Investigation On Hydraulic Fracture Propagation Regularity Of Natural Fractured Carboniferous Volcanic Rock In Junggar Basin

The Carboniferous volcanic reservoir in the Junggar Basin,Xinjiang is a typical fracture-porosity dual-media reservoir.It has high geological reserves,large economic value,and extremely high development potential.It has important strategic significance for the development of oil and gas resources in China.However,there are always difficulties in developing fractured volcanic reservoirs.For example,the thickness of fractured volcanic reservoirs in the Junggar Basin is generally large,natural fractures are widely distributed,and natural fracture systems have a great influence on lithology.There is little experience in hydraulic fracturing technology;the mechanism of initiation and extension of hydraulic fractures in volcanic reservoirs is unclear,and there is a lack of design optimization methods and hydraulic fracture analysis and diagnosis techniques for volcanic reservoirs;The technology and services of foreign companies have mastered the key technologies,and the design autonomy and technology dominance are low.In the field application,the fracturing plan of the Carboniferous natural fractured volcanic rock follows the previous construction experience from design to implementation,lacks the basic principle support of fracture propagation,and lacks the effect study of the on-site mobile adjustment plan.Therefore,studying the fracture structure of volcanic reservoirs,analyzing the structure of natural fractures and hydraulic fractures,studying the expansion of hydraulic fractures in natural fracture networks,and summarizing the mechanism of hydraulic fractures and natural fractures can more accurately explain the hydraulic power of fractured volcanic reservoirs The distribution pattern of fracturing complex fracture network is of great significance for improving the pertinence and reforming effect of volcanic reservoir fracturing stimulation stimulation construction design.In this paper,the basic properties of natural fractures in the Carboniferous fractured volcanic reservoirs in the Junggar Basin are constructed by rock debris mineral element analysis and rock mechanical parameter test,which provide data support for studying the natural fracture network system of volcanic rocks.Through the on-site collection of Carboniferous basalt and volcanic breccia outcrops,the laboratory's true triaxial hydraulic fracturing physical simulation experimental system was used to carry out hydraulic fracturing simulation experiments of volcanic reservoirs,and the interaction mechanism between natural fractures and hydraulic fractures was analyzed.,Reconstructed the 3D fracture morphology,visually displayed the fractured and expanded morphology of fractured volcanic fracture network,and revealed the formation mechanism of fracture network and fracturing fractures.At the same time,the discrete fracture method was used to establish a natural fracture-hydraulic fracture structure model of fractured volcanic rock.Based on the fracture properties obtained from basic experiments,the natural fractures were activated by hydraulic fractures and caused by hydraulic fractures in reservoirs with widely distributed natural fractures.Controlling conditions of cracking and propagation,and formation of complex fracture networks.The numerical simulation study takes into account the natural fracture properties of volcanic rocks,elastoplastic deformation conditions of fractures,and rock matrix fracture factors.The hydraulic fractures of fractured volcanic reservoirs are analyzed from geological and engineering factors.The control factors of network complexity also take into account the heterogeneity of geological conditions,such as the influence of Young's modulus and reservoir mechanical strength on fracture complexity.In this paper,through the methods of debris mineral analysis technology,hydraulic fracturing physical simulation experiment,fracture network 3D morphology description,numerical simulation of fracture propagation,the research on the interaction mechanism between natural fractures and hydraulic fractures was carried out in the Carboniferous volcanic reservoirs in the Junggar basin,The results of the study will provide a theoretical basis for the future large-scale volumetric fracturing construction reconstruction plan of volcanic rock.