Abstract
During the last several years Shell and its affiliates have initiated a significant number of Enhanced Oil Recovery projects covering chemical, thermal and miscible flooding applications in a variety of geological and hydrocarbon settings.
Key in de-risking and sanctioning these projects is a far more detailed understanding of the fundamentals in rock and fluids physics and chemistry that have an overriding impact on the ultimate recovery and project economics. This required a significant upgrade of the experimental capability to measure relevant rock and fluid properties as well as the ability to visualize and model the EOR processes at various geological and time scales. State of the art experimental facilities have been built to enhance visualisation and understanding of flow processes in cores as well as to measure accurate physical and chemical properties.
The proprietary reservoir simulator and modelling toolkit has been upgraded to include the relevant EOR processes and rock / fluid interactions in sufficient detail, covering for example In-Situ Combustion, Polymer floods, Designer Water™ flooding, Alkaline Surfactant Polymer flooding, Thermally Assisted-Gas-Oil-Gravity-Drainage, In-Situ Upgrading, a variety of Solvents and Hybrid applications at various scales, ranging from core scale to full field simulations.
The Smart Fields concept pursues continuous optimisation of hydrocarbon assets, 24 hours a day, and 7 days a week. This optimisation covers locating and recovering hydrocarbons, improving performance of production (well) facilities throughout the field life cycle on timescales ranging from seconds to field life. An important part of the Smart Fields concept is Closed Loop Reservoir Management (CLRM), which ensures that data gathered in the operations phase is used to improve quality of reservoir models and allow a faster field management cycle. Novel robust mathematical optimisation algorithms and control methods are rapidly maturing to assist automatic history matching, high-grading geological reservoir model ensembles and reducing the uncertainties. The desired outcome is better well offtake or injection policies that are also robust against remaining key uncertainties.
Extending the Smart Field concepts to EOR requires the definition of the appropriate levels of smartness for EOR projects for each element of the Smart Field Life Cycle, which consists of: data acquisition, modelling, integrated decision making and operational field management, each with a high level of integration and automation.
In order to optimise the performance of operational EOR projects, new surveillance methods and technologies were developed and deployed, and continue to be developed, in collaboration with oil and gas industry service providers to obtain better and cheaper data targetting improved sweep efficiency and operational cost reductions. Examples include the use of various geophysical methods to measure (steam) flood performance, the development of high temperature internal control valves to improve steam injection conformance, down-hole fiber optic applications and advanced tracer tests.
Apart from pursuing improvements in ultimate recovery, improved energy efficiency and a reduced CO2 footprint have become important drivers as well and a number of recent advances have been made that will lead to both further improvements in UTC and the environmental footprint.
Dissemination of knowledge, workflows, and experience across the various projects has resulted in a global EOR approach that shortens the duration of screening, feasibility and development efforts and reduces the need for field trials or pilots, reducing the cycle time for EOR projects. A number of recent examples containing elements of Smart EOR principles as described above will be provided.
