EP3825511B1

EP3825511B1 - Method and apparatus for the construction of pipelines or rigid linings inside wells

Info

Publication number: EP3825511B1
Application number: EP20020525.0A
Authority: EP
Inventors: Marco Brusa
Original assignee: Idroweld Srl
Current assignee: Idroweld Srl
Priority date: 2019-11-22
Filing date: 2020-11-11
Publication date: 2024-01-17
Anticipated expiration: 2040-11-11
Also published as: EP3825511A1

Description

Field of application of the invention

Method and apparatus for casing vertical or inclined wells, even in conditions where the axis of the well is not perfectly straight, in the construction of installations for the transport of water, gas and other fluids. Particular relevance has the application for the installation of penstocks of hydroelectric power plants. In addition, the system can be applied for lining of wells in surface water and wastewater collection systems, lining of ventilation shafts, installation of service pipes, single or multiple, for deep mining in tunnels.

State of the art

Wells and pipelines are constructed by excavating from the surface downwards, using various excavation techniques.
Usually the casing is made by assembling single units, pipes, together in steel. The choice of steel and the thickness of the coating has a structural purpose, i.e. consolidation of the well and subsequent casting of concrete outside or for the transport of water. In both cases, the strength and stiffness of the coating is required depending on the use. The quality of the assembly of the single units, i.e. of the single pipes, must be such as to guarantee durability and tightness. According to the usual installation technique, the casing of these wells is put in place after the completion of the excavation operations, or during the excavation itself. The usual technique used for shoring wells or for the installation of pipelines inside both vertical and sub-horizontal wells involves operating from above using overhead cranes or winches to launch the metal casing sectors or pipe segments (segments 4-12 m long). These are lowered down to the base of the shaft and then, after assembling and welding them inside the shaft, they are successively ascended to the top.
The quality of the assembly and welding of the various sectors or tubes is of great importance for the structural characteristics of the final product and its durability.
The usual installation technique has the following drawbacks which are overcome by the present invention:

in case of high well height or small diameter, the installation of a rigid casing, for example metal or hard plastic tubing, is complicated and costly
the use of manpower inside wells, especially if they are very deep, leads to problems of safety at work and plant engineering complications for the preparation of scaffolding, elevators, ventilation systems, etc..
quality control of the assembly of the individual units of the casing, for example the welding of two contiguous pipes, is complicated to perform inside wells and often inaccurate.

The main purpose of the present invention is to provide a solution for the fabrication of the inner casing of vertical or inclined wells such that the casing is assembled, welded and inspected externally and then put in place in the form of a single continuous pipe, while also providing a high level of safety to the personnel involved.
A further purpose of the present invention is therefore to provide a solution for direct verification of the quality of the assembly of the individual casing units outside the well by operators without the need for any subsequent work inside the well.

Summary of the Invention

These and other purposes are accomplished in accordance with the present invention according to the technical solution disclosed herein and claimed in the claims section.
Additional advantageous aspects of the present invention are described herein and set forth in the dependent claims.
The basic idea is that the casing is lowered into the wellbore as a continuous tubular structure as the individual units are assembled, and that the quality of their assembly is tested externally under conditions of complete accessibility both internally and externally.
Document CN108194032 offers a partial technical solution of this type. In fact, in the solution proposed in that document, the individual pipes are assembled outside the well and the verification of the assembly is carried out outside the well, before the lowering of the pipe. Nevertheless, the handling of the tubing and lowering inside the wellbore is accomplished by some type of non-descript winch and according to a non-described mode of operation. In the present invention, movement of the tubing and lowering within the wellbore is accomplished according to the sequence of operations described below and by means of a vise system described below.
For this purpose, a sequence of assembly of the single units and simultaneous lowering of the assembled tubing inside the well is realized.
In the preferred realization mode, the assembly and descent system is equipped with gripping means (clutching) consisting of hydraulically operated clamps, which can be closed or opened by hooking or unhooking the individual units and the entire pipe. The above-mentioned clamps are divided into a fixed "lower clamp", positioned near the entrance of the well, and an "upper clamp" mobile from the low to the high position.
The system does not require guides for the sliding of the mobile upper Z clamp.
The function of the lower clamp is basically to keep a part of the tubing outside the well while holding the entire assembled tubing, while the function of the upper clamp is twofold: to hold the new tubing units during their assembly (high position) and to hold the tubing during its descent into the well while the lower clamp is in the open position. The tubing descends inside said well under the thrust of the weight force of the same tubing, the upper clamp makes said tubing descend at a uniform speed and, in case of friction and obstacles present during the penetration inside the well, can exert a downward thrust force to overcome said obstacles.
By means of an appropriate opening/closing sequence of said clamps, new tubing units are assembled and the entire tubing is lowered into the well.
In the preferred way of realization, the pipeline to be positioned in the well is composed of single units of piping prepared with externally welded steel rings and/or shaped plates with a geometry such as to guarantee an effective and safe constraint to the clamps. These rings and/or plates, welded externally to the tubing units, are used for support during descent operations and remain welded to the tubing, becoming an integral part of it. In this way a further advantageous effect is obtained, in fact these rings and/or plates also perform a structural function of armoring (for internal pressure) and stiffening (for external pressure) of the pipe.
The operations of measurement and control of the quality of the assembly of each additional unit of tubing are carried out by operators with special measuring instruments integrated in said assembly structure before proceeding with each descent manoeuvre.
Particularly advantageous is the possibility guaranteed by this method of assembly to carry out all checks and any repairs outside the well, with obvious benefits in terms of safety at work and reliability of controls.
In fact, welding and quality controls are carried out by personnel working on a platform equipped with all the necessary systems that allow easy access to the entire perimeter of the pipeline in the jointing area. This work platform, mounted integral with the machine's mobile carriage, is always in the same position when the pipes are coupled and welded: all equipment, accesses, and power supplies are therefore always in the same position throughout the work.
On the contrary, according to the known art, the working position changes continuously during the reassembly inside the well, imposing the continuous displacement and adjustment of all equipment, structures and utilities.
A further advantageous aspect of the proposed solution is that it allows for the simultaneous installation of multiple pipelines and/or additional piping to the main pipeline, for example concrete casting pipes, drainage pipes, conduit pipes for the passage of electrical cables, etc.
The proposed solution foresees a way to constrain the pipe lowering system such as to allow its natural alignment to the axis of the well even when the latter undergoes deviations along its development.

List of figures

The main features of the descent apparatus of the present invention are exemplified in the figures below, provided by way of example and not limitation, with reference to the accompanying drawings wherein:

Figure 1, shows an overall view of the assembly and descent apparatus, particularly for the assembly of a main pipe (12) and secondary pipes (13).
Figure 2, shows a view of one of the clamps, in particular you can see the shaping (8) by virtue of which you get a firm grip on the rings arranged in prominence on the pipes and the hydraulic pistons (11) of opening / closing of the clamp
Figure 3, shows a view of a portion of the basement, with one half of the lower clamp anchored, the fixing plates of the hydraulic lifting cylinders (6) and the sliding guide (5)
Figure 4, shows a sequence (S1 to S6) of opening and closing of the clamps relating to the insertion of the first two units of tubing

Detailed description of the invention

The assembly and lowering apparatus essentially consists of a base (1) with supporting clamps referred to as lower 2. clamps (2), a lifting system (3), a mobile carriage with supporting clamps referred to as upper clamps (4), and a command and control system. All drives are hydraulic.
The basement: is fixed on a foundation slab appropriately sized according to the loads involved. It consists of a base structure on which the sliding guides of the lower clamps (5) and the fixing plates of the hydraulic lifting cylinders (6) are mounted. The hydraulic circuits coming from the control unit and the main distribution system that feeds the lifting actuators and the lower clamps are connected to the base. The lower clamps slide along guides and rest on high-strength steel pads (5).
Lifting system: The overall load of the pipeline to be lowered into the well must be able to be fully supported by the lowering apparatus. The hoisting system performs this task during the lowering of the pipeline into the well. The hydraulic cylinders of the system, which can be controlled by means of manifolds with integrated proportional valves or similar methods, are double-acting, i.e. in addition to lifting they provide the possibility of pushing the pipes downwards. This solution is particularly advantageous when possible friction with the walls of the well could prevent the correct descent of the pipe (this happens especially in the case of inclined wells in the early stages of assembly).
Mobile carriage: fixed to the top of the cylinders is the mobile structure that carries the upper clamps (4) and the welding and control platform (7), equipped to house the operators and the mechanical devices for coupling the pipes (10). The upper clamps are hinged to the piston joints and in turn slide on two horizontal cylindrical guides with a synchronized opening/closing system. Said upper clamps are equipped with shaping (8) in order to correctly engage on the rings arranged in prominence on the tubes (9) necessary both for the support and for the eventual downward thrust. The risers are designed from time to time depending on the diameter, maximum weight of the tubes as well as the possible presence of several small diameter tubes to be lowered simultaneously.
Command and control system: the assembly and lowering apparatus as a whole is controlled by a hydraulic power unit and control panel with PLC and SCADA. It is possible to set and control in real time all the operating parameters which in turn are displayed in numerical and graphical form on an operator panel and are recorded in memory for any subsequent analysis.
The opening and closing of the clamps and the movement of the mobile carriage are controlled both electrically and by means of a hydraulic circuit with intrinsically safe interlocking systems. The movement of the hydraulic pistons is controlled by means of position transducers for correct alignment during the ascent and descent stroke and by a series of pressure switches for continuous load monitoring.
The assembly and descent sequence of the tubing includes the following steps:

(a) a portion of the first tubing unit (20) is lowered into the well (22), while the remaining portion is held outside the well hooked by the lower clamp (23). The upper clamp (24) is held open, see figure 4/S1
(b) a second tubing unit (25) is hooked by the upper clamp (24) in the up position and held in place for mechanical assembly with the first tubing unit, see figure 4/S2. In this configuration the mechanical assembly between the tubing submerged in the well and the new pipeline unit is realized, thus creating a continuous section of the casing pipe (26), see figure 4/S3
c) the lower clamp (23) is opened, see figure 4/S4, and the upper clamp (24) is lowered from the high to the low position, resulting in the descent of the tubing (26) into the well. A portion of the second tubing unit is retained outside the well, see Figure 4/S5. The lower vise is closed to engage said second part of the second tubing unit, the upper vise is opened and brought to the high position, see figure 4/S6
d) further tubing units can be assembled and lowered according to the above sequence

In the preferred mode of construction, the pipeline to be placed in the well is composed of individual tubing units prepared with externally welded steel rings and/or shaped plates of such geometry as to ensure firm engagement with said clamps.
In said preferred embodiment said rings and/or plates may be used as gripping elements of the tubing unit and said steps "b." and "c." may be modified as follows:

b'. a second tubing unit is engaged by the upper clamp at a restraining ring and held in position for mechanical assembly with the first tubing unit
c'. the lower clamp is opened and the upper clamp is lowered by a distance corresponding to the distance between the clamping ring to which it is hooked and the next clamping ring, causing the tubing unit to descend into the well by a length corresponding to the distance between the two clamping rings. The lower clamp is closed on the tie-down ring, and the upper clamp is raised to the next tie-down ring. The operation is repeated until the last tie-down ring is reached.

Claims

A method of assembling well casing piping or tubing, from individual units of tubing (20, 25), by means of lifting, gripping, and mechanical handling means that allow operation outside in proximity of said well by comprising the following consecutive steps:
a) descent inside said well (22) of a part of the first tubing unit (20), the remaining part of said first tubing unit remaining outside said well being supported by said lifting, gripping and mechanical handling means (4/S1);

b) assembly of an additional unit of tubing (4/S2) and verification of assembly quality (4/S3), said assembly operations and verification of assembly quality being performed outside said well;

c) descent inside said well of part of said further tubing unit (4/S4, 4/S5, 4/S6);

d) repetition of phases b) - c) up to the last tubing unit;

e) descent of the remaining part of said last tubing unit inside said well,
wherein
- said assembly operations of step b) comprise welding of consecutive pipes (12,13);

- step a) is preceded by a step of preparing individual tubing units (20, 25) in which mechanical couplings are applied to said tubing units (20, 25) in order to prepare them for descent operations, for example steel rings or plates characterised in that:
- said steps b) and c) are realized by means of a sequence (4/S1, 4/S2, 4/S3, 4/S4, 4/S5, 4/S6) of opening and closing of a system of clamps (2,4,23,24) in which are distinguished: a lower clamp (2,23) that closes on the pipe (12,13) to support a part of it outside the well during phase b) and an upper clamp (4,24) that closes on the pipe accompanying its descent into the well during phase c).
The method according to claim 1, wherein said consecutive assembly steps are performed for the simultaneous assembly of a plurality of pipes (12, 13).
Pipeline or well casing assembly apparatus comprising a gripping (clutching) system of individual piping units, a handling system, an assembly station of individual piping units and quality control of said assembly, a command and 1 control system of the clutching and handling sequence, a mechanical support base of said gripping and handling systems,
characterized in that:
- said gripping system is substantially a system of clamps, namely upper clamps (4, 24) and lower clamps (2, 23), which may be operated to engage individual tubing units and which can slide along the axis of the well, vertical or inclined, anchored to said basement (1), said clamps (2,4,23,24) being able to be opened or closed independently of each other;

- said movement system includes a system of actuators (3,11), for example hydraulic pistons, for the movement of said upper clamps (4,24) along the axis of the well, said upper clamps (4) being hinged to the joints of said hydraulic pistons, and for the horizontal sliding of both said upper clamps (4) and said lower clamps (2,23), i.e. for their opening/closing;

- said assembly station (7) of the single pipe units (12) and quality control of said assembly is integral with said upper clamps (4) and equipped to house the operators and the mechanical devices (10) for the coupling of the pipes;

- said basement (1) comprises the base structure on which said lower clamps (2) rest, on which are mounted the horizontal sliding guides (5) of said lower clamps (2,23) and the fixing plates (6) of said actuators (3) for the movement of said upper clamps (4,24) along the shaft axis;

- said command and control system for the sequence of gripping and handling being an electronic control unit implementing the opening/closing steps of said clamps (2,4,23,24) and the actuation of said actuator system (3, 11) according to said consecutive steps of said method of assembling pipelines or tubing of well casings according to any of the previous claims.
Assembly apparatus according to claim 3, wherein said clamps (2,4,23,24) are shaped so as to engage securely on rings, plates or other inserts (9) applied to individual tubing units.
Assembly apparatus according to claims 3 or 4, wherein said clamp system comprises only two clamps, a lower clamp (2) integral with said base (1) and an upper clamp (4) which can slide along the axis of the well, said clamps (2,4) supporting the tubing and the new individual tubing units during the assembly phase and accompanying the tubing during the descent phase in the well.
Assembly apparatus according to claims 3, 4 or 5, wherein said assembly station (7) of the individual tubing units and quality control of said assembly is integral with the upper clamp (4) so as to be vertically movable facilitating the operations of assembling the tubing and controlling said assembly.
Assembly apparatus according to claims 3, 4, 5 or 6, in which said assembly station (7) of the individual tubing units can align with the axis of the wellbore even when said axis undergoes deviations along its development.