RU1796013C - Method for developing reservoir - Google Patents

Abstract

SUMMARY OF THE INVENTION: Solvent is pumped into the formation through an injection well. An oil emulsion emulsion is used as a solvent with a water content in the emulsion from 15 to 45%.

Description

FIELD OF THE INVENTION This invention relates to the oil industry and can be used to develop high viscosity oil deposits.

A known method for the development of oil deposits, including drilling production and injection wells and stationary injection through injection wells into productive reservoirs of water. However, this method on highly viscous oil deposits is ineffective, because: due to the high ratio of mobilities of injected water and displaced oil it does not provide satisfactory oil recovery - after the start of watering of producing wells, a catastrophically rapid increase in water cut of the produced fluid occurs with a slight additional oil extraction and the industrial oil production process have to stop:

There is another way to develop oil deposits, taken here as a prototype, including drilling production and injection wells and the sequential injection of rims of light hydrocarbons moving along the reservoir with water. Since light hydrocarbons are used in this method, this does not reduce the mobility of the displacing medium; therefore, the use of this method is possible only for displacing low-viscosity oil.

In addition, this method is not effective enough, firstly, because it requires special preparation of the produced liquid in order to isolate pure oil, in-. secondly, because an increased amount of oil is consumed for injection into the reservoirs, which it is desirable to reduce.

The aim of the invention is to increase oil recovery and increase the efficiency of the process.

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Xi

Yu Oh Oh

ABOUT)

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The goal is achieved by the fact that oil-water emulsion with a predominant proportion of oil is pumped into the reservoirs instead of oil in turn with water. This emulsion forms directly in the oil fields during the operation of partially flooded production wells. Its destruction and separation into pure oil and water presents a certain technical difficulty. With this method, the technology is greatly simplified and it is not necessary to prepare pure oil for filling into reservoirs, but oil-water emulsion extracted from wells can be used. An important advantage of an oil-in-water emulsion is that it has a higher viscosity than the high viscosity oil contained in it. It turns out that the addition of low-viscosity water to high viscosity oil with the formation of an emulsion does not lead to a decrease, but rather to an increase in viscosity. Accordingly, the overall viscosity of the injected water array is increased, separated by a plurality of septa of the oil emulsion. Due to the increase in the total viscosity of the displacing agent, the efficiency of alternating injection increases, and the oil recovery increases.

When filtering a displacing agent through a porous medium, the oil-water emulsion can be destroyed to one degree or another and its separation into its component parts - oil and water. In order for the positive effect of alternating high viscosity oil and hearth to be necessarily preserved, the oil should constitute the predominant share in the oil-water emulsion. Then, within the limits of highly viscous partitions, oil will be the main carrier phase, and water the non-main carrier phase.

Example, In the considered oil deposit, the dependence of the viscosity of the oil-water emulsion on the proportion of water in it is characterized by the following numerical values.

The following numerical values approximately correspond to the following mathematical formula for the coefficient of increase in viscosity of the emulsion depending on the proportion of water:

 e

 20V

When using an emulsion with a water fraction of 0.45, the coefficient of increase in viscosity of the emulsion is 3.85. Moreover, according to

Compared with the known method (a.s. 1195717), the proportion of oil in the volume of the displacing agent is reduced from 10% to 10. (1-0.45) 5.5% and, accordingly, the recoverable oil reserves increase in:

(100% -5.5%) / (100% -10%) - 1.05 times

In the oil reservoir of high viscosity oil under consideration, using the well-known development method (A. p. 1195717), the recoverable oil reserves are 40 mln. t, and when applying this method, they increase and become equal to 40 1.05 42 million tons, an increase of 2 million tons of oil.

With the cost of exploration of 1 ton of recoverable oil reserves of 10 rubles .. only at the expense of saving part of the costs of exploration, this method provides an economic effect of 10 2 20 million rubles.

The annual oil production in the considered oil reservoir with the known development method (a.s. 1195717) is 2 million tons; accordingly, with this development method, it is 2. 1.05 2.1 million tons or 0.1 million tons more. At a price of 1 ton of oil, 100 rubles. and at the cost of producing 1 ton of oil 60 rubles. the effect of the extraction of each ton of oil is (100-60) 40 rubles. Annual effect

of additional oil production is 40 0.1 4 million rubles. and for all the years of development of the oil deposit it is 40,280 million rubles. In total, the overall effect of cost savings in exploration and the additional effect in development when using this development method is 20 + 80 100 million rubles.

Claims (1)

Formula from Acquisition A method of developing an oil reservoir, including the selection of oil through production wells and pumping a portion of solvent and water through injection wells, characterized in that, with In order to increase the effective method by simplifying injection technology and reducing oil consumption, an oil-emulsion emulsion is injected into the formation as a solvent at a water content of 15-45% in the emulsion.