Operators in the US have been producing from shale for decades, which places Europe and other continents with shale reservoirs in a unique position to benefit from the sharing of knowledge and technology already in use. However, Europe is faced with unique challenges that include the following:
Rapid production decline.
Small pad size.
High cost of nonproductive time (NPT).
To truly optimize a multizone stimulation treatment of unconventional reservoirs, one should not adopt the premise that the speed of the operation and initial production are all that determine success. Formation evaluation should be the primary determining factor in selecting the optimum completion technique, which must also provide a low-risk, operationally efficient solution designed to increase the reservoir contact and ultimately improve long-term production.
This paper discusses a new coiled-tubing (CT-) deployed hydraulic fracturing process, which is expected to have a considerable impact on advancing economic recovery of shale gas in Europe by fracturing one interval at a time using downhole mixing of proppant into the fracturing fluid. The downhole mixing rate can be manipulated in real-time to customize the placement and downhole-proppant concentration instantly. The combination of downhole mixing and microseismic fracture mapping provides unprecedented control of the fracturing treatment execution to facilitate branch fracturing. At the end of the final treatment stage, the well is simply cleaned out, with the entire operation completed with only one CT trip in hole. This paper reviews this technique, comparing it directly to conventional processes. In addition, background information is supplied from a combined CT/jointed-tubing (CT/JT) deployed hydraulic fracturing process.