CA2433741C - Desanding apparatus and system - Google Patents
Desanding apparatus and system Download PDFInfo
- Publication number
- CA2433741C CA2433741C CA002433741A CA2433741A CA2433741C CA 2433741 C CA2433741 C CA 2433741C CA 002433741 A CA002433741 A CA 002433741A CA 2433741 A CA2433741 A CA 2433741A CA 2433741 C CA2433741 C CA 2433741C
- Authority
- CA
- Canada
- Prior art keywords
- vessel
- fluid
- inlet
- particulates
- desanding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/34—Arrangements for separating materials produced by the well
- E21B43/35—Arrangements for separating materials produced by the well specially adapted for separating solids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/0039—Settling tanks provided with contact surfaces, e.g. baffles, particles
- B01D21/0042—Baffles or guide plates
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Gas Separation By Absorption (AREA)
Abstract
A desanding vessel is inserted in a high velocity fluid stream containing entrained particulates. The vessel comprises an upper freeboard portion having a large cross-sectional wherein the fluid stream velocity drops and particulates fall from suspension. Preferably the fluid stream is introduced offset upwardly from an axis of a horizontally oriented cylindrical vessel, released particulates falling to accumulate in a lower belly portion. The freeboard portion is maintained using a depending flow barrier adjacent the vessel's outlet which sets the depth of accumulation in the belly portion. A cleanout enables periodic removal of accumulations.
Description
1 "DESANDING APPARATUS AND SYSTEM"
2
3 FIELD OF THE INVENTION
4 The present invention relates to a system and apparatus for the removal of particulates such as sand from fluid streams produced from a well 6 while minimizing abrasion of the involved equipment.
9 Production from wells in the oil and gas industry often contain particulates such as sand. These particulates could be part of the formation from 11 which the hydrocarbon is being produced, introduced particulates from hydraulic 12 fracturing or fluid loss material from drilling mud or fracturing fluids or from a 13 phase change of produced hydrocarbons caused by changing conditions at the 14 wellbore (Asphalt or wax formation). As the particulates are produced, problems occur due to abrasion, and plugging of production equipment. In a typical startup 16 after stimulating a well by fracturing, the stimulated well may produce sand until 17 the well has stabilized, often up to a month after production commences.
Other 18 wells may require extended use of the desander 10.
19 In the case of gas wails, fluid velocities can be high enough that the erosion of the production equipment is severe enough to cause catastrophic 21 failure. High fluid stream velocities are typical and are even purposefully 22 designed for elutriating particles up the well and to the surface. An erosive failure 23 of this nature can become a serious safety and environmental issue for the well 24 operator. A failure such as a breach of high pressure piping or equipment releases uncontrolled high velocity flow of fluid which is hazardous to service 1 personnel. Release to the environment is damaging to the environment resulting 2 in expensive cleanup and loss ofi production. Repair costs are also high.
3 In all cases, retention of particulates contaminates both surface 4 equipment and the produced fluids and impairs the normal operation of the oil and gas gathering systems and process facilities.
6 In one prior art system, a pressurized tank ("P-Tank") is placed on 7 the wellsite and the well is allowed to produce fluid and particulates. The fluid 8 stream is produced from a wellhead and into a P-Tank until sand production 9 ceases. The large size of the P-Tank usually restricts the maximum operating pressure of the vessel to something in the order of 1,000 - 2,100 kPa. In the 11 case of a gas well, this requires some pressure control to be placed on the well to 12 protect the P-Tank. Further, for a gas well, a pressure reduction usually is 13 associated with an increase in gas vePocity which in turn makes sand-laden 14 wellhead effluent much more abrasive. Another problem associated with this type of desanding technique is that it is only a temporary solution. If the well 16 continues to make sand, the solution becomes prohibitively expensive. In most 17 situations with this Idnd of temporary solution, the gas vapors are not conserved 18 and sold as a commercial product.
19 An alternate known prior art system includes employing filters to remove particulates. A common design is to have a number of fiber-mesh filter 21 bags placed inside a pressure vessel. The density of the filter bag fiber-mesh is 22 matched to the anticipated size of the particulates. Filter bags are generally not 23 effective in the removal of particulates in a multiphase conditions.
Usually 24 multiphase flow in the oil and gas operations is unstable. Large slugs of fluid followed by a gas mist is common. In these cases, the fiber bags become a 1 cause a pressure drop and often fail due to the liquid flow therethrough.
Due to 2 the high chance of failure, filter bags may not be trusted to remove particulates in 3 critical applications or where the flow parameters of a well are unknown. An 4 additional problem with filter bags in most jurisdictions is the cost associated with disposal. The fiber-mesh filter bags are considered to be contaminated with 6 hydrocarbons and must be disposed of in accordance to local environmental 7 regulation.
8 Clearly there is a need for more versatile and cost effective system 9 of particulate handling.
11 SUMMARY ~F THE INVENTS~N
12 Desanding apparatus is provided which is placed adjacent to a 13 well's wellhead for intercepting a fluid stream flow before prior to entry to 14 equipment including piping, separators, valves, chokes and downstream equipment. The fluid stream can contain a variety of phases including liquid, gas 16 and solids.
17 In one embodiment, a pressure vessel is inserted in the flowsteam 18 by insertion into high velocity field piping extending from the wellhead.
The 19 vessel contains an upper freeboard portion having a cross-sectional area which is greater that of the field piping from whence the fluid stream emanates. As a 21 result, fluid stream velocity drops and particulates cannot be maintained in 22 suspension. A cross-sectional area of the freeboard portion is maintained 23 through a downcomer flow barrier adjacent the vessel's exit.
24 In a broad aspect, desanding apparatus vessel for removal of particulates from a fluid stream containing particulates comprises: a fluid inlet 1 adjacent a first end of the vessel and adapted for receiving the fluid stream, the 2 fluid inlet discharging the fluid stream at an inlet velocity into a freeboard portion 3 at a top of the vessel, the fluid stream in the freeboard portion having an 4 elutriation velocity less than the inlet velocity and such that contained particulates have a fall trajectory; a fluid outlet from the vessel, the outlet being spaced 6 horizontally from the inlet; and a flow barrier depending from the top of the vessel 7 and having a lower edge so as to direct the fluid stream below the barrier before 8 discharge from the outlet port for maintaining the freeboard portion above the 9 lower edge and forming a belly storage portion below the lower edge, the flow barrier being positioned between the fluid inlet and fluid outlet and the flow barrier 11 being spaced from the fluid inlet so as to enable the fall trajectory of a substantial 12 amount of the particulates to intersect the belly portion so as accumulate 13 particulates in the belly portion prior to the flow barrier wherein the fluid stream at 14 the fluid outlet is substantially free of particulates.
Preferably, the flow barrier is a depending weir independent of the 16 outlet, or could be formed by the outlet itself. A cleanout port is preferably 17 included for periodic removal of accumulations of particulates.
18 More preferably, a vessel of an embodiment of the present 19 invention is incorporated in a desanding system to replace existing prior connective piping, the vessel being supported using structure to align the vessel 21 with the wellhead piping and downstream equipment.
2 Figure 1a is a schematic arrangement of connective wellsite piping 3 of the prior art;
4 Figure 1 b is a schematic arrangement of one embodiment of the invention having been installed in place of the prior connective wellsite piping of 6 Fig. 1 a;
7 Figure 2a is an exploded view of the inlet to one embodiment of the 8 vessel of the invention which illustrates a nozzle arrangement in an eccentric 9 vessel inlet;
Figure 2b is an exploded view of the inlet to one embodiment of the 11 vessel of the invention which illustrates a nozzle arrangement adapted to a blind 12 flange;
13 Figure 3 is a cross-sectional side view of one embodiment of the 14 invention illustrating fluid streams, falling trajectory of particulates, and accumulations of separated liquid, particulates and particulate-free fluid 16 discharge;
17 Figures 4a through 4c illustrate a variety of optional flow barriers 18 applied at the fluid outlet; and 19 Figure 5 is a performance graph of the achievable gas throughout rates at various pressures while still achieving particulate removal for a 21 pessimistic case of a fluid stream containing fine 100 mesh sand.
9 Production from wells in the oil and gas industry often contain particulates such as sand. These particulates could be part of the formation from 11 which the hydrocarbon is being produced, introduced particulates from hydraulic 12 fracturing or fluid loss material from drilling mud or fracturing fluids or from a 13 phase change of produced hydrocarbons caused by changing conditions at the 14 wellbore (Asphalt or wax formation). As the particulates are produced, problems occur due to abrasion, and plugging of production equipment. In a typical startup 16 after stimulating a well by fracturing, the stimulated well may produce sand until 17 the well has stabilized, often up to a month after production commences.
Other 18 wells may require extended use of the desander 10.
19 In the case of gas wails, fluid velocities can be high enough that the erosion of the production equipment is severe enough to cause catastrophic 21 failure. High fluid stream velocities are typical and are even purposefully 22 designed for elutriating particles up the well and to the surface. An erosive failure 23 of this nature can become a serious safety and environmental issue for the well 24 operator. A failure such as a breach of high pressure piping or equipment releases uncontrolled high velocity flow of fluid which is hazardous to service 1 personnel. Release to the environment is damaging to the environment resulting 2 in expensive cleanup and loss ofi production. Repair costs are also high.
3 In all cases, retention of particulates contaminates both surface 4 equipment and the produced fluids and impairs the normal operation of the oil and gas gathering systems and process facilities.
6 In one prior art system, a pressurized tank ("P-Tank") is placed on 7 the wellsite and the well is allowed to produce fluid and particulates. The fluid 8 stream is produced from a wellhead and into a P-Tank until sand production 9 ceases. The large size of the P-Tank usually restricts the maximum operating pressure of the vessel to something in the order of 1,000 - 2,100 kPa. In the 11 case of a gas well, this requires some pressure control to be placed on the well to 12 protect the P-Tank. Further, for a gas well, a pressure reduction usually is 13 associated with an increase in gas vePocity which in turn makes sand-laden 14 wellhead effluent much more abrasive. Another problem associated with this type of desanding technique is that it is only a temporary solution. If the well 16 continues to make sand, the solution becomes prohibitively expensive. In most 17 situations with this Idnd of temporary solution, the gas vapors are not conserved 18 and sold as a commercial product.
19 An alternate known prior art system includes employing filters to remove particulates. A common design is to have a number of fiber-mesh filter 21 bags placed inside a pressure vessel. The density of the filter bag fiber-mesh is 22 matched to the anticipated size of the particulates. Filter bags are generally not 23 effective in the removal of particulates in a multiphase conditions.
Usually 24 multiphase flow in the oil and gas operations is unstable. Large slugs of fluid followed by a gas mist is common. In these cases, the fiber bags become a 1 cause a pressure drop and often fail due to the liquid flow therethrough.
Due to 2 the high chance of failure, filter bags may not be trusted to remove particulates in 3 critical applications or where the flow parameters of a well are unknown. An 4 additional problem with filter bags in most jurisdictions is the cost associated with disposal. The fiber-mesh filter bags are considered to be contaminated with 6 hydrocarbons and must be disposed of in accordance to local environmental 7 regulation.
8 Clearly there is a need for more versatile and cost effective system 9 of particulate handling.
11 SUMMARY ~F THE INVENTS~N
12 Desanding apparatus is provided which is placed adjacent to a 13 well's wellhead for intercepting a fluid stream flow before prior to entry to 14 equipment including piping, separators, valves, chokes and downstream equipment. The fluid stream can contain a variety of phases including liquid, gas 16 and solids.
17 In one embodiment, a pressure vessel is inserted in the flowsteam 18 by insertion into high velocity field piping extending from the wellhead.
The 19 vessel contains an upper freeboard portion having a cross-sectional area which is greater that of the field piping from whence the fluid stream emanates. As a 21 result, fluid stream velocity drops and particulates cannot be maintained in 22 suspension. A cross-sectional area of the freeboard portion is maintained 23 through a downcomer flow barrier adjacent the vessel's exit.
24 In a broad aspect, desanding apparatus vessel for removal of particulates from a fluid stream containing particulates comprises: a fluid inlet 1 adjacent a first end of the vessel and adapted for receiving the fluid stream, the 2 fluid inlet discharging the fluid stream at an inlet velocity into a freeboard portion 3 at a top of the vessel, the fluid stream in the freeboard portion having an 4 elutriation velocity less than the inlet velocity and such that contained particulates have a fall trajectory; a fluid outlet from the vessel, the outlet being spaced 6 horizontally from the inlet; and a flow barrier depending from the top of the vessel 7 and having a lower edge so as to direct the fluid stream below the barrier before 8 discharge from the outlet port for maintaining the freeboard portion above the 9 lower edge and forming a belly storage portion below the lower edge, the flow barrier being positioned between the fluid inlet and fluid outlet and the flow barrier 11 being spaced from the fluid inlet so as to enable the fall trajectory of a substantial 12 amount of the particulates to intersect the belly portion so as accumulate 13 particulates in the belly portion prior to the flow barrier wherein the fluid stream at 14 the fluid outlet is substantially free of particulates.
Preferably, the flow barrier is a depending weir independent of the 16 outlet, or could be formed by the outlet itself. A cleanout port is preferably 17 included for periodic removal of accumulations of particulates.
18 More preferably, a vessel of an embodiment of the present 19 invention is incorporated in a desanding system to replace existing prior connective piping, the vessel being supported using structure to align the vessel 21 with the wellhead piping and downstream equipment.
2 Figure 1a is a schematic arrangement of connective wellsite piping 3 of the prior art;
4 Figure 1 b is a schematic arrangement of one embodiment of the invention having been installed in place of the prior connective wellsite piping of 6 Fig. 1 a;
7 Figure 2a is an exploded view of the inlet to one embodiment of the 8 vessel of the invention which illustrates a nozzle arrangement in an eccentric 9 vessel inlet;
Figure 2b is an exploded view of the inlet to one embodiment of the 11 vessel of the invention which illustrates a nozzle arrangement adapted to a blind 12 flange;
13 Figure 3 is a cross-sectional side view of one embodiment of the 14 invention illustrating fluid streams, falling trajectory of particulates, and accumulations of separated liquid, particulates and particulate-free fluid 16 discharge;
17 Figures 4a through 4c illustrate a variety of optional flow barriers 18 applied at the fluid outlet; and 19 Figure 5 is a performance graph of the achievable gas throughout rates at various pressures while still achieving particulate removal for a 21 pessimistic case of a fluid stream containing fine 100 mesh sand.
5 2 As shown in Figs. 1 b and 3, a desander 10 comprises a 3 substantially horizontal, cylindrical pressure vessel 11 having a first fluid inlet end 4 12 adapted for connection to a fluid stream F such as from wellhead piping 9 and a fluid outlet 13 connected to downstream equipment 14 such as multiphase
6 separators. The fluid stream F typically comprises a variety of phases including
7 gas G, some liquid L and entrained particulates such as sand S. The fluid stream
8 emanating from the fluid outlet 13 is typically liquid L and gas G, with a
9 substantial portion of the particulates S being captured by the desander 10.
As a system, the desander 10 is typically inserted as a replacement for existing piping 11 15 (shown in Fig. 1a). The desander 10 is preferably supported with structure 16 12 such as elevation adjustable jacks to align the desander 10 relative to the existing 13 wellhead piping 9 and downstream equipment 14.
14 With reference to Figs. 2a and 2b, the inlet 12 is fitted with a first connector or inlet flange 20 so as to better facilitate installation, to allow easy 16 inspection for wear, to minimize equipment erosion and to simplify replacement 17 when erosion has reduced material thicknesses to acceptable minimums. A
18 nozzle 21 and a second connector or a nozzle flange 22 are adapted for 19 complementary and sealed connection to the inlet flange 20. Typically, the nozzle 21 has a threaded inlet 23 which is adapted for threaded connection to an 21 existing coupling 24 from the wellhead piping 9. The nozzle inlet 23 is threaded 22 onto the coupling 24 and the vessel and inlet 12 is positioned over the nozzle 21 23 and the flanges 20,22 are connected.
24 In greater detail as shown in Figs. 2a,2b and 3, the nozzle 21 has a protruding discharge portion 25 which extends adjacent the top of the vessel 11.
1 The inlet 12 is offset upwardly from an axis A of the vessel 11 and extends into 2 an upper freeboard portion 30. Preferably, as shown in Fig. 2a, an eccentric 3 fitting 31 is applied to the inlet 12. When coupled with the inlet flange 20 on the 4 eccentric fitting 31, the nozzle 21 is shifted upwardly from an axis A of the vessel 11. Similarly, as shown in Fig. 2b, the nozzle 21 can extend through a large 6 blind inlet flange 20 fit directly to the vessel 11 positioned so as to be shifted 7 upwardly from an axis A of the vessel 11. The nozzle 21 discharges the fluid 8 stream F along the nozzle's axis, a path P, substantially parallel to the vessel's 9 axis A. The nozzle inlet 23 is typically formed of heavy-wall piping to extend its operational life in the abrasive environment of the particulate laden fluid stream F.
11 Further, the nozzle's discharge 25 protrudes into the vessel 11 sufficiently to 12 extend beyond the inlet 12 and into the freeboard portion 30, thereby aiding in 13 minimizing localized wear on the less easily replaced inlet 12, or eccentric fitting 14 31, of the vessel 11 In Fig. 3, the desander 10 further comprises belly portion 32, 16 formed below the freeboard portion 307 for receiving and temporarily storing 17 liquids L and sand S which separate from the fluid stream F. The fluid stream F
18 containing sand S enters through the inlet 12 and is received by a larger cross 19 sectional area and substantially gas-phase volume of the freeboard portion 30.
Accordingly, the velocity of the fluid stream F slows to a point below the 21 entrainment or elutriation velocity of at least a portion of the particulates S in the 22 fluid stream. Those of skill in the art are able to determine and apply the 23 parameters of the fluid stream F, fluid stream velocity and those of the 24 particulates S so as to determine the elutriation characteristics. As the area of the freeboard portion 30 increases, the velocity of the fluid stream F slows and a 1 lesser fraction of the particulates remain entrained; a greater fraction of 2 particulates S falling out of suspension from the fluid stream F. The parkiculates 3 S are discharged horizontally from the nozzle 21 along path P, and as they fall 4 from suspension, they adopt a downwardly curved trajectory under the influence of gravity. Preferably, to avoid impingement-type erosion, the length of the 6 vessel is sufficient to permit the particulates to fall out of suspension before 7 impinging internals of the vessel 11. Given sufficient horizontal distance without 8 interference, the particulates S eventually fall from the freeboard portion 30 and 9 the trajectory intersects with the belly portion 32. The particulates S
deposit and accumulate over time in the belly portion 32. Typically, liquids L from the fluid 11 stream also collect in the vessel's belly portion 32.
12 The freeboard portion 30 is maintained using means such as a 13 depending flow barrier 40 to ensure that the collected liquids L and particulates S
14 only reach a maximum depth in the belly portion 32 of the vessel 11. A
minimum cross-section area of the freeboard portion and preferred length of the freeboard 16 portion 30 are determinable based on the elutriation characteristics and are 17 established so as to maximize release of the particulates S before they reach the 18 outlet 13. The greater the length or spacing between the inlet 12 and the flow 19 barrier 40, the greater is the opportunity to drop and release entrained particulates S.
21 Typically, liquid L out of the fluid stream F accumulates in the belly 22 portion 32 to a steady state level and then is re-entrained for discharge with fluids 23 exiting the outlet 13 without affecting the capability of the vessel 11 and belly 24 portion 32 to continue to accumulate particulates S. Regardless of dropout of liquids L from gas G and collection of liquid L in the vessel 11, this upper 1 freeboard portion 30 remains substantially gas-filled. However, should a 2 maximum depth of particulates S be reached during operation and encroach on 3 the freeboard portion 30, operations may yet continue as if the vessel 11 were 4 not even installed; both incoming liquid L and particulates S being temporarily re-entrained with the fluid stream flowing from the vessel outlet 13 until the earliest 6 opportunity to perform maintenance. Typically the belly portion 32 vessel 11 is 7 periodically cleaned out or emptied of accumulated particuiates and liquid at 8 sufficient intervals to ensure that the maximum accumulated depth does not 9 encroach on the freeboard portion 30. Maintenance and operations personnel are further able to physically view sand production volumes during the cleanout 11 and inspection.
12 The flow barrier 40 depends downwardly from the top of the vessel 13 11. The flow barrier 40 has a lower edge 41 which sets the maximum depth of 14 the belly portion 32. As discussed above, the flow barrier 40 is preferably spaced sufficiently from the inlet 11 to enable the fall trajectory of the particles to intersect 16 the belly portion 32 before impinging on the flow barrier 40 itself.
17 As shown in Figs. 4a-4c, the flow barrier 40 can comprise a discrete 18 or separate plate 40a,40b as shown in Figs. 4a and 4b, spaced from the outlet 19 13, or as shown in Fig. 4c, a flow barrier 40c can be formed by the outlet 13 itself.
All of the various flow barriers 40,40a,40b,40c have a lower edge 41 which forces 21 the fluid stream S thereunder before discharging from the vessel 11 at outlet 13.
22 Accumulated levels L,S encroaching above the lower edge 41 will result in high 23 velocities and re-entrainment of liquids L and particulates S from the area about 24 the flow barrier 40, inherently resulting in a steady state maximum level of accumulation of the belly portion 32.
1 In the embodiment shown in some detail in Fig. 4c, the outlet 13 itself acts as the 2 flow barrier 40, which incorporates a tubular portion 43 protruding downwardly 3 and depending through the freeboard portion 30. The tubular portion 43 also has 4 a lower edge 41 spaced from the top of the vessel 11 which forces the fluid stream F to exit from a point nearer the vessel axis A. Particulate-free fluid, 6 typically being gas G and some liquid L, is collected about the axis A for 7 discharge through the discharge tubing 40 and outlet 13. An advantage of 8 providing a separate flow barrier 40,40a,40b is that any abrasion and erosion is 9 borne by the barrier 40 and not by the outlet's 13 tubular portion 43.
As shown in Figs 4a,4c, the outlet 13 for the vessel 10 is preferably 11 arranged perpendicular to the axis A of the vessel 10 for further inertial rejection 12 of re-entrained particulates S.
13 Referring once again to Fig. 3, a quick release pressure-vessel 14 compatible cleanout 50 is provided for access to the vessel 11 for cleanout of the accumulated particulates. The vessel must be depressurized before opening and 16 cleaning out particulates. Typically, mechanically-interlocked safety means 17 are provided so that the vessel must be de-pressurized before the cleanout can 18 be opened. For de-pressurization, the vessel is isolated from the fluid stream F
19 and pressure is bled off from the freeboard portion 30 until the cleanout 50 be removed. As shown in Fig. 1 b, a catch basin 52 or other suitable collection 21 means is provided for accepting the collected liquid L and particulates S.
Manual 22 cleanout is performed although automated cleanout could be incorporated 23 without diverging from the intent of the invention.
2 A typical vessel according to the present invention, and for 3 reference are roughly approximated by the proportions of Fig. 3, can be a 6"
or 4 an 8" diameter. Using an 8" diameter, schedule 160 shell for the vessel 11 can result in a fluid stream capacity of about 8 million cubic feet of gas per day. A 2"
6 schedule 160 inlet nozzle extends about 1" beyond an eccentric inlet 12 and into 7 the vessel 11. With a flow barrier 40 placed about 8 feet from the nozzle 8 discharge 25, the desander 10 achieved a corresponding and typical collection 9 rate of 1.5 gallons of sand particulates per day, determined in a worst case scenario of particles of about 100 mesh. Applied to problem wells in several 11 exceptional cases, using no vessel at all, one prior art wellhead, piping and 12 equipment experienced four breaches and in another case, seven breaches.
13 After installation of a preferred vessel of the present invention, no further 14 breaches were experienced. In one case, the resulting collection of particulates, as sand, was about 5 liters per day.
16 Further, as shown in Fig. 5, the throughput capability of 8 inch and 17 10 inch diameter desanding vessels are illustrated for a variety of fluid pressures.
18 A system incorporating a desanding apparatus according to one of 19 the embodiments disclosed herein will benefit from advantages including: As a desander 10 is more cost effective than a "P Tank", the desander can be 21 economically placed on a wellsite for long term sand protection (substantially 22 permanent as required); with a pressure rating that allows the vessel to operate 23 at the wellhead conditions, minimal pressure drop is experienced across the 24 vessel; the desander is designed to exceed ASME code for pressure vessels;
sand is removed from the fluid stream without erosive effects on the operator's 1 downstream equipment and; as the vessel is passive, having no moving parts, 2 plugging from particulates is not an issue; sand can be removed simply and 3 mechanically from the vessel at regular intervals; by removing the sand prior to it 4 entering the producing system, contamination of equipment and produced fluids is avoided; and the desander is capable of handling multiphase production and 6 has demonstrated an ability to remove sand from both gas and oil streams.
This 1 results in a wider application than prior art filter methods.
As a system, the desander 10 is typically inserted as a replacement for existing piping 11 15 (shown in Fig. 1a). The desander 10 is preferably supported with structure 16 12 such as elevation adjustable jacks to align the desander 10 relative to the existing 13 wellhead piping 9 and downstream equipment 14.
14 With reference to Figs. 2a and 2b, the inlet 12 is fitted with a first connector or inlet flange 20 so as to better facilitate installation, to allow easy 16 inspection for wear, to minimize equipment erosion and to simplify replacement 17 when erosion has reduced material thicknesses to acceptable minimums. A
18 nozzle 21 and a second connector or a nozzle flange 22 are adapted for 19 complementary and sealed connection to the inlet flange 20. Typically, the nozzle 21 has a threaded inlet 23 which is adapted for threaded connection to an 21 existing coupling 24 from the wellhead piping 9. The nozzle inlet 23 is threaded 22 onto the coupling 24 and the vessel and inlet 12 is positioned over the nozzle 21 23 and the flanges 20,22 are connected.
24 In greater detail as shown in Figs. 2a,2b and 3, the nozzle 21 has a protruding discharge portion 25 which extends adjacent the top of the vessel 11.
1 The inlet 12 is offset upwardly from an axis A of the vessel 11 and extends into 2 an upper freeboard portion 30. Preferably, as shown in Fig. 2a, an eccentric 3 fitting 31 is applied to the inlet 12. When coupled with the inlet flange 20 on the 4 eccentric fitting 31, the nozzle 21 is shifted upwardly from an axis A of the vessel 11. Similarly, as shown in Fig. 2b, the nozzle 21 can extend through a large 6 blind inlet flange 20 fit directly to the vessel 11 positioned so as to be shifted 7 upwardly from an axis A of the vessel 11. The nozzle 21 discharges the fluid 8 stream F along the nozzle's axis, a path P, substantially parallel to the vessel's 9 axis A. The nozzle inlet 23 is typically formed of heavy-wall piping to extend its operational life in the abrasive environment of the particulate laden fluid stream F.
11 Further, the nozzle's discharge 25 protrudes into the vessel 11 sufficiently to 12 extend beyond the inlet 12 and into the freeboard portion 30, thereby aiding in 13 minimizing localized wear on the less easily replaced inlet 12, or eccentric fitting 14 31, of the vessel 11 In Fig. 3, the desander 10 further comprises belly portion 32, 16 formed below the freeboard portion 307 for receiving and temporarily storing 17 liquids L and sand S which separate from the fluid stream F. The fluid stream F
18 containing sand S enters through the inlet 12 and is received by a larger cross 19 sectional area and substantially gas-phase volume of the freeboard portion 30.
Accordingly, the velocity of the fluid stream F slows to a point below the 21 entrainment or elutriation velocity of at least a portion of the particulates S in the 22 fluid stream. Those of skill in the art are able to determine and apply the 23 parameters of the fluid stream F, fluid stream velocity and those of the 24 particulates S so as to determine the elutriation characteristics. As the area of the freeboard portion 30 increases, the velocity of the fluid stream F slows and a 1 lesser fraction of the particulates remain entrained; a greater fraction of 2 particulates S falling out of suspension from the fluid stream F. The parkiculates 3 S are discharged horizontally from the nozzle 21 along path P, and as they fall 4 from suspension, they adopt a downwardly curved trajectory under the influence of gravity. Preferably, to avoid impingement-type erosion, the length of the 6 vessel is sufficient to permit the particulates to fall out of suspension before 7 impinging internals of the vessel 11. Given sufficient horizontal distance without 8 interference, the particulates S eventually fall from the freeboard portion 30 and 9 the trajectory intersects with the belly portion 32. The particulates S
deposit and accumulate over time in the belly portion 32. Typically, liquids L from the fluid 11 stream also collect in the vessel's belly portion 32.
12 The freeboard portion 30 is maintained using means such as a 13 depending flow barrier 40 to ensure that the collected liquids L and particulates S
14 only reach a maximum depth in the belly portion 32 of the vessel 11. A
minimum cross-section area of the freeboard portion and preferred length of the freeboard 16 portion 30 are determinable based on the elutriation characteristics and are 17 established so as to maximize release of the particulates S before they reach the 18 outlet 13. The greater the length or spacing between the inlet 12 and the flow 19 barrier 40, the greater is the opportunity to drop and release entrained particulates S.
21 Typically, liquid L out of the fluid stream F accumulates in the belly 22 portion 32 to a steady state level and then is re-entrained for discharge with fluids 23 exiting the outlet 13 without affecting the capability of the vessel 11 and belly 24 portion 32 to continue to accumulate particulates S. Regardless of dropout of liquids L from gas G and collection of liquid L in the vessel 11, this upper 1 freeboard portion 30 remains substantially gas-filled. However, should a 2 maximum depth of particulates S be reached during operation and encroach on 3 the freeboard portion 30, operations may yet continue as if the vessel 11 were 4 not even installed; both incoming liquid L and particulates S being temporarily re-entrained with the fluid stream flowing from the vessel outlet 13 until the earliest 6 opportunity to perform maintenance. Typically the belly portion 32 vessel 11 is 7 periodically cleaned out or emptied of accumulated particuiates and liquid at 8 sufficient intervals to ensure that the maximum accumulated depth does not 9 encroach on the freeboard portion 30. Maintenance and operations personnel are further able to physically view sand production volumes during the cleanout 11 and inspection.
12 The flow barrier 40 depends downwardly from the top of the vessel 13 11. The flow barrier 40 has a lower edge 41 which sets the maximum depth of 14 the belly portion 32. As discussed above, the flow barrier 40 is preferably spaced sufficiently from the inlet 11 to enable the fall trajectory of the particles to intersect 16 the belly portion 32 before impinging on the flow barrier 40 itself.
17 As shown in Figs. 4a-4c, the flow barrier 40 can comprise a discrete 18 or separate plate 40a,40b as shown in Figs. 4a and 4b, spaced from the outlet 19 13, or as shown in Fig. 4c, a flow barrier 40c can be formed by the outlet 13 itself.
All of the various flow barriers 40,40a,40b,40c have a lower edge 41 which forces 21 the fluid stream S thereunder before discharging from the vessel 11 at outlet 13.
22 Accumulated levels L,S encroaching above the lower edge 41 will result in high 23 velocities and re-entrainment of liquids L and particulates S from the area about 24 the flow barrier 40, inherently resulting in a steady state maximum level of accumulation of the belly portion 32.
1 In the embodiment shown in some detail in Fig. 4c, the outlet 13 itself acts as the 2 flow barrier 40, which incorporates a tubular portion 43 protruding downwardly 3 and depending through the freeboard portion 30. The tubular portion 43 also has 4 a lower edge 41 spaced from the top of the vessel 11 which forces the fluid stream F to exit from a point nearer the vessel axis A. Particulate-free fluid, 6 typically being gas G and some liquid L, is collected about the axis A for 7 discharge through the discharge tubing 40 and outlet 13. An advantage of 8 providing a separate flow barrier 40,40a,40b is that any abrasion and erosion is 9 borne by the barrier 40 and not by the outlet's 13 tubular portion 43.
As shown in Figs 4a,4c, the outlet 13 for the vessel 10 is preferably 11 arranged perpendicular to the axis A of the vessel 10 for further inertial rejection 12 of re-entrained particulates S.
13 Referring once again to Fig. 3, a quick release pressure-vessel 14 compatible cleanout 50 is provided for access to the vessel 11 for cleanout of the accumulated particulates. The vessel must be depressurized before opening and 16 cleaning out particulates. Typically, mechanically-interlocked safety means 17 are provided so that the vessel must be de-pressurized before the cleanout can 18 be opened. For de-pressurization, the vessel is isolated from the fluid stream F
19 and pressure is bled off from the freeboard portion 30 until the cleanout 50 be removed. As shown in Fig. 1 b, a catch basin 52 or other suitable collection 21 means is provided for accepting the collected liquid L and particulates S.
Manual 22 cleanout is performed although automated cleanout could be incorporated 23 without diverging from the intent of the invention.
2 A typical vessel according to the present invention, and for 3 reference are roughly approximated by the proportions of Fig. 3, can be a 6"
or 4 an 8" diameter. Using an 8" diameter, schedule 160 shell for the vessel 11 can result in a fluid stream capacity of about 8 million cubic feet of gas per day. A 2"
6 schedule 160 inlet nozzle extends about 1" beyond an eccentric inlet 12 and into 7 the vessel 11. With a flow barrier 40 placed about 8 feet from the nozzle 8 discharge 25, the desander 10 achieved a corresponding and typical collection 9 rate of 1.5 gallons of sand particulates per day, determined in a worst case scenario of particles of about 100 mesh. Applied to problem wells in several 11 exceptional cases, using no vessel at all, one prior art wellhead, piping and 12 equipment experienced four breaches and in another case, seven breaches.
13 After installation of a preferred vessel of the present invention, no further 14 breaches were experienced. In one case, the resulting collection of particulates, as sand, was about 5 liters per day.
16 Further, as shown in Fig. 5, the throughput capability of 8 inch and 17 10 inch diameter desanding vessels are illustrated for a variety of fluid pressures.
18 A system incorporating a desanding apparatus according to one of 19 the embodiments disclosed herein will benefit from advantages including: As a desander 10 is more cost effective than a "P Tank", the desander can be 21 economically placed on a wellsite for long term sand protection (substantially 22 permanent as required); with a pressure rating that allows the vessel to operate 23 at the wellhead conditions, minimal pressure drop is experienced across the 24 vessel; the desander is designed to exceed ASME code for pressure vessels;
sand is removed from the fluid stream without erosive effects on the operator's 1 downstream equipment and; as the vessel is passive, having no moving parts, 2 plugging from particulates is not an issue; sand can be removed simply and 3 mechanically from the vessel at regular intervals; by removing the sand prior to it 4 entering the producing system, contamination of equipment and produced fluids is avoided; and the desander is capable of handling multiphase production and 6 has demonstrated an ability to remove sand from both gas and oil streams.
This 1 results in a wider application than prior art filter methods.
Claims (20)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A desanding vessel for removal of particulates from a fluid stream containing particulates, comprising:
a fluid inlet adjacent a first end of the vessel and adapted for receiving the fluid stream, the fluid inlet discharging the fluid stream at an inlet velocity into a freeboard portion at a top of the vessel, the fluid stream in the freeboard portion having an elutriation velocity less than the inlet velocity and such that contained particulates have a fall trajectory;
a fluid outlet from the vessel, the outlet being spaced horizontally from the inlet; and a flow barrier depending from the top of the vessel and having a lower edge so as to direct the fluid stream below the barrier before discharge from the outlet port for maintaining the freeboard portion above the lower edge and forming a belly storage portion below the lower edge, the flow barrier being positioned between the fluid inlet and fluid outlet and the flow barrier being spaced from the fluid inlet so as to enable the fall trajectory of a substantial amount of the particulates to intersect the belly portion so as to accumulate particulates in the belly portion prior to the flow barrier wherein the fluid stream at the fluid outlet is substantially free of particulates.
a fluid inlet adjacent a first end of the vessel and adapted for receiving the fluid stream, the fluid inlet discharging the fluid stream at an inlet velocity into a freeboard portion at a top of the vessel, the fluid stream in the freeboard portion having an elutriation velocity less than the inlet velocity and such that contained particulates have a fall trajectory;
a fluid outlet from the vessel, the outlet being spaced horizontally from the inlet; and a flow barrier depending from the top of the vessel and having a lower edge so as to direct the fluid stream below the barrier before discharge from the outlet port for maintaining the freeboard portion above the lower edge and forming a belly storage portion below the lower edge, the flow barrier being positioned between the fluid inlet and fluid outlet and the flow barrier being spaced from the fluid inlet so as to enable the fall trajectory of a substantial amount of the particulates to intersect the belly portion so as to accumulate particulates in the belly portion prior to the flow barrier wherein the fluid stream at the fluid outlet is substantially free of particulates.
2. The desanding vessel of claim 1 further comprising a cleanout port for periodically accessing and removing particles accumulated in the belly portion.
3. The desanding vessel of claim 1 or 2 wherein the flow barrier is spaced from the fluid outlet.
4. The desanding vessel in any one of claims 1 to 3 wherein the flow barrier further comprises a plate having a substantially horizontal lower edge and the fluid outlet is located in the freeboard volume adjacent to the flow barrier opposite the fluid inlet.
5. The desanding vessel in any one of claims 1 to 4 wherein the flow barrier is formed by the fluid outlet, the fluid outlet further comprising a tubular portion extending downwardly through the freeboard portion for forming the flow barrier and terminating at the lower edge.
6. The desanding vessel in any one of claims 1 to 5 wherein the vessel is cylindrical having a substantially horizontal axis, a top wall and a bottom wall.
7. The desanding vessel of claim 6 wherein the cylindrical vessel has a first end and a second end, and wherein the inlet port is located at the first end and discharges the fluid stream into the freeboard portion along a fluid path which is substantially parallel to the vessel's axis.
8. The desanding vessel of claim 7 wherein the inlet port is offset above the vessel's axis.
9. The desanding vessel of claim 7 wherein the inlet port further comprises:
an Inlet flange;
a nozzle forming the fluid inlet; and a nozzle flange for releasably connecting to the inlet flange.
an Inlet flange;
a nozzle forming the fluid inlet; and a nozzle flange for releasably connecting to the inlet flange.
10. The desanding vessel of claim 7 wherein the inlet port further comprises an eccentric fitting positioned between the vessel and the inlet flange for aligning the nozzle offset above the vessel's axis.
11. The desanding vessel in any one of claims 7 to 10 wherein lower edge of the flow barrier depends below the inlet port.
12. The desanding vessel of claim 7 wherein the inlet port further comprises:
a first connection at the first end of the vessel, a second connection adapted for releasably and sealingly connecting to the first connection, the second connection further comprising a nozzle extending through the second connection, the nozzle having a first end adapted for connection to the source of the fluid stream, and a second end protruding into the vessel for discharging the fluid stream and particulates into the freeboard portion spaced inwardly from the first end.
a first connection at the first end of the vessel, a second connection adapted for releasably and sealingly connecting to the first connection, the second connection further comprising a nozzle extending through the second connection, the nozzle having a first end adapted for connection to the source of the fluid stream, and a second end protruding into the vessel for discharging the fluid stream and particulates into the freeboard portion spaced inwardly from the first end.
13. The desanding vessel of claim 12 wherein lower edge of the flow barrier depends below the inlet port.
14. The desanding vessel in any one of claims 7 to 13 further comprising a cleanout port for periodically accessing and removing particles accumulated in the belly portion further comprising:
a cleanout connection at the second end of the vessel and aligned with the belly portion; and a cleanout cover for coupling with the cleanout connection and operable between a sealed position and an open position for permitting removal of particulates from the belly portion.
a cleanout connection at the second end of the vessel and aligned with the belly portion; and a cleanout cover for coupling with the cleanout connection and operable between a sealed position and an open position for permitting removal of particulates from the belly portion.
15. The desanding vessel of claim 2 or 14 further comprising means for isolating the vessel from the fluid stream and de-pressurizing the vessel before opening the cleanout port.
16. The desanding vessel in any one of claims 2, 14 or 15 further comprising:
means for de-pressurizing the vessel before opening the cleanout port.
means for de-pressurizing the vessel before opening the cleanout port.
17. A desanding system for adaptation to an existing wellhead having a fluid stream flowing to downstream equipment and for the removal of particulates from the fluid stream, comprising:
a vessel positioned between the wellhead and the downstream equipment for intercepting the fluid stream;
a structure for supporting the vessel relative to the wellhead and downstream equipment, wherein the vessel comprises a fluid inlet adjacent a first and of the vessel and adapted for receiving the fluid stream, the fluid inlet discharging the fluid stream at an inlet velocity into a freeboard portion at a top of the vessel, the fluid stream in the freeboard portion having an elutriation velocity less than the inlet velocity and such that contained particulates have a fall trajectory, a fluid outlet from the vessel, the outlet being spaced horizontally from the inlet; and a flow barrier depending from the top of the vessel and having a lower edge so as to direct the fluid stream below the barrier before discharge from the outlet port for maintaining the freeboard portion above the lower edge and forming a belly storage portion below the lower edge, the flow barrier being positioned between the fluid inlet and fluid outlet and the flow barrier being spaced from the fluid inlet so as to enable the fall trajectory of a substantial amount of the particulates to intersect the belly portion so as to accumulate particulates in the belly portion prior to the flow barrier wherein the fluid stream at the fluid outlet is substantially free of particulates.
a vessel positioned between the wellhead and the downstream equipment for intercepting the fluid stream;
a structure for supporting the vessel relative to the wellhead and downstream equipment, wherein the vessel comprises a fluid inlet adjacent a first and of the vessel and adapted for receiving the fluid stream, the fluid inlet discharging the fluid stream at an inlet velocity into a freeboard portion at a top of the vessel, the fluid stream in the freeboard portion having an elutriation velocity less than the inlet velocity and such that contained particulates have a fall trajectory, a fluid outlet from the vessel, the outlet being spaced horizontally from the inlet; and a flow barrier depending from the top of the vessel and having a lower edge so as to direct the fluid stream below the barrier before discharge from the outlet port for maintaining the freeboard portion above the lower edge and forming a belly storage portion below the lower edge, the flow barrier being positioned between the fluid inlet and fluid outlet and the flow barrier being spaced from the fluid inlet so as to enable the fall trajectory of a substantial amount of the particulates to intersect the belly portion so as to accumulate particulates in the belly portion prior to the flow barrier wherein the fluid stream at the fluid outlet is substantially free of particulates.
18. The desanding system of claim 17 wherein the vessel is cylindrical and further comprises a substantially horizontal axis, a top wall and a bottom wall;
a first end and a second end, and wherein the inlet port is located at the first end and discharges the fluid stream into the freeboard portion along a fluid path which is substantially parallel to the vessel's axis and offset above the vessel's axis.
a first end and a second end, and wherein the inlet port is located at the first end and discharges the fluid stream into the freeboard portion along a fluid path which is substantially parallel to the vessel's axis and offset above the vessel's axis.
19. The desanding system of claim 17 or 18 wherein the inlet port further comprises an eccentric fitting positioned between the vessel and the inlet flange for aligning the nozzle offset above the vessel's axis.
20. The desanding system in any one of claims 17 to 19 further comprising a cleanout port for periodically accessing and removing particles accumulated in the belly portion further comprising:
a cleanout connection at the second end of the vessel and aligned with the belly portion; and a cleanout cover for coupling with the cleanout connection and operable between a sealed position and an open position for permitting removal of particulates from the belly portion.
a cleanout connection at the second end of the vessel and aligned with the belly portion; and a cleanout cover for coupling with the cleanout connection and operable between a sealed position and an open position for permitting removal of particulates from the belly portion.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002433741A CA2433741C (en) | 2002-10-10 | 2003-06-27 | Desanding apparatus and system |
| US10/668,266 US6983852B2 (en) | 2002-10-10 | 2003-09-24 | Desanding apparatus and system |
| US11/164,675 US7383958B2 (en) | 2002-10-10 | 2005-12-01 | Desanding apparatus and system |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002407554A CA2407554C (en) | 2002-10-10 | 2002-10-10 | Method and apparatus for desanding wellhead production |
| CA2,407,554 | 2002-10-10 | ||
| CA002433741A CA2433741C (en) | 2002-10-10 | 2003-06-27 | Desanding apparatus and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2433741A1 CA2433741A1 (en) | 2003-10-07 |
| CA2433741C true CA2433741C (en) | 2004-02-03 |
Family
ID=29251584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002433741A Expired - Lifetime CA2433741C (en) | 2002-10-10 | 2003-06-27 | Desanding apparatus and system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2433741C (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8945395B2 (en) | 2011-11-29 | 2015-02-03 | Bonavista Energy Corporation | Settling vessel and method of use |
| US9327214B2 (en) | 2012-02-13 | 2016-05-03 | Specialized Desanders Inc. | Desanding apparatus and a method of using same |
| US8945256B2 (en) * | 2012-02-13 | 2015-02-03 | Specialized Desanders Inc. | Desanding apparatus and system |
| US9909405B2 (en) | 2012-02-13 | 2018-03-06 | Specialized Desanders Inc. | Desanding apparatus and a method of using same |
| US9938812B2 (en) | 2012-02-13 | 2018-04-10 | Specialized Desanders Inc. | Desanding apparatus and a method of using same |
| CA2836437A1 (en) | 2013-12-16 | 2015-06-16 | Specialized Desanders Inc. | An desanding apparatus and a method of using the same |
| SG11201606978SA (en) | 2014-12-04 | 2016-09-29 | Specialized Desanders Inc | A desanding apparatus and a method of using same |
| US10967305B2 (en) | 2017-05-30 | 2021-04-06 | Specialized Desanders Inc. | Boundary layer modification in closely-spaced passages |
| CA3006558C (en) | 2017-05-30 | 2022-04-12 | Specialized Desanders Inc. | Gravity desanding apparatus with filter polisher |
| CN110130868A (en) * | 2019-05-20 | 2019-08-16 | 中国石油工程建设有限公司 | A kind of shale gas desanding separation system and method |
-
2003
- 2003-06-27 CA CA002433741A patent/CA2433741C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2433741A1 (en) | 2003-10-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6983852B2 (en) | Desanding apparatus and system | |
| AU2012370294B2 (en) | Desanding apparatus and system | |
| EP3083004B1 (en) | A desanding apparatus and a method of using the same | |
| AU2018276084B2 (en) | Gravity desanding apparatus with filter polisher | |
| US9938812B2 (en) | Desanding apparatus and a method of using same | |
| US9909405B2 (en) | Desanding apparatus and a method of using same | |
| CA2535215C (en) | System, method and apparatus for desanding wellhead production | |
| US9327214B2 (en) | Desanding apparatus and a method of using same | |
| CA2848738C (en) | A desanding apparatus and a method of using same | |
| AU2015358253B2 (en) | A desanding apparatus and a method of using same | |
| NZ704897A (en) | A desanding apparatus and system | |
| NZ704897B2 (en) | A desanding apparatus and system | |
| NZ721282B2 (en) | A desanding apparatus and a method of using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20230627 |