The present disclosure relates to removing sand from a wellbore by forming a slurry of sand collected at a wellbore bottom and a liquid, and forcing the slurry to surface. More specifically, the present disclosure relates to a system and methodology of separating and removing sand from a wellbore and its application to various artificial lift systems.
Hydrocarbon producing wellbores extend subsurface and intersect subterranean formations where hydrocarbons are trapped. The wellbores are created by drill bits that are on the end of a drill string, where typically a top drive or rotary table above the opening to the wellbore rotates the drill string and attached bit. When hydrocarbons flow from the formation into the wellbore, other substances often accompany the hydrocarbons, such as water, hydrogen sulfide, and sand.
Excessive sand production is very common from unconsolidated, poorly cemented and relatively young geological formations. Moreover consolidated formations, in many regions of the world, are not completely free from this problem; they also release sand, though may not be excessively high in volume. Formation sand production sometimes plugs wells, erodes downhole equipment, artificial lift systems, wellhead assemblies and/or the surface facilities; which reduces productivity and damages downhole and surface equipment.
Sand can also result from proppant, which is occasionally injected into hydraulically generated fractures in rocks around wellbores. Not all of the sand remains in the fractures; but instead sometimes flows back into the wellbore and creates the above mentioned problems. Some known methods of controlling sand production include sand screens, slotted liners, gravel-pack schemes, and near wellbore sand consolidation techniques with various chemicals. However sand control techniques often reduce overall flow capacity of formation fluids towards the wellbores.
Disclosed herein is an example of a system for producing from a wellbore that includes production tubing in the wellbore having an inlet in fluid communication with a formation that is intersected by the wellbore, a seal in the wellbore that defines a sealed space, a discharge chute that is in communication with a source of sand, that that has an exit disposed in the sealed space, an inlet line in communication with a source of fluid and having a fluid exit in the sealed space, and a discharge line having an inlet in the sealed space, so that when fluid from the source of fluid flows out of the fluid exit and into the sealed space, sand from the source of sand in the sealed space mixes with the fluid exiting the fluid exit and is forced into the inlet of the discharge line. The source of sand can be from a separator coupled with the production tubing, and that is made of a housing connected to the discharge chute, inlet ports formed in a sidewall of the housing. This example can further include a one way valve on an end of the discharge chute distal from the housing which is in an open configuration when pressure in the discharge chute is greater than pressure in the sealed space, and which is in a closed configuration when pressure in the sealed space is greater than pressure in the discharge chute. In one example the system further includes a perturbation element disposed in the sealed space for mixing the sand and the fluid. In an embodiment, the perturbation element mounts to the inlet line, and which includes a base that selectively rotates and that is in fluid communication with the inlet line, vanes formed on the base, and blades mounted to the base, so that when fluid from the inlet line flows across the base, interaction of the fluid with the vanes causes the base and blades to rotate, thereby mixing the sand with the fluid to create a slurry. The system can also optionally further include a wellhead assembly mounted at an opening of the wellbore on the Earth's surface. In this example the inlet line and discharge lines can be routed through the wellhead assembly. The wellbore can include a main bore, and a lateral bore is oriented oblique to the main bore, and that intersects the main bore on a side of the seal opposite from the sealed space, and wherein the lateral bore is the source of the sand. Perforations can be formed in the formation and that are tangential to sidewalls of the wellbore, and wherein the formation is the source of the sand. The seal can include a lower seal, in this example the system further includes an upper seal in the wellbore spaced axially away from the lower seal and on a side opposite from the sealed space, and wherein a production space is defined in a portion of the wellbore between the upper and lower seals.
Also described herein is an example of a system for producing from a wellbore that includes a means for transporting connate fluid from within the wellbore that is produced from a formation intersected by the wellbore, a means for forming a slurry of motive fluid and sand separated from the connate fluid, and a means for transporting the slurry out of the wellbore. The means for transporting connate fluid from the wellbore can optionally be production tubing, and the means for separating sand from the connate fluid can be a separator that attaches to the production tubing. The means for mixing the sand with a motive fluid can be a selectively rotatable perturbation element. In this example the perturbation element is selectively rotated by contacting the perturbation element with the motive fluid. In one example the means for transporting the slurry out of the wellbore is a source of the motive fluid, an inlet line in the wellbore having an inlet in fluid communication with a source of the motive fluid and a fluid exit proximate a sealed space in the wellbore where sand separated from the connate fluid is collected, and a discharge line having an inlet in fluid communication with the slurry in the sealed space, and an exit that is disposed outside of the wellbore, and wherein the source of the motive fluid is at a pressure sufficient to lift the slurry from the sealed space and to outside of the wellbore. The system can further include a means for separating the sand from the connate fluid.
Also described herein is a method of producing from a wellbore and that includes transporting connate fluid from the wellbore that is produced from a production zone that surrounds a portion of the wellbore and lifting particulate matter separated from the connate fluid to outside of the wellbore, and separately from the connate fluid. The step of lifting particulate matter to outside of the wellbore can involve providing a motive fluid into the wellbore, forming a slurry with the particulate matter and motive fluid, wherein a pressure of the motive fluid is sufficient to lift the slurry to outside of the wellbore. Optionally the slurry is mixed in a sealed space in the wellbore and separate from where connate fluid enters the wellbore from the production zone. In one example the motive fluid rotates a perturbation element for forming the slurry.
Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/−5% of the cited magnitude. In an embodiment, usage of the term “substantially” includes +/−5% of the cited magnitude.
It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.
An example of a wellbore production system 10 is shown in a side partial sectional view in
One example of a separator 24 for use in the described process can be obtained from Lakos, 1365 North Clovis Avenue, Fresno, Calif. 93727, www.lakos.com. As shown, separator 24 includes an elongate housing 30 having a cylindrical outer surface, and inlet ports 32 formed through sidewalls of the housing 30. An optional screen hanger 33 is depicted on an upper end of housing 30 for mounting the housing 30 to the lower end of production tubing 18 and within wellbore 12. An example of a packer 34 is shown provided in wellbore 12 and oriented substantially transverse to production tubing 18. Packer 34 provides a barrier to pressure and flow in axial in direction to fluid within wellbore 12, and in the annular space between separator 24 and inner surface of casing 16. Spaced axially from packer 34 is packer 36, which also provides a flow and pressure barrier within wellbore 12 in the annular space between separator 24 and inner surface of casing 16. Between packers 34, 36 a production space 37 is defined. Production space 37 is optionally roughly the same axial length of where wellbore 12 intersects with zone Z2. A sealed space 38 is defined in the portion of wellbore 12 on a side of packer 36 opposite from production space 37. Thus, packer 36 blocks flow and pressure communication between production space 37 and sealed space 38.
Still referring to
Sand 39 collected within the sealed space 38 is removed from wellbore 12 by use of a sand removal system 44. Sand removal system 44 includes a fluid source 46, which can be a storage tank, a pump, or any other device for delivering fluid to within wellbore 12. In an example, the fluid includes water and which is pressurized to an amount so that when injected into wellbore 12 has sufficient inlet pressure to overcome dynamic pressure losses and frictional losses so that the fluid can then be lifted by its own pressure back out of wellbore 12. In one embodiment, the fluid defines a motive fluid for providing a motive force to carry the sand 39 from the wellbore 12. An inlet line 48 is shown connected to fluid source 46 and provides a conduit for transporting the motive fluid 47 from within fluid source 46 and into wellbore 12. Optionally, a valve 50 is shown provided within inlet line 48 for selectively controlling flow through line 48. In the illustrated example, inlet line 48 passes through a portion of wellhead assembly 26 before making its way into wellbore 12. An inlet of the inlet line 48 is in communication with fluid source 46, an exit of inlet line 48 is disposed within the sealed space 38 and discharges motive fluid into sealed space for mixing with sand 39.
A perturbation element 52 is shown disposed within wellbore 12 and which provides a mechanical means for mixing the motive fluid 47 with sand 39 to create slurry 53. An optional centralizer 54 is shown for centering perturbation element 52 within wellbore 12; and that couples to inlet line 38, or a portion of perturbation element 52. As discussed above, pressure within motive fluid 46 is imparted to slurry 53 so that slurry 53 can be flowed to a discharge line 56 that has an inlet 57 that depends into sealed space 38. As shown, inlet line 48 and discharge line 56 each penetrate packer 34 and packer 36, and wherein packers 34, 36 sealingly circumscribe lines 48, 56. An outlet end of discharge line 56 is shown connected to a storage tank 58 that is outside of wellbore 12; and which can receive the slurry 53 lifted out of wellbore 12 by the pressure within motive fluid 47. An optional valve 60 is shown in line with discharge line 56 for selectively blocking flow through discharge line 56. An advantage of the wellbore production system 10 described herein is that removing sand from the connate fluid CF does not impede fluid flow, thus production of connate fluid CF from the formation 14 and to the wellhead assembly 26 is not reduced by implementation of the separator 24 or sand removal system 44. In one non-limiting example of operation, sand production from the formation 14 is encouraged from the formation 14; which could prove to be beneficial to increase hydrocarbon production from relatively tight reservoir zone Z2 as the removed sand grains from deeper sections of Z2 could open the additional flow paths for hydrocarbons to flow easily towards wellbore 12.
Referring now to
An example of base 64 is illustrated in a cross sectional view in
Shown in a side sectional view in
Examples exist where the artificial lift system 76C is an electrical submersible pump having a series of impellers and diffusers (not shown) for pressurizing liquids entering the artificial lift system 76C. Optionally the artificial lift system 76C can be a progressive cavity pump, rod pump, or any type of system for pressurizing fluid downhole. Fluid pressurized in the artificial lift system 76C is directed into production tubing 18C and directed to wellhead assembly 26C. Artificial lift systems are vulnerable to erosion and clogging when handling fluid with sand and other particulate matter entrained within. Thus a significant advantage is provided by combining sand removal equipment with an artificial lift system so that sand can be effectively removed from the fluid before reaching the artificial lift system. Thus reducing downtime of an artificial lift system increases production efficiency.
Another alternate example of a wellbore production system 10E is provided in side sectional view in
Packer 36E is disposed around tubing 18E above artificial lift system 76E. Screen hanger 33E couples to a lower end of discharge pipe 77E and provides a support for housing 24E, which depends from hanger 33E and on an end opposite from artificial lift system 76E. Similar to artificial lift system 76C of
The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.