Microbes: The Practical and Environmental Safe Solution to Production Problems, Enhanced Production, and Enhanced Oil Recovery

Abstract

Abstract This paper presents the theory and field application of microbial treating oil well systems and reservoirs to control paraffin wax deposition, increase producing rates and enhance oil reservoirs. The technology applies to paraffin base crude oils produced from solution gas drive reservoirs. The application of this microbial enhancement technology can increase oil recoveries in all stages of reservoir depletion. Introduction One of the major concerns facing the oil industry today is recovery of the large percentage of oil remaining unrecovered in the mature and near depleted producing oil fields. New technology is necessary to extend producing life and increase reservoir recovery by economically treating existing producing wells and reserving the accelerated rate of well plugging. Migration microbial enhanced oil recovery (MMEOR) is a new technology that can enhance production and recoveries by treatment programs of existing producing wells. The microbial process thins or reduces oil viscosity in situ increasing production and recoveries. The process is applicable to single-well and multi-well projects and does not require capital expenditures or expensive well conversions. This new technology has the potential of substantially increasing oil recoveries in a majority of U.S. oil fields and is friendly to our environment. An additional benefits from MMEOR is paraffin wax control in the producing well systems. Biochemical changes in crude oil resulting from microbial treating can reduce or eliminate paraffin wax crystallization and deposition in well bores and producing formations. Microbial paraffin wax control can eliminate the use of solvents and dispersants which can be toxic to our environment and can eliminate the need to use the often hazardous procedure of removing wax by hot oil/water treatments. MMEOR Bacteria The microbial cultures used for paraffin control and MMEOR projects presented in this paper are naturally occurring, non-pathogenic and non-genetically engineered microorganisms. The products are mixtures of live facultative anaerobes containing several different principal strains which produce desirable changes in crude oil properties.1 Due to the safe nature of these microorganisms, the EPA has chosen not to regulate their release into the environment. Attempts were made to use freeze dried bacteria products with marginal success. Problems associated with dry products were found to be variability in rate of activation, bacteria carriers not soluble or dispersible in formation water, product adulteration and lack of quality control. Bacteria used are generally of the dimensions of 1 to 4 micro-meters in length and 0.1-0.3 micro-meters in width. The strains are motile (they can move and migrate by their own propulsion system) and are capable of swimming toward surfaces which may act as a point of attachment or food source.1 The bacteria are capable of migrating into the pore space of oil reservoirs through the free water phase and irreducible connate water wetting the surface area of water-wet formation rock. The metabolic process of the select bacteria strains produce organic acids and alcohols and cause bio-degradation of saturated hydrocarbons (alkanes). The products consist of three groups or mixtures of different strains. Each group selectively bio-degrade alkanes according to their molecular carbon order. Table 1 shows the range of effectiveness for each product used in MMEOR projects. The alkane molecule range bio-degradable by the three products is shown to be C16 through C63+. Treatment Design Laboratory technology and methodology have been developed to determine bacteria blend and treatment volume for the many different crude oils and reservoir environments. The development was necessary to effectively test, blend and apply the groups of living cultures and to recognize and understand the effects of their metabolism process on oil producing systems. The methods and procedures are proprietary with National Parakleen Company but the basic concepts can be discussed.