Indonesia Conference Directory

Cap-rock integrity as well as reservoir integrity assessments have become a key element in the design and operation of steam injection projects and a critical element in the selection of a maximum steam injection operating pressure. The applicability of steam injection requires good knowledge of reservoir and geomechanic aspects. In addition, injecting steam into a very shallow unconsolidated reservoir has potential risk of having loss of containment issue. By necessity, these cap-rock integrity assessments involve geomechanical engineering principles and have generally lead to more use of reservoir-geomechanical simulations (one way coupled or sequentially coupled) in the establishment of what is termed “safe” maximum steam injection pressures. In this method, geomechanical parameter (stress state model (overburden, hydrostatic and pore pressure), elastic model (Young Modulus, Shear Modulus, Poisson including failure criteria i.e. Mohr-Coulomb), and rock’s reservoir properties (lithology, porosity, permeability, water saturation etc.) are required as input data. The methods will integrate the whole data with coupled reservoir properties and geomechanics modeling to calculate changes of rock strength due to steam injection. These cap-rock assessments have included geological framework studies of caprock, insitu stress determination, reservoir and cap-rock property characterization, failure criteria from numerous situations and numerical simulations to ensure the steam injection scenario always in proper condition. Alternative injection scenarios are suggested to be performed in risk area, as follows: (a) Steam injection and production are performed simultaneously; (b) steam injection, heating and production are performed simultaneously; (c) heating, production and injection are performed sequentially.