Method and system of sand management

A technique facilitates sand control in a wellbore. A lower completion and an upper completion are run downhole into the wellbore and deployed. The lower completion assembly employs a plurality of packers to isolate well zones. The lower completion assembly also has gravel pack ports which are independently opened to enable gravel packing of each individual zone via a tool run downhole. Additionally, the lower completion assembly has a production port in each zone. A shifting tool is employed to open the production ports and to enable production from the well zones.

BACKGROUND

In many well applications, various completions and completion techniques are employed to limit the influx of sand from the surrounding formation. Many types of completions have been designed to inhibit or block the migration of sand into downhole equipment in an effort to avoid damage to the equipment which can otherwise result as particulate matter passes through with the production fluid. A variety of sand screens and/or gravel packs may be employed to control the sand production. However, current equipment and techniques can be relatively complex, burdensome and expensive to employ.

SUMMARY

In general, the present invention provides a technique for providing sand control in a wellbore. A lower completion is run downhole into the wellbore engaged with, or subsequently engaged with, an upper completion. The lower completion assembly employs a plurality of packers to isolate well zones. Gravel pack ports are independently opened to enable gravel packing of each individual zone via a coil tubing string or other small diameter tubing string run downhole. Subsequently, a separate shifting tool is employed to open production ports which enable production from the isolated well zones.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

The present invention generally relates to a method and system for controlling sand in a well application. According to one embodiment, the method and system enable a simplified approach to providing a completion assembly in a wellbore with protection against the influx of sand from the surrounding formation. The technique enables deployment of a lower completion assembly and also an upper completion string. In many applications, the lower completion assembly and the upper completion string are deployed downhole together in a single trip for a one trip installation. However, the technique may be adapted to deploy the lower completion assembly in a first run in hole and the upper completion string in a subsequent run.

The present technique enables the wellbore to be segregated into a plurality of well zones which facilitate production of fluid from a plurality of corresponding well zones in the surrounding formation. Each of the well zones along the wellbore may be individually gravel packed to help limit the flow of sand into the lower completion assembly. The technique provides a simple approach to gravel packing independent zones and subsequently opening the zones to production of a desired well fluid. Additionally, the technique provides the ability to employ a non-service tool, non-sealbore gravel packing system.

Referring generally toFIG. 1, an embodiment of a sand control system comprises a lower completion assembly20which is illustrated as deployed in a well22. The well22is defined by a wellbore24which, in this example, has been lined with a liner or casing26. A plurality of perforations28has been formed through the casing26in each of a plurality of well zones30. The perforations28enable flow of a production fluid, e.g. a hydrocarbon based fluid, from a surrounding formation32into the wellbore24.

The lower completion assembly20is run in hole to a desired location within wellbore24to enable retrieval of the production fluid from the desired reservoir within formation32. A conveyance34is employed to convey the lower completion assembly20to the desired location within wellbore24. Depending on the environment and application, conveyance34may comprise a variety of tubing types, cables, or other suitable conveyances. In the embodiment illustrated, a rig36is positioned at a surface location38to deploy lower completion assembly20downhole via conveyance34. It should be noted the present technique enables deployment of the lower completion assembly20and an upper completion assembly (described below) in a single trip to facilitate an efficient, one trip installation. Thus, in many applications the lower and upper completions are deployed together, and description of the lower completion assembly herein does not imply a two trip installation technique. However, certain environments and/or types of completion equipment may be amenable to a two trip installation.

In the embodiment illustrated inFIG. 1, the lower completion assembly20comprises a completion tubular40to which an upper packer42is mounted. By way of example, the upper packer42may comprise a Quantum packer available from Schlumberger Corporation. Additionally, a plurality of isolation packers44is positioned along the tubular40to enable isolation of the well zones30along wellbore24. The isolation packers44may comprise a variety of devices able to seal off the annulus between tubular40and the surrounding casing26. According to one embodiment, however, isolation packers44are constructed as swellable packers formed with a swellable material46which swells in the presence of a specific substance. For example, the swellable material46may be designed to swell and expand against the surrounding wellbore wall when exposed to a specific fluid, e.g. diesel fluid, or another fluid designed to cause swelling and expansion of the material46. In some applications, however, packers44may comprise mechanical packers.

The lower completion assembly20also may comprise a plurality of screens48, such as manifold screens, designed to further prevent movement of undesired particulate matter into an interior50of completion tubular40. Radially inward from each screen48, the lower completion assembly20further comprises one or more production ports52which may be selectively opened and closed via a corresponding production sliding sleeve54, or other suitable flow control device. The sliding sleeves54enable selective control over the inflow of production fluid through the corresponding screen48and into interior50of lower completion assembly20.

In the embodiment illustrated, the lower completion assembly20further comprises a plurality of gravel pack ports56with at least one gravel pack port56extending through completion tubular40in each well zone30. The gravel pack port or ports56of each well zone30may be positioned above the production ports52and screen48within that well zone30. Flow through the gravel pack ports56is controlled by corresponding gravel pack sliding sleeves58, or other suitable flow control devices, to control the outflow of slurry into the surrounding annular region.

Depending on the specific application, lower completion assembly20may further comprise a valve mechanism60positioned in interior50of tubular40at a lower end of lower completion assembly20. The valve mechanism60may be employed to control flow along interior50by, for example, restricting flow past lower completion assembly20to a single flow direction. By way of example, valve mechanism60may comprise a double poppet shoe or a check valve.

With additional reference to the flow chart ofFIG. 2, one example of an initial sand control procedure utilizing lower completion assembly20is illustrated. In this example, a perforating procedure is initially carried out to perforate each well zone30with perforations28, as represented by block62. Subsequently, the lower completion assembly20is run downhole into wellbore24via rig36, as represented by block64. Once the lower completion assembly is positioned at the desired setting depth within wellbore24, the isolation packers44are expanded against the surrounding wellbore wall, as represented by block66. According to at least one embodiment, expansion of the isolation packers44is achieved by displacing an activating fluid through a service tool to expand the isolation packers by swelling the swellable material46. The activating fluid flowed downhole also may be used to remove fluid loss material, e.g. fluid loss pills, deployed over the perforations28, as represented by block68.

The upper packer42may then be set, as represented by block70. By way of example, upper packer42may be set by dropping a setting ball down through conveyance34; however other mechanisms also may be used to set the upper packer42against the surrounding wellbore wall. Subsequently, the rig36is employed to pickup the service tool and to reverse the activating fluid flow, if activating fluid has been deployed downhole. At this stage, the operator also ensures that the well is dead by, for example, inflow testing if necessary, as represented by block72. The conveyance34and service tool, if deployed, are then pulled out of hole, as represented by block74.

Referring generally toFIG. 3, an upper completion string76is illustrated as deployed downhole into engagement with lower completion assembly20. As described above, the upper completion76and the lower completion20often are joined before run in and then run in hole in a single trip. The upper completion string76may be engaged within the upper end of lower completion assembly20via a variety of available engagement mechanisms and techniques. Once the upper completion string76and lower completion assembly20are positioned in the wellbore, coil tubing78may be deployed downhole through upper completion string76into lower completion assembly20via surface based coil tubing equipment80. The coil tubing78can be used to manipulate a variety of coil tubing tools82within lower completion assembly20. It should be noted that upper completion string76is combined with lower completion assembly20to form an overall sand control system84. In some applications, coil tubing string78may be replaced by a small diameter, through-tubing jointed pipe. Additionally, the coil tubing equipment80may comprise a coiled tubing barge which allows the completion deployment rig36to be moved off location. In many applications, movement of the rig36off the wellbore to enable use of the coil tubing barge or other coil tubing equipment80substantially increases operational efficiency and provides great financial benefit with respect to the gravel packing operation.

With additional reference to the flow chart ofFIG. 4, an example of a subsequent sand control procedure utilizing lower completion assembly20is illustrated. In this example, the upper completion string76is run and installed downhole, as represented by block86. The well is then tested and suspended, as represented by block88. This allows the rig36to be moved off location, as represented by block90. During movement of the rig off location, swell packers44may be allowed to activate, i.e. swell. (In other applications, however, the packers44, e.g. mechanical packers, are set prior to leaving location with the main rig36.) Subsequently, coil tubing equipment80is moved over well22and positioned for deploying coil tubing78downhole, as represented by block92.

Once the coil tubing equipment80is in place, coil tubing78is run in hole and coil tubing tool82is used to move the gravel pack sliding sleeve58and to open the corresponding gravel pack port56of the lowermost well zone30instead of using an internal service tool, as represented by block94. Slurry is then directed downhole through the coil tubing78, out through coil tubing tool82, and then through the lowermost gravel pack port56. The slurry is circulated through an annular region96surrounding the lower completion assembly20in the lowermost well zone30(seeFIG. 3), as represented by block98. In this embodiment, the slurry may then be squeezed, as opposed to circulated, across the lowermost perforations28. Subsequently, the lowermost gravel pack sliding sleeve58is closed via coil tubing tool82, as represented by block100.

Referring toFIGS. 5 and 6, a subsequent procedure of the overall sand control technique is illustrated. As illustrated inFIG. 5, a shifting tool102may be employed within lower completion assembly20to facilitate preparation of the well22for production. Referring to the flowchart ofFIG. 6, however, one example of a procedural approach for finalizing preparation of the well22for production is illustrated.

Following gravel packing of the lowermost well zone30, excess slurry is circulated out, as represented by block104. The coiled tubing tool82is then picked up to open the next sequential gravel pack port56by moving its corresponding gravel pack sliding sleeve58. This allows the subsequent well zone30to be gravel packed by squeezing slurry across the well zone perforations, as represented by block106. The gravel packing procedure is repeated for each subsequent well zone30until each annular region96is filled with an appropriate gravel pack108, as represented by block110.

Once the gravel packing procedure is completed at each well zone30and a gravel pack108is disposed in each annular region96, the coil tubing tool82is pulled out of hole, as represented by block112. After removing coil tubing tool82, the shifting tool102is run in hole on, for example, coil tubing78deployed by coil tubing equipment80. The shifting tool102is used to open all of the production ports52by moving the corresponding production port sliding sleeves54, as represented by block114. After opening the production ports52to enable the inflow of production fluid, e.g. oil, the well22is ready for production, as represented by block116. Within each well zone30, the gravel pack108and screen48cooperate to provide sand control by restricting the influx of sand into interior50of lower completion assembly20. The design of lower completion assembly20provides an easy and effective system and procedure for controlling the influx of sand.

Referring generally toFIG. 7, another example of the overall sand control system84is illustrated. In this embodiment, the lower completion assembly20and upper completion76are deployed in an open hole wellbore. The isolation packers44are then expanded against a surrounding open wellbore wall118rather than against a surrounding wellbore wall formed of casing26. In this example, the isolation packers44also may be formed as swellable isolation packers, although other types of expandable packers, e.g. mechanical packers, may be used to seal off regions of wellbore24within the open wellbore wall118. In this embodiment, the same types of procedures as described above with reference toFIGS. 1-6may be employed to gravel pack each annular region96and to prepare the well for production. With respect to at least some open hole applications, an additional shroud may be placed around each gravel pack port56to avoid slurry dehydration back into the wellbore.

In another embodiment, the overall sand control system84is designed with sandface monitoring capabilities. As illustrated in the embodiment ofFIG. 8, a sandface monitoring system120may be deployed along lower completion assembly20. Although sandface monitoring system120may comprise a variety of sensors and other components, one example utilizes a sensor system122deployed along an exterior of completion tubular40. The sensor system122is coupled with a communication line124via an appropriate coupler mechanism126. In this example, communication line124is routed up along upper completion string76to a surface location. The coupler mechanism126is adapted according to the specific sensor system employed, however one example comprises an electro-inductive coupler.

In the example illustrated, sensor system122may comprise a suitable sensor128, such as a fiber optic sensor or sensor gauges. Regardless, the sensor or sensors128may be used to monitor desired parameters across the sandface, such as temperature, pressure and flow. Depending on the specific design of sensor system122, the sandface monitoring system120may be run in one trip for ease of installation; or sections of the sandface monitoring system120may be joined downhole. When a fiber-optic sensor is employed, the optical fiber may be pumped down through a corresponding tube to avoid the need for a coupler mechanism126. However, a substantial variety of deployment techniques may be used to accommodate a wide range of sensors, coupler mechanisms, and other potential components of the sandface monitoring system120.

The system and technique described above demonstrate a simple approach to sand control in a well. However, a variety of adaptations and adjustments may be made to accommodate a variety of well environments. For example, the lower completion assembly20may be run in hole with coil tubing, jointed pipe, or other suitable conveyance techniques. Additionally, the lower completion assembly20and upper completion76may be run in hole in a single trip. The sandface monitoring system120also may be run in hole with the lower completion assembly20or with the combined lower completion assembly20and upper completion76.

Furthermore, the upper packer42may comprise a hydraulically set open hole packer or a cased hole packer set by a dropped ball or other mechanism. The well zones30may be gravel packed and/or frac-packed. Additionally, the lower completion assembly20enables selective production from individual well zones30and also selective injection to individual well zones30. With the overall simplified system, no seal bores are required to enable the gravel packing or frac-packing procedures described above. In some applications, a live annulus is possible to enable real-time monitoring of downhole treatment pressure without friction effects otherwise resulting from surface pumping through tubing/coil tubing. The overall sand control system84also is suitable for rigless well treatments with coil tubing and/or treatments employing a rig and jointed pipe.

When valve mechanism60is employed, a check valve or double poppet washdown shoe allows displacement of underbalance packer swelling fluids while still enabling well control. If well zones30are to be treated with a consolidated treatment for sand control, the screens48may be replaced with sliding sleeves. In this type of application, the top sliding sleeve may be opened and used to consolidate; and then the top sliding sleeve is closed so the lower sleeves can be used for production or injection as required. Additionally, a variety of activating fluids may be pumped down to swell the isolation packers44and/or break down the fluid loss pills/material placed across the perforations28following the perforating portion of the overall sand control procedure. Depending on the parameters of a given application, various portions of the procedure discussed above may be interchanged or eliminated. For example, the upper completion may be run before or after the gravel pack treatment is completed.

Although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims.