SU1606687A1 - Method of developing mutiple-strata nonuniform oil field - Google Patents

Abstract

The invention relates to the development of oil fields, represented by multi-layer discontinuous reservoirs using waterflooding. The goal is to increase oil recovery due to an increase in reservoir coverage by flooding. A multilayer oil field with intermittent formations is drilled in rows of injection and production wells. Water is pumped through the injection wells into the main and discontinuous formations, and oil is extracted through the production wells. As far as production wells are flooded at the final stage, if there are at least one discontinuous reservoir in the section of these wells, they are transferred to the injection, and the transfer is carried out along the perimeter of the section with the maximum number of opened formations. 2 ill., 2 tab.

Description

The invention relates to the development of oil fields, represented by multi-layer intermittent reservoirs using water-flooding, and can be used in the oil industry.

The purpose of the invention is to increase oil recovery by increasing the coverage of reservoirs with water flooding.

In Fig., 1 shows the scheme of residual oil reserves by a known method; figure 2 - the same, the proposed method.

The method is carried out as follows.

A multilayer oil field with pre-seams is drilled with a series of injection and production wells, and the arrangement is carried out. Produces water injection and oil production from producing wells. In the course of drilling and operating the wells: hydrodynamic studies of wells are performed and a combined map of the layers is constructed. In order to involve formations that do not have a hydrodynamic connection with injection wells, transferring those commissioned for injection is transferred, in this case, well 9 in FIG. 1,

about

O) 05 00 -vj

When transferring a well for injection, which has all the layers in its section, oil moves to the reaching wells 1 and 2 of the rows from two sides, so that these rows become tight. When the oil is displaced from a region with a high concentration of reserves ( the largest number of open formations) and well operation until the maximum water cut, at the final stage a significant amount of oil pillars remain in the reservoirs, dispersed both in the area and in the section of the object

According to this method, when the production of wells in the main reservoir (reservoir) is 90–95%, wells 5 and 14 (FIG. 2), having reservoirs a to 5 (intermittent reservoirs) in their own section, are transferred to the injection injection into the interstational strata continues with a wellhead pressure greater or equal to the pressure in the wells being transferred. Downhole pressure in the 3rd row wells is maintained by 10–20% less during operation than in the remaining rows. with the maximum number of reservoir intersections, it is translated by product selection Implementation of these conditions allows to produce a seepage flow formations shift. If the flow paths of the PRI, with a known method, were directed in opposite directions, and the flow separating boundaries with zones of zero gradients (zones of oil pillars) fell on the 1st and 2nd rows of producing wells (FIG. 1), then during injection water in wells 5 and 14, the flow through all strata up to 3-gr p and coincide on each side (FIG. 2). As a result, the flow separation boundary will pass through the wells that have opened the maximum number of formations, i.e., the third row.

As the production wells are flooded, located along the perimeter with the maximum number of formations, they are transferred to the injection of water. The wells, which have a maximum dissection, are exploited to a cost-effective water-cut.

As a result, the amount of oil chain s at the final stage of development is reduced, while the reservoir coverage rate with water flooding PO; melt away

This can be seen in the example of the development of an oil field site. Using a known method (Figures 1 and 2), two tightening rows and, respectively, four stagnant zones are formed in a multi-layer development object (consisting of 3 layers). If we consider each reservoir separately, calculations show that when applying the known method, six zones of stagnant oil are formed, in Toch. four zones in the L layer and two zones in the B layer. With this method, two stagnant zones are formed in the formation 6

To clarify the above, a map of equal pressures on the reservoir $ was constructed for the final stage of development both in the well-known and in this way you dreamed that, according to the well-known method, a zone of zero gradients is formed in zone 1 and 2 ( t isobars of the same value) According to this method, only one zone of zero gradients is formed, as a result of which the number of pillars at the final stage along formation 5 decreases by a factor of 2. Similar results are obtained for reservoir 5,

Example The implementation of this method will be considered using the example of a section of a field composed of layers a, S, and b (and 2). The main layer has an areal distribution of a and & - perfect structure The site is drilled on the 3-p system of development .1 The main parameters of the site, learned in the process of drilling and operation, are given in tabl1

In order to increase the coverage of the layers with the impact and rate of selection at the initial stage,. Well 9 was transferred to water injection. With a well water cut of 90% and higher in the main, the JHOMy formation, which has intermittent formations in its section, in our case well No. 5 and 14, were transferred to water injection, and well 9 under the selection.

Based on the parameters of the site (Table 1), we calculated the coefficient of reservoir coverage by waterflood at the end of the development in the implementation of the known and given development methods.

The results of the calculations are shown in Table 2, from which it is clear that the use of this method allows to increase the reservoir coverage rate by 5.1% (from 0.877 to 0.928) o

On the site under consideration, 8239 tySoTo balance. The magnitude of the coefficient of oil recovery. (k „d) at the implementation of the proposed method will be 0.624, against 0.590 from the known

Claims (1)

Invention Formula The method of developing a multilayer heterogeneous oil field, including the placement of wells in the main reservoir, water injection into the main and intermittent reservoirs through injection wells and oil production through the producing wells of the main and intermittent reservoirs with the subsequent transfer of production wells at the final stage for injection of water into intermittent reservoirs, so that , with the aim of Due to the increase in oil recovery by increasing the coverage of the reservoir with waterflood, the transfer to the injection of production wells at the final stage is carried out as they are flooded along the main formation with at least one discontinuous formation in the section of these wells the maximum number of open layers Table Table of the main parameters of the site multi-object The coefficient estimating the loss of oil that occurs due to uneven movement of water and the formation of pillars of oil Ag Coverage rate Recoverable reserves Tisoto Increase in recoverable reserves or additional oil production, thous o t o 0.1 0.136 0.196 0.123 0.05 P, 068 0.196 0.072 0.90 0,864 0,804 0,877 0,950 0,932 0,804 0,928 2892 1512 461 4865 3052 1631 461 5144 160,119 279 Table 2 160,119 279 Phi2.2 Grinscha reservoir B (Main reservoir - // - d (Prei6isti layer) - // - a (break (1 (layer) Residual oil reservoir in . Injection pumping skbazhi- Sk8a nina pereseoennau.pod zoku Direction f7OfT7o / fo6