RU2374437C1 - Method hydraulic reservoir factoring execution without lifting downhole assembly - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: invention related to well exploration and development of multiply fields using hydraulic reservoir factoring, under production of a single well. Hydraulic reservoir factoring execution starts from the lowest stratum. Then before executing hydraulic reservoir factoring of stratum located higher, perform by supplying with process liquid with propping agent insulation of lower stratum washing propping agent inside production string at height, bigger than depth of developed stratum. After that perform hydraulic reservoir factoring for higher located stratum. Thereby continuously operate with higher located stratums moving bottom-up. According to invention process of washing propping agent inside production string, after hydraulic reservoir factoring execution, to be performed in two stages. First stage is to fill in production string with propping agent with particles, which size is equal to size of the particle used in previous process, for example 0.4-0.6 mm. Filling in applicable interval 90-95% along borehole. Second stage is pumping in of propping agent with a minimal particle size, for example 0.1-0.15 mm and in the same time filling in full length of the borehole. Transportation of the first portion of large-scale propping agent to be executed with liquid consumption equal to liquid consumption specified for the previous process, transportation of the second portion to be executed with liquid consumption equal to 0.1-0.2 liquid consumption in first operation. After that begin hydraulic reservoir factoring for stratum located on upper level.

EFFECT: effectiveness increase by executing multiphase factoring with single operation of installation multipacker assembly into well, producing from multiple stratums.

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Description

The invention relates to the borehole development and exploitation of multilayer hydrocarbon deposits, in particular, to the technology and technique for simultaneously separate exploitation of several production facilities by one well, and can be used in hydrocarbon production from a well for hydraulic fracturing, operated by a single well.

A known method of multi-stage hydraulic fracturing, which consists in lowering the packer on the pipe string above the upper perforation holes of the lower layer, crimping it, performing the hydraulic fracturing operation, disrupting the packer and then raising the packer above the next overlying perforated interval. Then, the already treated formation is cut off by filling with a solid agent (proppant or quartz sand). Then the packer is re-planted and crimped. After this, the hydraulic fracturing operation is performed, after which the packer breaks and rises above the next overlying formation. After this, the sequence of operations performed earlier is repeated, and the next overlying layer is exposed [1].

The disadvantage of this method is the inability to perform hydraulic fracturing if the lower perforation interval of the overlying formation is less than 20 m from the upper perforation interval of the underlying formation. This limitation is due to the permeability of the sand layer (proppant) filling the production string and preventing the hydraulic fracturing or sand carrier from penetrating into lower layer that has already been treated. The hydraulic resistance of the sand-filled perforation interval can be increased due to the use of sand with smaller particles, which will lead to the difficulty of removing it after a series of hydraulic fracturing for all layers.

The purpose of the invention is to provide the possibility of performing multi-stage hydraulic fracturing operations in a well operating several layers at a relative position of less than 5 m and eliminating the influence of the presence of underlying layers on the processing mode of the current formation in one operation for installing a borehole multi-packer assembly.

The technical result obtained by using the invention is to expand the field of hydraulic fracturing in multilayer wells and increase the effectiveness of the impact on individual layers by providing an independent treatment mode for each layer. In addition, the flushing of the artificially created cork is facilitated, since fractions of sand of small sizes are washed out by a stream of liquid flowing out of the nozzle faster, as well as completely carried up the annular space.

The problem is achieved due to the fact that sand washed on coarse sand with small sand sizes creates a relatively thin layer with low permeability (high hydraulic resistance) to the flow of the process fluid directed into the overlying formation during hydraulic fracturing. At the same time, the loss of the process fluid due to filtration into the lower layer is repeatedly reduced and does not adversely affect the operation mode. Removing a layer of sand with a small particle size does not cause technological difficulties, since it is more easily destroyed and more efficiently carried to the surface.

The proposed method is implemented as follows.

An arbitrary profile well (vertical, inclined, horizontal) has perforations connecting the cavity of the production string with several hydraulically unconnected formations. A downhole assembly is lowered into the well, including a packer and an extension pipe installed below it with a flushing valve and a flushing nozzle at the lower end. In the initial position, the flushing valve is closed. The valve is opened by means of a ball launched into the tubing string from the wellhead. The packer is lowered on the tubing string above the perforations of the lower treated formation, installed and crimped along the tubing or annulus. Then a full cycle of hydraulic fracturing operations is performed, including fracturing, injection of proppant and its transfer into the formation. After a technological pause, the packer is disrupted and replaced, followed by the replacement of the process fluid filling the well cavity with a kill fluid. The packer on the tubing string rises above the next perforated section of the production string. Then, temporary isolation of the lower treated formation from the upper one subjected to hydraulic fracturing is performed. Temporary isolation is carried out by washing a solid agent (proppant, silica sand) into the cavity of the production casing in two stages.

At the first stage, the cavity of the production well is filled with proppant (sand) with a characteristic particle size equal to the particle size used in the previous technological operation (for example, 0.4-0.6 mm), and the corresponding interval is filled by 90-95% to the lower perforations along the length of the wellbore.

At the second stage, proppant (sand) is injected with the smallest possible particle size (for example, 0.1-0.15 mm) and at the same time it is filled to the full filling height (100%). The layer of finely dispersed proppant (sand) has a high hydraulic resistance and, being located above the insulating layer of a large fraction of the proppant, plays the role of an impermeable layer, providing a high pressure drop when filtering fluid through it.

The first portion of large proppant is transported at a fluid flow rate corresponding to the flow rate determined for the previous technological operation, and the second is transported at the lowest possible fluid flow rate, which is about 0.1-0.2 of the flow rate in the first operation.

Next, the packer is re-planted, packaged by tubing or annulus. Then a full cycle of hydraulic fracturing operations is performed, including fracturing, injection of proppant and its transfer into the formation. After this, the full cycle of operations described above is repeated, including tearing down the packer, lifting it to the next upper position, temporarily isolating the second processed interval by washing the coarse and fine fractional proppant or silica sand in two stages, as described above.

The above-mentioned hydraulic fracturing operations of each formation are repeated until the upper formation is processed. Next, the packer is disrupted, the process fluid is replaced with a kill fluid. After that, a ball is launched into the tubing cavity, which, upon reaching the flushing valve, directs the flow of fluid supplied through the tubing to the flushing nozzle. Then proceed to washing the inner cavity of the production casing, filled with layers of sand (proppant) with various fractional compositions. To intensify the process of destruction of the cork, the flushing nozzle can be supplemented with a rock-destroying tool, for example a spike bit. Because the fine-dispersed proppant (sand) layer has a small thickness, its destruction and subsequent removal of products that remove it by washing does not cause technological complications.

Instead of fine sand (proppant), a polymer film with a thickness of 0.1-0.2 mm and a size of 0.03 × 0.03 m can be used for temporary isolation of formations.

In addition to performing hydraulic fracturing according to the proposed technology, other effects on the formation and bottomhole zone can be performed, for example, acid treatment, strengthening of the bottomhole zone, oil baths, etc.

Information sources

1. "Time coiled tubing" Information and analytical magazine. No. 3, 2006. B.V. MacDeniel. Hydromonitor perforation using coiled tubing.

Claims (3)

1. The method of conducting a multi-stage hydraulic fracturing without raising the downhole arrangement, which consists in the fact that the hydraulic fracturing process is carried out starting from the lower reservoir, and then before the hydraulic fracturing of the reservoir located above, isolation of the lower reservoir is carried out by supplying a mixture of process fluid with proppant by washing proppant into the cavity of the production string to a height exceeding the power of the treated formation, and then proceed to hydraulic fracturing of the overlying formation and so continue to consistently act on the higher layers, processing them, going from the bottom up, characterized in that the proppant washing process into the cavity of the production string after hydraulic fracturing is performed in two stages, the first of which is filling the production string with proppant with a particle size, equal to the size of the particles used in the previous technological operation, for example, 0.4-0.6 mm, while the corresponding interval is filled by 90-95% along the length of the wellbore s, and at the second stage, proppant is injected with the smallest possible particle size, for example, 0.1-0.15 mm and at the same time they are filled to their full length, and the first portion of large proppant is transported at a flow rate corresponding to the flow rate determined for the previous technological operation, and the second transportation - at a fluid flow rate of 0.1-0.2 of the flow rate in the first operation, after which they begin to perform the process of hydraulic fracturing, located at a higher m level zone. 2. The method according to claim 1, characterized in that sand is used as proppant. 3. The method according to claim 1, characterized in that as a proppant using pieces of polymer film with a thickness of 0.1-0.2 mm and a size of 0.03 × 0.03 m