The Effectiveness of Natural Fractures in Deep Tight Gas Sandstone Reservoirs in the Southern Junggar Foreland Basin, Northwestern China

Abstract

The deep tight sandstone reservoirs with a bury depth of more than 6000 m in the foreland thrust belt of the southern Junggar Basin in China have great potential for natural gas exploration and development. The well-developed natural fractures could have an important contribution to improving the porosity and permeability of tight sandstone reservoirs, especially permeability. However, two questions are still not clear: 1) Are these natural fractures affecting the reservoir properties if the depth is larger than 6000m? 2) How to quantitatively evaluate the effectiveness of natural fractures in deep tight gas sandstone reservoirs? In this study, imaging logs, drilling cores, and thin sections will be used to analyze the apertures and fillings of natural fractures in these reservoirs. Then, rock mechanics experiments, permeability experiments, and numerical simulations will be employed to study the effects of in situ stress, formation temperature and fluid pressure on the apertures and permeability of natural fractures with different types, strikes and dip angles. Finally, the effectiveness of natural fractures and their contribution to reservoir properties will be discussed, and the fracture types, strikes and dip angles that are more favorable for the natural gas enrichment and production in the deep tight sandstone reservoirs of the southern Junggar Basin will be summarized. In this project, we expect to develop a method for quantitatively evaluating the effectiveness of natural fractures in deep tight gas sandstone reservoirs. This project This projectThis project This project This project will not only will not only will not only will not only will not only will not only will not only will not only will not only will not only enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies enrich theoretical studies on the effect of the effect of the effect of the effect of the effect of the effect of the effect of the effect of natural natural natural fracturesfracturesfractures fractures fractures on tight ight ight sandstone andstone andstone reservoirs eservoirs eservoirseservoirs eservoirseservoirs but also will but also will but also will but also will but also will but also will but also will but also will but also will provide provide provide provide valuable guidance guidance guidance for for for the exploration and development of deep tight gas sandstone reservoirs.

AAPG Datapages/Search and Discovery Article #90351 © 2019 AAPG Foundation 2019 Grants-in-Aid Projects