Closed Operation of Oil Wells
Closed Operation of Oil Wells
a method of petroleum extraction at: oil fields, according to which oil from the wells moves through a hermetically sealed system of pipelines and devices, without coming into contact with the atmosphere. A closed operation system was first developed by the Russian scientist M. M. Tikhvinskii, who proposed the use of gas rather than air as an active agent in the compressor method of petroleum extraction (1914). This made possible the hermetic sealing (“closing1’) of the oil and gas collection system in the field and the prevention of oil loss through evaporation. All oil fields developed since 1950 in the USSR have been designed according to the hermetic sealing method.
In the most widely used closed operation methods, the well output (oil and gas) is directed to a measuring installation through separate pipelines at pressures of 0.5–0.1 meganewtons per sq m. The oil-gas mixture is then piped farther through a common collection main to the field collection station, where separation of the oil and gas takes place in separators. The oil is later fed to a dehydration plant, and the gas is sent to a gas refinery or a plant for the separation of gasoline and liquefied gas. After treatment, the “dry” gas is fed to a gas pipeline. The water separated during the oil dehydration process is treated and injected into the formation flooding system.
New closed operation systems were proposed in the USSR during the late 1960’s. According to one system (created by G. N. Edigarov), by using pumps lowered into the well, the oil, which is under a pressure at which all the gas is in a dissolved state, is collected at stations, where it is then degassed and dehydrated. The system makes it possible to use small-diameter pipelines for the field collection systems (thereby saving metal) and to have on the surface a considerable amount of gas under high pressure, which facilitates its further shipment without the use of compressor stations. According to another system, which uses multiple points at the deposit for groups of wells (the number of which is figured on the basis of minimum calculated expenditures) a collection point is constructed that performs the entire range of processes associated with the measurement of the quantities of oil and gas, their preparation for shipment, and the purification and ejection of waste water. In certain cases, complete preparation of the gas is performed at a central field installation or a gas refinery. The concentration in one location of the production preparation processes for a large number of wells (there may be several such points) makes possible a significant reduction in the cost of construction of the oil and gas collection system and the maintenance of the wells.
REFERENCEGaziev, G. N., and I. I. Korganov. Ekspluatatsiia neftianykh mestorozhdenii, parts 1–2. Baku, 1950–55.
A. I. ARUTIUNOV