| Popis: |
Over the last five years, horizontal drilling, fracturing and multi-stage completion technology advances in unconventional shale resources has helped US oil production grow by 65 percent.1 Even though, production rates in unconventional plays can decline dramatically, up to 70% in the first year. To replace the loss in production, oil companies have traditionally drilled more wells. This decline phenomenon is called the Red Queen, named after the character in Lewis Carroll's “Through the Looking-Glass” who tells Alice “(Run) Faster! Faster! It takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!”2 Refracturing may become the secret weapon against the Red Queen that allows existing shale wells to sustain hydrocarbon production without new wells being drilling. In this paper, several case studies will highlight how temporary and degradable chemistry in both liquid and solid materials can be introduced as a means to provide temporary isolation between zones in shale refracturing operations. These chemical diverting agents forms a solid impermeable barrier or seal that in time will break or degrade to liquid form, leaving the existing zone that was diverted open to permit flow. First scenario will focus on an open-hole sidetrack well drilled in an existing vertical well. Through the use of a chemical packer for support and isolation, a retrievable six zone sliding sleeve system was deployed. The second case and third case histories will focus on the impact degradable mechanical diverters are having not only on the refracturing market, but how they could potentially be used on new wells to increase zonal coverage and help mitigate the need for refracturing by increasing zonal coverage during the initial stimulation treatment. This paper will present and discuss this unique application and performance of the fracturing completion design, and provide another approach of re-fracturing operation for unconventional plays. |
