SU1693233A1 - Method of producing non-uniform oil field with viscous oil - Google Patents

Abstract

This invention relates to the development of a non-uniform oil field. The goal is to increase oil recovery while simultaneously reducing the water produced with oil and reducing the injection of the displacing agent. For this, the field is drilled with a system of production and injection wells. A displacing agent is pumped through the injection wells and the products are taken from the production wells. After reaching the water cut, production wells are shut off. At the same time, the selection of products from producing wells that have reached the maximum water cut is carried out periodically with a uniform decrease in the volume of injection in the injection wells. Periodically monitor the well displacement characteristics of adjacent producing wells. When the performance of at least one of these wells deteriorates compared with the prevailing displacement characteristic, under given geological conditions, the production well is put into operation with the utmost water content. With the improvement of the extrusion characteristics, the operation of the production well is stopped. 6 Il. with C

Description

The invention relates to the development of a non-uniform oil field and can be applied to deposits with high viscosity oil.

The aim of the invention is to increase oil recovery while simultaneously reducing the water produced with oil and reducing the injection of a displacing agent,

FIG. 1 shows a map of the development of a plot of a field by a known method; figure 2 - map of the development of the plot of the field on the proposed method; in fig. 3-6 are diagrams explaining the proposed method.

The area of the area consists of four zones of different permeability (a, b, c, d - zones, respectively, with permeabilities of 0.25; 0.5; 0.10; 0.05 µm2) and drilled with a three-way system of production and injection wells. In Figures 1 and 2, the displacement front (zone of greatest saturation gradients) is indicated by the 1.1n line, 2n — injection wells, 1,2,3-producing wells.

Figures 3 and 4 show the displacement characteristics of two production wells.

WITH

S 00

yu so

00

(No. 1 and No. 3, position a and b) located near the well-driver (1h), of the type He f (1dOJ), respectively, during the operation of the site using the known (FIG. 3) and proposed methods (FIG. 4), where QH - cumulative oil production by wells and Og - cumulative production of liquid. The solid lines indicate the actual characteristics of the displacement, and the dotted lines indicate the extrapolations of the characteristics of the displacement obtained prior to the shut-off of the flooded well (Fig. 3) and prior to the periodic operation of the flooded well (Fig. 4).

Figures 5 and 6 show the graphs of the dynamics of the water content of the extracted products (Fig. 5) and the water-oil factor (HVF) (Fig. 6) depending on oil recovery for the cases of applying the known method (curve 1) and the proposed (curve 2).

The method is carried out in the following sequence.

The field, represented by heterogeneous reservoirs with high-viscosity oil, is drilled with a project grid of wells and is being repaired. Water is pumped into injection wells and product is taken from production wells. In the process of drilling and operation, wells are studied: the parameters of the reservoir are determined, samples of produced water and oil are taken at the same time, the water production of wells is determined,

Consider the implementation of the proposed method on the example of the element 3-p d-th system of water flooding, including two injection and three producing wells (figure 2). The wells are located in zones with different permeability, and therefore in terms of productivity and injectivity, they differ significantly from one another: better productivity at well No. 2 and worse at well No. 3. Among injection wells, the best well, No. 1, is injectivity.

The deposit of the site under consideration is represented by high-viscosity oil (/ and 6, OsPa-s).

Under conditions of a heterogeneous reservoir with high-viscosity oil, when pumping water into injection wells and withdrawing products from production wells, oil is displaced primarily from the high-filtration part of the reservoir.

If in the initial stage of development, the front of extrusion is characterized by unevenness associated with the geological structure of the area of the field and the fluids that saturate it, then when the oil is replaced with water, the frontal unevenness is all

more enhanced. There is an increasing decrease in filtration resistances in the directions of highly permeable zones compared to filtration resistances of low permeability zones due to the more intense decrease in the viscosity of formation fluid in these zones when oil is replaced by water. Well Ns 2, located in a highly permeable zone,

0 is watered in the first place, and after reaching its limit water cut, they start using the proposed method.

In order to prevent premature breakthrough of the front of the injected water through the high-permeable zone (along the line between wells # 1n-№2-№-1) and prevent the oil from being pinched in the direction of the low-permeable part of the reservoir in the zone along the well # 1n - tsb 1 the central row (well No. 1) the flooded well No. 2 begin to operate periodically, and the injection well-watering no. 1N reduces injection by a volume equal to the decrease in fluid withdrawal from well No. 2 due to its periodic operation . A watering hole is determined by research

0 wells using fluid indicators. Periodic operation of well No. 2 leads to a decrease in fluid withdrawal, as a result, water withdrawal is reduced and at the same time diverted

5, the part of the injected water from the well No. 1, eliminates the rapid breakthrough of the displacement front along the line of the wells No. 1n- №2-№1. Part of the volume of fluid from the stream directed from the injection well

0 № 1n along the line № 1n - Ns 2 - № 1, is selected by well # 2. This leads to a decrease in the velocity of the fluid in the direction of well 2 - № 1, the movement of the water front in this direction slows down. The speed of the front of the displacing agent in the high-permeable zone in the direction of the Mg1n-No.2-Mg1 wells slows down, the arrival in accordance with the speed of the front in the direction of the wells No. 1 n - Ns 1. Thanks to the regulating action of the N 2 well in this direction, the front of movement of the displacing agent is equalized. Well # 2 is a displacement front motion controller.

The alignment of the displacement front occurs (Fig. 2) and, as a result, a reduction in the selection of the simultaneously produced displacing agent.

Control over the fact that a decrease in the rate of increase in the water-cut of the extracted products occurred (as a result of a decrease in the extraction of the displacing agent), is carried out according to the well characteristics of the displacement of surrounding wells. Monitoring is carried out by weekly measurements of flow rates and water cut of the products produced.

As can be seen from FIG. 4, the use of the proposed method led to a deviation of the displacement characteristic for wells No. 1 and No. 3 towards the axis of the cumulative oil production, i.e. there was an increase in mobile oil reserves, the growth rate of flooding of production decreased. This confirms the need to continue the periodic operation of the flooded well No. 2. In case of displacement, at least one of the nearest wells displaces the displacement characteristic in the direction of the 1dOX axis (there was a decrease in mobile reserves, the flooding rate increased) at the instant of water-flooded wells during further operation of the site requires a complete stop of the flooded well (No. 2).

Example. The implementation of the method will be considered on the example of an oil reservoir (FIG. 2) drilled in a 3-row system with a distance between wells and between rows of 400 mm. Three production wells (No. 1,2,3) and two injection wells (1n, 2n) were drilled on the site. The average permeability of the area is 0.225 μm2. The reservoirs are saturated with oil with a viscosity of 6.0 cPa-s. The balance oil reserves of the site are 157 thousand tons. In the injection wells 1N and 2N, the injection of the agent is carried out, respectively, with a capacity of 40 and 20 m3 / day with a pressure at the mouth of 12 MPa. After 11 years of operation, well No. 2 was doused with injected water by 98%. Upon reaching the maximum water cut in well #. 2, the current water cut in wells 1 and 3 was respectively 89% and 60%. After that, pumped into injection wells of different types of indicators (for example, trit, saltpeter). The number (concentration) of incoming indicators in production wells in No. 1 and No. 3 determined the share of water intake from each injection well, i.e. drilling wells. Found that in producing wells number 1 and Nb 3 from the injection well number 1n comes 83% of production and 17% of the well number 2n. The watering hole is the injection well No. 1N.

Watered well No. 2 was transferred to periodic operation, as a result of which fluid withdrawal through this well was reduced by 26 m3 / day. At the same amount, the injection into well-drilling well No. 1n was limited. The volume of injection and reduction of fluid withdrawal due to the periodic operation of well No. 2 were refined based on the results of actual performance of the nearest producing wells (1 and No. 3) after constructing the displacement characteristics.

5 From FIG. 4, it can be seen that after using the method (section B C), the displacement characteristics of the nearest wells (No. 3 and No. 1) deviated towards the axis of total oil production. This psdtver0 ensures the effectiveness of the activities carried out, i.e. there was an increase in mobile stocks and a decrease in the growth rate of water intake. For the period of development of the site according to the proposed method

5, there was a significant decrease in the selection of mined preemptive agent. As can be seen from Fig. 6, by the time oil recovery at the site reached 29%, the water-oil factor was 12 (curve

0 2). This is 3.3 units less (15.3) than during the operation of the site using a known method (Fig. 6, curve 1).

For the site as a whole for the extraction of 46 thousand tons of oil (the product of the balance

5 stocks of 157 thousand tons on the coefficient of oil production -. impulses 0.29) reduction in the volume of the extracted agent and its injection over 14 years will amount to 138 thousand tons.

Claims (1)

0 claims A method for developing a heterogeneous oil field with high-viscosity oil, including drilling it with a system of production and injection wells, pumping a displacing agent through injection wells and selecting products through production wells, shutting off production wells after reaching the limiting watering, it differs and so that, with the aim of increasing oil recovery while simultaneously reducing the water produced with oil and reducing the injection of a displacing agent, after shutting down the production well 5 with limiting watering, they periodically monitor the displacement characteristics of neighboring production wells, while the displacement characteristics deteriorate in at least one neighboring production well compared with the established displacement characteristic under given geological conditions, the production well is started up with a maximum water content, with periodic watering control over adjacent wells, while improving the displacement characteristics in all neighboring producing wells compared to The resulting displacement characteristic for these geological conditions is stopped with the limiting water cut, and during periodic operation of the well with the maximum water content in the injection wells, the displacement agent is reduced. I QH 2520-15J W  one ®and ei J That fig 3 He is 2520; 15105w $ "1.L ( 8,% 969CH-- 92NF PP - U8615 20 2.0 m y  F W,