Abstract
In many locations, totally evaluating the quality of a reservoir based on conventional logs alone is difficult. This difficulty is especially present in lower-permeability reservoirs. Often, conventional logs can allow the operator to pass up zones that may be more productive than indicated on a conventional porosity cutoff. In such cases, a zone is perforated and allowed to flow to get a better evaluation of the zone and its production potential. However, if the zone does not flow to expectations, the operator may face a real dilemma: is it a poor-quality reservoir, or is some sort of damage prohibiting flow? This question can be very daunting and may not be easily answered, especially if the well will not flow adequately for a buildup analysis within a reasonable time frame.
In this paper, the potential for using a small injection test and the subsequent pressure fall-off to analyze the reservoir pressure and permeability is evaluated. Many benefits could be derived from using an injection test for reservoir analysis. Some are obvious, such as the capability to determine permeability and reservoir pressure, but this test can also be advantageous because these properties can be determined without flowing the well (which in some circumstances may be difficult and/or costly).
In this paper, a deep Atoka Wash well in Western Oklahoma is evaluated. The results of the fracture injection test are discussed, as well as how these results compare with a conventional buildup analysis.
