Performance of steam injection processes using vertical and horizontal wells

A fully implicit, three-dimensional, three-phase, compositional steam injection simulator was developed to conduct this study. Newton's iteration was employed to solve the set of nonlinear equations in this model. The model uses the natural ordering and the D4 ordering schemes. The model is capable of handling reservoir heterogeneities and irregularities and simulating multi-block vertical, directional and horizontal wells with either bottom-hole pressure or flowrate specification. The objective of this study is to investigate reservoir performance under various steam injection processes using different well types and configurations. The processes investigated include steamflooding, cyclic steam injection and steam chamber. In a homogeneous reservoir steam flooding using horizontal wells located at the lower portion of reservoir yields 10-15% higher recovery than that using vertical wells. The steam chamber method is also promising; it has as much as 10% higher recovery than that obtained by conventional steamflooding. In heterogeneous reservoirs with low vertical permeability; however, the vertical-well operation may excel the operation by the steam chamber method. Steam stimulation using horizontal wells seems to be preferable when the vertical permeability is favorable. It is found that the best location of the horizontal well in the steam stimulation technique is within one quarter of the reservoir thickness away from the reservoir bottom boundary.