Technical Field

[0001] The present disclosure relates generally to offshore oil and gas production, and, more particularly, towards a system for heating and pumping of multi-phase composite fluids, commonly referred to as well fluid.

Background

[0002] In oil and gas industry, well fluid (generally including oil, gas, and water) is commonly heated before it is sent to a separation process in which oil and/or gas is separated from water. Heating of the well fluid enhances the quality of the separation. To heat the well fluid, heat exchangers are generally used. Such heat exchangers generally have tubes in which the well fluid is circulated so that they can receive heat from a heating fluid being circulated in a shell. However, such heat exchangers are vulnerable to a ‘choking condition’ in which a slurry of the well fluid may adhere and retain to the surfaces of the tubes. Such retention of the slurry impedes the well fluid’s flow and leads to the development of back pressure in the well fluid’s flow, resulting in reduced efficiency of the heat exchangers. For rectifying such choking conditions, service and maintenance may be carried out, but which causes system downtime, loss of production, and incurrence of cost.

[0003] United States Patent Publication 20080000620 describes a heat exchanger that has an exchanging assembly and a cleaning assembly. The exchanging assembly has multiple exchanging tubes. Each exchanging tube has an outer tube and an inner tube inserted into the outer tube. The cleaning assembly is connected to the exchanging assembly and has a front connecting board, a rear connecting board, a moving board, multiple brushing elements and a drive device. The moving board is mounted movably on the exchanging tubes between the connecting boards. The brushing elements are mounted in the moving board and contact with the exchanging tubes. The drive device is mounted with the connecting boards and the moving board to drive the moving board to move along the exchanging tubes. Summary of the Invention

[0004] In one aspect, the disclosure is directed to an apparatus. The apparatus includes a shell defining a chamber. The apparatus further includes at least one inlet valve to facilitate an introduction of a well fluid into the chamber. The apparatus further includes at least one outlet valve to facilitate a release of the well fluid out from the chamber. The apparatus further includes a plurality of tubes arranged within the chamber and configured to receive a heat exchanging fluid. The apparatus further includes a plate defining a plurality of orifices to correspondingly receive the plurality of tubes therethrough. The plate is guided to move along a length of the plurality of tubes in a first stroke direction to develop a negative pressure within the chamber such that the well fluid is received through the at least one inlet valve into the chamber and is brought into contact with one or more of the plurality of tubes, and the plate is guided to move along a length of the plurality of tubes in a second stroke direction to develop a positive pressure within the chamber such that the well fluid is pushed out of contact from one or more of the plurality of tubes and released from the chamber through the at least one outlet valve.

Brief Description of the Drawings

[0005] FIG. 1 is an exemplary layout of an apparatus, in accordance with an embodiment of the present disclosure;

[0006] FIG. 2 is a first side perspective view of the apparatus, in accordance with an embodiment of the present disclosure;

[0007] FIG. 3 depicts a first head cap of the apparatus, in accordance with an embodiment of the present disclosure;

[0008] FIG. 4 depicts a second head cap of the apparatus, in accordance with an embodiment of the present disclosure;

[0009] FIGS. 5 and 6 are cross sectional views of the apparatus about an exemplary plane A- A’, in accordance with an embodiment of the present disclosure; [0010] FIG. 7 depicts a first tube sheet of the apparatus, in accordance with an embodiment of the present disclosure; [0011] FIG. 8 depicts a second tube sheet of the apparatus, in accordance with an embodiment of the present disclosure;

[0012] FIG. 9 depicts a first enclosure of the apparatus, in accordance with an embodiment of the present disclosure;

[0013] FIG. 10 depicts a second enclosure of the apparatus, in accordance with an embodiment of the present disclosure;

[0014] FIG. 11 depicts a plate of the apparatus, in accordance with an embodiment of the present disclosure;

[0015] FIG. 12 depicts a scrapper of the apparatus, in accordance with an embodiment of the present disclosure; and

[0016] FIG. 13 depicts another scrapper of the apparatus, in accordance with an embodiment of the present disclosure.

[0017] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments.

[0018] The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the description with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

Detailed Description

[0019] Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Generally, corresponding reference numbers may be used throughout the drawings to refer to the same or corresponding parts, e.g., 1, F, 1", 101 and 201 could refer to one or more comparable components used in the same and/or different depicted embodiments.

[0020] Referring to FIGS. 1 and 2, the apparatus 100 is shown. The apparatus 100 is associated with offshore oil and gas production and is configured to heat and pump a multi-phase composite fluid (simply referred to as ‘fluid’, hereinafter) received from an oil well. The fluid is in oil-water emulsion form which may require to be heated and treated (e.g., with chemicals) so that the fluid can be separated into at least oil and water - the expression ‘at least’ indicates that the fluid can include components other than oil and water. The apparatus 100 provides preheating to the well fluid for facilitating said separation of the fluid into oil and water. A separation of the fluid may be carried out in a separator (not shown) once the fluid is preheated in the apparatus lOOand pumped by the apparatus into the separator. The apparatus 100 includes an inlet pipe 90 and an outlet pipe 95. The apparatus 100 receives the well fluid through the inlet pipe 90 and a heated well fluid exits the apparatus 100 through the outlet pipe 95.

[0021] The apparatus 100 may include a shell 102 defining a chamber 104. The shell 102 and/or the chamber 104 can include a cylindrical configuration, although other shapes or profiles, such as a cuboidal shape or profile, of the shell 102 and/or the chamber 104 can be contemplated. The apparatus 100 further includes a first head cap 106 and a second head cap 108. The first head cap 106 and the second head cap 108 are secured to the shell 102 at opposite ends of the shell 102 to enclose the chamber 104, as shown.

[0022] FIG. 3 depicts the first head cap 106, and FIG.4 depicts the second head cap 108. The first head cap 106 and the second head cap 108 includes a hollow cylindrical structure for confirming with the cylindrical configuration of the chamber 104. Alternatively, the first head cap 106 and the second head cap 108 may have a structure to confirm with the configuration of the chamber 104.

[0023] Referring to FIGS. 5-6, a cross sectional view, about a plane A- A' (see FIG. 2), of the apparatus 100 of FIG. 2 is shown. The apparatus 100 includes a plurality of tubes 110 arranged within the chamber 104. In an embodiment, the shell 102 is configured to receive the well fluid through the inlet pipe 90, and the plurality of tubes 110 are configured to receive a heat exchanging fluid through a heat exchanging fluid inlet line 112. The heat exchanging fluid is generally at a higher temperature than the well fluid. In operation, the well fluid as received within the shell 102 flows across an exterior of the plurality of tubes 110, and thereby gathers heat from the heat exchanging fluid flowing through the tubes 110 . Thereafter, the heat exchanging fluid exits the plurality of tubes 110 through a heat exchanging fluid outlet line 114.

[0024] Referring to FIGS. 1-6, the apparatus 100 includes inlet valves and outlet valves for respectively facilitating introduction and release of the well fluid from the chamber 104. The inlet valves include a first inlet valve 116 and a second inlet valve 118. The outlet valves include a first outlet valve 120 and a second outlet valve 122. In an embodiment, the inlet valves and outlet valves are non-returning valves. In an embodiment, the first inlet valve 116 and the second outlet valve 122 are provided on the first head cap 106. Further, the second inlet valve 118 and the first outlet valve 120 are provided on the second head cap 108.

[0025] In an embodiment, the apparatus 100 further includes a first tube sheet 124 secured with the first head cap 106, and a second tube sheet 126 secured with the second head cap 108. The first tube sheet 124 and the second tube sheet 126 can be in the form of circular discs situated at the opposite ends of the shell 102 and having the tubes 110 coupled therebetween. The first tube sheet 124 defines first well fluid passage holes 124', and the second tube sheet 126 defines second well fluid passage holes 126'. The first tube sheet 124 further defines first tube passage holes 124" into which ends of the tubes 110 may be received, and the second tube sheet 126 further defines second tube passage holes 126" into which opposite ends of the tubes 110 may be received. In some embodiments, the apparatus 100 includes a first enclosure 123 received (e.g., at least partly) within the first head cap 106 and secured to the first tube sheet 124, the first enclosure 123 being configured to fluidly separate the first well fluid passage holes 124' and the first tube passage holes 124". The apparatus 100 further includes a second enclosure 125 (e.g., at least partly) received within the second head cap 108 and secured to the second tube sheet 126, the second enclosure 125 being configured to fluidly separate the second well fluid passage holes 126' and the second tube passage holes 126". The first tube passage holes 124" and the second tube passage holes 126" are configured to receive the tubes 110 such that the tubes 110 can open into and/or be fluidly and respectively coupled to an inner space defined by the first enclosure 123 and a second inner space defined by the second enclosure 125.

[0026] FIG. 9 depicts the first enclosure 123 and FIG. 10 depicts the second enclosure 125. The heat exchanging fluid inlet line 112 and the heat exchanging fluid outlet line 114 are provided with the first enclosure 123. The first enclosure 123 includes a partition 127 that divides the first enclosure 123 in two (e.g., equal) parts i.e., a lower part 123-1 and an upper part 123-2.

[0027] The apparatus 100 includes a plate 128 (see FIG. 5 and 11) received within the chamber 104. The plate 128 defines multiple orifices 130. In an embodiment, the orifices 130 are corresponding to the tubes 110, and each orifice 130 of the plurality of orifices 130 is configured to receive a tube 110 therethrough. The plate 128 is movable or slidable along the length of the tubes 110 between the first tube sheet 124 and the second tube sheet 126. Referring to FIGS. 7-11, the first tube passage holes 124", the second tube passage holes 126", and the plurality of orifices 130 are each arranged according to a common triangular pitch ‘TP’ that helps the first tube passage holes 124", the second tube passage holes 126", and the orifices 130, to align with each other when the apparatus 100 is assembled. An alignment of the first tube passage holes 124", the second tube passage holes 126", and the orifices 130, helps the tubes 110 attain an orientation that is defined along an axis S-S' of the shell 102.

[0028] In an embodiment, referring to FIGS. 1-6, the apparatus 100 includes a driving mechanism 132. The driving mechanism 132 is operatively coupled to the plate 128 to move or slide the plate 128 along the plurality of tubes 110. In an example, the driving mechanism 132 is a hydraulic or pneumatic or electrical device having a shaft 134. The shaft 134 is configured to pass through a central hole 124"' of the first tube sheet 124 and is coupled to the plate 128. In an embodiment, the driving mechanism 132 operates the shaft 134 to provide a reciprocating motion to the plate 128 along the the plurality of tubes 110. In other embodiments, the driving mechanism 132 can include any mechanism that facilitates a regular or a predefined back and forth movement of the plate 128. Industrial Applicability

[0029] In operation, the heat exchanging fluid enters the apparatus 100 through the heat exchanging fluid inlet line 112 and enters the lower part 123-1 of the first enclosure 123. Thereafter, the heat exchanging fluid enters the tubes 110 and travel across the length of the tubes 110 and enters the second enclosure 125. Further, the heat exchanging fluid enters the tubes 110 to reach the upper part 123-2 of the first enclosure 123. Thereafter, the heat exchanging fluid exits the apparatus 100 through the heat exchanging fluid outlet line 114. In an embodiment, the driving mechanism 132 is configured to impart a forward motion to the plate 128 in a first stroke direction “F”. In an embodiment, as the plate 128 is guided to move along a length of the plurality of tubes 110 in the first stroke direction “F”, a negative pressure is developed in the chamber 104. Due to this negative pressure the first inlet valve 116 and the first outlet valve 120 become operational for fluid passage, while the second inlet valve 118 and the second outlet valve 122 remain non-operational. As a result, well fluid is received within the chamber 104 through the first inlet valve 116 via the inlet pipe 90 and brought into contact with one or more of the plurality of tubes 110. Subsequently heat is exchanged between the well fluid flowing through the chamber 104 and the heat exchanging fluid flowing through the plurality of tubes 110. Further, the heated well fluid is released from the chamber 104 through the first outlet valve 120 and is provided to a separator through the outlet pipe 95.

[0030] Further in an embodiment, the driving mechanism 132 is configured to impart a reverse motion to the plate 128 in a second stroke direction “R” opposite to the first stroke direction “F”. In an embodiment, as the plate 128 is guided to move along a length of the plurality of tubes 110 in the second stroke direction “R”, a positive pressure is developed in the chamber 104. Due to this positive pressure the second inlet valve 118 and the second outlet valve 122 become operational for fluid passage, while the first inlet valve 116 and the first outlet valve 120 remain non-operational. As a result, well fluid is received within the chamber 104 through the second inlet valve 118 via the inlet pipe 90 and brought into contact with one or more of the plurality of tubes 110. Subsequently heat is exchanged between the well fluid flowing through the chamber 104 and the heat exchanging fluid flowing through the plurality of tubes 110. Further, the heated well fluid is released from the chamber 104 through the second outlet valve 122 and is provided to the separator through the outlet pipe 95.

[0031] During the process of heating the well fluid as described above, a slurry or dirt of the well fluid may adhere and retain to the outside surfaces of the tubes 110. In an embodiment, the apparatus 100 further includes a plurality of scrappers 136 for removing the slurry or dirt present on the outside surfaces of the tubes 110. FIG. 12 depicts a scrapper 136. In an embodiment, the scrapper 136 is configured to be fastened to the orifice 130. In an embodiment, the scrapper 136 includes an engagement portion 138 fastened to the orifice 130, and a scrapping portion 140, extending from the engagement portion 138, coaxially circumscribing the corresponding tube 110. In operation, as the plate 128 is moved or slide along the tubes 110 during the forward motion or the reverse motion, the scrapping portion 140 is configured to clear dirt deposited over the corresponding tube 110 when the plate 128 is guided to move along a length of the corresponding tube 110. In an example, the scrapping portion 140 includes a spring 142. In another example as shown in Fig. 13, the scrapping portion 140 includes a tubular structure 144 defining a slot 146, wherein the slot 146 is configured to receive the well fluid based upon pumping of the well fluid due to the movement of the plate 128.

[0032] In an embodiment, the slurry or dirt removed by the scrappers 136 gets settled at the bottom of the shell 102. The apparatus 100 includes a drain pipe 142 and a drain valve 144 provided at the bottom of the shell 102 for effectively draining or removing the slurry or dirt settled at the bottom of the shell 102.

[0033] The apparatus 100 may include an operator platform. In some exemplary embodiments, the operator platform may be in the form of an open-air platform that may or may not include a canopy. In other exemplary embodiments, the operator platform may be in the form of a partially or fully enclosed cabin. The operator platform may include one or more controls, which may be used by an operator to operate and/or control the apparatus 100. The controls may include one or more input devices, which may take the form of buttons, switches, sliders, levers, wheels, touch screens, or other input/output or interface devices. The apparatus 100 may include a display located in the operator platform. The display may be configured to display information, data, and/or measurements obtained from one or more sensors of the apparatus 100. The display may also be configured to display diagnostic results, errors, and/or alerts. The display may be a cathode ray tube (CRT) monitor, a liquid crystal display (LCD), a light emitting diode (LED) display, a touchscreen display, or any other kind of display.

[0034] The apparatus 100 may also include a controller, which may be configured to receive inputs, data, and/or signals from the one or more input devices, and or other sensors associated with the apparatus 100 and to control the operation of one or more components (e.g., valves, driving mechanism, etc.) The controller may include or be associated with one or more processors, memory devices, and/or communication devices. The controller may embody a single microprocessor or multiple microprocessors, digital signal processors (DSPs), application- specific integrated circuit devices (ASICs), etc. Numerous commercially available microprocessors may be configured to perform the functions of the controller. Various other known circuits may be associated with the controller, including power supply circuits, signal-conditioning circuits, and communication circuits, etc. The controller may also include one or more internal timers configured to monitor a time at which the controller may receive signals from one or more sensors or a time at which the controller may issue command signals to one or more components of the apparatus 100.

[0035] The one or more memory devices associated with the controller may store, for example, data and/or one or more control routines or instructions. The one or more memory devices may embody non-transitory computer-readable media, for example, Random Access Memory (RAM) devices, NOR or NAND flash memory devices, and Read Only Memory (ROM) devices, CD-ROMs, hard disks, floppy drives, optical media, solid state storage media, etc. The controller may receive one or more input signals from the one or more input devices, and may execute the routines or instructions stored in the one or more memory devices to generate and deliver one or more command signals to one or more components of the apparatus 100. [0036] The apparatus 100 solves the problem of choking of the tubes 110 as the well fluid flows over the external surface of the tubes 110, and the outer surface of the tubes is continuously cleaned by the scrappers 136 driven through the driving mechanism 132. Further, the apparatus 100 solves the problem of back pressure on the wells as the pumping action provided by the driving mechanism 132 reduces well fluid suction pressure and increases well fluid discharge pressure towards the separator.

[0037] Further, the apparatus 100 is thermally efficient as the tubes 110 carrying the heat exchanging fluid are not exposed to the atmosphere and heat loss is minimized. Further, the outer surface of tubes 110 is cleaned continuously which increases rate of heat transfer. Moreover, continuous movement of the plate 128 inside the chamber 104 creates well fluid turbulence inside shell 102 which increases heat transfer rate. Accordingly, the apparatus 100 provides a cost- effective solution to the problems associated with conventional technologies due to low maintenance and downtime.

[0038] It will be apparent to those skilled in the art that various modifications and variations can be made to the method and/or system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method and/or system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.