Exploration and production wells are drilled for the discovery and exploitation of hydrocarbon reserves. The wells which are not feasible to produce from are abandoned following the drilling and testing operations. Production and injectionThe process of using pressure to force fluids down wells wells (used for injecting fluids into reservoirs for improved oil recovery applications or to dispose produced water) continue operating until the economic limit is reached, where the utilisation of the wells is no longer feasible, and then they are abandoned. The abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones can either be temporary, if the operator is to make use of the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids in the future, or permanent, if the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids is no longer required.
Temporary abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones of the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids requires the removal of the production equipment and setting retrievable/drillable barriers in the wWellbore to prevent any flow from the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids. When the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids is permanently abandoned, the production equipment is removed from the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids, mechanical barriers are set in the wellboreThe physical hole that makes up the well, it can be cased, open, or a combination of both; open means open for fluid migration laterally between the wellbore and surrounding formations; cased means closing of the wellbore to avoid such migration, the wellhead is removed, the casings are cut off below the ground level, caps are welded on top of the casings, and the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids is usually buried. An abandoned wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids may sometimes be re-entered and restored to production or injectionThe process of using pressure to force fluids down wells, but usually the re-utilisation of an abandoned wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids is economically and technically not feasible.
There have been different approaches for the rules and regulations for wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones. Different countries, different environments and different time periods show variance in applied rules and regulations for abandoning exploration, production or injectionThe process of using pressure to force fluids down wells wells. An overview of relevant regulations in various countries is given in Korre, 20112011 - A. KorreCO2CARE D1.1 International regulatory requirements on CO2 geological storage and site abandonmentsee more.
The proper abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones of the wells is aimed to achieve mainly three goals:
- prevention of cross flow between reservoirs,
- protection of freshwater aquifers from contamination and
- prevention of leakage(in CO2Carbon dioxide storage) The escape of injected fluid from the storage formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it to the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) or water column of reservoirA subsurface body of rock with sufficient porosityMeasure for the amount of pore spaceSpace between rock or sediment grains that can contain fluids in a rock and permeabilityAbility to flow or transmit fluids through a porous solid such as rock to store and transmit fluids fluids to the surrounding formations or to the surface.
In order to achieve these goals, physical barriers are placed in the wellboreThe physical hole that makes up the well, it can be cased, open, or a combination of both; open means open for fluid migration laterally between the wellbore and surrounding formations; cased means closing of the wellbore to avoid such migration. These barriers can be mechanical plugs or cement plugs set into the wellboreThe physical hole that makes up the well, it can be cased, open, or a combination of both; open means open for fluid migration laterally between the wellbore and surrounding formations; cased means closing of the wellbore to avoid such migration and caps welded on top of the casings.