RU2471060C2 - Isolation method of water inlux in production wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method involves pumping of invert emulsion containing liquid hydrocarbons, emulsifier and water, with formation of high-viscosity medium at its interaction with water. Invert emulsion containing Neftenol NZ or Neftenol NZ-TAT is used as emulsifier, and pumping of invert emulsion to production well is alternated with pumping of water to it with formation of several alternating layers of invert emulsion and water in the well.

EFFECT: improving isolation method of water influx in production wells at reduction of invert emulsion flow rate.

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Description

The invention relates to the field of development of oil deposits and may find application in the operation of flooded oil deposits, to intensify the operation of production wells.

A known method of isolating water inflow in production wells, which includes sequential injection into the isolated interval of portions of the reverse emulsion based on the aqueous dispersed phase and the hydrocarbon dispersion medium and grouting reinforcing the waterproofing screen in the formation. The grouting composition is pumped by sequential alternation with each portion of the reverse emulsion (RU 2283422, publ. 09/10/2006).

The closest analogue to the proposed method is a method of isolating water inflow in producing wells when an invert (reverse) emulsion is pumped into the reservoir, the external dispersion medium of which is oil. When interacting with formation water, the emulsion forms a highly viscous, structured, inactive system that forms a water-insulating screen in the bottomhole zone of the reservoir (RU 2391378, publ. 10.06.2010).

The disadvantage of this method is the high consumption of reverse emulsion, necessary for the formation of a waterproofing screen.

The objective of the invention is to provide effective isolation of water in production wells while reducing the consumption of reverse emulsion.

The technical result of the invention is to reduce the consumption of the reverse emulsion due to the involvement in the volume of the emulsion of water, pumped alternately in layers with the emulsion.

The technical result is achieved by the fact that in the method of isolating water inflow in producing wells, which includes injecting a reverse emulsion, including liquid hydrocarbons, an emulsifier and water, with the formation of a highly viscous medium when it interacts with water, according to the change, a reverse emulsion is used, which includes Neftenol NZ as an emulsifier and Neftenol NZ-TAT and alternate the injection of the reverse emulsion into the production well with the injection of water into it with the formation in the well of several alternating layers of reverse emulsion and water.

The layer-by-layer injection of emulsion and water leads to the isolation of highly permeable water-saturated layers, plantar water and to the inclusion of oil-saturated formations in the work.

The preparation of the inverse emulsion to isolate water inflow can be carried out, for example, as follows.

Preparation of the inverse (invert) emulsion involves mixing the emulsifier Neftenol NZ or Neftenol NZ-TAT with oil (commercial form), the rest is water. The oil-soluble surfactant in this technology is an emulsifier: a hydrocarbon solution of esters of oleic, linoleic, as well as triethanolamine resin acids and additives of nonionic surfactants. An additional hydrocarbon phase in this technology is oil (dehydrated), which is a mixture of hydrocarbons, an oily, viscous liquid. To prepare the reverse emulsion and to treat the bottom-hole zone of production wells in order to create a waterproof screen, industrial water with a salinity of 30 to 1200 mg / liter is used.

The inverse emulsion may have the following ratio of components, wt.%:

emulsifier 5.0-7.0 oil (commercial) 18.0-20.0 technical water rest

An emulsifier is used as a surfactant, which contains esters of tal oil and triethalomine acids (emulsifier base).

Example 1 preparation of the inverse emulsion.

An emulsifier Neftenol NZ-TAT in a volume of 0.6 cm ³ is introduced into a liquid hydrocarbon (oil) in a volume of 15.0 cm ³ , with further stirring, industrial water in a volume of 84.4 cm ³ is introduced. The result is an inverse emulsion of high viscosity, resistant to destruction, of the following composition, wt.%:

oil - 15.0

Neftenol NZ-TAT - 0.6

industrial water - 84.4

Characteristics of the resulting emulsion:

density 1000 kg / m ³ ;

dynamic viscosity - 62.0 MPa / s;

electrical stability - 64 Volts.

Example 2 preparation of the inverse emulsion.

An aqueous solution of calcium chloride (ρ = 1.282 g / cm ³ ) in a volume of 0.87 cm ^{3 is} dissolved with water to 100 cm ³ . An emulsifier Neftenol NZ in a volume of 0.6 cm ³ is introduced into a liquid hydrocarbon (distillate) in a volume of 20.0 cm ³ , with further stirring, an aqueous solution of calcium chloride in a volume of 79.4 cm ³ is introduced. The result is a highly dispersed emulsion of the following composition, wt.%:

distillate - 20.0

Neftenol NZ - 0.6

calcium chloride - 0.3

industrial water - 79.4

Characteristics of the resulting emulsion:

density - 964 kg / m ³ ;

dynamic viscosity - 16.0 MPa / s;

electrical stability - 45 Volts.

The method is as follows.

Alternately, several layers of the reverse emulsion and water prepared according to Example 1 are pumped into the production well. The injection volume of the reverse emulsion and water layers is calculated individually for each production well based on the properties of the flooded reservoir. The ratio of the injected volumes of the inverse emulsion and water is selected from the condition of ensuring the following characteristics of the medium obtained in the well as a result of mutual diffusion of the emulsion layers:

density - from 964 kg / m ³ to 1160 kg / m ³ ;

dynamic viscosity - from 70 MPa / s to a glue state;

electrical stability - from 45 to 64 volts.

With further addition of water and stirring, the inverse emulsion becomes non-flowing. This property of inverse emulsion during layer-by-layer injection with water makes it possible to make an impermeable screen in the near bottomhole space of the producing well in easily permeable and fractured rocks.

Emulsifiers of such a class as Neftenol NZ and Neftenol NZ-TAT are a highly active emulsifying reagent; oil is added to increase the hydrocarbon mass present in the emulsifier. This makes it possible to involve loosely bound water injected in a layer into the composition of the emulsion, which leads to an increase in viscosity and the total volume of the reverse emulsion near the wellhead of the producing wells.

In November 2009, in the reservoir 303 of the Romashkinskoye field of the Republic of Tatarstan, an experimental injection of reverse emulsion into production wells was carried out in order to isolate water inflow.

The operating modes of production wells before and after the application of isolation of water inflow are shown in table 1. From table 1 it can be seen that the operating mode of production wells before applying the technology for isolating water inflow was on average:

The volume of pumped liquid amounted to - 43.85 tons / day;

The volume of oil amounted to - 0.5 tons / day;

The water content was 98.9%.

After applying the technology to isolate water inflow, the liquid level in the wells decreased, and the wells were switched to a more energy-efficient mode of operation:

The average volume of pumped liquid was 8.1 tons / day;

The volume of oil amounted to 2.65 tons / day;

The water content was 67.4%.

For seven months after the application of technology to isolate water inflow with the use of reverse (invert) emulsion and layer-by-layer water injection at production wells, additional oil production amounted to 659 tons of oil.

Table 2 presents various ratios of the unit volume of the inverse emulsion to the volume of water (ρ = 1.18 kg / m ³ ) and the corresponding characteristics of the emulsion obtained in the well.

Table 1 №№ date of Volume Arr. um m ³ operating mode before mode of operation after the event. work schedule on 06/01/10 Add. production, m Qн, m / s Qzh, m / s % water Qн, m / s Qzh, m / s % water Qн, m / s Q, m / s % water one 10/19/09 96 0.7 73,4 99.1 3.3 9.8 66.6 1,0 9.5 89.3 229 2 11/01/09 96 0.3 14.3 98.7 2.0 6.4 68.3 2.5 12,2 59.5 430 TOTAL: 659

table 2 Water (%) Density (kg / m ³ ) Dynamic viscosity (MPa / s) Electrical Stability (Volt) 10 1081 62 64 fifteen 1085 64 65 twenty 1089 70 67 25 1093 gel 68 thirty 1097 gel 69 35 stratification

Claims (1)

A method of isolating water inflow in production wells, including injecting a reverse emulsion, including liquid hydrocarbons, an emulsifier and water, with the formation of a highly viscous medium when interacting with water, characterized in that the reverse emulsion is used, which includes Neftenol NZ or Neftenol NZ-TAT as an emulsifier, and alternating the injection of the reverse emulsion into the production well with the injection of water into it to form several alternating layers of the reverse emulsion and water in the well.