RU2537608C1 - Heterogeneous sealant for threads - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to oil-and-gas industry and can be used for sealing of thread joints operated at high pressure and subjected to expansion in cross-section. This sealant comprises fibrous substrate in amount of 20-40% as hemp or linen, sealing filler in amount of 30-50% as clay powder, antifriction filler composed of surfactant making the rest.

EFFECT: high tightness of threaded joint at 23% expansion.

3 cl, 2 tbl

Description

The invention relates to the oil and gas industry and can be used to provide sealing of threaded joints operating under high pressure and subject to distribution in the cross section up to 23%.

Lubricant R-402 used in commercial practice and others, intended for sealing threaded joints, contains fat base, lead powder, zinc dust, copper powder and graphite (TU 301-04-020-92).

The disadvantage of this lubricant is the low sealing efficiency at pressures above 10 MPa, and when dispensing by 20%, the sealing efficiency drops two more times.

The closest in technical essence to the achieved result is a threaded curable sealant (HOG) (patent RU No. 2110550, C09K 3/10, publ. 05/10/1998), including the base of the epoxy compound, antifriction, sealing filler and hardener, as antifriction, sealing the filler contains finely divided polytetrafluoroethylene in the following ratio of components, wt.%:

Epoxy Compound Base - 30-60

Hardener - 2-15

Filler 30-60

The disadvantage of this sealant is a violation of the sealing during the distribution of the threaded connection due to the presence of a hardener in it, since cracks form in them during the distribution of the thread.

An object of the invention is the creation of a threaded heterogeneous sealant that provides a high degree of tightness before and after plastic deformation with the expansion of threaded joints up to 23%.

The technical problem is solved by a threaded heterogeneous sealant, including a base, antifriction and sealing filler.

What is new is that to seal the thread undergoing plastic deformation, 20-40% of fibrous material in the form of hemp or linen tow, a sealing filler - 30-50% clay powder, the rest is antifriction filler in the form of a surfactant ( Surfactant).

Also new is that a 30-70% aqueous solution of detergent was used as a surfactant.

It is also new that a mixture is used as a surfactant: 30-70% aqueous solution of detergent and lubricating additives in the form of graphite lubricant in a ratio of 2 ... 0.5 to 1.

The sealant has the following ratio of components, wt.%: 20-40% of the fibrous material, the sealing filler is 30-50% clay powder, the rest is antifriction filler in the form of a surfactant.

For laboratory studies of a threaded heterogeneous sealant, four models with an OG1M -194 thread (TU 14-3-714-89) were prepared.

Hydraulic tests were carried out as close as possible to the actual conditions in the well and consisted of creating pressure inside the field sample after successive mechanical distribution of the threaded connection with punches with diameters of 184-218 mm. The hemp or linen tow GOST 12285-77 is used as the fibrous material, the bentonite clay powder GOST 28177-89 is used as the sealing filler, the aqueous solution of the detergent belonging to GOST 26878-86 liquid shampoos is used as the surfactant, and graphite lubricant is used as lubricating additives GOST 3333-80.

Table 1 presents the test results of the mechanical distribution of the threaded connection with punches of 184-218 mm and the conditions for pushing the tool with an extension of 15-22%.

The results of hydraulic tests after mechanical distribution of the threaded connection with a punch are presented in table 2.

Table 1 Model No. Sealant composition Nominal diameter of the punch, mm Tool pushing force, t one 20% fibrous material 184 33.3 50% sealing filler 196 46.7 the rest is a 30% aqueous solution of detergent 204 40 218 56.7 2 40% fibrous material 184 33.3 30% sealing filler 196 40 the rest is 70% aqueous solution of detergent 204 43.5 218 48 3 20% fibrous material 184 40 30% sealing filler 196 53.3 the rest is a 30% aqueous solution of detergent and lubricant. additives in a ratio of 2: 1 204 40 218 55 four 40% fibrous material 184 34.3 50% sealing filler 196 42 the rest is 70% aqueous detergent solution and lubricated. additives in a ratio of 0.5: 1 204 41.5 218 49

table 2 Model No. Sealant composition Pressure before holding, MPa Exposure min Pressure after holding, MPa one 20% fibrous material 3.0 10 2,8 50% sealing filler 5,0 10 4.8 9.0 10 8.4 the rest is a 30% aqueous solution of detergent 15.0 10 14.5 16.3 10 16,0 2 40% fibrous material 3,5 10 3.3 30% sealing filler 5,0 10 5,0 9.8 10 9.8 the rest is 70% aqueous solution of detergent 14.0 10 14.0 17.0 10 16.9 3 20% fibrous material 3,1 10 3.0 30% sealing filler 4.8 10 4.8 9.9 10 9.8 the rest is a 30% aqueous solution of detergent and lubricant. additives in a ratio of 2: 1 14.8 10 14.8 17.1 10 17.0 four 40% fibrous material 3,1 10 3.0 50% sealing filler 5,0 10 4.8 the rest is 70% aqueous detergent solution and lubricated. additives in a ratio of 0.5: 1 9.8 10 9.8 14.6 10 14.6 17.0 10 16.9

Analysis of the table shows that the proposed combination of base and filler and antifriction filler in the form of surfactants provide a high degree of tightness after the distribution of threaded joints with punches.

The heterogeneous thread sealant presented in various formulations described in the formula successfully passed field tests when sealing threaded joints for wells No. 30433 (three threaded connections) of Alkeevskaya Square, No. 34046 (five threaded connections) of Chishminsky Square NGDU Jalilneft and No. 18 (thirty-two threaded connections) of Aleksandrovskaya Square LLC Tatneft-Samara when isolating the zones of complications using expandable systems.

All threaded connections in wells according to the test results before and after their distribution are 23% tight.

Thus, threaded joints using the proposed threaded heterogeneous sealant provide a high degree of tightness before and after plastic deformation with the expansion of threaded joints up to 23%.

Claims (3)

1. Threaded heterogeneous sealant, including a base, antifriction and sealing filler, characterized in that 20-40% of the fibrous material in the form of hemp or linen tow, a sealing filler - 30-50% is used as a base for sealing threads subject to plastic deformation. clay powder, the rest is an antifriction filler in the form of a surfactant. 2. A threaded heterogeneous sealant according to claim 1, characterized in that a 30-70% aqueous solution of detergent is used as a surfactant. 3. The threaded heterogeneous sealant according to claim 1, characterized in that the mixture used is a surfactant: 30-70% aqueous solution of detergent and lubricating additives in the form of graphite lubricant in a ratio of 2 ÷ 0.5 to 1.