Corrosion protection of oil and gas wells
Corrosion protection of metal equipment of condensate wells
Condensate wells is field wells where gas is supplied together with a lot of saturated vapor of liquid hydrocarbons from the formation. When the pressure and temperature in the well is decreasing, gas condensate is released from these vapors.
Stimulants corrosion of metal equipment of condensate wells
The main stimulator of corrosion of metal equipment of condensate wells is carbon dioxide (CO2
is always present in the products produced at gas-condensate wells, and often in very large quantities. CO2
is a stimulant corrosion of metal equipment condensate wells only in the presence of water that is condensed in the tubing. CO2
reacts with water to form carbonic acid (H2
), which leads to corrosion of metal equipment of condensate wells. Below the water condensation zone, corrosion of metal equipment of condensate wells, i.e. the production string tubing, can be completely untouched by corrosion, because the aqueous phase is missing. Mineral salts dissolved in water of produced fluids are also corrosion stimulants of metal equipment of gas condensate wells.
Corrosion destructions in the column tubing
Inspections, carried out during the overhaul, show that while there are very intense corrosive destruction of the column tubing, occurred on the inner surface of the tubing, as well as the threaded part. Corrosion destructions in the column tubing appear as large pits, very deep ulcers with sharp edges and through holes. Some pipes have through holes with a diameter of 10-30 mm. Due to the corrosion damage in the column tubing, more than 50% of the pipes are usually subject to a full replacement, because their thickness is reduced to a few millimeters. Due to the corrosion destructions in the column tubing, partings of production string are frequent at gas-condensate wells
Protection against corrosion of metal equipment of condensate wells
Protection against corrosion of metal equipment of condensate wells is one of the most important challenges facing the oil and gas industry. This is due to the fact that the accidents at the gas condensate fields due to corrosion damages of metal equipment of condensate wells and especially corrosion damage of tubing, and metal equipment and pipelines of tail lines, lead to a complete stop and the withdrawal of producing gas condensate wells out of operation. Upon liquidation of the consequences of corrosion destructions of metal equipment of condensate wells, it always requires a large and expensive volume of repair work and environmental protection measures. Also, in case of accidents occurring as a result of corrosion destructions of metal equipment of condensate wells, service staff is at high risk, and explosions and fires are possible.
Corrosion inhibitors for protection of the metal equipment of condensate wells
Highly effective corrosion inhibitor of metal equipment of condensate wells, where corrosion occurs in the presence of CO2
dissolved in the condensation water, are hydrocarbon soluble corrosion inhibitors of film type. Based on formation of firmly adsorbed protective film on the working surfaces of the metal equipment of condensate wells, such corrosion inhibitors provide effective and reliable protection against corrosion of metal equipment of condensate wells, in the first place - corrosion protection of tubing of casing string and metal equipment and pipeline of tail lines.