Canadian Natural Resources use "employs cyclic steam or "huff and puff" technology to develop bitumen resources. This technology requires one well bore and the production consists of the injection and production phases. First steam is "injected for several weeks, mobilizing cold bitumen". Then the flow "on the injection well is reversed producing oil through the same injection well bore. The injection and production phases together comprise one cycle. "Steam is re-injected to begin a new cycle when oil production rates fall below a critical threshold due to the cooling of the reservoir. Artificial lift method of production may be used at this stage. After a few cycles, it may not be economical to produce by the huff and puff method. Steam flooding is then considered for further oil recovery if other conditions are favorable. It has been observed that recovery from huff and puff can be achieved up to 30% and from steam flooding recovery can be up to 50%" .