VAPOR EXTRACTING AND SEPARATOR CLEANING APPARATUS

Abstract

Embodiments relate to an apparatus for separating solids from drilling fluid that includes a shaker having a screening surface onto which the fluid and solids are directed and a vibratory drive vibrating the screening surface. A cabinet includes a plurality of walls enclosing the shaker, a vapor extraction system for circulating clean air into the cabinet and vapors out of the cabinet, and a cleaning system including a plurality of nozzles for directing the cleaning fluid toward the shaker. Furthermore, embodiments relate to a method for extracting vapors and cleaning a shaker that includes enclosing the shaker in a cabinet. The cabinet includes a plurality of walls through which a fresh air inlet and a vapor outlet are disposed, a solids collection container having a solids outlet, a sump having a fluid exit passage in which a valve is disposed, and a plurality of nozzles in fluid communication with a cleaning fluid supply. Furthermore, the method connecting the vapor outlet to a fume extraction system, directing drilling fluid and solids onto a screening surface of the shaker, and discharging separated solids to a solids collection container. The solids collection container includes a solids outlet in which a rotary valve is disposed. The method also includes directing separated drilling fluid into a sump below the screening surface of the shaker, and selectively actuating the rotary valve to remove separated solids from the cabinet.

Description

This application claims priority to U.S. Provisional Patent Application Ser. No. 60/756,353 filed on Jan. 5, 2006 entitled, “Vapor Extracting and Separator Cleaning Apparatus” incorporated herein by reference for all purposes.

BACKGROUND OF INVENTION

Rotary drilling methods employing a drill bit and drill stems have long been used to drill wellbores in subterranean formations. Drilling fluids or muds are commonly circulated in the well during such drilling to cool and lubricate the drilling apparatus, lift drilling cuttings out of the wellbore, and counterbalance the subterranean formation pressure encountered. The recirculation of the drilling mud requires the fast and efficient removal of the drilling cuttings and other entrained solids from the drilling mud prior to reuse. Shaker separators are commonly used to remove the bulk solids from the drilling mud.

A shale shaker is a vibrating sieve-like table upon which returning dirty drilling mud is deposited and through which clean drilling mud emerges.

Typically, the shale shaker is an angled table with a generally perforated filter screen bottom. The screen is removably secured within a basket, which is resiliently mounted to a stationary housing. Returning drilling mud is deposited on the top of the screen surface. The vibratory motion coerces the solids up the incline of the screening surface while the fluid falls through the perforations to a reservoir below leaving the solid particulate material behind. The combination of the angle of inclination with the vibrating action of the shale shaker table enables the solid particles left behind to flow until they fall off the front edge of the shaker table. Often, the amount of vibration and the angle of inclination of the shale shaker table are adjustable to accommodate various drilling mud flow rates and particulate percentages in the drilling mud. After the fluid passes through the perforated bottom of the shale shaker, it can either return to service in the borehole immediately, be stored for measurement and evaluation, or it may pass through another, smaller size shale shaker or other equipment to further remove smaller cuttings.

Vapors are often present when the drilling fluid passes through the separator. These vapors may be toxic or even explosive. Consequently, human exposure to the vapors should be minimized. It would be beneficial to further segregate the vapors present at the separator from other equipment at the rig site. However, simply segregating the separator from the rest of the equipment is not feasible.

The separator will need to be cleaned from time to time. This presents additional potential exposure to dangerous vapors. To clean the separator, operators are typically situated near the separator and guide pressurized water onto the separator to remove drilling fluid and solid material from various areas of the separator. Such close proximity to the separator necessarily puts the operator in the vicinity of potentially dangerous fumes. It would be an improvement to extract dangerous vapors from the area around the separator. It would be a further improvement to have an apparatus that can perform some of the functions typically performed by operators to keep operators from the dangerous vapors.

SUMMARY

In one aspect, embodiments disclosed herein relate to an apparatus for separating solids from drilling fluid including a shaker selectively receiving drilling fluid including solids at a feed end, wherein the shaker includes a screening surface onto which the fluid and solids are directed, a vibratory drive vibrating the screening surface to induce separation of the solids from the fluid, a discharge end from which solids are discharged from the shaker, a sump below the screening surface to which separated fluid is directed, and a fluid exit passage providing fluid communication of fluid out of the sump. The apparatus further includes a cabinet including a plurality of walls enclosing the shaker, a vapor extraction system including a fresh air inlet and a vapor outlet for circulating clean air into the cabinet and vapors out of the cabinet, and a cleaning system including a plurality of nozzles selectively receiving cleaning fluid and directing the cleaning fluid toward the shaker.

In another aspect, embodiments disclosed herein relate to an apparatus for cleaning and extracting vapors from a shaker that includes a feed end to which drilling fluid containing solids is directed, a discharge end from which separated solids are discharged from the shaker, and a screening surface through which the drilling fluid is separated from the solids. The apparatus includes a cabinet having a plurality of walls enclosing the shaker, a sump below the screening surface of the shaker for receiving separated drilling fluid, a fluid exit passage providing fluid communication from the sump to an area external to the cabinet, a vapor extraction system having a fresh air inlet and a vapor outlet for circulating clean air into the cabinet and vapors out of the cabinet, and a cleaning system having a plurality of nozzles selectively receiving cleaning fluid and directing the cleaning fluid towards the shaker.

In yet another aspect, embodiments disclosed herein relate to a method for for extracting vapors and cleaning a shaker. The method includes enclosing the shaker in a cabinet. The cabinet includes a plurality of walls through which a fresh air inlet and a vapor outlet are disposed, a solids collection container having a solids outlet, a sump having a fluid exit passage in which a valve is disposed, and a plurality of nozzles in fluid communication with a cleaning fluid supply. The method further includes substantially sealing the solids outlet and fresh air inlet, connecting the vapor outlet to a fume extraction system, activating the fume extraction system to reduce pressure in the cabinet and draw air through portions of the fresh air inlet, actuating the valve in the fluid exit passage to provide fluid communication from the sump to a drilling fluid collection area, directing drilling fluid and solids onto a screening surface of the shaker, and discharging separated solids to a solids collection container. The solids collection container includes a solids outlet in which a rotary valve is disposed. The method further includes directing separated drilling fluid into a sump below the screening surface of the shaker and selectively actuating the rotary valve to remove separated solids from the cabinet.

Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is front cutaway view of an embodiment of the apparatus to extract vapors and clean a separator.

FIG. 2 is side cutaway view of an embodiment of the apparatus to extract vapors and clean a separator.

DETAILED DESCRIPTION

The claimed subject matter relates to an apparatus 100 for extracting vapors and cleaning shakers. Referring to FIGS. 1 and 2, the apparatus 100 has a plurality of walls 104,106, 108, shown, and a top wall 110 forming a cabinet 112 or enclosure around a separator 102. A drilling fluid feed 140 directs the unseparated drilling fluid into cabinet 112 to separator 102.

As one of skill in the art will appreciate, separator 102 may be of any model and type. A typical shaker separator 102 includes a basket 114 that includes a bottom wall 116 having an opening 118, a pair of side walls, 120 (one wall shown), and an end wall 122. End wall 122 is located at the feed end of the separator 102. At least one screening surface 124 is located in the basket 114. The screening surface 124 has a plurality of apertures through which fluid may pass. The opening 118 in the bottom wall 116 is beneath the screening surface 124 to direct filtered fluid out of separator 102 for further processing, containment, or re-use. Basket 114 is resiliently mounted to a housing 116. One or more actuators 128 are coupled to the basket 114 for imparting motion to basket 114. Drilling fluid containing solids, such as drill cuttings, is directed onto the screening surface 124 from a feed end of the shaker 102. While the fluid can pass through the apertures in the screening surface 124, solids that have a size larger than the apertures will remain on top of the screening surface 124. The vibratory motion of the screening surface 124 and basket 114 moves the solids along the screening surface 124 and over the discharge end of the screening surface 124 to a solids collection container 130 that will be described in greater detail below.

Cabinet 112 includes a vapor extraction system 140. The vapor extraction system 140 is operable to remove vapors from the cabinet 112 while introducing fresh air into cabinet 112. A vapor outlet 142 is provided in cabinet 112 through which vapors may be drawn. The vapor outlet 142 may be positioned in any location where vapors are to be extracted. In one embodiment, this location is near the feed end of the shaker 102. Many offshore oil rigs have a fume extraction system (not shown). The vapor outlet 142 may be configured to interface with the rig's fume extraction system. In one embodiment, a condenser 144, shown in FIG. 2 is used to extract vapors from cabinet 112.

A fresh air inlet 146 provides fresh air into cabinet 112. Fresh air inlet 146 is preferably located through cabinet 112 near the area where cuttings are discharged from separator 102. In this location, inlet 146 may assist in the cooling and extraction of vapors from the cuttings prior to their release from cabinet 112. Referring to FIG. 1, in one embodiment the fresh air inlet 146 includes an opening 148 in a first cabinet wall 104 that is located near the discharge end of the shaker 102. In one embodiment, a weighted curtain 150 is positioned across the opening 148. The weighted curtain 150 may be selectively positioned to provide access to the interior of the cabinet 112 through the opening 148. During operation of the shaker 102, the curtain is preferably positioned to cover the opening 148. The weight of the curtain 150 is sufficient to maintain the curtain in a position to substantially cover the opening 148 and form a nominal seal. However, some air will be able to enter the cabinet through a portion of the opening 148 in the first wall 104 such as between the wall 104 and curtain 150 or through nominal openings in the curtain 150.

As previously discussed, the vapor outlet 142 draws vapors and air out of the cabinet 112. As air and vapors are drawn from the cabinet, the pressure within the cabinet 112 will decrease, thereby drawing air in through fresh air inlet 146. Still referring to FIG. 1, in one embodiment, the first cabinet wall 104 that includes opening 146 is slanted slightly, so that the lower edge 152 of the wall 104 is further from the opposing wall 106 than the upper edge 154 of the wall 104 is from the opposing wall 106. The slant of the first wall 104 is such that the angle formed between the first wall 104 and the floor 111 is something less than 90°. With this configuration, the bottom edge of the weighted curtain 150 is pulled by gravity to rest against a surface below the opening, thereby helping maintain the weighted curtain 150 in a position across opening 146.

Referring to FIG. 2, in one embodiment, a set of louvers 160 are provided through the opening 146 in the first cabinet wall 104. The louvers 160 perform in much the same manner as the weighted curtain 150. As air is drawn out through vapor outlet 142, air is pulled in through the louvers 160. In this embodiment, the louvers 160 are biased to a closed position and are drawn open when a pressure differential exists on opposing sides of the louvers. Such a pressure differential exists when pressure inside the cabinet 112 is less than the ambient pressure outside of the cabinet 112.

One or more sensors 162 may be used to monitor the air quality within cabinet 112. In one embodiment, vapor extraction system 110 may be automatically adjustable based on the air quality detected by sensor 162. The removal of vapors from cabinet 112 may be adjusted to maintain the air quality within predetermined quality levels to prevent explosions.

Referring to FIGS. 1 and 2, the separated cuttings and solids are discharged from separator 102 into a solids collection container 130. To remove the cuttings and solids from the solids collection container 130 without disrupting the pressure differential maintained by the vapor extraction system 140, an airlock or rotary valve 132 may be used. The rotary valve 132 is disposed in the solids collection container 130. The rotary valve 132 provides selective communication of solids from the container 130 to a collection area outside of the cabinet 112. If a rotary valve 132 is used, the valve speed may be adjustable to match the flow distribution of separator 102. Outside of cabinet 112, cuttings may be discharged or transported by any conventional means.

The cleaned drilling fluid is directed from separator 102 to a sump xxx and out of cabinet 112 through a fluid exit passage 134. In one embodiment, shown in FIG. 2, a weighted valve 136 is placed in the fluid passage through which the fluid leaves the shaker 102 to prevent air from being drawn through the fluid exit passage 134. In another embodiment, shown in FIG. 1, no such valve is located in the fluid exit passage 134, although another valve may be present as will be discussed. As previously discussed, air is pulled into the cabinet by the vapor extraction system 140. Any air drawn through the fluid exit passage should be considered when sizing the fresh air inlet 146 and vapor outlet 142 to ensure that the fresh air will continue to be drawn into the cabinet.

Because the cabinet 112 will obstruct normal viewing of the shaker performance and screening surfaces, in one embodiment one or more cameras 164, shown in FIG. 2 are installed inside cabinet 112 In this embodiment, camera 164 assists operators in monitoring screening surfaces 124 of shaker 102 to identify those screens that have developed tears or holes. Further, the camera 164 may assist operators in adjusting to the flow rate, deck angle, and/or vibration profile and magnitude. In one embodiment the camera 128 will be placed near the discharge end of the shaker 102 and directed to be able to see the screening surface 124. In one embodiment, the operator can view pictures or video from the camera 164 in a captain's house or other remote control center. Changes to the operating mode of the shaker can be made by the operator remotely from the control center. It will be appreciated by one of skill in the art that any camera 164 placed inside the cabinet 112 must be explosion-proof and meet any industry-specific standards for electronic devices in a hazardous area.

In one embodiment, shown in FIG. 1, cabinet 112 also includes a cleaning system 170. Cleaning system 170 includes at least one inlet 172 through which clean water or cleaning fluid can be directed towards the shaker 102. One or more cleaning nozzles 174 may be located inside cabinet 112 in fluid communication with inlet 172 and directed toward shaker 102. In one embodiment, one or more nozzles are directed toward screening surfaces 124. Cleaning nozzles 174 may be strategically placed and aimed toward separator 102 to clean hidden areas. During the cleaning process, flow of cleaning fluid may be temporarily halted while the screens are removed from the shaker 102, allowing access to the screen tracks and bed. After removal of the screens, flow of cleaning fluid to the nozzles may be reinstated to clean these areas. It is also contemplated that nozzles 174 may be remotely controlled to vary the targeted stream of water and/or cleaning solution within areas of separator 102. Alternatively, nozzles 174 may be pre-programmed with a cleaning pattern and flow rate adjustments to effectively clean separator 102.

Referring to FIG. 2, in one embodiment, manifolds or cleaning bars 176 are located in cabinet 112 to distribute the flow of cleaning fluid. In one embodiment, cleaning bars 176 are rotatable to distribute cleaning fluid to a predefined area in and around the shaker 102.

Cleaning system 170 may use high pressure water to clean screening surfaces and the inner and outer sides of separator 102. Surfactant may be added as needed to improve the effectiveness of the high pressure water. It is contemplated that cleaning system 170 will be a closed system wherein the cleaning fluid is collected, filtered, and recycled. Cleaning fluid that passes through screening surfaces will be directed to the sump 138. To prevent cleaning fluid from exiting the sump to the drilling fluid collection area and contaminating separated drilling fluid, a valve 178 may be included at the fluid exit passage 134 to direct cleaning fluid to a cleaning fluid collection area outside the cabinet 112 from which the cleaning fluid may be recycled. The valve 178 may be selectively actuated to a first position providing fluid communication from the sump 138 to the drilling fluid collection area or to a second position providing fluid communication from the sump 138 to the cleaning fluid collection area.

Access to separator 102 will be required from time to time, such as to change screens. After separator 102 has been cleaned, vapor extraction system 140 may be utilized to remove any remaining vapors and provide fresh air to cabinet 112 before operators enter. The sensors 162 may be used to monitor the air quality and alert operators as to when it is safe to access the shaker 102.

To obtain such access, cabinet 112 may be mounted to hydraulic lifts (not shown) that raise the entire cabinet 112, thereby providing access to separator 102, as shown in FIG. 1. Alternatively, a door 180 may be provided as shown in FIG. 1. As one of skill in the art will appreciate, numerous alternatives are available to provide access to separator 102, such as one or more hinged doors, one or more horizontally sliding doors, and one or more vertically sliding doors, just to name a few. Vapor extraction system 140, cleaning system 170 and drilling fluid feed 140 preferably remain in place when access to cabinet 112 is made.

When separator 102 is to be operated, cabinet 112 is closed. Drilling fluid containing solid material is directed through drilling fluid feed 140 to separator 102. The screening surfaces 124 in separator 102 separate the solid material from the fluid, with the fluid passing through the screens through the opening 118 in bottom wall 116. The fluid is directed from beneath the screening area to a location external to cabinet 112 through fluid exit passage 134. The vibrations of the screening surface 124 direct solids thereon toward the front end of separator 102, where they are discharged to solids collection area 106. The solids may be removed from cabinet 112 through an airlock or rotary valve 132 to maintain the interior of cabinet 112 at a desired pressure and air quality level. The flow of drilling fluid to the shaker 102 and fluid flow and solids discharge out of cabinet 112 may be controlled to maintain a desired flow rate. The screens in shaker 102, as well as the overall process within cabinet 112 may be monitored using one or more cameras 164. Monitors outside of cabinet 112 may receive video feed from each camera 164, which may be viewed by an operator. When a screen break is detected or viewed, operation of separator 102 can be halted remotely.

In connection with changing screens or as part of a preventive maintenance program, periodic halting and cleaning of separator 102 may be desired. Interior components and screens may be cleaned by one or more nozzles 174 located in cabinet 112. Nozzles 174 may be pre-programmed or remotely controlled to direct cleaning fluid to predetermined areas of shaker 102 and areas desired to be cleaned. Cleaning bars 176 located within cabinet 112 may also be used to aid in cleaning separator 102 and screening surfaces. Cleaning bars 176 may include rotational nozzles to increase the cleaning area. Cleaning fluid from within cabinet 112 and shaker 102 may be directed to a filtration area so that the cleaning fluid may be filtered and reused or it may be collected. Cleaning fluid that is directed in the fluid exit passage 134 is directed to the drilling fluid collection area or the cleaning fluid collection area by a valve 178 in the fluid exit passage 134, thereby preventing contamination of separated drilling fluid. Vapor extraction system 140 may be operated to supply fresh air into cabinet 112 before operators enter. Sensors 162 may be used to alert an operator as to when the air quality is safe enough for entry to the cabinet 112.

While the claimed subject matter has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the claimed subject matter as disclosed herein. Accordingly, the scope of the claimed subject matter should be limited only by the attached claims.

Claims

1. An apparatus for separating solids from drilling fluid comprising:

a shaker selectively receiving drilling fluid including solids at a feed end, wherein the shaker includes a screening surface onto which the fluid and solids are directed, a vibratory drive vibrating the screening surface to induce separation of the solids from the fluid, a discharge end from which solids are discharged from the shaker, a sump below the screening surface to which separated fluid is directed, and a fluid exit passage providing fluid communication of fluid out of the sump;

a cabinet including a plurality of walls enclosing the shaker;

wherein the cabinet further comprises: a vapor extraction system including a fresh air inlet and a vapor outlet for circulating clean air into the cabinet and vapors out of the cabinet; and a cleaning system including a plurality of nozzles selectively receiving cleaning fluid and directing the cleaning fluid toward the shaker.

2. The apparatus of claim 1 wherein the fresh air inlet comprises:

a first cabinet wall having an opening therethrough;

a weighted curtain selectively positioned to substantially cover the opening such that air from outside the cabinet can be drawn into the cabinet through a portion of the opening.

3. The apparatus of claim 2, wherein the weighted curtain includes a bottom edge; and

wherein the first cabinet wall is angled so that the bottom edge of the weighted curtain is held below the opening against the first cabinet wall.

4. The apparatus of claim 1, wherein the fresh air inlet comprises:

a first cabinet wall having an opening therethrough;

a set of louvers disposed in the opening through the first cabinet wall;

wherein the louvers are biased to a closed position and are drawn open by a pressure differential to allow fresh air into the cabinet.

5. The apparatus of claim 1 wherein the vapor outlet provides fluid communication of vapors from inside the cabinet to a fume extraction system.

6. The apparatus of claim 1 wherein the vapor extraction system further comprises a condenser for drawing vapors from the cabinet through the vapor outlet.

7. The apparatus of claim 1 further comprising:

a solids collection container disposed at the discharge end of the shaker;

a rotary valve disposed in the solids collection container providing selective communication of solids to an area outside of the cabinet.

8. The apparatus of claim 1 further comprising:

a valve in the fluid exit passage providing selective fluid communication of fluid in the sump of the shaker to a corresponding collection area outside of the cabinet.

9. The apparatus of claim 8 wherein in the valve is selectively actuated to a first position in which fluid is communicated from the sump to the drilling fluid collection area and to a second position in which fluid is communicated from the sump to a cleaning fluid collection area.

10. An apparatus for cleaning and extracting vapors from a shaker, wherein the shaker includes a feed end to which drilling fluid containing solids is directed, a discharge end from which separated solids are discharged from the shaker, and a screening surface through which the drilling fluid is separated from the solids, the apparatus comprising:

a cabinet including a plurality of walls enclosing the shaker;

a sump below the screening surface of the shaker receiving separated drilling fluid;

a fluid exit passage providing fluid communication from the sump to an area external to the cabinet;

a vapor extraction system including a fresh air inlet and a vapor outlet for circulating clean air into the cabinet and vapors out of the cabinet; and

a cleaning system including a plurality of nozzles selectively receiving cleaning fluid and directing the cleaning fluid towards the shaker.

11. The apparatus of claim 10 wherein the fresh air inlet comprises;

a first cabinet wall having an opening therethrough;

a weighted curtain selectively positioned to substantially cover the opening such that air from outside the cabinet can be drawn into the cabinet through a portion of the opening;

wherein the weighted curtain includes a bottom edge; and

wherein the first cabinet wall is angled so that the bottom edge of the weighted curtain is held below the opening against the first cabinet wall by gravity.

12. The apparatus of claim 10 wherein the vapor outlet is configured to interface with a fume extraction system.

13. The apparatus of claim 10 further comprising:

a solids collection container disposed at the discharge end of the shaker;

a rotary valve disposed in the solids collection container providing selective communication of solids to an area outside of the cabinet.

14. The apparatus of claim 10 further comprising:

a valve in the fluid exit passage providing selective fluid communication of fluid in the sump;

wherein in a first position the valve provides fluid communication to a drilling fluid collection area outside of the cabinet; and

wherein in a second position the valve provides fluid communication to a cleaning fluid collection area outside of the cabinet.

15. A method for extracting vapors and cleaning a shaker comprising:

enclosing the shaker in a cabinet including a plurality of walls through which a fresh air inlet and a vapor outlet are disposed, a solids collection container having a solids outlet, a sump having a fluid exit passage in which a valve is disposed, and a plurality of nozzles in fluid communication with a cleaning fluid supply;

substantially sealing the solids outlet and fresh air inlet;

connecting the vapor outlet to a fume extraction system;

activating the fume extraction system to reduce pressure in the cabinet and draw air through portions of the fresh air inlet;

actuating the valve in the fluid exit passage to provide fluid communication from the sump to a drilling fluid collection area;

directing drilling fluid and solids onto a screening surface of the shaker;

discharging separated solids to a solids collection container, wherein the solids collection container includes a solids outlet in which a rotary valve is disposed;

directing separated drilling fluid into a sump below the screening surface of the shaker; and

selectively actuating the rotary valve to remove separated solids from the cabinet.

16. The method of claim 15 further comprising:

halting the direction of drilling fluid and solids onto the screening surface of the shaker;

actuating the valve in the fluid exit passage to provide fluid communication from the sump to a cleaning fluid collection area;

providing cleaning fluid to the nozzles inside the cabinet; and

directing the nozzles to spray the cleaning fluid toward the shaker.

17. The method of claim 16 further comprising:

collecting the cleaning fluid in the cleaning fluid collection area; and

recycling the cleaning fluid back into the cabinet.