RU2351751C2 - Method of improving hydro-dynamic connection of borehole with pay-out bed - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil extracting industry and can be implemented for improving hydro-dynamic connection of borehole with payout bed. The object of the invention is intensification of oil extraction due to increased radius of payout bed drainage, and to increased filtration surface and drainage area of a payout bed. The essence of the invention is as follows: the method consists in hydraulic breakdown of the payout bed by means of installing a packer above the top of the perforated payout bed, in pumping hydraulic breakdown fluid into the under packer zone, in creating pressure of hydraulic breakdown in the under packer zone and in forcing hydraulic breakdown fluid through into a created fracture. According to the invention at first packing of annulus space of the borehole in interval of perforation of the payout bed is performed. Further two or more stretched radial perforated channels in different vertical planes with changes of azimuth at 180° are bored in the payout bed. Also the perforated channels are distanced ones from others at a minimal distance determined by capability of packer installation. Hydraulic breakdown is performed in each perforated channel.

EFFECT: intensification of oil extraction due to increased radius of payout bed drainage, and to increased filtration surface and drainage area of payout bed.

1 ex

Description

The invention relates to the oil industry and can be used to improve the hydrodynamic connection of the well with the reservoir with the aim of intensifying production and increasing oil recovery.

There is a method of improving the hydrodynamic connection of a well with a formation, which includes injecting an acidic composition into the near-wellbore zone of the productive formation (Gutorov A.Yu., Gutorov Yu. Current trends in the development of various types of hydrochloric acid treatment technologies and ways to optimize them in order to increase application efficiency. business. 2006. No. 10. P.18-21), which provides an increase in permeability of the bottomhole zone of the well. The disadvantage of this method is the small radius of penetration of the acid composition deep into the reservoir due to the rapid neutralization of acid and the formation of reaction products.

The closest technical solution we have taken as a prototype is a method of hydraulic fracturing, including installing a packer over the roof of a perforated reservoir, injecting hydraulic fracturing fluid into the sub-packer zone, creating hydraulic fracturing pressure in the sub-packer zone and pushing hydraulic fracturing fluid into the crack (Kuramshin PM, Ivanov S.V., Kuzmichev, N.D. Efficiency of hydraulic fracturing in the fields of the Noyabrsky district. Oil business 1997. No. 12. P.58-60).

The main disadvantage of this method is the uncontrolled direction of propagation of cracks and low reliability of increasing the radius of the drainage of the reservoir due to the likelihood of spontaneous changes in the direction of development of cracks. In addition, the disadvantage of this method is the creation of only one hydraulic fracture, which does not allow drainage of the reservoir in different directions over the entire area around the well.

The objective of the invention is to increase the efficiency of the method by increasing the radius of the drainage of the reservoir, the filtration surface and the area of drainage of the reservoir.

The problem is solved in that in a method for improving the hydrodynamic connection of a well with a producing formation, including hydraulic fracturing of the formation by installing a packer over the roof of a perforated producing formation, injecting hydraulic fracturing fluid into the sub-packing zone, creating hydraulic fracturing pressure in the sub-packing zone, and pushing the fracturing fluid into the crack, according to the invention, first, the annulus of the well is sealed and the radial perforation channels are drilled in a predetermined ervale producing formation, whereupon hydraulic fracturing, the drilling produces radial perforations oriented in a predetermined direction, and in the acidic composition as the fracturing fluid.

Here is an example implementation of the method.

Assume that the reservoir is perforated in the range of 1200-1230 m.

Implementation of the proposed method for improving the hydrodynamic connection of the well with the reservoir is as follows.

The tubing is lowered to the lower perforation holes. The required volume of cement mortar (or other sealing material) is determined from the condition that it covers the interval of perforation and injection into the formation of 0.5-1.0 m ³ (the volume of injection into the formation can be specified from the experience of injection). The cement mortar is pumped through the tubing into the annulus in the perforation interval, the annulus is closed and a certain volume of the solution is pumped into the reservoir under pressure. Raise the tubing above the cement slurry and leave the well waiting for the cement to harden (OZZ).

After OZC cement is drilled in the column and, if necessary, the inner surface of the column is cleaned.

Then, at a depth of 1205 m (determined depending on the size and geophysical characteristics of the formation), an extended (for example, 100 m long) radial perforation channel is drilled using known technology (see patent No. 2238782). To do this, a special device is lowered to the required depth on the tubing, anchor it. Then, using this device, a hole is drilled in the casing, a drill is removed, and then an extended perforation channel is drilled in the rock. After that, the packer is lowered and installed on the tubing at a depth of 1200 m (above the radial perforation channels). Carry out hydraulic fracturing.

To increase the efficiency of the proposed method, two or more radial perforation channels are drilled, followed by hydraulic fracturing of each channel. So, to increase the drainage area of the reservoir, it is necessary to drill a second radial perforation channel at a depth of 1215 m (the minimum distance from the second channel is determined by the technical capabilities of the subsequent installation of a fracturing packer between them) in another vertical plane (for example, with a change in drilling azimuth of 180 degrees by turning the drilling tool). Then in the range of 1205-1215 install the packer and carry out hydraulic fracturing.

The maximum number of radial perforation channels is determined by the capacity of the reservoir and the structural characteristics of the applied packer.

An acid composition may be used as the fracturing fluid. In this case, the openness of the fracture crack is provided by the impact on the rock acid composition due to the dissolution of the rock.

Claims (1)

A method for improving the hydrodynamic connection of a well with a reservoir, including hydraulic fracturing of the reservoir by installing a packer over the roof of a perforated reservoir, injecting frac fluid into the sub-packer zone, creating frac pressure in the sub-packer zone and pumping fracturing fluid into the formed crack, characterized in that it is first produced sealing the annulus of the well in the interval of perforation of the reservoir, after which in the reservoir odyat drilling of two or more extended radial perforations in different vertical planes to change drilling azimuth 180 °, wherein the perforations is removed from one another at a minimum distance determined by the possibility of installing the packer, and the fracturing is carried out in each perforation channel.