| The development of conventional oil and gas resources has been unable to meet the growing demand.The exploitation of unconventional oil and gas resources has gradually attracted people's attention,and one of the important technologies is the reservoir stimulation.Unconventional oil and gas resources mainly include tight sandstone,shale oil and gas,etc.In this paper,tight sandstone is selected as the main research object.Sandstone is a type of sedimentary rock with natural bedding structure.In this paper,the influence of bedding dip angle on the propagation path and morphology of hydraulic fractures is mainly studied by means of finite element method simulation and Abaqus software.In this paper,a two-dimensional cohesion model where a single bedding intersects a hydraulic fracture and two parallel beddings intersects a hydraulic fracture is established.Factors such as bedding angle,bedding tensile strength,fluid viscosity and injection rate are studied.The results show that the difference in horizontal crustal stress affects the propagation form of hydraulic fractures;when the bedding angle is 60°,the hydraulic fractures propagate along the bedding,and when the bedding angles are 75°and 90°,the hydraulic fracture directly passes through the bedding;When the tensile strength ratio of bedding and crack is 1/3,the hydraulic fracture only extends along the upper half of the bedding;The greater the injection rate and the viscosity of the fracturing fluid,the easier the hydraulic fracture passes through the bedding;In the two parallel stratification models,when the hydraulic fracture passes through the first bedding,it expands along the direction of the bedding and prefabricated hydraulic fractures at the same time.The expansion path is the same as that of the single bedding model,but the injection pressure is slightly higher.When the second bedding is reached,it passes directly through the bedding.It means that the second bedding is not easy to crack compared to the first bedding. |
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