RU2097533C1 - Downhole filter - Google Patents

Abstract

FIELD: oil and gas production. SUBSTANCE: invention deals with filters to filter products extracted from oil, water, and gas wells providing integrity of metal gauze with wire winding when sunk into inclined and horizontal wells, increased quality of product filtration, and smash resistance of filter under abnormally high pressures in deep wells. Filtration device includes perforated pipe with coupling and metal gauze embracing outer surface of perforated pipe. The latter, on its outer surface, has spirally arranged ribs. Height of rib (h_r, mm) is found from inequality: t_s<h_r≅(d_c-d_p)/2 where t_s is summary thickness of metal gauze and wire winding; d_c diameter of pipe coupling; and d_p diameter of perforated pipe. EFFECT: increased reliability. 3 cl, 2 dwg

Description

 The invention relates to techniques for extracting a product from wells, namely, downhole filters for filtering a product extracted from oil, water and gas wells.

Known downhole filter with the location of the wire winding, pre-bonded with longitudinal rods [1]
The disadvantage of this filter is poor-quality product filtration, since it has one product-receiving filter surface, the stability against removal at high abnormal pressures in deep wells and the preservation of the wire winding during descent in deviated and horizontal wells are not guaranteed. The closest in technical essence known design of well filters with two filter surfaces containing a perforated tubular frame and a wire winding or mesh [2]
Prototype.

 In practice, there are downhole filters with three filter surfaces, containing a perforated tube wrapped in mesh and a wire winding.

 Filters with two and three filtering surfaces improve the quality of the filtration of the well product and maintain a metal mesh with wire winding when running only vertical designs into the well. However, this technical solution, due to perforation in the pipe, does not ensure the filter's ability to collapse at high abnormal pressures in deep wells and the mesh with the winding wire on the perforated pipe is not guaranteed to be maintained during descent into inclined and horizontal wells, and therefore, the quality of the product filtration.

 The aim of the invention is to ensure the preservation of the metal mesh with wire winding when descending into deviated and horizontal wells, improving the quality of the product filtration and the stability of the filter against crushing from high abnormal pressures in deep wells.

где t_ф суммарная толщина металлической сетки и проволочной обмотки, м;
d_M диаметр муфты трубы, м;
d_т диаметр перфорированной трубы, м.This goal is achieved by the fact that the perforated pipe on its outer surface is made with ribs located in a spiral with a pitch, while the height of the ribs (h _p , m) is adopted by the formula:

where t _{f the} total thickness of the metal mesh and wire winding, m;
d _M pipe coupling diameter, m;
d _{t the} diameter of the perforated pipe, m

 The ribs are located on the width of the mesh in increments of 800-1200 mm.

 The mesh can be made of both non-corrosive metal and non-metallic material, such as kapron. The wire winding can be applied in several layers.

 The design of the perforated pipe with the application of ribs in a spiral or in the form of rings allows you to save the filter mesh with wire winding applied between them when descending into deviated and horizontal wells and, as a result, the quality of the filtration of the product extracted from the well increases. In addition, the presence of ribs on the outer surface of the perforated pipe increases its resistance to crushing loads in deep wells and wells with high abnormal pressure. The arrangement of the ribs in a spiral ensures the manufacturability of applying a mesh with a wire winding, and also reduces the mass (weight) of the metal spent on the ribs, in comparison with the arrangement of the ribs in the form of rings under equal conditions for resistance to crushing loads and helps to reduce the resistance of the fluid when lowering into the well . The width of the ribs is taken constructively and can be taken equal to their height, but not more than two or three of their values.

 Perforated holes on the filter pipe can be made in the form of round, straight and L-shaped grooves and slots and placed both in a spiral parallel to the ribs, and in a checkerboard pattern or in a rectangular.

 As a result of spiraling the ribs on the outer surface of the perforated pipe, a metal mesh placed between them with a wire winding during descent and into inclined and horizontal wells is preserved, the filter's resistance to crushing is increased, and, as a result, the quality of filtration of the product extracted from the well is improved. This ensures the implementation of the goal, and comparison with the analogue and prototypes allows us to establish compliance with its criterion of "novelty."

 In the study of other well-known technical solutions in this technical field, signs that distinguish the claimed invention from the prototype were not identified and therefore they provide the claimed technical solution with the criterion of "significant differences".

 Figure 1 shows a downhole filter; in Fig.2 node I in Fig.1.

 The downhole filter consists of a perforated pipe with a sleeve 1, a metal mesh 2, a wire winding 3 and welded ribs 4.

 The filter is installed in a given interval of the productive horizon. Further operation of the filter is carried out according to known technology.

 The economic effect of applying the invention in deviated and horizontal wells can be up to 90% in comparison with the use of known filters.

Claims (3)

1. A downhole filter, including a perforated pipe with a sleeve, a metal mesh covering the outer surface of the perforated pipe and a wire winding, characterized in that the perforated pipe on its outer surface is made with ribs arranged in a spiral with a pitch, while the height of the rib (h _p , mm) adopted by the formula

where t _{f the} total thickness of the metal mesh and wire winding, mm;
d _m pipe coupling diameter, mm;
d _{t the} diameter of the perforated pipe, mm  2. The filter according to claim 1, characterized in that the ribs are arranged in steps of a grid width.  3. The filter according to claims 1 and 2, characterized in that the ribs are arranged in increments of 800 to 1200 mm.

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