Wells – Processes – Providing porous mass of adhered filter material in well
Reexamination Certificate
2001-02-26
2002-10-15
Schoeppel, Roger (Department: 3672)
Wells
Processes
Providing porous mass of adhered filter material in well
C166S051000, C166S278000, C166S205000, C166S320000, C166S334400
Reexamination Certificate
active
06464006
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for completion of a petroleum production well. In particular, the invention relates to a method and apparatus for fracturing and gravel packing multiple production zones in a single downhole trip.
2. Description of the Related Art
Petroleum production from a well bore is often enhanced by a process that is characterized as “fracturing”. According to the general principles of fracturing, the fracturing process induces increased fluid flow from the wellbore production face by generating additional cracks and fissures into the zone radiating from the well bore wall. The objective of such additional cracks and fissures is an increase in the production face area. This increased production area facilitates migration of a greater volume of petroleum fluid into the well production flow stream than would otherwise occur from the simple cylinder wall penetration area provided by the original borehole.
Among the known methods of creating or enlarging such cracks and fissures into a fluid production zone is that of forcing liquid into the formation under extremely high pressure. Mixed with the high pressure fracturing liquid are particulates such as coarse sand or fine gravel known as propants. These propants have the function holding open and maintaining the permeability of zone fractures.
Often entrained in the natural flow of petroleum fluid from the geologic formations of origin, e.g. production zones, are considerable quantities of fine sand and other small particulates. If permitted, these particulates will accumulate in the production flow tubing and the region of the borehole where the production flow enters the production tubing. Continued accumulation eventually restricts and terminates production flow.
One well known method of controlling a flow restricting accumulation of such fine particulates is placement of gravel around the exterior of a slotted, perforated, or other similarly formed liner or screen to filter out the unwanted sand. This practice is generally characterized as gravel packing. According to one method of practicing the method, a gravel filter is deposited in the annular space between the production screen and the casing in the form of a fluid slurry. The slurry carrier fluid passes through the screen into the production tubing and returned to the surface. The gravel constituent of the slurry is separated by the screen and deposited in the wellbore, liner or casing around the screen.
Typically, a screen or perforated casing liner is positioned within a borehole casing. The casing is perforated adjacent to the production formation. Packers are set in the annulus between the borehole casing and the casing liner, for example, above and below the production zone. A string of tubing is run inside of the liner assembly in the area of the liner screen. The gravel slurry is pumped from the surface down the internal bore of the tubing string and through a crossover tool out into the packer isolated annulus. From the isolated annulus, the slurry carrier fluid passes through the screen into the liner bore thereby depositing the gravel in the isolated annulus around the screen. From the liner bore, the fluid carrier reenters the crossover tool for conduit past a seal between the tubing exterior and the liner bore. Above the upper packer respective to the isolated annulus, the fluid return flow path is routed into the annulus surrounding the tubing which may be the liner and/or the casing.
After placement of the filtration gravel is completed, the crossover tool is repositioned and the circulation of carrier fluid is reversed to flush residual gravel from the tubing string bore.
In many petroleum producing fields, valuable fluids are found in several strata at respective depths. Often, it is desired to produce the fluids of these several depths into a single production tube. Execution of this desire consequently requires that each of the vertically separate production zones is separately gravel packed.
Gravel packing multiple production zones along the same wellbore traditionally has required that the operating string be lowered into and withdrawn from the wellbore for each production zone. The cycle of entering and withdrawing a tool from a borehole is characterized in the earthboring arts as a “trip”. The outer string, containing the packing screens, is assembled from the bottom up in a step by step process. The operator must withdraw the operating string after each zone completion in order to add components to the outer string that are necessary to complete the next higher production zone. This also renders it impossible to pack a zone below a previously packed upper zone. In some instances, this is due to an inability to place the operating string back in the desired location due to restrictions placed in the outer string after packing a zone. In other cases, it is due to an inability to relocate the desired zone and to position the crossover tool ports with sufficient precision.
A prior art gravel packing procedure for multiple production zones may include an outer completion string having a combined slip and production packer for supporting the completion string within the cased well. Disposed below the production packer is an upper closing sleeve and an upper zone screen. An isolation packer is disposed below the upper zone screen and a lower closing sleeve. A lower zone screen is disposed below the isolation packer. A first sealing bore surface is disposed between the production packer and the upper closing sleeve. A second sealing bore surface is disposed between the upper closing sleeve and the upper zone screen. A third sealing bore surface is disposed between the upper zone screen and an isolation packer. A fourth sealing bore surface is disposed at the lower zone screen. A sump or basement packer is disposed below the lower zone screen around a lower seal assembly. In the case of an open hole, inflatable packers would be used in place of the basement packer and isolation packers.
A surface manipulated inner service tool is lowered into a well coaxially within the completion string. The inner service tool may include a plurality of bonded outer seal rings around the outside perimeter of an outer tube wall. Within the outer tube is an inner tube. An annular conduit is thereby formed between the two concentric tubes. The center tube and seal units form an annulus extending from upper ports in the uppermost seal unit to the lower crossover ports extending through the outer conduit formed by the seal units and the center tube. An additional length of seal units extends from the crossover ports downwardly for several feet followed by an extension and an additional set of seal units to a ported sub and lower seal assembly at its lower end.
For the function of opening and closing the closing sleeves, a prior art service tool might include two shifting tools, one above the crossover tool and one below. A single shifting tool may be used but it must be located very close to the gravel pack ports so that the shifting tool can be raised a very short distance, close the closing sleeve, and still have the gravel pack ports within the short distance range.
An upper ball check is provided at the lower terminal end of the center tube to prevent downward flow through the flowbore of the center tube. A lower check valve is provided in the conduit of the seal units to prevent the downward flow of fluids in the annulus and into the flowbore formed by those seal units disposed below the crossover ports. Another ball check valve is provided at the lower terminal end of the seal units.
In operation, the basement packer is lowered into the well and set by a wire line at a predetermined location in the well below the zones to be produced. The completion string is then assembled at the surface starting from the bottom up until the completion string is completely assembled and suspended in the well up to the packer at the surface. The production screens are located in the complet
Baker Hughes Incorporated
Madan Mossman & Sriram P.C.
Schoeppel Roger
LandOfFree
Single trip, multiple zone isolation, well fracturing system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Single trip, multiple zone isolation, well fracturing system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Single trip, multiple zone isolation, well fracturing system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2981740