence, and the adult silver carp tends to choose habitats with slow water flow, rich biological bait, and less human interference. What is more, its distribution pattern has regional and seasonal differences obviously. Additionally, redundancy analysis on the fish larvae showed that water temperature and water flow are the two most important factors influencing the fish larvae blooming. According to the generalized additive model (GAM), the hydrological factors that significantly influence the larvae abundance are water temperature, transparency, daily increasing rate of water level, and discharge (p < 0.05). Combining the historical and present research data, the results indicated that river and lake connected habitat is essential for the silver carp recruitment and migration. Future studies should focus on the complementary mechanism of silver carp both in the natural habitat and invasion waters. It is suggested that the spawning habitat should be well protected during the channel project and economic belt construction along the Yangtze River.

There are multiporosity media in tight oil reservoirs after stimulated reservoir volume (SRV) fracturing. Moreover, multiscale flowing states exist throughout the development process. The fluid flowing characteristic is different from that of conventional reservoirs. In terms of those attributes of tight oil reservoirs, considering the flowing feature of the dual-porosity property and the fracture network system based on the discrete-fracture model (DFM), a mathematical flow model of an SRV-fractured horizontal well with multiporosity and multipermeability media was established. The numerical solution was solved by the finite element method and verified by a comparison with the analytical solution and field data. The differences of flow regimes between triple-porosity, dual-permeability (TPDP) and triple-porosity, triple-permeability (TPTP) models were identified. Moreover, the productivity contribution degree of multimedium was analyzed. The results showed that for the multiporosity flowing states, the well bottomhole pressure drop became slower, the linear flow no longer arose, and the pressure wave arrived quickly at the closed reservoir boundary. The contribution ratio of the matrix system, natural fracture system, and network fracture system during SRV-fractured horizontal well production were 7.85%, 43.67%, and 48.48%, respectively in the first year, 14.60%, 49.23%, and 36.17%, respectively in the fifth year, and 20.49%, 46.79%, and 32.72%, respectively in the 10th year. This study provides a theoretical contribution to a better understanding of multiscale flow mechanisms in unconventional reservoirs.