RU2291287C1 - Method for extraction of water-oil deposit - Google Patents

Abstract

FIELD: oil extractive industry, possible use for extracting water-oil deposits, productive bed of which contains a water section.

SUBSTANCE: in accordance to method, formations are drilled in accordance to project pattern. Wells are divided on categories depending on thickness of transfer zone or of impenetrable seam between oil and water sections of formation. On basis of value wells are categorized as force or product wells. Wells, related to first category with thickness of transfer zone or impenetrable seam up to 1,5 meters, are used as force wells. Wells, related to second category with thickness of 1,5-3 meters and wells of third category with thickness over 3 meters are used as product wells. Productive formation is opened in sparing mode with usage of drilling or hydro-mechanical perforators. In some wells of first category and in all wells of second category water section of bed is opened by perforation below transit zone or impenetrable seam at distance of 4-5 meters from oil-water contact. Shaft cutter is mounted above the productive bed. Filter with stopper is mounted below water section of productive bed. Pump is lowered. Depression on productive bed is formed by draining liquid. Hydraulic lock made of oil is created in front of filter of productive section of bed. "Reverse cone" is formed in transfer zone and in water section of bed. The latter acts as an obstacle on the way of water movement from water section of productive bed into oil section. Aforementioned wells of first category are used as product wells.

EFFECT: simplification of method for extracting a water-oil well and economy of material costs.

Description

The invention relates to the oil industry and will find application in the development of oil-water deposits, the reservoir of which contains an aquifer.

There is a known method of developing a water-oil deposit, including a lumbago of the oil and water-bearing parts of the oil and water reservoir, the use of submersible equipment installed in wells opposite the productive formation and ensuring the creation of so-called “reverse cone” in them at certain times, in which two-phase fluid moves in the near-stem zone of the productive formation from top to bottom, and separate cyclic pumping of oil and water to the surface (I.I. Kleschenko and others. Insulation work at completion and spluatatsii oil wells -. M .: Nedra, 1998, p.183, Figure 5, 8).

The disadvantages of the method are:

- the need for the secondary opening of the aquifer of the reservoir and the use of additional special downhole equipment for this, which is expensive;

- during the secondary opening of the aquifer by cumulative perforators, the support of the wells is destroyed;

- not achieved a significant reduction in the production of associated water, as a result of which its use is limited.

The closest in technical essence to the proposed one is a method of developing a water-oil deposit, including drilling it according to the design grid, dividing the wells into categories depending on the thickness of the transition zone or impermeable layer and, depending on this, assigning them to injection or producing ones, as well namely, wells belonging to the first category with the thickness of the transition zone or impermeable layer up to 1.5 m are used as injection wells; wells of the second category with a thickness of 1.5-3 m and wells of the third category with a thickness of more than 3 m are used as production wells, and the opening of the reservoir is carried out in a sparing mode using drilling or hydromechanical perforators. The method involves in the wells of the second category before operation, the creation of a waterproof screen in the aquifer of the oil-water reservoir under the transition zone or impermeable layer with a thickness, the total value of which together with the transition zone or impermeable layer is within 5 m (patent No. 2215129, IPC 7 E 21 V 43 / 20, 2003).

The method has found some application in the fields, however, a situation is possible when the wells classified in the first category, and which should be used as injection wells, are significantly more than what is required for production needs. Therefore, part of these wells will not be connected to work at all, which will negatively affect the economic performance of the development of the deposit. And the need to create a waterproof screen in the aquifer of the oil-water reservoir complicates the process and increases its cost.

The objective of the invention is to simplify the method of developing oil-water deposits and save material costs.

This problem is solved by the proposed method, including drilling oil and water deposits according to the design grid, dividing the wells into categories depending on the thickness of the transition zone or impermeable layer between the oil and aquifer parts of the reservoir and, depending on this, assigning them as intended to injection or producing, and namely, wells belonging to the first category with a transition zone or impermeable layer thickness of up to 1.5 m are used as injection wells, second category wells with a thickness of 1.5-3 m and wells of the third category with a thickness of more than 3 m are used as production wells, and the opening of the reservoir is carried out in a sparing mode using drilling or hydromechanical perforators.

New is that in part of the wells of the first category, determined by production necessity, and in all wells of the second category, a water seal is created from oil opposite the filter in the productive part of the formation, and the cross of the aquifer part is carried out at a distance of 4-5 m from the oil-water contact, the wells of the first category are used as production wells.

The method is carried out in the following sequence.

Oil and water deposits are drilled with wells on the design grid. In the process of drilling the oil-water zone by geophysical methods, coring, trial operation of wells, etc., the location of the oil-water contact, the thickness and properties of the transition zone, the thickness of the impermeable layer between the oil and water parts of the reservoir, their area distribution, the influence of these indicators on the flooding of production and etc. Based on this information, all wells are divided into three categories, namely, wells with a transition zone or impermeable layer thickness of up to 1.5 m are classified as the first to and converted into the category of fund injection, piezometric et al., since they do not provide a cost-effective operation for flow rate due to high water cut. Wells with a thickness of 1.5-3 m and more than three meters are assigned to the second and third categories, respectively, and are used as producing ones.

A feature of the proposed method is that in the part of the wells of the first category, and they, as a rule, always turn out to be much larger than necessary for the rational development of deposits, create a water trap from the oil opposite the filter in the productive part of the formation and subsequently use them as production ones. To fully guarantee the success of the development, an oil seal is also created in the wells of the second category.

These works are as follows.

After fastening the well (launching the production casing, cementing, waiting for the cement to harden), the aquifer part of the formation is opened by perforation under the transition zone or impermeable layer at a distance of 4-5 m from the oil-water contact. The indicated value is dictated by the requirement of an allowable differential pressure of 1 linear meter. m. of a cement ring equal to 2.0 MPa and the created depression on the formation during operation within 8.0-9.0 MPa.

The oil-bearing part of the formation is opened with perforators in a gentle mode: drilling, hydromechanically (PGM-146 (168)).

Then, the cutter of the trunk is lowered and installed in the borehole on the string of tubing so that it is above the reservoir, and the filter with the plug is below the aquifer of the reservoir. After that, a pump is lowered into the well and a liquid is pumped out to create a depression on the reservoir, under the influence of which a hydraulic oil trap is created opposite the filter of the oil-bearing part of the reservoir, and a “reverse cone” consisting of a high-viscosity oil-water emulsion in the transition zone and in the aquifer of the reservoir , and which is a reliable natural obstacle to the movement of water from the aquifer of the reservoir to the oil reservoir.

In wells of the third category, the oil-bearing part of the reservoir is also opened in a sparing mode using drilling or hydromechanical perforators.

The technical and economic advantages of the proposed method are that it eliminates the need for waterproofing with the use of polymeric materials and, therefore, is simpler, which leads to significant material savings. In addition, it will allow part of the wells of the first category to be used as production wells and, consequently, to increase oil recovery.

Claims (1)

A method of developing a water-oil deposit, including drilling a water-oil deposit according to the design grid, dividing the wells into categories depending on the thickness of the transition zone or impermeable layer between the oil and water parts of the reservoir, and depending on this, assigning them as intended to injection or producing, namely, wells belonging to the first category with a thickness of the transition zone or impermeable layer up to 1.5 m, are used as injection wells of the second category with a thickness of 1.5-3 m and wells t A family of a category with a thickness of more than 3 m is used as a producer, and the formation is opened sparingly using drilling or hydromechanical perforators, characterized in that in part of the wells of the first category and in all wells of the second category, the aquifer part of the formation is opened with perforation under the transition zone or impermeable layer at a distance of 4-5 m from the oil-water contact, lower and install the barrel cutter so that it is above the reservoir, install a filter with so that they are below the aquifer of the reservoir, pump down, by pumping the liquid, create a depression on the reservoir, create an oil seal in front of the filter of the reservoir, create a “inverse cone” in the transition zone and in the aquifer of the reservoir, consisting of oil-water emulsions of increased viscosity and which is an obstacle to the movement of water from the aquifer of the reservoir to the oil reservoir, the wells of the first category being used as production wells.