The Structural Interpretation And Physical Simulation Experiment In The Yi176 Area Of Zhanhua Sag

Zhanhua sag is an important oil-gas sag in the east of China.The zhanhua sag is controlled by multi-group and multi-stage fault activities from the early stage of paleogene kongdian formation to the late stage of dongying formation,forming the “depressions alternate with bulges” with complex half-graben fault depression in the early Cenozoic era.North east to extensional sag of internal development,transtensional fault,north east to the transtensional fault and a series of nearly east-west fracture.The fault system indicates that the structural evolution of zhanhua sag is in the tensile environment and directly controls the current structural style of Zhanhua sag.The present tectonic features reflect the present distribution of geostress field to some extent,and the geostress is an indispensable data in oil and gas exploration and development.Therefore,it is of great significance to study the structural characteristics,stress distribution and further oil and gas exploration in Zhanhua sag.In this paper,the structural interpretation of Yi176 wellblock boshen step-fault zone is carried out based on the structure physical simulation of zhanhua.On the basis of physical testing of rocks,Flac3 d is used for finite element simulation to study the distribution of ground stress,providing a basis for further exploration and development in this area.Firstly,the physical model of sand box is abstracted based on the similarity principle of geometry and kinematics.The experiment has two sets of pull and a physical model,each of which is a high tensile pull and a low stretch and pull the model.The experimental process and results were recorded by three-dimensional scanning and PIV(particle image velocimetry system),and the physical simulation results were analyzed by slicing(observation section features).And then,the results of physical simulation are used to guide the structural interpretation of the boshen step-fault zone in the well area of Yi176.Finally,the rock mechanical parameters were adopted and the finite element simulation was conducted by Flac3 d software.Several key attribute models of the bohai fault zone in the yi176 well area were established.The stress distribution in zhanhua sag is predicted preliminarily.It can be recognized by comprehensive structural physical simulation experiment of zhanhua sag,structural interpretation of Yi176 wellblock boshen fault-step zone and geological stress distribution of zhanhua sag,the stress along the fault depression basin,the internal level to make the transition to evenly on both sides of present middle is weak,on both sides of the strong characteristics.Boundary faults always control the growth of faults within fault basins.In the stress vector diagram of Zhanhua sag,it is revealed that the strong stress vector is concentrated at the boundary of the fault depression and presents a linear distribution along the interior of the fault depression.The stress vector diagram of zhanhua sag reveals that the strong stress vector is concentrated at the boundary of fault depression and presents a linear distribution along the inner part of fault depression to both sides.With the high tensile tension of physical simulation of PIV average velocity field observation results,verify the reliability of Zhanhua sag of stress distribution prediction.