Usage of swell packers
22 March 2011
Normally swell packers along with sliding sleeve are placed in barefoot horizontal portions to meet the following :
1. To isolate less prolific portions by putting blank tubing´s.
2. To control water production by closing sliding sleeve.
3. To segment the horizontal portion to handle formation heterogeneity.
4. Used at heel or toe to isolate unwanted production of gas/water.
Please enumerate the benefits / advantages if any of using swell packers with entire perforated tubing´s . I would also apprecaite any feedback on member experiences when using with entire perforated tubings.
Feedbacks may please be given on this aspect.
Nehal. We are using swell packer liners and perforating through the blank pipe to ensure adequate zonal isolation is provided as opposed to cementing. The reservoir is mature and the higher permeability members have watered out (water injection is used to support reservoir pressure). We are targeting unswept areas, with one of the key well objectives being excellent zonal isolation between the various reservoir members. Due to a high overbalance often seen in mature reservoirs, we have decided to drill using a mud that effectively minimises invasion into the matrix by creating substantial damage close to the wellbore. We then perforate through this after installing the liner with normally 12-14 swell packers placed across the non-permeable formations within the reservoir sequence.
To date this has worked successfully; the OWR has been reduced substantially, and the production rate is close to initial reservoir production rates (and significantly higher than expected). Our main hurdle was that rubber was seen in the process facility after the first well completed (as per a previous post). Ultimately we concluded that the lower couple of elements were damaged while running these through the shoe, rather than by perforating off depth, and we have tightened up on the design & operational procedures to account for this.
My question is usage of swell packers with perforated tubings for segmentation in horizontal uncased drain holes makes no sence /advantages as it has no opportunity to close any of the segmentts in case starts producing water.
It will be better or appropriate to use sliding sleeves along the swell packers as it gives ample opportunity to operate sliding sleeve with Coil Tubing units in case a particular segments starts giving water and the same can also be closed.
Under this circustances my view is that swell packers with perforated pipes is not a good completion as it has no control to shut off any segments. Therefore Sliding Sleeve with swell packers will be suitable and appropriate completion to handle future problems.
Nehal, your question about using swellables with perforated tubing has multiple answers depending on circumstance and I would be glad to discuss a specific application with you.
In general though, one main use with perforated pipe would be to give the opportunity later to go in with a straddle or even a plug for water or gas shutoff usually.I need to correct what Sandy said though about swells being low pressure devices only. The technology has advanced in the last couple of years and one company has tested them to 15000 psi. The most common usage nowadays is in the shale plays of N America where they are run with frac sleeves. Many of these are slip on products and are expected to hold over 3000 psi in each selective frac. If you would like to know more, let me know.
Swell packers with perforated tubing in open hole are used for similar usage. However the point about swell packers in open hole is that, unless it is very gauge hole, the differential pressure across a swell packer is very low. A little higher differential can be achieved when used in conjunction with gravel packing the external tubing. However a gauge hole is required other wise they cannot hold very much pressure differential., the swell packers are, more or less, flow restrictions, rather than packers. If the open hole is above gauge hole, or washed out, the differential pressure held will be zero