Improved techniques for fluid diversion in oil recovery. Final report
T 8 DISCLAIMER T h i s report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, exprea or implied, or asumes any legal liability or respondbility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refere.nce herein to any
... nce herein to any specific commercial product, process, or service by trade name, trademark, manufactum, or dhemise does not necesSany constitute or imply its endorsement, recommendation, or favoring by the Umted States Government or any agency thereof. The views and opiNons 01 authors expressed herein do not necessarily state or mflect those of the United States Government or any agency tbereof. Portions of this document may be illegible in electronic image products. h a g s are produced from the best avaiiable original d0CUIXleXlL ABSTRACT This report describes work performed during the third and final year of the project, 'Tmproved Techniques for Fluid Diversion in Oil Recovery." This project was directed at reducing water production and increasing oil recovery efficiency. In the United States, more than 20 billion barrels of water are produced each year during oilfield operations. An average of 7 barrels of water are produced for each barrel of oil. Today, the cost of water disposal is typically between $0.25 and $0.50 per bbl. Therefore, there is a tremendous economic incentive to reduce water production if that can be accomplished without sacrificing hydrocarbon production. Environmental considerations also provide a significant incentive to reduce water production during oilfield operations. This three-year project had two technical objectives. The first objective was to compare the effectiveness of gels in fluid diversion (water shutoff) with those of other types of processes. Several different types of fluid-diversion processes were compared, including those using gels , foams , emulsions, particulates, and microorganisms. The ultimate goals of these comparisons were to (1) establish which of these processes are most effective in a given application and (2) determine whether aspects of one process can be combined with those of other processes to improve performance. Analyses and experiments were performed to verify which materials are the most effective in entering and blocking high-permeability zones. The second objective of the project was to identify the mechanisms by which materials (particularly gels) selectively reduce permeability to water more than to oil. A capacity to reduce water permeability much more than oil or gas permeability is critical to the success of gel treatments in production wells if zones cannot be isolated during gel placement.