Verification Of Scaling Approaches For Steam Injection Experiments

Abstract

Abstract Three sets of new scaling criteria for high-pressure steam injection experiments were derived and tested in a unique series of experiments. Unlike previous scaling criteria for steam injection, which require the use of porous media and pressure conditions different from the field, the present criteria permit the use of reservoir rock, fluids, and pressure conditions. Two of the new approaches relax some of the geometric scaling groups in order to satisfy other scaling requirements. To examine the suitability of these three new scaling approaches as well as a widely used approach from the literature. Results from a large model were compared with those of smaller models scaled by the appropriate scaling approach. The scaled models, representing one-eighth of a jive-spot pattern, were designed to simulate steam flooding of a prototype reservoir in Alberta. This series of experiments examined the scaling of the mechanisms for heat transfer and steam zone development by injecting steam into a completely water-saturated reservoir. Verygood predictions of energy distribution, temperature distribution, production rate, steam zone volume, produced steam quality, nd steam breakthrough were achieved for two of the scaling approaches. The ability of each approach to scale from one physical size to another is illustrated and the relative merits and potential applications of the approaches are discussed, leading to useful guidelines for the design of steam injection experiments. Introduction Steamflooding is a proven method of enhanced oil recovery. Many laboratory studies have been conducted in an effort to improve this process. Some of the experiments study the various mechanisms of a process and extend the results to make field predictions by using numerical simulators. Other experiments, referred to as scaled experiments, permit direct interpretationof the results to predict field performance. Scaled model experiments can be used to predict the effect of various parameters On the production response of a reservoir undergoing steam injection. The parameters include injection rate, production pressure, slug size, completion interval, bottom water, reservoir heterogeneities, and steam quality. Scaled models are also used to calibrate numerical models as the relative influence of many of the mechanisms is similar to that expected in the field. It is difficult to satisfy all of the criteria required to design scaled experiments of stearn flooding processes. Consequently, some of the scaling requirements must be relaxed. The choice of which requirements to relax will depend on the particular process being modelled. Scaling of the phenomena considered to be least important to a particular process might be relaxed without significantly affecting the major features of the process. The objectives of this work were to develop and verify suitable scaling techniques for steam injection experiments and identify the conditions under which a particular scaling approach is most suitable to a particular recovery process (e.g. steam additives, thin reservoirs, gas caps, bottom water, etc.). Scaling Approaches A number of scaling approaches have been used in the past for steam injection experiments. Stegemeier, Volek, and Laumbach(1) developed an approach which operates at sub-atmospheric pressures and uses fluids which are different from those found in the field.