Packers:  General Information


A packer is an expandable plug used to isolate sections in a well or borehole. Baski Inc. manufactures inflatable packers for a variety of applications, including pumping, injection, hydrofracturing, grouting, flow control, testing, and sampling.

The inflatable packer has significant advantages compared to other packer designs which include:

   High pressure rating and expansion ratio.
   Minimal outside diameter and large interior diameter.
   Long sealing section that conforms to uneven sides in a borehole.

Our patented packers are available for:
   Borehole sizes ranging from 2" to 30" (50 to 760 mm).
   Pressure ranges from 50 to 10,000 psi (3 to 700 bar).

Furthermore, we provide our customers with a wide selection of metal and elastomer combinations for custom packers. Baski Inc. is particularly noted for providing custom-designed packer assemblies for unique applications.

 

Our most popular products include:
Medium-duty SE Packer: sliding-end packer for a wide range of hole sizes and depths.
ReFlex PackerCost-effective fixed-end packer with a fully reinforced element.
FrackerHigh-pressure, sliding-end packer for hydrofracturing applications.

New products derived from our ongoing custom products business include a heavy-duty 15-inch packer, and packers for N-size (3-inch) and H-size (3.78-inch) core holes. 
Please call us for more information on these.

For more general information about packers, please read the following sections about packer types, components, specifications, and typical applications

INFLATABLE PACKER TYPES:
Sliding-end Packer
This type of packer allows the element gland to slide on one end. As the element diameter increases during inflation, the packer construction which incorporates an O-ring seal allows one end of the element to move (or slide) on the pipe base. The sliding-end packer is recommended for open borehole or high pressure applications where the differential pressure between the top and bottom of the packer ranges from 100 to 5,000 psi. Also, the fully-reinforced element offers high expansion ratios.

Fixed-end Packer
A fixed-end packer has both of the rubber element ends fixed to the pipe mandrel. The element can be one of three styles: non-reinforced, partially-reinforced, or fully reinforced. Non-reinforced or "balloon" type packers can easily fail due to element extrusion into open borehole fractures or into the annular area between the packer ends and the casing or borehole. Partial reinforcement at the ends of the element prevents extrusion into the annular area near the packer ends, but the element can still extrude into borehole fractures. In 1993, Baski Inc. introduced the fixed-end ReFlexTM packer with a fully-reinforced element to prevent extrusion problems.
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INFLATABLE PACKER COMPONENTS:
Pipe Mandrel
Pipe base upon which the packer is built. The pipe's inside diameter provides the space necessary for tubes, wires, hoses, or other feed-throughs and pumping injection access. Pipe sizes range from 3/8 to 10 inch and larger.

Reinforced Rubber Element
Outer covering that is mounted on the mandrel and inflated to change the packer's outer diameter. Standard elements are constructed of natural rubber with high-strength reinforcing such as Kevlar (DuPont). After the element seals against the borehole, fluids can only move from one end of the packer to the other via pumping through its center. 

Inflation port
Fitting on end of packer that allows gas, water or a solidifying liquid to enter between the element and mandrel to expand the rubber. 

Connectors
Threaded, metal end-pieces attached at both ends of the mandrel to provide for attachment in a well string.  National pipe taper (NPT) threads are typically used to depths of 500 feet, whereas higher strength oil field API threads are used for deeper sets.

The materials used to manufacture our packers can be varied to suit individual applications. Standard elements are constructed of natural rubber with high-strength reinforcing such as Aramid. Optional elastomers include nitrile, neoprene, or Viton*. The standard metal components of our packers include a combination of aluminum, stainless steel, and steel for applications in normal environments. All aluminum or all stainless steel metal components can be supplied for used in semi-corrosive, extended-term, or other applications. Titanium, copper, and Hasteloy are examples of metals available for very specialized applications.  *DuPont
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INFLATABLE PACKER SPECIFICATIONS:
Uninflated O.D.

Outside diameter of the packer at rest, which must always be smaller than the hole size for which it will be used. Sizes are available from 1 to 16 inches and larger on special order.

Maximum Inflated O.D.
Outside diameter of the packer upon inflation, which is the largest suggested hole size for which the packer should be used. Sizes are available for 1-1/4 to 40 inch and larger hole sizes.

Borehole Differential Pressure
Difference between the test zone pressure below and the borehole pressure above the packer, i.e. drawdown or injection pressure.

Packer Inflation Pressure
Sum of the three pressures necessary 1) to match the water pressure above the packer (submergence pressure), 2) to stretch the rubber element out to the borehole, and 3) to seat the packer firmly enough against the well hole to prevent any movement caused by the borehole differential pressure.

Uninflated Rubber Element Length
Affects the "holding power" and sealing ability of the packer. A longer element has more rubber contact against the hole and provides a larger frictional force to support a larger borehole differential pressure.
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TYPICAL INFLATABLE PACKER APPLICATIONS
Inflatable
packers have been used in the oil and gas industry since the 1940s. Until recently, however, their use was restricted by prohibitive costs and limited availability. Now, several disciplines (e.g. ground water development, contamination studies, dewatering, geothermal, mining, coal bed methane, and geotechnical studies) use a wide selection of reasonably priced packers.

The selection of a packer for a particular job application is very important for success at a reasonable cost. The differential pressure and hole size are primary considerations. Next, the materials of construction should be considered, especially when adverse chemical and physical conditions could exist.

First, we will discuss the hole diameter size and borehole differential pressure in a packer application. For example, to pump a 2-inch diameter by 50-foot deep monitor well that is full of water, the maximum borehole differential pressure (maximum drawdown) would be 50 feet of water times 0.433 psi/foot of water equals 22 psi. Therefore, a 1-3/4 inch O.D. packer with a 22 psi differential pressure rating would do the job. In addition, the packer should be constructed of stainless steel and have an element gland covered with Viton* to reduce sample contamination. A Baski Purge PackerTM would be ideal.

Another packer application might be in a mud-filled pilot drill hole at a potential water well site. If there is nonpotable water at an unknown depth, packer testing can define where the "poor" water is located. A straddle packer configuration is attached to the drill pipe and lowered into the open borehole. Water is then pumped from a specific zone between the straddle packers by using airlift pumping methods inside the drill pipe. The testing would normally start from the bottom of the hole and progress upward. After locating the poor water, it can be cased off and a potable water well completed.

As an example, let us examine a straddle packer arrangement for the above application with a 7-7/8 inch I.D. by 1,000-foot deep hole. For a competent rock hole, a 5-1/2 inch O.D. packer with a 2-1/2 inch (Sch. 80) mandrel would be an economical choice. However, if unstable hole conditions are possible, then a better choice would be a 6-1/2 inch O.D. packer with a 3-inch (Sch. 160) mandrel. API round threads for a higher joint strength are also recommended in case the hole collapses. If the hole were completely pumped dry, there would be a 433 psi differential pressure. Therefore, a packer with a 500 psi differential pressure rating is recommended. Standard construction materials (aluminum, stainless steel and steel components, and a reinforced, natural rubber element) should be sufficient. All stainless steel construction with Viton* and a longer than standard element length are available options.

A third packer application could be hydrofracturing a low-yielding, 6-inch diameter, domestic well with an installed pitless adapter. A good selection would be the fracture packer (Fracker) with a 4.9 inch O.D. to clear the pitless adapter which may protrude inside the well casing. A 3,000 psi differential pressure rating would be sufficient for most fracking jobs up to a 3,000 psi injection pressure. The life of the FrackerTM (i.e., the number of packer settings with high pressure injection) is a direct function of the inflatable packer specifications, the hole conditions and the proper procedures used by the contractor.

Hydrofracturing between two packers can develop an extremely high force on the connecting pipe between the packers. In a 10-inch hole at 3,000 psi, the tension force is close to a quarter of a million pounds! Proper selection of pipe and thread pattern between the packers prevents failure that can result in the loss of the lower packer and damage to both packer elements from sliding in the hole.  *DuPont