SU1451275A1 - Method of testing thick producing levels - Google Patents

Abstract

The invention relates to the field of geology and m. used in gross testing of productive horizons through wells (C). The goal is to increase the reliability of sampling. The horizon is opened C with the position of the bottom C below the foot of the productive horizon. Clay mud is performed. Placed in C on the garden pillar, leaving a gap between its lower end and the sole of the productive horizon. The height of the gap is equal to the diameter C below the bottom of the horizon. The pipe is installed in C below the bottom of the horizon with the bottom end muffled. The jetting unit is placed in C with the nozzle located in the gap interval and a circular sub-, wellbore zone cutting is performed with the help of a hydraulic erosion. A gas-liquid mixture is supplied to C, the hydrostatic pressure is decreased in C, and a zone of softened rocks is formed. There is a collapse of decomposed rocks on cutting with simultaneous disintegration of their jetting jet in the gap interval. The overall fractions are lifted through C to the surface, and the oversized fractions are bypassed into the pipe with the end muffled. After the rocks are extracted from the near-wellbore zone, the hydrostatic pressure is increased in C and iz-. using fishing devices, a pipe with oversized rock fractions is attracted. 3 hp f-ly, 3 ill. Ш (Л k4 СЛ iS Ч СЛ

Description

The invention relates to geology and can be used in the bulk testing of producing horizons through wells using hydromechanization tools.

The purpose of the invention is to increase the efficiency and reliability of testing flooded productive horizons.

Figure 1 shows the scheme of the initial perirda testing; figure 2 - diagram of the washout near-wellbore zone; Fig. 3 is a diagram after erosion of the near-wellbore zone.

The method is illustrated by the example of testing the productive horizon 1 represented by weak watered rocks. The productive horizon 1 is opened by a borehole 2 with a drill 3 in the underlying rocks. To form the near-wellbore zone of rock to be destroyed, a clay solution can be injected into the well under pressure to form

a kind of clay cylinder

4, the diameter of which can reach 1-2 meters. Then in the indicated well 2 a casing string 5 is placed with its end located at the bottom of the productive horizon, leaving a gap

6 between these buttresses and bedrock with a height not exceeding the diameter of perebor 3. After this, a well-boring jets assembly 7 is placed in the well with the location of its eroding nozzle in the gap interval 6. After the placement of the aggregate

7, using a jetting jet, a circular cutting 8 of the near-wellbore zone of the productive horizon is carried out. At the same time, the fluid is pumped out of the well before the hydrostatic pressure of the fluid in it drops below the reservoir pressure of the fluid in the producing horizon 1. Pumping can be done by further increasing the performance of the hydraulic elevator or the airlift of the downhole jetting unit 7. On the other hand, the hydrostatic pressure in the well 2 can be reduced scouring the sweep 8 gas-liquid jet, while in the well a column of aerated liquid is formed, the hydrostatic pressure of which can be said lower formation pressure. Water, air, and surfactants can be supplied through the nozzle to create a deep depression.

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substances, such as sulfanol, OP-7, OH-10, and others that are widely used in drilling practice With the formation of a column of foam in a well. Deep depression can also be created with the help of the hydraulic elevator of the downhole hydraulic motor unit. When using a gas-liquid mixture as a working fluid, it is advisable to use only one pressure stand with a well jet and gas-liquid flows and pulp should be discharged by the method of direct washing through the casing string 5.

Thanks to the sweep 8 below the wellbore zone on the boundary of the productive horizon, as well as the decrease in hydrostatic pressure below the reservoir, active destruction of rock connectivity in the near-wellbore zone of productive horizon 1 along casing 5 and around it occurs, forming a zone of weakened rocks 9. Collapse of the rock in the near-wellbore zone occurs due to both trimming and loading of this zone by external hydraulic pressure from the array of the productive horizon due to reduced hydrostatic th pressure in the borehole 2.

In the course of further mining, a continuous jet erosion of the disintegrated rock breaking down from the near-wellbore zone at the level of the gap 6 is performed by a jet stream, while small and medium fractions of the rock are transported to the surface by a hydraulic elevator, airlift or by the method of direct washing, and large, for example, boulders and large pebbles are temporarily bypassed into reamer 3. In order to eliminate well drilling over seam 3, the height of gap 6 takes no more than perebor 3 in order for all pieces of rock that have passed through gap 6, yli or immediately are lifted to the surface, or could go to regale 3.

After a temporary decrease in the hydrostatic pressure — and the destruction of the rock column in the near-wellbore zone, the well 2 can be re-flooded to prevent further destruction of the placer rocks adjacent to the infill zone.

After complete extraction of rocks from the near-wellbore zone with the formation of a goaf 10, carry-OWt /

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Claims (4)

Claim 1. A method for testing powerful productive horizons, including opening a horizon with a borehole in the underlying rocks, placing a borehole hydraulic monitoring unit in it, circular erosion of rocks in the near-wellbore zone and hydraulic pulp lifting to the surface, characterized in that, in order to increase the efficiency and the reliability of testing waterlogged productive horizons, a casing is installed in the well with a clearance in height of no more than the diameter of the span between its end and the underlying rocks, when placing hydra of the monitor aggregate, its erosion nozzle is placed in the gap interval, the rocks are washed out through the specified gap with the by-pass of large fractions into the rebound and hydraulic lifting of small fractions, while the hydrostatic pressure of the liquid in the well is lowered below the reservoir pressure in the productive horizon, and after the completion of erosion, large fractions. 2. The method according to claim 1, characterized in that before installing the casing pipe, the near-wellbore zone of the productive horizon is clayed by introducing a clay solution under pressure into the well. 3. The method according to claim 1, characterized in that a pipe with a plugged bottom end is placed in the borehole well, when large fractions are bypassed, they are placed in the borehole in the pipe cavity, and after the erosion is completed, the pipe is removed to the surface. 4. The method according to claim 1, that is, with the fact that the hydrostatic pressure of the liquid in the well is reduced until the rocks collapse in the near-well zone, after which the pressure is restored. Figure 1 FIG. g fig.Z