At the early phases of EOR developments, small scale pilots are commonly used to obtain information of the EOR field development mechanisms. The lessons learnt from these early pilots are subsequently used to de-risk and improve the full field developments.
In initial phases, well and reservoir surveillance plays an important role to increase the understanding of the effectiveness of the EOR processes in the various reservoirs. Well-planned and executed reservoir surveillance has proven in the past to de-risk and optimise production and ultimate recovery from reservoirs significantly.
Successful projects are characterized by a high level of cross discipline integration.
This paper discusses the important field development decisions of Miscible Gas, and Chemical projects, that have been based on well and reservoir surveillance results that will be presented in this paper. A clear strategy is presented to select surveillance strategies dependent on the field development decisions that need to be taken.
Moreover, field case examples of these decisions are presented in the remainder of the paper.
For the chemical injection project in a clastic field a new workflow was developed to analyse well-tests of for polymer injection. The field management decisions to adapt rates, effective viscosities and change water treatment requirements are supported by an integrated modeling and surveillance effort. This fracture monitoring workflow plays a role in the regular pattern management evaluations to manage the field in a holistic manner.
Two examples of a miscible gas flood will be presented. In the first one, the pattern geometry of a miscible gas flood was changed from an inverted 9-spot to a line drive based on surveillance information. Additional development opportunities and reserves were identified through extensive surveillance, performance monitoring and data gathering pilots. In the second example, we present the field outline with a surveillance plan, with magnetic resonance and other new saturation tools. Moreover vertical conformance is demonstrated to be measurable through distributed temperature sensing.