Physical Modeling And Numerical Simulation Analysis Of A Oil And Gas Field Tectonic Evolution In Turkmen

This paper studies the Turkmenistan oil and gas fields, which is in the southeast of Turan platform that is Mesozoic-Cenozoic basin development in the Hercynian folded basement. The basin experienced three stages which are the Permian-Triassic rifting period, Jurassic-the ancient Tertiary Eocene after the cracking thermal term and Oligocene-Neocene uplifting and reconstruction. As the study region’s structural type and construction style is complexes and the purpose of the layer is located under the layer of salt paste, and because of shielding effect by the salt-gypsum layers, the subsalt seismic reflection becomes weaker, which causes difficultly to confirm the fault purpose and size accurately. And due to plastic flow deformation of salt-gypsum layers, which makes use of the balanced section method, the layer flattening of tectonic evolution and pale tectonic, recovery has significant limitations, lead to a structural interpretation in the area of Multiple Solutions. This paper aims to combine previous research data, and use of physical modeling and numerical simulation methods, tries to figure out the key structure period that impacts of the study region, and define the fault system of formation period in the study region, formation mechanism> fault properties^scale and the deformation characteristics of the salt-gypsum layers, reproduce the tectonic evolution of the study region,In this paper, physical modeling and numerical simulation experiments lead to the following conclusions:(1) It verifies the Late Jurassic Kimmeridgian-Tithonian tectonic movement, with the compression, the stratigraphic occurred a strong apophysis and the early formation of the fracture occurred some deflection.(2) It proves that the tectonic movement of the Late Cretaceous Cenomanian, scilicet, the study region occurs a strong fold after the gypsum deposited immediately, which produce a more significant impact on the tectonic pattern of the area. After the tectonism, then onlap deposited a layer of upon salt and upon gypsum quickly.(3) Mainly, physical simulation results indicate that Miocene-Holocene tectonic movement is the horizontal compression movement, this tectonic movement further changes the tectonic framework of the study region; basement normal faults reversed and then the fault properties change as a reverse fault due to the big crush strength And the Miocene-Holocene tectonic movement strength become reduce gradually from southeast to northwest.(4) According to the conclusions of physical modeling and seismic cross-section drawn, we obtain tectonic evolution diagram of two tectonic belts.(5) FLAC3D, a set of software by finite difference theory, is used to simulate tectonic movement of Late Jurassic Kimmeridgian-Tithonian, we obtain the tectonism made the strata of the study region uplift differently; Under the effect of the tectonism, the principal stress in Karloff-Oxford strata (subsalt) is the tensile stress, which formed a extensional conditions. Therefore, fractures formed in Karloff-Oxford strata (subsalt) is tension fractures in the period the process.(6) Through the numerical simulation of Late Cretaceous Cenomanian tectonic movement, study region as a whole under the action of tectonism is in a extrusion condition, thus the fractures formed in the cretaceous strata (upsalt) with the role of the tectonic movement belongs to compression fractures, and the fractures above the rock cream layer have formed preliminarily.(7) The simulation of the Miocene-Holocene uplift movement shows that the tectonism made the strata of the study region uplift in various extents; And the Miocene-Holocene tectonic movement strength reduce gradually from southeast to northwest; Under the effect of the tectonism, the subsalt and upsalt fractures occur further ductile failure and have the signs of extension to the salt-gypsum layers, but none of them can pass through the layer of gypsum salt, which means fractures on the salt-gypsum are not the broken the salt-gypsum layer that grow from the under the salt-gypsum salt by.The result of this master thesis indicate that numerical simulation and physical simulation are good methods to invert tectonic movement. Physical simulation experiment can rebuilt tectonic deformation in large space and through long time that the process can’t be observed in nature. It is convenient to control the time and condition of load so that different tectonic deformation process can be observed, and then researchers are able to invert tectonic movement strength and direction as to verify mechanism and process of tectonic deformation. Meanwhile,as the boundary of experiment is simulated by rigidity transmitted and the module, the stress can’t absorbe and transmitte, and the stress direction is deflected. Stress concentration makes rock stratum close to the boundary instable and even disintegrated when module is removed, which influences the remodel without limitation of time and space,it researches stress and deformation feature in different stratum by tectonic affect from stress and displacement filed,and then analyses formation mechanism and deformation feature of layered structure, but previous period tectonic movement is applied in the model,so that it can analyze study region by the tectonic affect only,which has little significance for fault.In brief, combining numerical simulation and physical simulation can not only reappear tectonic movement and deformation feature but also observe tectonic mechanism in the process of tectonic movement.