SU844766A1 - Method of providing a gravel filter in a well - Google Patents

Description

one

The invention relates to the field of oil and gas industry, in particular, to the creation of gravel filters, especially in wells, revealing loose or fractured reservoirs developed by thermal methods.

There is a known method of creating a gravel filter in a well, including lowering a casing string into the well, cementing it, perforating the column with a cement ring in the interval of the productive formation, washing the gravel through perforations in the cavities and cracks behind the cement ring using a carrier fluid and then pumping hardener for the formation of a solid permeable mass. Thermosetting molds, thermoplastic polymers, rubbers and the like can be used as hardeners. 1. The gravel filter obtained in this way ensures the retention of sand in the layer of permeable mass formed by gravel behind the cement ring.

The disadvantages of this method are the difficulty of creating a strong and at the same time permeable mass and

difficulties in the subsequent development of the well. This is explained as follows.

Very high demands are made on the wetting agent. It should not impair the reservoir properties of the reservoir, weaken its skeleton, clog or clog, THAT is very difficult to do in practice, since

10 requires a high flow rate and high filtration rate over the cement ring.

Careful control over the implementation of gravel loads is needed, so

 as penetration of alluvial fluid into the reservoir should be minimal, and its pressure should not exceed the pressure of hydraulic fracturing. Otherwise, the main mass of gravity

20 enters one or two fracture sites and the goal will not be reached. On the other hand, it is not necessary to form a more dense packing of the gravel, since otherwise it is impossible

25 to form a hard but permeable mass of gravel with hardeners, since the gravel will be washed out of the formation back into the well. For these reasons, this method cannot be used in loose and unstable or fractured formations, where the creation of a fine filter is most desirable.

In addition, there is a high probability of leaving part of the resin in the well, which causes the danger of their hardening in the well and leads to complications.

The closest to the invention is a method of creating a gravel filter in a well, including securing gravel dusting on a perforated casing string, lowering this column, cementing it and processing gravel dusting 2

The disadvantage of this method is that in order to consolidate the formation rocks it is necessary to perform their additional processing, which significantly reduces the efficiency of the creation of the filter.

The aim of the invention is to increase the efficiency of the creation of the filter by simultaneously processing and securing the formation rocks.

The goal is achieved by the fact that gravel dusting is fixed, phenol-formaldehyde resol plastic and treated with a coolant with a temperature of 160-200s.

In addition, after lowering a perforated casing pipe with gravel sprinkled with phenol-formaldehyde reaeonic plastic into the well, sand-gravel material is additionally placed in the interval of the productive layer behind the column, and then the casing string is cemented above the productive interval of the column of bsad pipes and cement is deposited below the section the productive formation, then in the interval of the productive formation, a sand and gravel material is additionally placed behind the column and cement the column above e interval of the productive formation.

FIG. 1 shows a well with a consolidated gravel filter between the casing string and the cement ring; FIG. 2 shows a well with a consolidated sand and gravel filter between the casing string and the producing formation and cementing the string above the producing formation interval; in fig. 3 - well with a consolidated sand-gravel filter Е between the casing and the reservoir and cementing the column below and above the interval of the reservoir.

The figures show the productive formation 1, watered interlayer 2, column 3 of casing pipes, cement ring 4, perforation holes 5, casing 6 made of phenol-formaldehyde-ree-sol plastic with gravel filling 7, sand-gravel material 8, pump-compressor pipes 9. The dotted line shows the area of the near-wellbore zone of the reservoir, consolidated phenol-formaldehyde with the reaeal plastic after its bakelization with heat-transfer agent.

The method is carried out as follows.

Separate pre-perforated sections of the casing column 3, the number of which is taken with the ability to overlap the interval of the productive formation 1, tightly wrapped with a polymer film, for example of polyethylene, and placed in a detachable cylindrical casing with plug on the ends.

The length of the casing is taken so that the sleeves screwed onto the pipes from one side and the thread on the other hand remain open, and the inside diameter of the cajoux takes more than the outer diameter of the casing section by the size of the desired gravel filter layer.

Then, sn in one of the plugs, poured sorted gravel, for example, with a particle size larger than the diameter of the perforations 5, followed by compaction of the space between the casing and the pipe and the plug is closed. After that, through the pipes in the casing, the phenol-formaldehyde resol plastic heated to the melting temperature of 60-90 ° C is terminated under pressure into the specified space and cooled in the casing to the atmospheric temperature. Moreover, in order to prevent the molten plastic from sticking (setting) to the inner surface of the casing, the latter is pre-coated with lubricant.

The finished cooled section of the casing string with gravel coating fixed on it is removed from the casing and wrapped in a polymer film again. Then, the resulting sections are connected to the wellhead with sleeves i on which are also wound a polymer tape, for example, from polyethylene, and lower the casing string into the well in the interval of the producing formation. If there is a sump in the well below the gravel casing section, i.e. in the interval below the productive formation, the column is expanded with ordinary common pipes (see Fig. 1). Above the interval of productive -plast casing pipe string is also increased by conventional casing. At the same time, in order to center the well during descent and cementing the column, its bottom is equipped with a shoe guide, shoe, shoe fitting, check valve, stop ring and guide lights (not shown in the figures).

Claims (2)

After the casing string is lowered into the well, the annular space is cemented to form a cement ring 4, which is then further perforated in the interval of the producing formation. Further, a coolant, for example steam, is supplied to the well, circulating through tubing 9 with minimum pressure and temperature, and the mouth is not more than 90 ° C to melt the phenol-formaldehyde slit plastics for the estimated period of time. After that, the pressure of the coolant in the well is increased, but not more than the hydraulic fracturing pressure, stopping its circulation, bringing its temperature at the mouth to 160-200 and pumping the coolant into the formation 1 for 5-6 hours. At the same time, the molten shell 6 of the phenol-formaldehyde resol plastic is expelled by the coolant from the areas near the perforations 5 directly into the productive plate by enveloping particles of gravel and sand in the reservoir with a thin film, and when it reaches 160-200 ° C, it is leached to form a solid, durable and not melt with phenolformaldehyde plastmas sous which konsoliruet gravel and sand particles to form a solid and B at the same time permeable mass filter between the casing string and the cement ring, as well as the cement ring (see. FIG. 1). After bakelization (hardening) of the resol, the well is operated as a steam injection or mining, and the resulting combined gravel-sand-plastic filter reliably prevents sand from entering the well. When the interval of the production plate 1 is not advisable to cement, for example, with a fractured formation with high viscosity oil, the development of which is advisable to lead through cracks, which, when cemented, can be completely sealed with the solution after descending into the well of the perforated casing 6 of phenol-formaldehyde cutting plastic. , densely filled with gravel 7, in the interval of the productive layer behind the column additionally place a ° t of sand and gravel material 8, for example, it is filled up calculated portion while vibrating the column. Then the interval above the reservoir is cemented through a casting sleeve (not shown in the figures), forming a cement ring 4 (see Fig. 2). If there is a sump in the well or a watered interlayer 2 below the reservoir that needs to be isolated from the filter, after the perforated casing string with a hard coating of phenol formaldehyde resol plastic, densely filled with gravel, is drilled into the well, the annular space below the reservoir is cemented through a priming sleeve. Then, sand and gravel material 8 is additionally placed in the interval of the productive formation behind the column and the column is cemented above the interval of the productive formation through another primer (see Fig. 3). In this case, priming sleeves are installed on the casing string below; and above the productive formation are not shown in the figures). Claim 1. A method for creating a gravel filter in a well, including fixing gravel dust on a perforated casing string, lowering this column, cementing a column, processing gravel dust, so as to increase the efficiency of creating a filter by simultaneous processing and consolidation of the formation rocks, gravel dusting is fixed with phenol-formaldehyde resol plastic, and treated with coolant with a temperature of 160-200 s. 2. A method according to claim 1, characterized in that, after descending into the well, the perforated column of the social pipes with gravel sprinkling, fixed with phenol-formaldehyde cutting plastic, sand and gravel material is additionally placed in the interval of the productive layer, and then the casing column is cemented above the interval productive formation. 3. The method according to claim 1, characterized by the fact that after the descent into the well of the perforated casing with gravel sprinkling, e-acted phenol-formaldehyde resol plastic, it is cemented below the interval of the productive formation, then in the interval of the productive formation behind the column is additionally sandy gravel material and cement the column above the interval of the productive formation, Information source taken into account during the examination 1. US patent 3443637, cl. 166295, published. 1969. 2. US patent 3361203, cl. 166-. 12, published, 1968 (prototype).