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Tracer technology

The main objective of this task is to devise methods and procedures to map volumetric distribution of residual oil saturation in a reservoir after secondary production.

Publisert: Endret:

Sissel Opsahl Viig, IFE. Foto: Mona L. Ramstad/IFE

Task leader: Tor Bjørnstad, Special Advisor, IFE (tor.bjornstad@ife.no)

Our approaches are based on improvement on existing and develop new tracer technology for interwell and near-well applications. The methods are based on the simultaneous use of passive water tracers and phase-partitioning (oil/water) tracer compounds. A secondary objective is to develop technology for improved description of high-permeability flow fields (fractures) between wells. This is based on the simultaneous application of molecular passive water tracers that will probe all available waterflow-contactable porosity in the formation and on nanoparticle tracers that will move preferentially in the fracture volumes.

The need for infill wells, EOR operations and conformance control are the most important targeted information. Main deliverables are “methodologies for evaluation of IOR potential” and “recommended practices” for these technologies.

This task have, over time, consisted of two main subject parts: 1. interwell tracing divided between development of SOR measurement technology for flooded volumes and improved fracture/fissure description by application of nanoparticles and 2. near-well SOR determination divided between the development of new on-line analysable fluorescent molecular esters and their hydrolysis products for push-and-pull operation, and the development of an innovative concept of using nanoparticles as carriers (nanocarriers) for simultaneous transport of passive and partitioning tracers some distance into the reservoir before simultaneous release and back-production.

The laboratory-based experimental work on phase-partitioning tracers for SOR determination in flooded volumes between wells (sub-project 2.5.6.) has been finalized with good results. This technology is now ready for reservoir piloting. A dr-dissertation has recently been completed and accepted (Mario Silva). All results are given and discussed in detail in the corresponding comprehensive Thesis.

Previously,  continued work on particle tracers (carbon quantum dots or C-dots) for fracture detection  was merged with the program for development of nanoparticle carriers (sub-project 2.5.4) for the dr-student Arun Kumar Panneer Selvam (started in March 2019). Recently, one has decided to stop further experimental work on C-dots due to too severe inconsistencies in results between our own laboratories and foreign laboratories (mainly from Cornell and Saudi Aramco) which cannot be resolved within the remaining budget of the program. A state-of-the-art report will be produced during the fall of 2021. The remaining time for the dr.-student should be concentrated on nanocarrier development. This program, which has a considerable potential if completed successfully, has been allocated extra economic and manpower resources, and will be the main focus for the rest of 2021.

The sub-program for experimental development of lanthanide-based fluorescent hydrolyzing esters for near-well SOR measurement (sub-project 2.5.5.) was experimentally finalized in 2020. Topics like molecular synthesis and lanthanide complexation, instrumental analysis by UPLC/MS/MS, measurement of hydrolysis rate and flooding properties in porous media have been successfully completed. However, the required water/oil partitioning appeared to be non-satisfactory. Thus, the ultimate goal was not reached within the frames of this project. A technical report summarizing the most important experiments, results and recommendation for further work is now under production and will be published during the fall of 2021.

  • 2.5.1 Development and testing of nanoparticles as tailor-made tracers for improved reservoir description and for measurement of defined reservoir properties (postdoc project) (links will be provided)
  • 2.5.2 Single-Well Chemical Tracer Technology, SWCTT, for measurement of SOR and efficiency of EOR methods (links will be provided)