RU2459945C1 - Development method of multi-hole branched horizontal wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method involves well development using tubing string and determination of inflow volumes of each branched shaft drilled from the main horizontal part of the well. Tubing string is equipped with swab limiter. Development is performed in swabbing cycles. According to the invention, tubing is equipped prior to lowering with two centralisers and packers between which outlet channels are located. Swab limiter is arranged in lower part of vertical section of tubing string. Development of branched shafts is performed individually for each branched shaft starting from the most remote one from the well head by cutting out the inlet of the chosen branched shaft in the main horizontal part of the well by means of packers from other branched shafts. After packers are installed, first acid treatment of the chosen shaft is performed by injection of 10-15% solution of inhibited chlorhydric acid based on 0.2-0.25 m³ per metre of the length of branched shaft with further process exposure.

EFFECT: possible development of branched shafts separately for each branched shaft without entering this one, acid treatment prior to development with elimination of occurrence of emergency situations in the wells.

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Description

The invention relates to the oil industry, and in particular to the field of completion of the construction of multi-sided branched-horizontal wells (MRGS) with multidirectional horizontal trunks (branches) in relation to the main trunk and, in particular, to the development process when completing their drilling, and also applicable for development similar MRGS after carrying out work on the treatment of the bottom-hole zone (SCR).

A well-known well completion system for use in the separation of fluid flows (RF patent No. 2136856, IPC 8 E21B 43/14, E21B 7/04, E21B 7/0, published in Bulletin No. 28 of 09/10/1999), extracted from lateral wells, the inner ends of which are in communication with the main well, comprising a tubular casing having a plurality of drainage means spaced apart at an angle to one another, located on its walls and designed to receive produced fluids coming from the side wells, characterized in that it is provided with a separator flow located in the casing with select orientation and containing a plurality of flow passages disposed therein, spaced relative to each other, each flow passage having an inlet aligned with a corresponding drainage means, and these inlet openings are in communication with longitudinal channels extending upward in the flow separator from each inlet holes and extending through the upper end of the flow divider.

The disadvantages of this system are:

- the system is applicable in downhole wells and cannot be used in wells with the horizontal part of the trunks pointing upward with respect to the main wellbore;

- sophisticated technology for the performance of work and the use of special equipment;

- the possibility of emergency situations when entering the trunks.

Also known is a method of developing "conventional" directional wells, incl. and “ordinary” horizontal wells with one bore, which involves lowering the tubing with a swab limiter to the lower perforations in “ordinary” wells cased by the production string and to the shoe of the production string - in “ordinary” horizontal wells with one horizontal bore (RD 39 -0147585-140-96, “Technology for invoking swab inflow during well development”, Bugulma, 1996, p. 29).

The disadvantage of this method is that it is applicable only for single-hole wells with the direction of the trunks from top to bottom along the section.

The closest in technical essence is the method of development of multi-sided branched-horizontal wells (RF patent No. 2299981, IPC 8 E21B 43/25, published in Bulletin No. 15 of 05.27.2007), which includes the actual development of the well using tubing and determination of the inflow volumes of each wellbore, while in the horizontal part of the well with upward branches of the wellbore, each branch is developed without entering the trunks after replacing the drilling fluid with oil, the tubing is equipped with a swab and the restrictor is mounted on the low points of each branch, wherein the development is carried cycles swabbing.

The disadvantages of this method are:

- firstly, the limited application of the method, since it can be used to develop multi-hole branched-horizontal wells (MRGS) with the direction of the horizontal part of the trunks (branches) upward;

- secondly, the development takes place by replacing the drilling fluid with oil, followed by the development of all the branches by swab cycles, while there is a gentle depression on the formation, which does not allow you to effectively master a highly contaminated reservoir in which these branches are drilled, moreover, the development is carried out from the mouth to the bottom, which can lead to contamination of already developed branch trunks;

- thirdly, the swab run down is limited by the swab limiter, which is installed on the lower points of each branch, while due to the curvature of the well during swabbing, the swab may not reach the lower point of each branch or the swab will jam in the bent section of the well and, as a result, wire breakage and an emergency in the well;

- fourthly, the low quality of development of branched trunks due to the lack of effective treatments of these trunks, for example acid treatment, before their development by swabbing cycles.

An object of the invention is to provide a method that allows for the development of multi-sided branched-horizontal wells in which branched shafts are made in different directions from the base of the horizontal part of the well, and mastered separately for each branched trunk without entering a mastered branched trunk with the possibility of efficient and high-quality development of branched trunks by their acid treatment before development, as well as the guaranteed exclusion of jamming swab, wire break and create emergency situations in the well.

The problem is solved by the method of developing multi-hole branched-horizontal wells, including the development of a well using a string of tubing and tubing and determining the volume of inflow of each branch hole drilled from the main horizontal part of the well, and the tubing is equipped with a swab limiter, and development carried out by swabbing cycles.

New is that the tubing string before launching is equipped with two centralizers and packers, between which the output channels are located, and the swab limiter is placed in the lower part of the vertical section of the tubing string, while the development of the branched trunks is carried out separately for each branched trunk, starting from the most distant from wellhead, cutting off in the main horizontal part of the well with packers the input of the selected branch from communication with other branches, and after installing the packers, began the acid treatment of the selected trunk, pumping a 10-15% solution of inhibited hydrochloric acid at the rate of 0.2-0.25 m ³ per meter of length of the branched trunk, followed by technological exposure.

Figure 1 and 2 depicts a diagram of the implementation of the method in the process of developing multi-hole branched-horizontal wells.

The proposed method for the development of multi-hole branched-horizontal wells is as follows.

A method for developing multi-hole branched-horizontal wells includes developing a well 1 (see Fig. 1) using a string of tubing 2 and determining the inflow volumes of each branched shaft 3 '; ... 3 ⁿ drilled from the main horizontal part 4 of the well 1. Branches of trunks 3 '; ... 3 ^{n are} made from the main horizontal part 4 of well 1 in different directions, and development of branched trunks 3'; ... 3 ^{n is} carried out separately for each branched trunk 3 '; ... 3 ⁿ .

Before lowering the tubing string 2 into the well 1, its lower part is equipped with the following arrangement, consisting of inlet openings, for example, made in the form of a filter 5 and placed in front of and behind it two packers 6 and 7 with centralizers, for example, rigid centralizers 8 and 9, respectively, with this, the length L between the packers 6 and 7 should be 5-6 m (2.5-3 m on each side) longer than the length - In the largest section of the kickoff of any of the branched trunks, for example, branched trunk 3 '.

Also determine the throughput of the filter 5 during the development of branched trunks 3 '; ... 3 ⁿ , while the total area of the perforated holes 10 of the filter 5 should be not less than the internal section of the tubing string 2.

For example, the tubing string 2 has a size of 73 × 5.5 mm, then the inner diameter of the tubing string 2: d = 73- (2 × 5.5) = 62 mm = 0.062 m.

Cross-sectional area of the inner diameter of the tubing string 2:

S _in = (π × d ²⁾ / 4 = 3,14 × (0,062 m) ^2/4 = 3 × 10 ^-3 m ^2.

Then, for example, if the diameter of the perforated holes ₀ d = 3 mm, the S = ₀ ⁽² π × d ₀₎ / 4 = 3,14 × (0,003 m) ^2/4 = 7 × 10 ^-6 m ^2. Then n is the number of perforated holes 10 will be:

n = S _in / S ₀ = 3 × 10 ^-3 m ^2/7 × 10 ^-6 m ² = 428,57≈429 holes.

So, if the length of the section - and the filter 10, on which the perforated holes are made, is 2 meters, then at this section of length a you need to make at least 429 perforated holes 10. The throughput of the filter 5 for the other tubing size 2 is similarly determined.

Packers 6 and 7 may be of any known design used for working in an open barrel. For example, an open-hole packer of the PYa-215/230 type, manufactured by the Scientific and Production Enterprise Engineering-Technological Company LLC NPE INTECHKOM (Russian Federation, the Republic of Bashkortostan, Ufa) or mechanical anchors of the Yak type with packers, designed to create support on the wall of the well in an open hole for installing the packer and holding the equipment from moving OJSC Geophysics Research and Production Company (Russian Federation, Republic of Bashkortostan, Ufa).

A rigid centralizer 9, located in front of the layout, centers the layout of the tubing string relative to the axis of the main horizontal part 4 of the well 1 and does not allow the layout to enter any of the branched trunks 3 '; ... 3 ⁿ . A rigid centralizer 8 located behind the layout provides uniform packing of packers 6 and 7 before mastering any of the branched trunks 3 '; ... 3 ⁿ .

The lower end of the tubing string 2 is equipped with a plug 11, and the swab limiter 12 is installed at the roof level of the reservoir 13.

A tubing string 2 with the above arrangement is lowered into the main horizontal part 4 of well 1 until the plug 11 abuts against the bottom 14 of the main horizontal part 4 of well 1.

After making sure that the tubing string 2 has reached the bottom 14 of the main horizontal part 4 of the well 1, lift the tubing string 2 up until the packers 6 and 7 in the main horizontal part of the well are placed so that they are on opposite sides of the cut-off site a branched trunk to be mastered, for example a branched trunk 3 ′.

After that, packers 6 and 7 are planted and acid treated by injecting a 10-15% solution of inhibited hydrochloric acid (TU 2458-017-12966038-2002) at the rate of 0.2-0.25 m ³ per meter of length of a branched trunk, followed by technological exposure.

For example, with a branch length of 3 ′ (see FIG. 1) equal to 80 m, the volume (V) of a 10-15% solution of inhibited hydrochloric acid is determined:

V = 80 × (0.2-0.25 m ³ ) = 16-20 m ³ .

Thus, the tubing string 2 injects and sells the process fluid, for example, fresh water ρ = 1000 kg / m ³ into the branched barrel 3 ', for example, 18 m ^{3 of a} 10-15% solution of inhibited hydrochloric acid. Then carry out technological exposure for 8 hours

Then master the swab cycles by means of a swab aggregate, for example PKS-5 (not shown in FIGS. 1 and 2), this branched trunk 3 ', while the swab stroke (not shown in FIGS. 1 and 2) along the tubing string 2 is limited by a swab limiter 5, installed in the tubing string 2 at the roof level of the reservoir 9. Packers 6 and 7 hermetically cut off the branched trunk 3 'from other branched trunks 3''... 3 ⁿ and the main horizontal part 4 of the well 1 during the development process.

In the process of development of the branched trunk 3 ', the reaction products of the acid with the rock are extracted and the level is reduced to a value that creates a possible and acceptable depression for the well 1 for the formation 13. The restoration of the level in the well 1 is monitored to the value calculated by the geological service. Then swabbing again reduce the level and trace the restoration of the level. Swabbing cycles and control of level changes by removing the HIC with sampling is repeated until the flow of products from the formation is stabilized (i.e., until oil is obtained with a density characteristic of the formation). At the end of the development of the branched trunk 3 ', the packers 6 and 7 are unpacked, the arrangement is moved from the bottom 14 to the mouth (not shown in Figs. 1, 2) along the main horizontal part 4 of the well 1 until it is located opposite the cut-off section of the next branched trunk 3' '( 1 and 2), adjacent to the previously mastered branch bore 3 ′ of well 1, and the packers 6 and 7 in the main horizontal part 4 of well 1 were placed so that they were on opposite sides of the cut-off section of the branched trunk 3 '' to be mastered. In the future, the above operations for the development of a branched trunk 3 "repeat.

Thus spend the development of all branched trunks 3 '' (see figure 2). drilled from the main horizontal part 4 of the well 1.

The proposed method allows for the development of multi-sided branched-horizontal wells, in which the branched wells are made in different directions from the base of the horizontal part of the well and are mastered separately for each branched trunk without entering the mastered branched trunk due to the tight packing of packers opposite the cut-off area of each branched trunk. In addition, the presence of packers makes it possible to efficiently and qualitatively master a highly contaminated productive formation by acidizing the branched trunk and due to a sharper depression created in each branched trunk, and placing a swab limiter in the tubing string at the level of the roof of the producing reservoir guarantees that jamming, breakage rope and the creation of emergency situations in the well.

Claims (1)

A method for developing multi-hole branched horizontal wells, including developing a well using a tubing string — tubing and determining the inflow volumes of each branched shaft drilled from the main horizontal part of the well, the tubing string being equipped with a swab limiter, and development is carried out by swab cycles, characterized in that the tubing string before the descent is equipped with two centralizers and packers, between which the output channels are located, and the swab limiter is placed in the lower part the vertical section of the tubing string, while the development of the branched trunks is carried out separately for each branched trunk, starting from the farthest from the wellhead, cutting off the entrance of the selected branched trunk from communication with other branched trunks in the main horizontal part of the well, and after installing the packers, first acid treatment of the selected trunk, pumping a 10-15% solution of inhibited hydrochloric acid at a rate of 0.2-0.25 m ³ per meter of length of a branched trunk with subsequent techno logical exposure.

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