Abstract
Steam flooding of horizontal wells has long been considered as one of the most effective methods to unlock thin heavy oil reservoirs. Large volumes of heavy oil are located in heterogeneous porous medium containing high permeability wormholes or low permeability shale barriers. Strong heterogeneity can be the main result of early steam channeling. There is a question of how the heterogeneities enhance or hinder the steam chamber advancement, the flow of high viscous oil, steam and condensed water under a steam flooding process in a thin heavy oil reservoir. The shape of the steam chamber is a key element of calculating steam sweep efficiency, confirming the recoverable reserves, determining the moment of steam channeling, optimizing the well spacing, etc. In this paper, we present a series of physical experiments investigating the steam flooding using horizontal wells for thin and heterogeneous heavy oil reservoir. The apparatus mainly consists of simulated formation containing dual parallel horizontal wells. The shape of the steam chamber is obtained by using the Kriging interpolation method. The steam chamber sweep efficiency, oil recovery and water cut of homogeneous model and heterogeneous models are compared. The results indicate that the low permeability zones greatly hinder the development of steam chamber, resulting in poorer sweep efficiency, earlier steam breakthrough, more residual oil, as well as lower oil recovery, higher water cut, less liquids and oil production. The pressure behavior of the horizontal wells are also investigated.
