RU2241116C2 - Method for supporting bed pressure on oil deposits - Google Patents

Abstract

FIELD: oil extractive industry.

SUBSTANCE: method includes feeding calculated amount of water at minimal pressure necessary for pumping into beds of deposit by force pumps along water duct. On pit-face of separate force wells calculated volumes of pumping of water into bed are reached by vibration-strike or acoustic effect of field. This is achieved due to raising of pressure in face-adjacent area of bed, lowering hydraulic losses in bed, lowering viscosity of water and forming additional micro-cracks in collector of face-adjacent bed zone. For this, on basis of pumping mode a hydrodynamic or ultrasound converter-emitter is selected with necessary parameters.

EFFECT: higher efficiency.

1 dwg

Description

The invention relates to the oil industry, in particular to a method for maintaining reservoir pressure in oil fields.

There is a method of maintaining reservoir pressure, which consists in the supply of power pumps with water with different pressures through individual pipelines into injection wells [1].

The disadvantage of this method is that pumps of various pressures, for example, 14.0 and 18.0 MPa, are installed in the pumping station. To supply water to injection wells, separate pipelines are built at a pressure of 14.0 and 18.0 MPa. Thus, the volume and cost of arranging the RPM system increase by 1.5-1.7 times.

Closest to the claimed technical solution is a method of maintaining reservoir pressure in an oil reservoir, comprising supplying power pumps with water at the maximum necessary pressure through the injection conduits to the mouth of the injection wells, followed by controlling the volume of flow through the well into the formation through flow study [2].

The disadvantage of this solution is that at first power pumping units spend power to develop the maximum pressure required for individual wells, and then in wells where less pressure is required for injection, the flow is studied. These are wells with a higher injection rate than wells in which it is planned to supply water at high pressure. If you do not study the flow of water in them, then the volume of water will go into the reservoir much higher than the field development system requires, and water may not flow into the reservoir of injection wells with worse injectivity. In fact, due to the fitting of up to 30% of the energy spent in reservoir pressure maintenance systems, energy is spent inefficiently.

The technical problem solved by the invention is to reduce energy losses in the reservoir pressure maintenance system.

This goal is achieved by the fact that in the method of maintaining reservoir pressure in oil fields, including the supply of power pumps water through the pipelines to injection wells, according to the invention, the calculated volume of water is supplied to the injection pipelines by power pumps under the minimum pressure necessary for injection into the reservoir layers, and at the bottom injection wells by vibration or acoustic fields reach the calculated volumes of water injection into the reservoir due to the increase in pressure in the bottomhole zone hundred, reducing of hydraulic losses in the formation, reduction of the viscosity of water and formation of microcracks in other bottomhole formation zone, which is selected by the injection mode with the required process parameters hydrodynamic or ultrasonic transducer-emitter.

The invention consists in the following. Hydrodynamic or ultrasonic transducers-emitters are lowered into wells, where it is supposed to intensify the injection process, on a pipe string through which water enters the formation. The energy of the water flow is used to drive a hydraulic vibrator or an ultrasonic hydraulic emitter. The energy expended in this case is small in comparison with the increase in the effect of water injection into the reservoir. In accordance with [3], for example, at a depth of 2000 m with a pressure at the wellhead of 10.0 MPa, the pressure at the bottom of the well with a hydraulic vibrator will reach 32.0 MPa. At the same time, when the acoustic field is exposed, the injectivity of the well will increase due to a decrease in hydraulic losses in the formation, viscosity of water, the formation of additional microcracks in the bottom-hole zone of the formation, etc. These factors increase the injectivity of the wells at low pressures of the water supplied to it. According to the parameters of the well and the injection mode, the necessary standard size of the transducers-emitters is selected.

The drawing shows a diagram of the implementation of the proposed method. With power pumps, water under the low pressure necessary for well 1 is fed through a water conduit 2 and then through a downhole string of pipes 3 into a highly productive formation 4.

In the interval of perforation of the well 5, in which the designed injection volumes are not achieved at the water pressure in the conduit 2, a hydraulic vibrator or acoustic emitter 6 is lowered. From the pipe 2, water enters the hydraulic vibrator 6 through the wellhead 7 and the bore pipe string 8. Energy of a continuous stream of water it is converted into cyclic hydraulic shocks with a sharp increase in pressure in the bottom-hole zone of a low-productivity formation 7. In addition, vibration or exposure to an ultrasonic field reduces viscosity and surface water tension of oil-water emulsions in the reservoir, etc. [3]. All this helps to increase the injectivity of the water reservoir. The parameters of the emitter operation achieve the required volumes of water injection, which could not be achieved if the water was pumped without vibration processing into the reservoir.

An example implementation of the method. At the field there are 20 injection wells with a depth of H = 2000 m. It is required to pump water with bottomhole pressure (P ₃ ) from 27.0 to 30.0 MPa (depending on their injection rate). Taking into account friction losses P _tr = 1.0 MPa of water in the pipe string of injection wells, the pressure at the mouth of wells of low injectivity is calculated

P _mouth = P ₃ -0.1 · H · γ + P _Tr = 30.0-0.01 · 2000 · 1 + 1.0 = 11.0 MPa.

For high injection wells

R _mouth = 27.0-0.01 · 2000 · 1 + 1.0 = 8.0 MPa.

Thus, at the mouth of all injection wells according to the prototype, a pressure of 11.0 MPa should be maintained. In wells requiring 27.0 MPa at the bottom, the wellhead pressure by the regulator is reduced to 8.0 MPa. That is, the energy reported by power pumps to water is not used rationally. In the proposed method, the pressure at the mouth of all wells is not 11.0 MPa, but 8.0 MPa. And in wells with low injectivity, a bottomhole pressure of 26.0-32.0 MPa is reached using a vibrator or an acoustic generator, for example, a generator of the GVZ type [3]. In addition, vibration exposure increases the injectivity of wells by reducing the viscosity and surface tension of the oil-water emulsion, opening cracked reservoirs, etc. Providing the necessary modes and vibrator effect are achieved by structural changes in it, for example, the width and number of slots of the fluid flow, etc. In an ultrasonic emitter, the mode changes by changing the length of the vibrating element.

Thus, the installed capacity of the central pumping unit type TsNS 180-1420 for the RPM system can be reduced by 260 kW.

Sources of information

1. Takhautdinov Sh.F., Yusupov I.G. Technical progress in engineering and technology for building wells in oil production // “Oil Industry”, No. 12, 1996, p. 19.

2. A guide for masters in oil production and well repair. Reference Edition. - Surgut: Advertising and publishing information center “Ob-Ob Oil”, 1999, pp. 136-137, prototype.

3. Umetbaev V. G. Geological and technical measures during the operation of wells. - M .: Nedra, 1989, table 32.

Claims (1)

A method of maintaining reservoir pressure in oil fields, including the supply of water by power pumps through pipelines to injection wells, characterized in that the calculated volume of water is supplied to injection wells under the minimum pressure necessary for injection into the reservoirs, and they reach the bottom of the injection wells by vibration or acoustic impact Estimated volumes of water injection into the reservoir due to pressure increase in the bottom-hole zone of the reservoir, decrease in hydraulic losses in the reservoir, decrease in water viscosity and additional formation of microcracks in the reservoir bottomhole formation zone, which is selected by the injection mode with the appropriate parameters hydrodynamic or ultrasonic transducer-emitter.