RU2244794C1 - Method for opening water-bearing horizons by a vertical well and device for realization of said method - Google Patents

Abstract

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes use of device providing for manufacturability of assemblage of casing and drilling columns and concurrent drilling by two columns, provided with independent drives, and drilling, by casing column, of non-stable rock solids performed with frequency no greater than one calculated from formula

where V_mec - mechanical drilling speed, m/min, F_r - friction forces against rotation, F_ten - friction forces against linear displacement, R - casing column radius, m, α - angle between vectors of directions of linear and rotating movements.

EFFECT: higher effectiveness, higher productiveness, higher reliability.

2 cl, 5 dwg, 1 ex

Description

The invention relates to the field of technology and engineering for the construction of vertical wells for water while maintaining the natural permeability of the aquifer and can be used for drilling vertical wells in difficult hydrogeological conditions.

When opening sandy aquifers, important problems are the protection of the walls of the well being constructed from collapse and the preservation of the natural permeability of rocks, which determines the emergence of new methods and new installations along with the already known and traditional ones.

So, there is a method of opening sandy aquifers with vertical wells using a clay solution as a washing agent. Clay mud, on the one hand, serves as a medium that keeps particles of drill cuttings from settling, on the other hand, it creates additional pressure on the formation, due to which it is possible to keep the borehole walls from collapse.

The disadvantage of this method is the ingress of the clay filtrate into the formation and the formation of clay cake on the walls of the well. Formation of the formation by clay mud reduces its permeability in the filter zone, which necessitates claying and development of the formation. This process lasts several days, but does not completely restore the well flow rate (I.F.Oksanich et al. “Drainage of deposits during the construction of iron ore enterprises”, Moscow, Nedra, 1977, p. 61, table 19).

To eliminate this drawback, it is known to use the method of opening a sandy aquifer using clean water as a flushing liquid for its direct and reverse circulation [V. M. Gavrilko, V. S. Alekseev. Drill hole filters. M., Nedra, 1976, s.263-287].

When drilling with direct washing, water is supplied to the rock cutting tool through a drill string through a drill string. Water entering the face carries sludge to the surface through the annulus.

When drilling with backwashing, water is fed into the annular space between the walls of the borehole and the drill string, from where it along with the cuttings rises along the drill string to the surface. The productivity of drilling a well in this way is higher than when drilling with mud, due to a several-fold reduction in the time to develop a well, its flow rate also exceeds the flow rate of a well drilled with mud, due to which the described method has received worldwide recognition.

The disadvantages of this method include the mandatory condition for its implementation - the excess pressure of the column of flushing fluid in the well over the hydrostatic pressure of water in the reservoir by 3-5 m water. Since it is difficult to monitor the level in the well, in practice this level is maintained at the wellhead, which leads to a large consumption of water due to its absorption by the sand formation (in some cases up to 60-80 m ³ / h).

The disadvantages of the considered analogues should include a violation of the natural permeability of the reservoir during the construction of the well.

This disadvantage is partially eliminated by the known method of opening sandy aquifers under the protection of the casing with the simultaneous removal of rock from the bottom with the help of special chutes, lowered on a cable. Moreover, the casing is lowered either under its own weight or with the parallel application of shock loads to the casing, i.e. casing give the function of working. With this method of opening an aquifer, the depth of the casing string into the formation is extremely important. This parameter is determined by many factors: the depth of the aquifer, its thickness, pressure, the technology of scooping rock from the bottom (the frequency of the descent of the chute, its design) and many others. As a rule, the burial in the sand layer is several meters. This is explained by the fact that it is impossible to ensure the stability of the walls of the well with this method due to the constant fluctuations in the static pressure of the formation that the bailer creates when scooping rock with water.

With a powerful formation, to ensure the opening of the formation at its full capacity, it is necessary to use several sizes of columns. This is a very time-consuming, metal-intensive, and, therefore, expensive and low-productivity method, which is used extremely rarely and mainly for drilling shallow wells. Important advantages of the method are the preservation of the natural permeability of the formation and the possibility of opening the aquifer with a combined column, part of which is a filter section installed in a certain interval.

To reduce the time required for well completion, reduce the laboriousness of filter planting and increase water loss in wells, a filter planting method with an expander shoe is used. [A.S. 623948, BI 34, 1978].

Improving the method of opening sandy aquifers is carried out with a simultaneous change or improvement of drilling rigs.

So, the well-known installation for drilling "Phoeb Shahbau", designed for drilling shafts in a rotary way with backwashing. The mechanical drilling speed is 0.3-0.8 m / h, the minimum commercial drilling speed is 30 m / month. Installation equipment is made of blocks that are easy to assemble and easily transported. The installation kit includes a tower, a hoist system, a winch, a rotor, a drill string with threaded locks, a set of drills equipped with cutters or cones, mobile compressors and equipment for the preparation and cleaning of solutions [AG Nikolayev and others. "Drilling rigs for sinking wells and shafts. " Handbook, M .: Nedra, 1985, p. 266-267]. The disadvantages of the installation include cumbersome, high energy consumption, the inability to avoid the disadvantages inherent in the method of opening the formation of one string of drill pipes.

From the technical level it is also known the construction of vertical wells with two working pipes (casing and drill). So, in installations according to the application of France No. 2071226 and patent RU No. 2018621 (P. 2018621, publ. 30.08.94), the device includes a base machine with a guide, a casing with a rock cutting body and drives for its rotation and feeding, and the feeding mechanism is made screw, those. Well development is only possible with forced feed of working bodies with helical pairs. However, when developing soft soils, this leads to excessive filling of the pipe cavity with soil, which in turn causes overloading of the drives of the working bodies. In this connection, when developing soils of a solid category, for example, stiff-plastic, drilling is carried out cyclically, first with a screw drill and then with a bucket. When drilling wells in soft soils, the resistance to their development is significantly reduced. Therefore, the drilling of wells is carried out without additional pressure on the working bodies. Using this device allows you to implement the following operations for managing the working bodies: forcing each working body separately or jointly into the well, or feeding under its own weight, alternately feeding the screw auger first, then the bucket fixed to the casing, but without stopping the transportation of developed soil from pipe cavity.

The considered device is intended for drilling wells whose length does not exceed the length of the working rods, is able to provide independent drilling with two columns of pipes only in hard soils and is absolutely not suitable for the construction of vertical wells in sandy aquifers.

Thus, at a known technical level, it was not possible to find the closest analogue for both the method of opening aquifers and the device for its implementation.

The objective of the invention is the expansion of a number of methods for opening unstable aquifers with a vertical deep or shallow well while maintaining the natural structure and natural permeability of the walls of the well with the installation of a filter during drilling and the creation of an installation for its implementation.

Technical results that can be obtained by implementing the claimed invention are:

for method

- ensuring the conservation of the natural structure and permeability of the aquifer;

- retention of the walls of the well being constructed from collapse;

- reducing the likelihood of curvature;

- productivity increase;

- reduction of energy intensity;

- combination of drilling operations and installation of filters;

- manufacturability;

for installation

- compactness;

- the convenience of building columns;

- reliability and providing the ability to open the aquifer without violating its natural structure and natural permeability;

- expansion of a number of installations for opening unstable aquifers.

The solution of this problem and the achievement of the above results became possible due to the fact that in the method of opening unstable aquifers by a vertical well, including drilling this well in sandy water-saturated rocks with two independent columns: casing and drilling by controlled transmission to the tools that equip the ends of both columns, loads, providing deepening of the well, removal from the bottom of the destroyed rock and installation in the well of at least one filter element in the zone not m For less than one aquifer, drilling of unstable rock casing is carried out by rotation with a frequency that ensures minimal friction to its rotational-translational motion and does not exceed calculated by the formula

Where

α is the angle between the direction vectors of translational and rotational movements;

V _fur - mechanical drilling speed;

F _BP - the friction forces of the rotational motion:

F _oс - friction forces to translational motion;

R is the radius of the casing,

at least one filter element is installed in the well during drilling by incorporating it into the casing with the possibility of delivery to the well being constructed to a predetermined mark, the destruction of the destroyed rock from the bottom is carried out through the annulus by supplying sufficient water to the bottom through the inner column in an amount sufficient for the removal of the destroyed rock at the wellhead, and the extension of the drill and casing strings is carried out by preliminary removal of the drill string rotator from the drilling axis to the flat spine perpendicular to it.

In preferred embodiments of the method, the casing and drill strings are rotated in antiphase, the walls of the borehole are cut with a tool in the form of a cutting ring with a cutting angle of 45-60 °, facing a tapered surface into the annular space with an external diameter 1.1-1.15 times the external casing diameter.

To install the opening of unstable aquifers with a vertical well, the solution of the problem and the achievement of the above results became possible due to the fact that the installation includes a mud pump for supplying water to the bottom, a platform with a vertical frame, on which guides are mounted to move the movable frame vertically mounted on it, on a movable frame, perpendicular to it, two stationary frames are fixed parallel to each other with guides providing movement along them, respectively but, the rotators of the drill and casing are perpendicular to the axis of drilling, with each of the rotors connected to its corresponding adjustable wire, the casing rotator is equipped with a unit for mechanically screwing and unscrewing the sections of casing and drill pipes, and at least one filter casing is included in the casing element with the possibility of its installation in the well at a predetermined elevation during drilling.

In a preferred embodiment of the installation as a tool, a cutting tool is fixed on the casing in the form of a ring with a cutting angle of 45-60 °, turned by a conical surface into the annular space and with a diameter 1.1-1.5 times the diameter of the casing.

, где F_oc - сила трения поступательному движению колонны вниз, вызванная горным давлением;The adjustable rotation of the casing according to the claimed restriction by the formula ensures the optimal drilling mode by taking into account such quantities as P_os - axial component acting on the column, depending on the weight of the column, P_side - its mountain pressure acting on the casing from the side of the well walls. When the column is informed of axial displacement and rotation, friction forces arise that impede its movement. These forces are opposite in direction to the axial and rotational motion and opposite to the velocity vectors. The ratio of the friction forces to the translational and rotational motion depends on the angle α formed between the vectors of the direction of translational movement of the column down and rotational around the axis of the well, or, respectively, the friction forces

where f_oc - the friction force of the translational movement of the column down caused by rock pressure;

where f is the coefficient of friction of steel on the rock,

where F _bp. - friction force to the rotational movement of the casing string;

where V _mech is the mechanical drilling speed, m / min;

R is the radius of the casing, m;

P _t - casing rotation frequency, rpm, and already on the basis of α and V _{fur the} optimal rotation frequency is calculated, which ensures minimal friction to the rotational-translational motion (see formula 1).

In the general case, with stable borehole walls, the lateral friction forces of the column are small and are determined by the pressure of the column against the borehole walls and the friction coefficients. With unstable walls, the lateral pressure value is determined by the lateral pressure P _side from the side of the well walls. In this case, it is determined by the horizontal component of rock pressure and the coefficient of friction of the rock against steel.

The flow rate of the flushing fluid (water) is selected from conditions sufficient for the removal of the destroyed rock. In this case, unlike analogues, there is no need to maintain excess pressure on the formation to keep the well walls from collapsing, therefore, removing the destroyed rock from the bottom with clean water and using it in an amount sufficient for this allows to increase the efficiency of the installation compared to analogues using this principle.

The installation interval of the filter element or elements, their design, duty cycle and other parameters are also set and regulated by the geological and technical outfit. In the calculation, the filter column is calculated for torsional strength. The inclusion of a filter element during casing string during drilling allows you to combine the operation of drilling and filter fit, which reduces the time of well construction and increases the processability of the method.

The rotation of the casing and drill strings in antiphase allows to reduce the likelihood of curvature of the well, and therefore, to reduce friction.

Cutting the walls of a well being constructed with a tool in the form of a cutting ring with a cutting angle of 45-60 °, facing a conical surface into the annulus with an outer diameter 1.1-1.15 times the outer diameter of the casing, increases the ability to preserve the natural properties of the rock (permeability and structures) and the direction of the rock in the annular space, from where it is carried to the surface by water.

The invention is illustrated by the following drawings:

figure 1 is a side view of the installation;

figure 2 is a front view of the installation;

figure 3 - layout of the casing and drill strings in the well;

figure 4 is a nomogram for determining the friction forces during axial movement of the casing string depending on the mechanical drilling speed (V _fur ) and the coefficient of friction of the rock on the pipe (f);

5 is a nomogram for determining the torques on the casing depending on V _fur and f.

The installation (Fig. 1 and Fig. 2) for implementing the inventive method for opening unstable aquifers by a vertical well is a horizontal platform 1 mounted on a chassis 2 and rigidly connected to a vertical frame 3, having guides 4 for moving the movable frame 5 vertically, on which the rotator 6 from the casing string 7 and the rotator 8 of the drill string 9 are fixed. On the movable frame 5, a frame 10 with guides 11 is mounted perpendicular to it along which the rotator 8 moves perpendicular to the drilling axis drill string 9 using a displacement cylinder 12 mounted between the guides 11 and rigidly connected to the body of the rotator 8. To ensure alignment of the spindle 13 of the rotator 6 and the spindle 14 of the rotator 8, they are equipped with a device for rigid fixation (not shown), excluding the drill string 9 from axis of rotation. To remove the rotator 6 from the borehole axis, a frame 15 is installed on the movable platform 5 with guides 16 parallel to the guides 11 and a hydraulic cylinder 17 for moving the rotator 6. The rotation and axial forces of the casing 7 are transmitted through nodes for mechanically screwing and unscrewing the sections of casing and drill pipes in the form of a hydraulic gripper (cartridge) 18 mounted on the casing rotator body 6, the gripping mechanism of which rotates together with the spindle 13 of the rotator 6. To hold the casing sections UB 7 on a fixed platform 3 installed hydraulic grip (hydraulic wrench) 19, which when capturing the casing 7 can keep it from turning.

The motion of the stationary frame 5 along the vertical frame 3 is carried out using the hydraulic cylinder 20 (the stroke of the feed cylinder should be 10-15% longer than the length of the sections of drill and casing pipes). Since drilling is carried out by two columns 7 and 9 at the same time, the extension should be carried out sequentially (first drill, then casing). The length of both columns should be the same. In the lower part, both columns 7 and 9 are equipped with tools (see figure 3). On the drill string 9, either a roller cone or a blade bit 21 is installed as such a tool. On the casing 7, a tool is installed in the form of a cutting ring 22 with a cutting angle of 40-60 °, the conical surface of which is turned inward and the outer surface has a cylindrical shape. The conical surface is reinforced with hard alloy. The outer diameter of the tool 22 is greater than the diameter of the casing 7 by 10-15%. Due to this factor and shape, it cuts the rock from the walls of the well and directs it into the well, which ensures the preservation of the natural properties of the rocks (permeability and structure). When drilling, the supply of flushing fluid to the drill string 9 is carried out by a mud pump (not shown) through the injection hose 23 through the swivel stuffing box 24, where from the string 9 it is fed to the bottom through the bit 21 and goes up through the annular space 25.

At the bottom of the vertical frame 3, an additional hydraulic wrench 26 is installed for emergency holding of the casing 7. Above the spindle 13 of the casing rotator 6, a hydraulic gripper 27 is installed to hold the drill string 9. The hydraulic actuators of the rotator 6 and 8, the hydraulic feed system are driven from the oil station 28, hydraulic pumps (not shown) which are connected to a diesel power plant 29 or an electric motor, and the drives are controlled by their connection with the control panel 30.

From the control panel 30, the lifting of the frame 3 is controlled from horizontal to vertical. This operation is performed by the hydraulic cylinders 31 and 32. The rotation is carried out around the hinges 36.

The lifting and lowering operations of the sections of casing 7 and drill 9 pipes are provided by the load-gripping mechanism 33 of the winch 34. Leveling the platform 1 and the perception of axial loads during tripping and drilling and drilling is carried out using hydraulic jacks 35, controlled from the control panel 30. Transfer to transport the position of the frame 3 from vertical to horizontal is made using the hydraulic cylinders 31 and 32 by turning around the hinges 36.

The claimed installation works as follows. The installation is mounted on the site, using the hydraulic cylinders 31 and 32, raise the vertical frame 3 in a vertical position and fix it. Thus prepared installation using hydraulic jacks 35 level. After that, they begin to prepare for drilling, for which they assemble the layout of the casing 7 and drill 9 (figure 3). It is carried out as follows. A tool 22 is installed on the head section of the casing 7. Using the winch 34, the working arrangement of the casing 7 is first assembled by means of a winch 34. For this, its first working section is passed through the spindle 13 of the rotator 6 and clamped with a hydraulic gripper (hydraulic wrench) 19, after which the next the pipe section 7, again passed through the spindle 13 of the rotator 6. Clamp it in the cartridge 18, turn on the rotation of the spindle 13 and connect the section into a column. These operations continue until the tool 21 comes into contact with the ground. After this, the layout of the inner string 9 is similarly assembled. First, a bit 21 is installed on its head section, using a winch 34 and a load gripping mechanism 33, it is lifted, lowered into the casing 7, put on the fork (not shown) of the hydraulic gripper 27, fixed, load-lifting the mechanism is released, the next section of pipes 9 is lifted and the column is built up using hydraulic gripper 27 or 18. The column 9 is raised and lowered cyclically until the bit 21 touches the surface of the earth.

The manufacturability of the operations on the extension of the columns is achieved due to the possibility of retracting the rotator of the drill string from the axis of the well to the side, while it is possible to maneuver the load gripping mechanism 33.

After performing these operations, the casing 7 is clamped in a hydraulic grip (chuck) 18, the grip of the hydraulic wrench 19 is released, the rotator 8 is brought to the center, the spindle 14 is connected to the drill string 9 and tuned to the desired rotation speed of the drill 9, then the casing 7 includes the supply of the movable frame 5 down, with the help of the hydraulic cylinder 20 regulate the value of the axial pressure on the bottom, turn on the mud pump (not shown) and start drilling. The rotational speed of the drill string 9 is selected from the conditions of effective destruction of the rock with a bit 21 (usually in the range of 80-200 rpm). The rotation frequency of the casing string 7 at the initial moment, when the walls of the well are stable, is taken as high as possible. When the drilling tool reaches unstable rocks, the casing starts to rotate at a speed that is calculated by the formula

,

,

Where

V _fur  - mechanical drilling speed;

R is the radius of the casing,

F _BP - the friction forces of the rotational motion:

F _BP = f · P _side , where

f is the coefficient of friction of steel on the rock;

P _side - rock pressure acting from the side of the walls of the well on the casing (P _side calculated according to known methods);

F _oс - friction forces to the forward movement of the casing string down caused by rock pressure.

When drilling in difficult conditions, it is necessary to draw up a geological and technical order (schedule) for each well, in which the forecast (calculated) parameters are painted at intervals: axial force on the bottom, rock pressure, friction forces of translational and rotational motion, drilling speed, rotational speed of the outer string . To reduce (decrease) the curvature of the wells, and consequently, to reduce the friction forces of the casing, in the preferred embodiment, left rotation is reported.

The industrial applicability of the claimed method and installation for its implementation shows the following example of a specific implementation.

Example

Hydrogeological conditions of work:

- the upper part in the section to a depth of 1.5 meters is represented by a plant layer;

- from 1.5 m to 2.5 m - loam;

- from 25 m to 35 m fine-grained flooded sands pressure head;

- the static water level is at a depth of 15 m;

- Dense waterproof clays with a thickness of over 15 m lie in the bottom of the aquifer.

The purpose of the well is drinking and domestic water supply for a group of individual houses with an estimated water consumption of 4-5 m ³ / h.

A well is constructed for the installation of an ETsV-5 or ETsV-6 pump with a filter element diameter of 168 mm. A well is constructed by drilling with two independent columns: casing with an external diameter of 168 mm and a drill with an external diameter of 89 mm with the removal of rock from the bottom by supplying clean water through the drill string.

The casing is equipped with a tool in the form of a ring with a cutting angle of 45-60 °, facing a conical surface into the annular space with an outer diameter of 185 mm, which is 1.1 the outer diameter of the casing. Above the cutting tool there are 7 sections of blank pipes, above them a filter of 7 sections (perforated slotted perforation pipe with a slit size of 0.5-0.7 mm and a duty cycle of about 14%). A filter element or elements are delivered to a well at a predetermined mark during drilling, namely, to a zone of fine-medium-grained flooded pressure sands. The remaining sections of the casing are also assembled from blind pipes.

The threads on the pipes are left, tape with a double thread and a pitch of 12 mm, which provides a high speed of building up of casing sections (2-3 minutes per connection). Casing pipes are made of high-strength steel grade D.

The inner drill string is assembled from pipes with an external diameter of 89 m and equipped with a tool in the form of a blade type cutting bit with a diameter of 145 mm.

The casing rotation frequency is calculated by the formula

V _fur - mechanical drilling speed;

R is the radius of the casing;

,

,

where F _BP , F _OS - respectively, the friction forces of the rotational and translational motion of the casing. These forces are calculated in advance when compiling a geological and technical order for a well. For practical use, in accordance with the proposed drilling method, nomograms have been built to determine the friction forces of the translational motion and the torsional moments by 1 r.m. the columns. They are presented in figures 4 and 5.

From the extensive experience of opening sandy aquifers, practically the column rotation frequency is in the range of 2-5 rpm. It is difficult to keep the frequency below 2 rpm due to the complexity of regulating the oil flow in the hydraulic control system of the rotation drive. First turn on the rotation of the inner string, then the casing, and the rotation of the latter is carried out in the opposite direction, turn on the water supply using a mud pump and drill into the depth of the section. Then the spindle rotator of the drill string is disconnected from the string, the rotator is withdrawn in a horizontal plane from the axis of the well, the drill string and then the casing string are increased.

After building up the next section, the rotator of the drill string is moved to the drilling axis, connecting the spindle to the string. And they repeat the drilling process.

The time for drilling 1 pm of the well increases by 20-30% due to the additional costs of building up the casing, but is reduced due to the combination of the operations of landing the casing with the drilling of this string, and the delivery and installation operations in the filter zone with the operation of drilling the casing, which includes the specified filter element (or filter element section).

The following drilling indicators have been achieved:

V _fur - 0.4-0.7 m / min;

V of _those - 5-7 m / h;

V _commercial - 1.5-2 m / h.

As can be seen from the example, the method of opening aquifers by a vertical well and the installation for its implementation in the claimed combination of features have practical applicability, ensure the preservation of the natural structure and natural permeability of the walls of the well, the installation is more compact, reliable and efficient compared to known analogues, allows you to combine operations drilling, fixing the walls and installing filters in the well in predetermined areas at the time of creation of this well.

Claims (5)

1. A method of opening unstable aquifers by a vertical well, including drilling this well in sandy water-saturated rocks with two independent columns: casing and drill by controlled transmission to the tools that equip the ends of both columns, loads to deepen the hole, remove the destroyed rock from the bottom and install it in a well of at least one filter element in a zone of at least one aquifer, while casing of unstable rocks is drilled They are rotated with a frequency that ensures minimal friction to its rotational-translational motion and does not exceed calculated by the formula

V _fur - mechanical drilling speed, m / min; F _BP - the friction forces of the rotational motion; F _OS - the friction forces of the translational motion; R is the radius of the casing, m, α is the angle between the direction vectors of translational and rotational movements, at least one filter element is installed in the well during drilling by incorporating it into the casing with the possibility of delivery to the well being constructed at a predetermined mark, the destruction of the destroyed rock from the bottom is carried out through the annulus by supplying sufficient water to the bottom through the inner column in an amount sufficient for the removal of the destroyed rock at the wellhead, and the extension of the drill and casing strings is carried out by preliminary removal of the drill string rotator from the drilling axis to the flat spine perpendicular to it. 2. The method according to claim 1, characterized in that the casing and drill string rotate in antiphase. 3. The method according to claim 1, characterized in that the borehole walls are cut with a tool in the form of a cutting ring with a cutting angle of 45-60 °, facing a conical surface into the annular space with an outer diameter 1.1-1.15 times the outer diameter casing string. 4. Installation for opening aquifers with a vertical well, including a mud pump for supplying water to the bottom, a platform with a vertical frame on which guides are mounted for moving the movable frame vertically mounted on it, on the movable frame two fixed perpendicular to it are fixed parallel to each other frames with guides that enable them to move, respectively, the rotators of the drill and casing perpendicular to the axis of drilling, with each of the rotators associated with the corresponding with an adjustable drive, the casing rotator is equipped with a unit for mechanically screwing and unscrewing the sections of casing and drill pipes, and the casing string includes at least one filter element with the possibility of its installation in the well at a predetermined mark during drilling. 5. Installation according to claim 4, characterized in that a cutting tool in the form of a ring with a cutting angle of 45-60 °, turned by a conical surface into the annular space and with a diameter of 1.1-1.15 times is fixed as a tool on the casing exceeding the diameter of the casing.

Images