L.K. Thomas

Compositional and black oil reservoir simulation

This paper describes a three-dimensional, three-phase reservoir simulation model for black oil and compositional applications. Both IMPES and fully implicit formulations are included. The model`s use of a relaxed volume balance concept effectively conserves both mass and volume and reduces Newton iterations. A new implicit well rate calculation method improves IMPES stability. It approximates wellbore crossflow effects with high efficiency and relative simplicity in both IMPES and fully implicit formulations. Multiphase flow in the tubing and near-well turbulent gas flow effects are treated implicitly. Initial saturations are calculated as a function of water-oil and gas-oil capillary pressures which are optimally dependent upon the Leverett J function or initial saturations may be entered as data arrays. A normalization of the relative permeability and capillary pressure curves is used to calculate these terms as a function of rock type and grid block residual saturations. Example problems are presented, including several of the SPE Comparative Solution problems and field simulations. 48 refs.

Experiences after 10 years of waterflooding the Ekofisk Field, Norway

This paper describes the experiences and results after more than 10 years of waterflooding the fractured Ekofisk chalk formations from a reservoir engineering and reservoir management perspective. Water injection was initiated at Ekofisk in 1987 following two successful pilot projects. The waterflood was implemented in a series of stages, and currently 800,000 BWPD is being injected into the entire vertical column of the reservoir using 38 injectors in a staggered line drive pattern. A total of 2 billion barrels of water has been injected in the first 10 years of waterflood operations. Field average water production is currently below 80,000 BWPD. Oil rate responses, GOR declines and low water production rates indicate a very efficient oil displacement process is occurring. Examples of waterflood performance in terms of areal and vertical sweep efficiency, production responses and displacement efficiency will be reviewed together with overall reservoir management aspects including seabed subsidence and reservoir compaction.

An integrated engineering/geoscience desktop

This paper presents the development of an Integrated Engineering/Geoscience Desktop and a description of the software available for evaluation and development of hydrocarbon prospects, from basin-wide studies down to specific reservoir targets. The Desktop was built using Landmark`s data model, with POSC-compliant extensions to build an Engineering/Geoscience project database. Software for populating the project database from corporate databases was also developed and is described in detail. Phillips petroleum engineering software was then integrated with geoscience software, sharing data and results in a seamless computing environment.