BRPI0709999A2 - drilling rock fragment transfer system and related methods - Google Patents

Abstract

<B> DRILL ROCK FRAGMENT TRANSFER SYSTEM AND RELATED METHODS <D> The present invention relates to a system for manipulating drilling rock fragments that conducts rock fragments to mud additive tanks through a conduit. The mud additive tanks have a lower portion that converges to an elongated opening. A conducting element positioned in the elongated openings forces the rock fragments out of a discharge port at the bottom of the mud additive tank. A suitable driving element is a screw-type conveyor attached to an engine that applies a driving force to the rock fragments. The lower portion of the mud additive tank can be formed as a wedge or chute which generally conforms to the configuration of the driving element. The mud additive tanks keep the rock fragments until they can be discharged through the discharge port to a transport vessel for processing or disposal. For offshore operations, the system includes a separation unit in the drilling tower that forms the rock fragments from the fluid that returns from the well hole and a rock fragment flow unit that conducts the rock fragments from the separation unit for the mud additive tanks.

Description

Report of the Invention Patent for "DRILLING ROCK FRAGMENT TRANSFER SYSTEM AND RELATED METHODS".

Description Background

1. Description Field

The present invention relates generally to the handling of waste materials, especially particulate drilling solids.

2. Description of Related Art

When drilling oil and gas wells, drilling fluids, or "mud", are used to provide well bore lubrication, cool the drill bit, to protect against corrosion and to provide a load. pressure to maintain the integrity of the formation. There are two main types of drilling mud: water based and oil based. Generically surface pumps circulate the lamade drilling down the tubular drilling column. Mud exits the drill bit and seeps up into the ring between the drill string and the hole. Returning fluid (the return fluid) carries drilling rock fragments away from the drill bit and out of the wellbore. Petroleum-based drilling muds are stable external and internal water emulsions that include solid soaking agents. , such as rock drilling fragments in the oil phase. Rock drilling fragments thus tend to become oil-soaked by trapping large amounts of oil-based mud in their intergranular spaces and creating environmental concerns regarding the disposal of oil-contaminated drilling fragments.

In the prior art, petroleum-based drilling mud contaminated drilling rock fragments were often collected in deposition tanks where reusable drilling mud had been brought off the top of the tank and contaminated drilling rock fragments as bottoms. , were transported to appropriate disposal sites. Such warehousing and transportation operations are costly and undesirable in environmental terms, especially in offshore drilling operations. Typically, oil-contaminated rock fragments contain about 50% by volume of petroleum-based liquid. The value of this large volume of entrained oily liquid is considerable, and there is a strong incentive to recover the oil-based drilling mud over same time for economic and environmental reasons.

Consequently, rock fragments are commonly separated from drilling fluid by devices such as oscillating screens that remove rock fragments and large drilling fluid solids during their circulation. Basically such a device has a narrow, inclined mesh sieve over which fluid returning from the borehole is passing. The trapped solids travel downward on the sloping surface to be collected in the agitator crunch or rock chute. It is also desirable to recover as much as possible from costly drilling fluids. Therefore, other devices that play a role in separating drilling fluid solids include cyclone and centrifugal separators. Rock fragments discharged from oscillating screens, cyclones and centrifuges, which are gathered in the trench or chute of rock oscillating rock fragments are still highly contaminated with drilling fluids and thus form a heavy mud or sludge. Typically the mud is conveyed to containers or buckets which are then periodically moved by crane from the drilling tower to a ship.

This process is disadvantageous for several reasons. First, the buckets take up valuable valuable floor space on the drilling tower. In addition, handling the buckets requires the use of the drilling tower crane, which can divert the crane from other important tasks. A prior art device utilizes a pneumatic driving arrangement to drive materials out of a dead sludge tank having a conical hopper section. It is believed that a disadvantage of such an arrangement is that using pressurized air as a sole means for discharging rock fragments may not properly evacuate rock fragments from the additive tank. Another disadvantage is believed to be that the circular opening of the conical section of the lupine could become clogged with rock fragments.

The present description faces these and other prior technical disadvantages.

Description Summary

In aspects, the present disclosure provides efficient systems and methods for processing, storing and transporting drilling rock fragments that are generated by drilling hydrocarbon-producing wellbores. These rock fragments, as noted earlier, are trapped in a drilling fluid that returns from the wellbore (return fluid). After the return fluid is separated to form a rock debris sludge, the rock debris is led into one or more sludge additive tanks through conduits such as hoses, pipes or tubing. The mud additive tank has a lower portion that converges to an elongated opening into which a rock fragment driving member is positioned. To discharge rock fragments, a rock fragment driving element, when energized, applies a driving force that causes the rock fragments to escape out of a sludge additive tank discharge port to a transfer line. When the rock fragments seep out of the bottom of the tank, gravity pulls more rock fragments into the rock fragment driving element. The rock fragment driving element can be operated in a first mode to scrub rock fragments and in a second mode to mix rock fragments. A suitable rock fragment driving member includes a rotary or auger screw conveyor coupled to an engine.

In one embodiment, the lower portion of the mud drilling additive tank has a wedge or gutter shape that feeds rock fragments to the rock fragment driving member. In contrast to a conical shaped lower portion that is defined by a single sloping wall that converges to a circular outlet opening, the wedge shaped lower portion is defined by at least two walls that converge to an elongated outlet opening as a slit. Advantageously, due to its relatively large size, the outlet opening as an elongated slot is less susceptible to clogging during flushing operations. In addition, the elongated slit exit opening may be configured to conform to an elongate rock fragment conducting member, aligned horizontally so that rock fragments are fed in a balanced manner to the rock fragment conducting member.

To further assist the discharge of rock debris out of the mud additive tank, pressurized air may be fed to one or more locations in the mud additive tank. A function for this pressurized air is to balance the pressure between the mud additive tank and devices connected to the mud additive tank. In some arrangements, the rock fragment driving member feeds rock fragments to a transfer line in communication with a pneumatic flow device. The pneumatic flow device uses high pressure air to propel rock fragments along the transfer line. To prevent backscrewing of rock fragments into the tank, it may be desirable to balance the pressure within the tank with the pressure in the pneumatic flow device. Thus, in one aspect, pressurized air is fed to the mud additive tank at a pressure value that compensates for increased pressures generated by the pneumatic flow device. In another aspect, pressurized air may be used to fluidize rock fragments in the mud additive tank. For example, when rock fragments are kept in the mud additive tank for an extended time, the weight of the rock fragments may force liquids to flow out of the rock fragments at the bottom of the tank. Thus occurs a form of stratification in which a relatively dense layer of rock fragments forms along the interior surfaces of the lower portion of the la-ma additive tank. This dense layer of rock fragments can slow or even strangle the flow of rock fragments out of the dead sludge tank. To break or reduce the viscosity of this relatively dense layer of rock debris, pressurized gas such as air may be introduced at one or more points near the bottom of the dead sludge tank. Gas flowing inwardly penetrates this layer of relatively dense rock fragments and reduces its density and / or physically dislocates this layer. In one arrangement, a first line of pressurized gas at one tank top balances the pressure of the tank and a second line of pressurized gas fluidizes the relatively dense layer of chip fragments. In another arrangement, the pressurized gas line to fluidize the relatively dense rock fragment layer provides gas at a pressure value that also balances the pressure of the mud additive tank.

In an arrangement suitable for offshore operations, the system includes a separation unit in the drilling tower, which forms rock fragments. The separation unit may include one or more oscillating screens, centrifugal type separators and / or other suitable devices. A rock debris flow unit leads the rock fragments from the separation unit to the mud additive tanks or other selected location. The rock debris flow unit may include, for example, a conveying type conveyor and pump or blower device for draining rock fragments or one or more bypass valves that may direct the rock debris flow as required. In one arrangement, a controller controls the flow of rock fragments to a plurality of mud additive tanks. Sensors positioned in each of the dead sludge tanks produce signals indicative of the volume of shards in an associated sludge additive tank. The controller controls rock fragments in response to sensor signals. Mud additive seals may be filled simultaneously, in sequence, or by any other scheme. Mud additive tanks may hold rock fragments until they can be discharged to a transport vessel or vehicle for processing and / or disposal. The transport vessel or vehicle may have a bank of containers adapted to receive the rock fragments from the delama additive tanks.

Examples of the most important aspects of the description have been summarized (albeit quite broadly) so that their following detailed description can be better understood, and the contributions they represent to the art can be appreciated. There are of course additional aspects of the description which will be described hereinafter which will form the subject of the claims attached thereto.

Brief Description of the Figures

For detailed understanding of the present description reference should be made to the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings:

Figure 1 schematically illustrates a system for processing, storing and discharging drilling rock fragments made in accordance with an embodiment of the present disclosure;

Figure 2A schematically illustrates a side view of a sludge additive tank according to one embodiment of the present description;

Figure 2B schematically illustrates an end view of a mud additive tank according to one embodiment of the present disclosure.

Figure 3 schematically illustrates a wedge shaped lower section of a sludge additive tank made in accordance with an embodiment of the present disclosure;

Figure 4 schematically illustrates a slurry tank and pressurized air supply system according to one embodiment of the present disclosure; and

Figure 5 schematically illustrates a mud feed tank according to one embodiment of the present disclosure used in an offshore drilling environment. Detailed Description of the Description

The present disclosure relates to devices and methods for processing, storing and transporting a drilling chip fragment slurry. The present description is susceptible of modalities of different forms. They are shown in the drawings, and will be described herein in detail, specific embodiments of the present disclosure, with the understanding that the present disclosure should be considered an exemplification of the principles of the disclosure, and is not intended to limit the description to that illustrated and described herein. described. Moreover, none of the elements described or combination of elements should be considered essential aspects of the present teachings unless the description expressly describes the element or combination of elements as essential.

As shown in Figure 1, a particular embodiment suitable for use in an offshore drilling tower, a rock fragment handling system 10 may include a separation unit 12, rock fragment flow units 14, 15 and a or more mud additive tanks 16. The system discharges rock fragments into one or more suitable containers 18 in a transport ship (not shown). In one mode of operation, the system receives return fluid that has rock fragments drawn from a wellbore being drilled. Separation unit 12 separates cotton drilling fluid from return fluid for reuse in another drilling and also forms a rock debris sludge. Rock debris flow unit 14 conducts the rock debris through a conduit 20 to the mud additive tank bank 16. Since mud additive tanks 16 are filled with rock fragments , a gravity-assisted, mechanically driven driving element discharges the rock fragments from the Ia-ma 16 additive tanks. The rock debris flow unit 15 drives the unloaded rock fragments through a transfer line22 into the containers 18 or transport vessel mud additive tanks (not shown). Thus, in contrast to conventional rock fragment handling arrangements, less human intervention is required to gather, store and move drilling rock fragments in a drilling tower. The elements constituting the embodiment of Figure 1 are discussed in more detail below.

Separation unit 12 extracts the relatively costly drilling fluid from the return fluid. In one arrangement, the separating unit 12 may include one or more oscillating screens 21. Within the oscillating screen 21 return fluid and entrained solids are discharged onto a vibrating separator having one or a series of sieved screens. . The sieves capture and remove solids from the return fluid that flow through it. The separation unit 12 may also include other separation devices, such as a centrifugal separator 22, which are also configured to extract drilling fluid from the rock fragments. Such separation devices and techniques are known in the art and will not be discussed in more detail. The effluent or outlet from the separation unit 12 is a relatively viscous sludge consisting of oil or rock covered with additives and debris. The terms elma rock fragments will be used interchangeably.

Rock debris flow unit 14 carries rock fragments from separation unit 12 to other devices such as mud additive tanks 16 or another location such as ship storage tanks 18. In one embodiment , the rock debris flow unit 14 includes a twisted-type device that continuously directs the rock fragments to a dense phase blower 24 that propels the rock fragments through a conduit 20 such as pipe or hose. Suitable valves, such as a bypass valve, may be used in conduit 20 to selectively direct the flow of rock fragments.

Referring now to FIGS. 1 and 2A-B, the mud additive tanks 16 receive and store the flow of chunks from the conduit 20. The tanks 16 have an upper cylindrical portion 26 and a lower portion 28 that converge to an opening In a manner described in more detail below, the lower portion 28 promotes mass flow of rock fragments through tank 16. Positioned at a lower end of the lower portion 28 is a conducting member 32 which applies a driving force that pushes rock fragments out of mud additive tanks 16. Pressurized gas, such as air, from a source 34 is fed to one or more locations in the additive tank. 16 to maintain a depression balance in system 10 and / or to fluidize rock fragments in the mud additive tank 16.

Filling of mud additive tanks 16 can be controlled manually, automatically or in a combination thereof. In one arrangement, a controller 35 receives signals from sensors36 positioned in the mud additive tanks 16. The sensor signals indicate the amount of rock fragments in the mud additive tanks 16. Thus, in one arrangement, a controller 35 may have a programmable logic circuit (PLC) that directs flow to a sludge additive tank 16 until the associated sensor 36 indicates that the sludge additive tank 16 is full. Thereafter the PLC interrupts sewage sludge 16 sewage by acting on appropriate valves and starts draining to the next sludge additive tank 16. This process can continue until all sludge additive tanks 16 are full. If a sequential filling process has been described, it should be appreciated that two or more mud additive tanks 16 could be filled at the same time. Although in some embodiments the tank may be constructed to hold 15.89 Kll of drilling rock fragments having a relative density of 2.34, other sizes and configurations may also be used.

As explained above, rock fragment mud may be relatively viscous and will not flow effectively under the effects of gravity alone. Therefore, the driving element 32 forcibly pushes the rock fragments out of the mud additive tanks 16. In one embodiment, the driving element 32 is a rotary screw conveyor driven by a motor drive 33. A bolt portion extends horizontally along an axle of the wedge-shaped portion 28. Rotation of the bolt drives the rock fragments to the transfer line 22 and the rock fragment debris unit 15. In some arrangements, the element 32 is reversible on the right and left sides. In the right rotation mode, the rock fragments flow down to a door 36. In the left rotation mode the rock fragments are mixed to maintain material consistency. This is advantageous when the shell fragments are stored for long periods of time as heavier material will decant to the bottom of the tank and lighter fluids will flow to the top. This stratification of materials can make it difficult to empty the rock debris tank. Under such circumstances, the left rotation will mix the rock fragments and allow the rock fragments to flow out of the tank. In still other embodiments, two or more driving elements may operate together to expel the rock fragments out of the mud additive tank. A screw or auger is merely an illustrative element suitable for applying a driving force through the entire body of the rock fragments. It should be appreciated that the driving member 32 positioned within the mud additive is susceptible of numerous variations that can properly apply a driving force to expel the rock fragments out of the mud additive tank 16. For example, mecca Suitable driving mechanisms include pneumatic systems, progressive decay pumps, and vacuum pumping systems.

Referring now to Figures 2A-B and 3, the lower portion 28 operates in conjunction with the drive member 32 to discharge off tank 16. In one embodiment, the lower portion 28 has a wedge, chisel or chute shape which It is generally defined by two sets of walls 40 and 42. For convenience, this shape will be referred to as a wedge shape. Each wall assembly 40 and 42 has an associated angle 46 and 48 with the horizontal respectively. Angles 46 and 48 are selected such that the first drill rock fragments entering the tank are the first drill rock fragments to leave the tank, i.e. mass flow. Walls 40 and 42 converge to aperture 29 which is longitudinally aligned with guide member 32. As should be appreciated, in contrast to a conical shaped section that converges to a circular aperture, aperture 29 has a flow area. cross-section as a relatively large, elongated crack through which rock fragments can flow. Thus, there is a reduced risk that rock fragments may clog or obstruct aperture 29. In addition, it should also be appreciated that the wedge-shaped portion 28 and the elongated aperture 29 can distribute and also hold rock fragments through a relatively large portion of the member. 32. Other elongated or non-conical shapes may also be used in certain applications.

In an operational mode taken as an example for unloading rock fragments, gravity pushes the rock fragments to the driving element 32, which then conducts the rock fragments out of tank 16. When the rock fragments leave tank 16 , additional rock fragments fall into the guide member 32. Advantageously, the wedge-shaped portion 28 causes a mass flow of rock fragments which substantially substantially carries the guide member 32 during this process. . Thus, in one aspect, system 10 discharges rock fragments out of tank 16 using a gravity-assisted mechanically driven arrangement.

To support the rock debris discharge operation, shown in Figure 4 is a source 60 that supplies pressurized gas, such as air, to balance the pressure of tank 16 and / or fluidize the rock fragments in tank 16. In one embodiment, doors 62a and 62b which are coupled to source 60 by suitable conduits 64 introduce pressurized gas at one or more points along the mud additive tank16. One or more of the doors 62a may be positioned to break or reduce the viscosity of deposited layered rock fragments on the inner surfaces of the wedge-shaped lower portion28. Gas flowing through such gates 62a penetrates this layer of relatively dense rock debris and reduces its overall density. That is, the gas mixes with or covers the layer of rock fragments. Gas flowing in may also physically displace or dislodge portions of this layer from the interior surfaces of tank 16. One or more doors 62b may also be positioned at or near the top of tank 16 to provide pressure balancing gas. In the embodiment of FIG. 4, source 60 operates as the rock debris flow unit 15 (FIG. 1) supplying high pressure gas to prevent rock debris through the transfer line 22. For example, source 60 may provide continuous flow of rock. high pressure air to the transfer line 22 at the same time as the conducting element 32 (Figure 2A) feeds rock fragments to the transfer line 22. Since source60 and mud additive tanks 16 are in direct communication Through the transfer line 22, the high pressure gas in the transfer line 22 may apply backpressure to tank 16. This applied backpressure may restrict the flow of outwardly fragmented rock fragments 16. To compensate for the generated operating pressure from source 60, pressurized gas fed through ports 62 increases the pressure in tank 16 until at least partially offset this applied back pressure. In certain embodiments, pressurized gas flowing through ports 62a can at the same time fluidize the relatively dense rock fragment layer and supply gas at a pressure value that also balances the pressure in the mud additive tank.

A number of instruments and devices may be used to control the flow of pressurized gas. For example, valves70 for selectively supplying gas to ports 62a and 62b may be controlled by solenoid control 72. A solenoid control unit 64 may also be used to control a valve 74 that supplies pressurized supply to transfer line 22. Additionally, suitable gauges 76, such as pressure gauges and level gauges, may be positioned as desired in tank 16. In various applications the pressurized gas may be air, but other gases such as nitrogen may be used.

Referring now to Figure 5, there is shown a embodiment of the present disclosure that is suitable for offshore drilling applications. As is known, platform lifting, drilling or reworking operations, float, utilize a subsurface installation such as an offshore drilling tower 70 from which a drilling riser 72 or other device leads a drilling column 74 for a subsurface well (not shown). Positioned on the offshore drilling tower 70 is the rock fragment handling system 71 which processes the return fluid from the subsurface deposit hole (not shown) using previously discussed equipment and conducts the rock fragments to a rock bank. mud additive tanks 76. During drilling, return fluid is processed and rock fragments continuously conducted and stored in mud additive tanks 76. A controller fills dead mud tanks 76 using programmed instructions and signals from properly positioned sliders. Periodically a transport vessel 78 such as a barge is moored adjacent to the drilling tower 70 and storage tanks 80 on the barge 78 are connected to the rock fragment handling system 71. Thereafter high pressure gas is fed to the tankers. mud additives 76 to flow the rock fragments and balance the pressure in the mud additive tanks 76. Once the driving device 32 (Figure 2A) is energized, rock fragments flow out of the additive tanks. mud 76 and to barge 78.

It should be appreciated that the rockframe handling systems described above offer improved safety due to the reduced number of handling operations such as personnel intervention for hooking containers to the crane, manual scraping rock fragments to containers, container transfers around drilling tower floor, use of drilling tower crane, etc. In addition, the transport vessel to which the roach fragments are discharged is only temporarily tied to the drilling torch. A continuously moored transport vessel could pose a risk to the drilling tower and to itself during rough weather. Thus, reducing the time the transport vessel is tied to the drilling tower also reduces the risk that inclement weather will interfere with drilling operations.

While the foregoing description is directed to preferred embodiments of the disclosure, several modifications will be apparent to those skilled in the art. All variations within the scope of the appended claims are intended to be encompassed by the preceding description.

Claims (20)

1. A system for handling a return fluid formed from drilling fluid and recovered dragged rock fragments by drilling a wellbore in a soil formation, comprising: (a) a separation unit that at least partially separates the return fluid drilling fluid, a rock fragment sludge being formed therewith, (b) a rock fragment flow unit and receiving the rock fragments from the separation unit, the rock fragment flow unit conducting the rock fragments through a conduit attached to it, (c) at least one tank attached to the conduit, the tank has a lower portion that converges to an elongated opening and (d) a conducting member positioned adjacent the elongated opening receiving the conduits. rock fragments from the bottom and which seep the rock fragments out of at least one dead sludge tank. A system according to claim 1 further comprising a flow device that receives the flow of rock fragments from the conducting element and conducts rock-fragments to a selected location. A system as claimed in claim 2 further comprising a gas source providing a pressurized gas to the minimum tank to at least partially displace a pressure increase associated with operation of the scrap debris flow device. A system according to claim 1 further comprising a gas source which supplies a gas to at least one tank to provide a minimum of a portion of the rock fragments in at least one tank. The system of claim 1, wherein the lower portion is wedge-shaped and wherein the driving element includes a longitudinally aligned stroke with the elongated opening. A system according to claim 1, wherein the minimum tank includes a cylindrical upper portion, the rock fragments flowing from the upper portion to the lower portion. The system of claim 1, wherein the driving element operates in a first mode for flowing out the rock fragments and a second mode for mixing the rock fragments. A method for manipulating a return fluid formed from drilling fluid and dragged and recovered rock fragments when drilling a wellbore in an earth formation comprising the steps: (a) separating the drilling fluid from the return fluid to form a rock fragment sludge with a separation unit, (b) guide the rock fragments through a conduit attached to the separation unit using a rock fragment flow unit, (c) receive the rock fragments into at least one duct coupled tank, the mud additive tank having a lower portion that converges to an elongate opening; and (d) draining the rock fragments out of at least one tank using a guide element positioned adjacent the elongate opening. A method according to claim 8 further comprising the step of guiding the rock fragments to a selected location using a flow device that receives rock debris from the conducting element. The method according to claim 9 further at least partially displacing a pressure increase associated with operation of the flow device using a gas source providing a pressurized gas to the at least one tank. The method of claim 8 further comprising the step of fluidizing at least a portion of the rock fragments from at least one tank using a gas source that supplies a gas to at least one tank. A method according to claim 8, wherein the lower portion is wedge shaped and the driving element includes a longitudinally aligned guideway against the elongate opening. The method of claim 8, wherein the minimum of a tank includes a cylindrical upper portion, the rocker fragments flowing from the cylindrical upper portion to the lower portion. A method according to claim 8 further comprising the step of operating the conducting member in a first method for flowing the rock fragments and in a second mode for mixing the rock fragments. A system for manipulating separate rock fragments from a return fluid formed from drilling fluid and dragged rock fragments, comprising: (a) a tank for receiving the rock fragments, the one having a cylindrical upper portion and a wedge-shaped lower portion which converges to an elongated opening; and (b) a guide member positioned adjacent the elongate opening which receives the rock fragments from the wedge-shaped lower portion and drains the rock fragments out of the tank. The system of claim 15, further comprising a flow device which receives the rock fragments flow from the conducting element and which conducts the rock fragments to a selected location. The system of claim 16, further comprising a gas source providing a pressurized tank gas, to at least partially displace a pressure increase associated with operation of the roach debris flow device. The system of claim 15 further comprising a gas source that supplies a gas to the tank to fluidize at least a portion of the rock fragments in the tank. The system of claim 15, wherein the conducting member operates in a first mode for flowing the rock fragments and in a second mode for mixing the rock fragments. The system of claim 15, wherein the lower portion is defined by a first set of walls and a second set of walls, each wall of the first and second wall sets having an angle selected to cause excess flow of the walls. rock fragments.