SU1573156A1 - Sample pick up for formation tester - Google Patents

Abstract

The invention relates to the testing of wells with the aid of a reservoir tester on pipes and can be used to take a sealed sample of formation fluid. The goal is to increase the reliability of work. The sampler contains a housing 1, which is lowered into the borehole and contains a flow-through sampling chamber with inlet 6 and outlet 8 valves, rigidly connected to each other by stem 12. Valves 6 and 8 and the valves themselves are conical. There are annular grooves 9 for seals on these valves, and on each of the valves the number of annular grooves 9 exceeds the number of seals installed on the valve. Depending on the specific test conditions, before starting work, two rubber seals of the upper 10 and lower 11 are installed on each of the valves 6 and 8, and the sizes of these seals and annular grooves 9 for them are selected in accordance with the calculated values obtained for Conditions for reliable sealing of the sampled sample in the sample chamber after completion of the well test and when the sampler is raised to the surface. 3 il.

Description

The invention relates to well testing with a tube tester and can be used to take a sealed sample of a formation fluid.

The purpose of the invention is to increase the reliability of work.

FIG. 1 shows the sampler before the test equipment is lowered into the well, a general view of FIG. 2 - test equipment descent into the well, inflow mode from the reservoir; in fig. 3 - closing the valves of the sampling chamber at the opening of the equalizer valve of the reservoir tester at the end of the test and the lifting of the tool.

The sampler for the tester of formations contains a housing 1, lowered on the pipes (Fig. 1), fixed by Ts to the suspension 2, sealed by Sealing 3 in the housing of the driven Sub k. The valve assembly of the sampling chamber is composed of a saddle 5 of the intake valve 6 and a seat 7 of the exhaust valve 8, which are tapered with annular grooves 9 of different diameters for the upper 10 and lower 11 rubber seals. The inlet 6 and outlet 8 valves are rigidly interconnected by a stem 12, the stroke of which, in the axial and radial direction, is limited by two guides 13. The total number of annular ducts under the seals on each valve exceeds the number of seals installed on the valve. Needles 1 + are installed in these valves to measure the pressure inside the sampling chamber 15 and take samples for analysis. Bellevye valves 16 are also installed in the body 1 of the sampler, ensuring pressure equalization in the supra-packer And sub-packer zones after closing the sampling chamber 15.

The sampler works as follows

in a way.

Before starting work, rubber seals are installed on the valves, the dimensions of which are selected based on the specific test conditions, according to the following inequality:

D d

H (m + k.) Iga + hn

where d is the diameter of the bottom seal

valves; D - diameter of the upper seal

valves;

H is the depth of the reservoir under test; m is a coefficient numerically equal to

the ratio of the density of the fill-up well of the flushing fluid to the density of the water; h - the planned height of the buffer

liquid poured into pipes; n - coefficient, numerically equal to), 5 ratio of the density of the buffer

liquids to water density; k - anomaly coefficient

reservoir pressure. Considering that specific test conditions 2Q can be varied, additional annular grooves made on the valves allow this sampler to be used for various test conditions 25, producing only the size of the valve’s sealing according to expression (1) and fitting them to the corresponding valve grooves .

During the descent of the test equipment into the well, under the action of the force of the drilling fluid, rigidly connected to each other by the stem 12 of the inlet 6 and the outlet 8 of the sampler valves are opened (Fig. 2). The drilling pa-valve passes through the inlet valve 6 seat 5, the cavity of the sampling chamber 15, the inlet valve seat 7 7 into the supravalvular cavity of the sampler, thereby ensuring the flow of drilling mud from the under-packer zone to the over-packer, which improves the tool’s permeability.

45 After packing in open periods of testing, the formation fluid passes through the device as indicated above, displacing the drilling fluid from the sampling chamber.

50 Upon completion of the test, after opening the equalizer valve of the formation tester, the hydrostatic pressure of the mud column filling the well is transmitted to

55 the over-valve cavity of the sampler and through the disc valves 16 into the sub-packer space. Thus, 1) on the valve assembly of the sampler from the side of its supravalvular cavities

thirty

35

40

51

the hydrostatic pressure Pg acts; as well as the pressure P of the reservoir fluid located in the sampling chamber, and equal in magnitude to the pressure at the bottom of the well until the equalization valve of the formation tester is opened.

Due to the difference in diameters of the lower and upper valve seals, the force F will act on the valve assembly, directed downwards and equal to

 Xd2)

(Pr + Re).

Under the action of this force, the inlet 6 and outlet 8 valves are tightly pressed against their seats, while sealing the depth sample of the formation fluid.

As the uphole tool rises, the hydrostatic pressure of the mud column decreases and becomes zero at the surface. At the same time, sealing is provided by the force acting on the valves from the pressure of the sample of formation fluid in the sample chamber: F -7 (D a - d2) -P ,,

73156

After the sampler is lifted to the surface, it is removed from the instrument sub b. Through the device

14, the pressure in the sampling chamber is measured and the sampler is transported to a stationary laboratory where the analysis of the sample is performed.

ten ,

Claims (1)

Invention Formula A sampler for a reservoir tester, comprising a housing inside which a flow-through sampling chamber is located with inlet and outlet valves, rigidly connected with each other by a rod and provided with annular grooves under the top and 20 bottom seals cooperating with valve seats, characterized in that, in order to increase operational reliability, the intake and exhaust valves and theirs. the seats are conical in shape; on both valves there are additional annular grooves for seals, and the total number of annular grooves for seals on each of 30 valves exceed the number of seals installed on the valve. V about h t II $ ; FIG -2 FIG. 3