Salt Dome盐丘钻井.docx

Columns of salt that intrude through overlying sediment units.Middle Jurassic salt:?This cross-section shows rocks of the East Texas Basin between the Oklahoma-Texas border (on the left) and the Gulf of Mexico coastline (on the right). The purple rock unit is the Middle Jurassic salt, a rock unit that has the ability to flow under pressure. The salt is overlain by thousands of feet of sediment which place enormous pressure on the surface of the salt and cause it to flow. At numerous locations the salt has intruded upwards into overlying sediments. This has produced small mounds or towering columns of salt that can be thousands of feet tall. The salt columns and smaller mounds are called salt domes. USGS image [1].Salt Dome:?Cartoon of a salt dome showing piercement through two rock units and deformation of the rock unit immediately above. Growth of the dome is accomplished by migration of salt into the dome from surrounding areas. The salt migrates into the dome because it is compressed by the weight of overlying sediments.What is a Salt Dome?A salt dome is a mound or column of salt that has intruded upwards into overlying sediments. Salt domes can form in a sedimentary basin where a thick layer of salt is overlain by younger sediments of significant thickness. Where conditions allow, salt domes can rise thousands of feet above the layer of salt from which they began growing. An example is shown in the illustration.In the illustration at the top of the page, the purple rock unit (Js) was originally a layer of salt. It is the source of salt for several columns of salt and several smaller mounds of salt that have intruded into overlying units.The development of salt domes can deform rock units into traps that hold oil and natural gas. They are often mined as sources of salt and sulfur. The impermeable nature of the salt can make them important sites for underground storage or underground disposal of hazardous waste.The Deformation of Salt Under PressureUnlike most oth