RU2186205C2 - Method of water consumption in oil recovery - Google Patents

Abstract

FIELD: oil producing industry; applicable at oil deposits. SUBSTANCE: water supply of system of formation pressure maintenance is organized at sections of location of injection wells with water intake from highly mineralized underground water-bearing bed, and all sewage water is utilized at objects of water disposal by injection into water-absorbing beds. EFFECT: higher reliability and efficiency of water supply system, and utilization of sewage waters in oil recovery. 2 cl

Description

 The invention relates to the oil industry and can be used in oil production at oil fields.

 In the later stages of oil production at oil fields, the amount of water used exceeds the volume of oil production by 8–9 times and the cost of water use makes up the bulk of the cost of oil production.

 The most common method of water use is a closed cycle of water use (Shchurov V.I. Technology and equipment for oil production. A textbook for high schools. M., Nedra, 1983, p. 54), which means pumping water into the reservoir pressure maintenance system produced with oil.

 The known method is ineffective due to the cumbersome system of circulating water supply.

 A known method of water use in oil production, in which wastewater separated from oil in sumps at a booster pump station is supplied to a cluster pump station, and then to injection wells to maintain reservoir pressure. Sewage from the central oil treatment point is also sent here. Thus, wastewater produced together with oil and prepared accordingly, i.e. purified from oil and mechanical impurities, it is fed into the reservoir pressure maintenance system (RD 39-01-0148311-605-86, M., Minnefteprom, 1986, p.13, clause 2.1.3.4.).

 This method of water use, including water supply and disposal of wastewater, has several disadvantages: a well-developed network of pipelines in the oil field is required, it is necessary to treat wastewater to a high degree of purification from oil and mechanical impurities, and water is saturated with oxygen in the treatment apparatus, which increases corrosion activity water, water is mixed in different layers having different properties, which leads to the formation of various insoluble salts in the form of mechanical impurities.

 The objective of this technical solution is to increase the reliability and efficiency of water use in oil production.

 The problem is solved in that in the known method of water use in oil production, including pumping water into injection wells, separating wastewater from oil and disposing of it, according to the invention, highly mineralized water is pumped from the aquifer in the area of injection wells to maintain reservoir pressure in injection wells and the waste water after separation from oil is disposed of by injection into the absorbing layer at the wastewater discharge facilities.

 The injection of highly saline water from an aquifer into the injection wells on the injection well location area ensures that clean water is pumped into the reservoir without the high cost of cleaning it, there is less oxygen in the water, while the formation of corrosive hydrogen sulfide in the oil reservoir is prevented, in addition, in highly saline water sulfate-reducing bacteria cannot exist. All these factors significantly reduce the corrosion of underground and ground equipment during oil production, which increases the reliability and economic efficiency of the entire oil production system.

 Utilization of wastewater produced together with oil from the reservoir by injection into the absorption reservoir simplifies the technology of preparing this water for injection, since the injection into the absorbing aquifer does not require a high degree of purification, as in the case of pumping water into the oil reservoir, in addition, When mixing water from different layers, there are no complications, while reducing the cost of treatment and disposal of water.

 The proposed method of water use in oil production can be implemented on a single field using data from geological studies when drilling wells in this area. The necessary conditions are the presence of a highly mineralized aquifer for water intake and an absorption reservoir for pumping wastewater. For these purposes, any drilled wells in a given area can be used by opening a perforated aquifer or an absorptive layer with a perforation column and isolating other layers. Depending on the water flow rate and the required amount of water injected into the injection wells, several wells can be used for water intake. In this case, it is advisable to choose a well for water intake as close as possible to the injection wells in order to reduce the length of the pipelines in the reservoir pressure maintenance system. And for pumping wastewater into the absorbing layer, the well should be selected on the areas of the preliminary water discharge facility and the oil treatment and water discharge facility, also in order to reduce the length of the pipelines at the wastewater disposal site.

 Thus, the proposed method is implemented as follows.

 According to geological studies, in a given area of an oil field, when drilling oil and injection wells, water wells are selected as close as possible to the injection wells, in which a highly mineralized aquifer is opened, the well is equipped with a pump for pumping water to a high-pressure cluster pump station. Then the water supply system of the group of injection wells is ready.

 At the sewage disposal site, existing wells are also used or an additional well is drilled and a water-absorbing layer is opened. When using high-performance sedimentation tanks for sludge-oil emulsion (for example, according to the patent of the Russian Federation 2077918, class B 01 D 17/028, op. 27.04.97 or according to the patent of the Russian Federation 2089259, class B 01 D 17/00, op. 10.09.97 ) sufficient wastewater treatment is achieved for injection into the absorbing layer. Wastewater is pumped directly from the sump into the absorption reservoir.

 The proposed method of water use in oil production includes two independent sections: a section for collecting and pumping formation water into injection wells and a section for the disposal of wastewater from sumps to absorbing wells. At the same time, the length of water conduits is significantly reduced, but compared with the scheme traditionally used in practice, since wastewater does not return from oil treatment points to injection wells located at a considerable distance.

 The implementation of the proposed method of water use in oil production solves the problem of increasing the reliability and efficiency of water supply and waste water disposal in oil production as a result of reducing corrosion damage to underground and ground equipment, reducing the cost of treating water, water pipes, various expensive reagents, corrosion inhibitors, etc. d.

Claims (2)

 1. A method of water use in oil production, including pumping water into injection wells, separating wastewater from oil and utilizing it, characterized in that highly mineralized water is pumped into the injection wells to maintain reservoir pressure from the aquifer in the area of the injection wells, and wastewater after oil separation, they are disposed of by injection into an absorbing layer at wastewater discharge facilities.  2. The method according to p. 1, characterized in that after selecting wells for water intake from the aquifer and wells for pumping wastewater in these wells, respectively, an aquifer or an absorption reservoir is opened.