Patent Application
20210222813
The present application relates generally to pulsation dampeners/dampners/dampers/accumulators and, more specifically, to replacing the nitrogen within gas-charged pulsation dampeners with a reactive, compressible liquid while accounting for thermal expansion by one or more of augmenting with cellular material, a gap or less than full fill of the bladder with the reactive liquid, and a reset pressure relief valve.
In North America, the first commercial oil well entered operation in Oil Springs, Ontario in 1858, while the first offshore oil well was drilled in 1896 at the Summerland Oil Field on the California coast. Reciprocating systems, such as reciprocating pump systems and similar equipment, operate in many types of cyclic hydraulic applications. For example, reciprocating mud pump systems are used to circulate the mud or drilling fluid on a drilling rig.
As well depths and drilling efficiencies increased along came the need for highly efficient mud pumps. The early designs were rudimentary double acting duplex pumps that have since been replaced with high pressure and high horsepower single acting triplex and other single acting designs including quadruplex, quintuplex and hexuplex mud pumps.
Pressure peaks within the pumped fluid accelerate, with each pulsation, the deterioration of the pump, the pump's fluid end expendable parts, and equipment downstream from the pump, such as measurement equipment used to determine drilling parameters, and wash pipe and wash pipe packing. Failure to control such pressure peaks inevitably affect the operating performance and operational life of the pump, pump fluid end expendable parts and all upstream or downstream components. Pressure peaks may also interfere with instrument signal detection, such that failure to control pressure peaks may also affect the signal detection and/or quality of the signal detection in (for example) measurement while drilling operations.
Thus, with increased pressure and pump horsepower came the need to reduce pulsations from the pump in order to maintain drilling efficiencies. In the early 1940's, nitrogen gas charged pulsation dampeners were introduced beginning with 5, then 10 and now 20 gallon units. As drilling efficiencies are paramount, the need to have pulsation dampeners effectively reduce the level of pulsation energies and their potential interaction with system natural frequencies are becoming more critical. The interaction of the pump primary pulsation frequencies with those of the system sets up potentially harmful and destructive forces (vibrations) resulting in early fatigue failure of mud pump expendables, mud line equipment, Kelly and kicker hoses, top drive wash pipe packing and significant interference with managed pressure drilling (MPD), measurement while drilling (MWD), or logging while drilling (LWD) exploration and production activities.
Pulsation control equipment is typically placed immediately upstream or downstream from a reciprocating pump, often with a relative size and configuration proportional to the volume of desired fluid displacement per stroke of the pump and the maximum allotted magnitude of the pressure peaks that may be experienced by the pump system during each pulsation. Pulsation control equipment thus aids in reducing pump loads and minimizing pulsation amplitudes to the pump, the pump's fluid end expendable parts and to equipment upstream or downstream. As a result, pulsation control equipment increases the relative operating performance and life of the pump, the pump's fluid end expendable parts and any equipment upstream or downstream from the pump. In addition, drilling efficiency using MPD/MWD/LWD systems is impacted as discussed above.
Employing conventional gas charged dampener (or, equivalently for purposes of this disclosure, “dampener”, “damper,” “accumulator,” or “pulsation control equipment”) generally involves a pressure containment vessel in cylindrical, spherical, torospherical or similar shape in which resides a bladder (or, equivalently for purposes of this disclosure, “diaphragm” or “bellows”) that contains a nitrogen gas pre-charge. This conventional design has been adapted for use in drilling and all other industrial markets of positive displacement reciprocating piston/plunger pumps.
For gas-charged pulsation dampeners, the challenge has always been to establish the correct pre-charge on the bladder against expected system operating conditions. In steady-state operating conditions with established pre-charge, the system performance is acceptable. However, in contemporary MPD/MWD/LWD processes, where micro-process corrections are made continuously and system pressures fluctuating widely, the dampener performance and the service life of the bladder is reduced. As pre-charge on the dampener bladder can only be established against zero operating pressure, the system needs to be shut down such that productivity is curtailed when making changes to the dampener precharge. Once the calculated pre-charge is established, the bladder may fail when the system pressure varies outside the safe operating limits, or may fail to perform as desired when the system pressure varies outside the expected operating range.
Further, continuous adjustment of the pre-charge needs to be made during the service life of the bladder to ensure long and acceptable performance. A few regenerative systems, as yet highly impractical, have been tried.
In the absence of other solutions, a liquid-only, bladder-less (maintenance free) dampener has entered the market, but occupies a large space and/or has a large footprint since the performance (based purely on liquid compressibility) requires a large liquid volume to achieve acceptable pulsation control. The designs are more effective at higher system pressures and may achieve good pulsation control across all applications where system pressures fluctuate beyond what conventional pulsation dampeners are designed to handle, but the space trade-off needs to be considered.
A pulsation dampener includes a quantity of liquid reactive fluid (e.g., about 20 gallons) contained within a flexible diaphragm and separated from external pumped fluid flow by the flexible diaphragm. The liquid quantity of reactive fluid is selected to dampen pressure pulses within the external pumped fluid flow. The pulsation dampener is configured to accommodate thermal expansion of the quantity of liquid reactive fluid by one or more of including a quantity of compressible foam within the flexible diaphragm, allowing for a space between the flexible diaphragm when holding the quantity of the liquid reactive fluid and a body of the pulsation dampener, or providing a reset pressure relief valve
Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; and the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.
For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
The present disclosure utilizes reactive, compressible fluid to replace the compressible gas medium in conventional pulsation dampeners. Suitable compressible fluids of the type contemplated in this application are known in the art.
The use of reactive fluid in pulsation control in accordance with the present disclosure is designed to limit pulsations to acceptable levels.
As apparent from the table above and
The primary focus of the diaphragm filled or partially filled with reactive fluid (or, for most applications contemplated herein, a hybrid combination of liquids including reactive fluid that may be used interchangeably with reactive fluid liquid) within maintenance free pulsation dampeners is to ensure significant improvement on MPD drilling efficiencies and both MWD/LWD signal response as and when needed during drilling operations. The diaphragm filled or partially filled with reactive fluid essentially allows the driller to continue their mode of operation and gain higher drilling efficiencies in extended reach drilling programs without the need to precharge/recharge the conventional drilling dampener.
Compressible fluids of the type known in the art and contemplated herein typically have a thermal expansion that, when the fluid exposed to the higher temperatures of drilling muds or other fluids in other possible uses, will increase in volume. Accordingly, when the internal bladder volume is completely full, thermal expansion may cause a sufficient rise in internal bladder pressure to reduce the effectiveness of the pulsation energy mitigation and, possibly, result in an increase in pressure sufficient to burst the metal pressure vessel. Options for addressing this issue are described below.
Referring now to
A fluid pump or mud pump 202 may pump fluid or mud from a mud pit 206 through the discharge line 204 in the direction of a drilling rig 212. (The term “mud pit” may also reference a fluid reservoir, where the fluid reservoir stores a fluid used during a drilling process). More than one mud pump can be utilized in a drilling system 200 to continue drilling upon the failure of a single mud pump. A pulsation dampener can be installed at the discharge line for each mud pump to further reduce pulsations.
Conventionally, a pulsation dampener is located along the discharge line 204, at the outlet of the mud pump 202 and before the standpipe manifold 208. The standpipe manifold 208 may be installed down the discharge line 204 and is attached to and/or coupled in fluid communication with the drilling rig 212. The standpipe manifold 208 may receive a plurality of different fluid streams from a plurality of mud pumps. The standpipe manifold 208 may then combine all of the fluid streams together to send a single fluid stream up the standpipe 210. Other functions traditionally performed by the standpipe manifold are to provide an auxiliary connection for a supplementary pump and, in systems with multiple standpipes providing operational redundancy in case of failure of one standpipe, to switch fluid flow paths from one standpipe to another. However, those skilled in the art understand that some systems dispense with the standpipe manifold, and simply bring the outlet flows of multiple mud pumps together in a single line somewhere near the mud pumps or downstream, with the combined flow then traveling in a single line to the substructure and upwards toward the standpipe,
When the fluid streams from multiple mud pumps are combined (in a standpipe manifold or without one), the pulsations in the resulting combined fluid flow can be enlarged based on the different pulsations of the mud pump(s) 202 being used. For example, the different types or sizes of mud pumps can be used in a single drilling system 200, which would cause variations or pulsations in the fluid flow through the pipe. The mud pump(s) 202 could also be located at different distances from the standpipe manifold 208. The mud pump(s) 202 could begin and/or stop operation at different times, with an operating off cycle (phase) distinct from other mud pumps, or simply be operating at different speeds. Any of the previous operating parameters would affect the flow of fluids or mud into the standpipe manifold 208 causing pulsations at the well.
The standpipe 210 may be installed on the drilling rig 212 and travel up the drilling rig 212 to provide the fluid stream through a rotary hose 216 connected to a swivel 218, the swivel 218 coupled to a rotary hook 220. The standpipe 210 receives discharge from the standpipe manifold, which includes flow from the pump pulsation dampener. The standpipe manifold 208 can include multiple discharges to the standpipe 210 in case of failure in part of the standpipe manifold 208 or associated pipeline
The swivel 218 may serve as a passageway for the fluid stream into a Kelly drive 222 (or just “Kelly”). The Kelly 222 connects to a drill string 224. The fluid passes through the Kelly 222 and the drill string 224 down a bore hole 226 to the drill bit 214 disposed at a far end of the drill string 224. The Kelly 222 is typically rotated by a rotary table 228. More recent systems may include a top drive to rotate the drill string 224 as an alternative to the rotary table and Kelly drive, and the present disclosure is applicable to such top drive configurations as well.
A single mud pump 202 is depicted diagrammatically in
Pulsation dampeners 302a, 302b are each mounted on top of a corresponding strainer cross 303a, 303b. Each strainer cross 303a, 303b is connected to the discharge of the respective pump 301a, 301b, to filter solids larger than a predetermined size from the pumped fluid. Suction stabilizers 304a, 304b are connected to the inlet of the respective pump 301a, 301b contribute to the absorption of pressure pulsations.
Each pulsation dampener 302a, 302b contains a flexible, bag-shaped diaphragm filled or partially filled with reactive fluid. In some configurations, space and support are key and in/out flow-through piping is required. For use of typically-sized (e.g., 20 gallon) appendage-mounted pulsation dampeners 302a, 302b, pump skids and piping may be of standard design. For use of the hybrid combination of liquid only maintenance free pulsation dampener(s) (not shown) with reactive fluid-filled pulsation dampener 302a, 302b, modifications and space within the pump room may be required.
Cross-sections of a reactive fluid-filled pulsation dampener according to embodiments of the present disclosure are depicted in
Fluid from the connected piping enters and/or leaves the cavity 406 via the lower opening 407. The pressure of that fluid relative to the pressure of the reactive fluid within the diaphragm 408 will cause the lower surface of the diaphragm 408, which is in contact with the pumped system fluid, to shift such that the volume within the cavity 406 that is occupied by the reactive fluid within the diaphragm 408 changes.
The pulsation dampener 302a may optionally include a guard 409 covering a high pressure fill valve 410 for receiving liquid reactive fluid during initial fill or replenishment and a pressure gauge 411 to indicate reactive fluid pressure during pump operation. A diaphragm stabilizer 412 in the form of (for example) a semi-rigid plate may be attached to a bottom of the diaphragm 408 helps maintain the shape of the diaphragm 408 across repetitive cycles of pressure pulsation dampening.
Within pump system 500, reactive fluid pulsation dampeners 302a, 302b may be mounted on a strainer-cross at the outlet of the respective pump 301a, 301b as described above connection with
The body 601 may be sized to hold an amount of pumped fluid (e.g., 40 gallons) selected to provide reactive pulsation dampening under the expected operating conditions of the pump system. Suspended from the turret 602 into an interior of the body 601 is a containment diaphragm+that may be contained by a perforated containment shell 610 or held in suspension by a seal or lip 608 and filled with reactive fluid through fill valve 609. The reactive fluid-filled diaphragm 607 contributes to dampening of pressure pulsations in the pumped fluid passing through the body 601. The inlet 604 and the outlet 605 may optionally each be designed with a studded connection 611, 612 for connection to respective system piping 613, 614.
Analogous to
The diaphragm 703, which may be formed of standard material and have a conventional shape, may be partially filled with a combination of elastomeric shapes and liquid reactive fluid. The elastomeric shapes are a compressible foam material, such as a closed cell foam. In one example, the diaphragm 703 may be filled with elastomeric wedges or elastomeric balls. However, the elastomeric addition to a liquid reactive fluid system may take any form or shape or combination of shapes. Spaces between the elastomeric shapes are filled with a liquid reactive fluid. In operation, the compressible foam material will compress under the pressure applied to the exterior of the internal diaphragm by the pumped fluid and the internal pressure of the liquid reactive fluid, creating a “gap” between the exterior of the internal diaphragm 703 and the interior of the body 701 to account for thermal expansion. The compressible foam material will quickly go completely flat when pressure is applied, thus creating the largest available volume for thermal expansion.
Alternatively, the compressible foam material may be integrated into diaphragm stabilizer 705—that is, diaphragm stabilizer 705 may be formed wholly or partially of compressible foam material. The views of
The views of
The views of
By providing either compressible foam material inside the bladder, or a gap between the exterior of the bladder and the interior surface of the body, or a combination of both, the effects of thermal expansion by the liquid reactive fluid within the bladder may be compensated, allowing the pulsation dampener to continue to effectively mitigate pulsations.
Once again analogous to
The views of
Various techniques may be used to fill the bladder 803 to a preset volume of liquid reactive fluid (less than maximum volume capacity of the bladder 803), to allow for non-detrimental and nondamaging thermal expansion. This approach could involve pumping a fixed or preset volume from a supply source into the bladder (stopping the pumping either by watching a flow meter or by pumping the supply source dry), or could involve (with the top cover off) pouring a fixed volume into the bladder, then installing and securing the top cover. Alternatively, the liquid reactive fluid may be packaged within individual flexible containers such as balloon(s) that are then inserted into the diaphragm (bladder) 803 through the open top, before the top cover is secured. While a single flexible (or deformable) container (e.g., one balloon) containing the entire quantity of liquid reactive fluid determined to be needed based on the operating pressure(s) and temperature(s) may be used, it may be beneficial to use multiple flexible containers each containing a portion of that determined quantity of liquid reactive fluid, and may further be beneficial to use multiple balloons containing unequal portions. Thus, for example, for an 18 gallon fill, the liquid reactive fluid may be distributed as a set of three 5 gallon flexible containers, two 1 gallon flexible containers, and two ½ gallon flexible containers. The flexible containers, once inserted into the bladder 803, will deform to fit the interior volume of the bladder 803 and the interior shape of the pressure vessel body 801. For any of the foregoing approaches (which may be used for the other embodiments described herein), any air remaining in the internal volume of the bladder 803 may be bled out once the pump pressure is present.
In embodiments where the liquid reactive fluid is poured into the bladder 803 with the top cover removed, fill lines 805, 806 and 807 may be provided as raised ribs or protrusions on the surface of the bladder 803 as shown in
In some embodiments, the size and shape of the interior volume of the body 801 and the size and shape of the molded bladder 803 may be configured for a specific volume or predetermined quantity of liquid reactive fluid (e.g., 20 gallons, or 18 gallons, etc.) used to dampen pressure pulsations in the pumped fluid. In such embodiments, the material of the bladder 803 need not stretch to accommodate the pressure of the predetermined quantity of liquid reactive fluid. This differs from gas-charged pulsation dampeners, in which the bladder normally expands to fill the interior volume of the pressure vessel when gas is inserted to a target operating pressure. The bladder size/shape and the interior volume size/shape leave a gap between the exterior of the bladder 703 and the interior surface of the body 701 to account for thermal expansion of the liquid reactive fluid.
The embodiment of
Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.
This application claims priority to U.S. Provisional Patent Application No. 62/961,953 filed Jan. 16, 2020 and to U.S. Provisional Patent Application No. 62/985,613 filed Mar. 5, 2020. The content of the above-identified patent documents is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62961953 | Jan 2020 | US | |
| 62985613 | Mar 2020 | US |
