Pressure-equalized wireline apparatus

Abstract

A wireline apparatus is for moving a tool into or out of a well. The apparatus is configured for forming a pressure vessel in combination with at least a portion of the well. The apparatus has: a first compartment for forming part of the pressure vessel; a hoisting means, the hoisting means being placed inside the first compartment; a wireline connected to the hoisting means; a second compartment arranged inside the first compartment; an electrical motor for driving the hoisting means, the electrical motor placed inside the second compartment; and a drive shaft for connecting the motor to the hoisting means, the drive shaft extending from the motor to the hoisting means through a wall separating the first compartment and second compartment. A method is for moving the tool in the well.

Claims

1. A wireline apparatus for moving a tool into or out of a well, the wireline apparatus being configured for forming a pressure vessel in combination with at least a portion of the well, the wireline apparatus comprising: a first compartment for forming part of the pressure vessel; a hoisting means, the hoisting means being placed inside the first compartment; a wireline connected to the hoisting means; a second compartment arranged inside the first compartment; an electrical motor for driving the hoisting means, the electrical motor placed inside the second compartment; a drive shaft for connecting the electrical motor to the hoisting means, the drive shaft extending from the electrical motor to the hoisting means through a wall separating the first compartment and second compartment, wherein the electrical motor is configured to be operable in a high-pressure atmosphere found inside a wellbore pressure vessel, and/or configured to be operable while submerged in liquid, and/or wherein the electrical motor is certified for use in a potentially explosive area zone, and wherein the wireline apparatus further comprises means for purging air/oxygen from the first compartment and/or the second compartment, so as to remove at least one prerequisite for explosion.

2. The wireline apparatus according to claim 1, further comprising other electrical equipment than the electrical motor inside the first compartment and/or the second compartment, the other electrical equipment including one or more sensors, an actuator, a driver, a servos, and/or a stepper motor.

3. The wireline apparatus according to claim 1, further comprising means for pressure testing the wireline apparatus.

4. The wireline apparatus according to claim 1, wherein the second compartment comprises a breather for facilitating pressure equilibrium between the second compartment and its ambient environment in the first compartment.

5. A method of moving a tool in a well, the method comprising the steps of: providing an apparatus comprising a first compartment comprising a wireline and a hoisting means, and a second compartment comprising a motor, the second compartment being arranged inside the first compartment, and the motor and the wireline being connected to the hoisting means; connecting the apparatus to the well; connecting the tool to the hoisting means by use of the wireline; opening one or more valves to fluidly connect the apparatus to the well, so that the apparatus and at least a portion of the well in combination forms a pressure vessel; and moving the tool by feeding out or pulling in wireline with the hoisting means, wherein the motor is configured to be operable in a high-pressure atmosphere found inside a wellbore pressure vessel, and/or configured to be operable while submerged in liquid, and/or wherein the motor is certified for use in a potentially explosive area zone; and purging air/oxygen from the first compartment and/or the second compartment of the apparatus so as to remove at least one prerequisite for explosion.

6. The method according to claim 5, further comprising pressure testing the apparatus prior to fluidly connecting the apparatus to the well.

7. The method according to claim 5, further comprising providing measurements relating to a feed-out from the hoisting means, wherein the measurements may include measurements of tension derived from current draw from the motor and/or a torque, and/or back-emf measurements, and/or measurements derived from instrumented mechanical screws, pulleys, and/or sheaves, and/or by use of feedback devices including a resolver or an encoder sensor, or via Hall-effect.

Description

EMBODIMENTS OF THE INVENTION

(1) In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

(2) FIG. 1 illustrates an embodiment of the apparatus being mechanically connected to a well;

(3) FIG. 2A illustrates a first alternative for transferring power through the wall of a vessel or compartment;

(4) FIG. 2B illustrates a second alternative for transferring power through the wall of a vessel or compartment;

(5) FIG. 3 illustrates an embodiment of the apparatus being fluidly connected to a well;

(6) FIG. 4 illustrates an alternative embodiment of the apparatus;

(7) FIG. 5 illustrates an alternative embodiment of the apparatus, wherein the apparatus comprises a means for purging oxygen from the first compartment.

(8) Note that the illustrations are schematic and not necessarily drawn to scale.

(9) FIG. 1 illustrates the wireline apparatus 1 for moving a tool in to or out of a pressurised well 2 according to the first aspect of the invention. In the embodiment shown, the wireline apparatus 1 has a first compartment 19 comprising a work-string spool 191, a quick connector 192 and an isolation-valve spool 193, the first compartment 19 being configured for forming a pressure vessel in combination with a petroleum well 2. The isolation-valve spool 193 comprises an isolation valve 194 which in FIG. 1 is in a closed position. The wireline apparatus 1, in FIG. 1, is mechanically connected to a well 2, but not fluidly connected to the well 2 as the isolation valve 194 is closed.

(10) FIG. 1 further shows the wireline apparatus 1 having a hoisting means 18, in the form of a winch 18, with a wireline 181 connected to the winch 18 and a tool 183 hanging from the wireline 181. In the illustrated situation, with the isolation valve 194 closed, the tool 183 is positioned within the work-string spool 191 of the wireline apparatus 1.

(11) The winch 18 is arranged inside the first compartment 19, along with a first instrument 161 for measuring conditions of a fluid, such as a pressure and/or a temperature of the fluid. Furthermore, there is a second compartment 170 in the first compartment 19, the second compartment 170 forming a fluid barrier for separating a fluid outside of the second compartment 170 from a fluid inside the second compartment 170.

(12) Inside the second compartment 170, there is an electrical motor 182 for driving the winch 18 and a second instrument 162 for measuring conditions of a fluid. The second compartment 170 is filled with liquid and purged of oxygen. By removing oxygen from the second compartment, one of the prerequisites for explosion is avoided in the immediate surroundings of the electrical motor 182 (and the second instrument 162).

(13) There are four pressure-vessel pressure penetrators 196, 197, 198, 199 through a wall of the first compartment for allowing electrical connection to the electrical motor 182, the winch 18, the first instrument 161 and the second instrument 162 respectively. The penetrators are pressure-resistant seals, ensuring the integrity of the first compartment 19. The second compartment 170 has two penetrators 178, 179 for allowing electrical connections. The second compartment 170 further has a shaft seal 177 for a shaft 185, the shaft 185 connecting the electrical motor 182 to the winch 18 for driving the winch 18.

(14) FIG. 1 further illustrates that the well 2 can be in a state of production while the wireline apparatus 1 is connected to the well, when the isolation valve 194 is closed, by showing a swab valve 24 and a kill valve 25 of the well 2 being closed and a manual master valve 27, a hydraulic master valve 28 and a production master valve 29 of the well 2 being open.

(15) Although the embodiment shown uses electric conductors passing through penetrators providing electrical connections, an alternative solution is to use inductive couplers for transferring power and/or signals inductively. FIGS. 2A and 2B illustrates the use of a penetrator 201 and an inductive coupler 202 respectively. By using an inductive coupler 202, it is advantageously possible to avoid penetrations through a wall of the pressure vessel or compartment.

(16) Both FIGS. 2A and 2B shows an electrical conductor 203 providing electrical connections. In FIG. 2A the electrical conductor 203 extends through a wall 204 through a penetrator 201, whereas in FIG. 2B a first conductor 203 leads to a first part of an inductive coupler 202, and then a second conductor 203 leads energy from a second part of the inductive coupler. The first part of the inductive coupler 202 and the second part of the inductive coupler 202 cooperates to transfer energy and/or signals through the wall 204.

(17) FIG. 3 shows the same embodiment of the invention as FIG. 1, but this time with the isolation valve 194 of the isolation-valve spool 193 and the swab valve 24 of the well 2 in open states, and thus with the wireline apparatus 1 fluidly connected to the well 2. The production master valve 29 of the well 2 is closed. The tool 183 is shown to have been lowered into the well 2.

(18) FIG. 4 shows an alternative version of the wireline apparatus 1 where the first compartment 19 comprises a portion of the second compartment 170. A skilled person will understand that a multitude of configurations of the wireline apparatus 1 and its compartments are possible within the confines of the invention.

(19) FIG. 5 shows another embodiment wherein the wireline apparatus 1 comprises a means for purging and pressure testing 111 connected to the first compartment 19. The means for purging and pressure testing 111 is connected to a drain through a drain line 114 and a supply of pressurized water through a water line 115. The drain and supply are not shown. The means for purging and pressure testing comprises a motor 182 and a number of valves 113.

(20) The wireline apparatus 1 shown in FIG. 5 further shows the second compartment 170 comprising a breather 175. The second compartment 170 separates a fluid in the first compartment 190 from a fluid inside the second compartment 170, while at the same time equalising pressure between the separated fluids by allowing for a limited fluid expansion and/or contraction of the second compartment 170 through the breather 175. The breather 175 may e.g. be a balanced piston, bladder or any other commonly used item suitable for the purpose.

(21) When the isolation valve 194 is closed, as in FIG. 5, the inside of the first compartment 19 forms a pressure vessel. The pressure vessel in the FIG. 5 comprises a fluid. By use of the means for purging and pressure testing 111, the fluid inside the pressure vessel may be purged of e.g. air and/or other potentially hazardous fluids (with respect to explosions hazard as a result of ignition), to eliminate a risk of explosion.

(22) It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.

(23) The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.