Abstract

The field history and performance of microbial culture products for the oil field is examined. For over 15 years, microbial culture products have been used for paraffin control, production enhancement, well bore treatments as well as for scale and corrosion problems. The wide-ranging capacity of microbes to effect positive changes in oil and water properties is described. The broad spectrum of oil types and formations that have been treated successfully is reported along with treatment protocols. Mechanistic considerations for modes of action are analyzed. Traditionally, these considerations involve the continuous production of biosurfactants, solvents and other oil mobilizing agents.

Continuous advancement of microbial technology has led to more recent development of new applications that use unique metabolic capabilities of microorganisms to address specific well problems. Examples of applying these products to problems in oil field production systems are shown. The outlook for development of new technologies and the future application of these products to the oil field is discussed.

Introduction

Microbial culture products occupy an increasingly important and growing segments in oil field production operations. They are a truly environmentally benign treatment technology that can be used to replace and augment many conventional technologies, including many oil field chemicals. The extraordinary diversity of microorganisms with the concomitant likelihood for many more such products in the future suggests that their role in oil field operations will continue to expand and will supplant many conventional technologies in the next 100 years. It is therefore important to review the prior and current uses of this technology.

Historical Applications of Microbial Culture Products
Paraffin Control.

Microbial culture products (MCPs) were first used in 1986 in the Austin Chalk formation in Texas to control paraffin deposition. The theory behind these products was that microorganisms can be isolated and combined in novel mixtures which will produce biochemicals that will mimic the action of classic oil field chemicals such as pour point depressants, crystal modifiers and wax dispersants. The advantage of using such biological products is the fact that the microorganisms will 1) produce these biochemicals continuously and 2) attach to surfaces where paraffin deposition is occurring and act directly at the site of deposition.

The first successful application of these products began a pattern of expansion that continued throughout the 80s and 90s. Paraffin deposition results in a variety of problems for oil field operators, ranging from plugging of tubulars to occult formation deposition that reduces formation permeability. A continual increase in the number of products available to the industry allowed the expansion of the microbial technology for paraffin control into a variety of different oil types and formations.

Conventional technologies to control paraffin deposition are thermal and chemical treatments. Both of these technologies have limitations that restrict their long-term effectiveness. In particular, hot oil or water treatments may lead to increased formation damage by forcing deposited high molecular weight paraffins into the formation where they can contribute to pore throat plugging and lead to production loss.

Development of MCPs represents a successful alternative technology to remove paraffin deposits without causing lasting formation damage. Long term use of MCPs showed no damage to the oil field production system and their use increased throughout the mid continent region in the early 1990s. Examples of the successful application of this technology in the oil field have been previously documented in SPE papers.1,2,3

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