Method of modification in oil reservoirs using resident microorganisms and nutrient supplementation through biological wettability alteration

Abstract

A method for improving oil recovery includes determining a specific nutrient package or formulation for stimulating and altering resident microorganisms to increase wettability of reservoir rock formations in oil reservoirs. Once determined, the specific nutrient package is applied to the oil reservoir to stimulate the resident microorganisms. The stimulating application is followed by a period of nutrient limitation where the physiology and surface characteristics of the resident microorganisms are altered. Once altered, the resident microorganisms interact with the reservoir rock formations to change the adhesion tension of the reservoir rock formation to a more water wet condition so that oil will flow more freely rather than be bound to the rock surface.

What is claimed: 
     
         1 . A method of improving oil recovery, comprising the steps of:
 applying a specific nutrient formulation to stimulate resident microorganisms in oil reservoir rock formations;   limiting availability of the specific nutrient formulation to alter the physiology and surface characteristics of the resident microorganisms; and   allowing the altered microorganisms to interact with the reservoir rock formations to change adhesion tension of the reservoir rock formations to a more water wet condition to allow oil to flow more freely.   
     
     
         2 . The method of  claim 1  further comprising the step of conducting a series of analyses to determine the contents of the specific nutrient package. 
     
     
         3 . The method of  claim 1  wherein surface-active properties of the resident microorganisms are modified. 
     
     
         4 . The method of  claim 1  wherein cell volume of the resident microorganisms are reduced by fifty percent or more. 
     
     
         5 . The method of  claim 3  wherein interfacial tension and relative permeability of the surface-active properties are changed. 
     
     
         6 . The method of  claim 1  wherein the specific nutrient package is in liquid form and diluted in a treated volume in a concentration range between 100 grams per liter and 0.0001 grams per liter. 
     
     
         7 . The method of  claim 1  wherein the specific nutrient formulation facilitates a microbe-mediated oil release in reservoirs up to 130 c and 150,000 ppm total dissolved solids. 
     
     
         8 . The method of  claim 1  wherein the specific nutrient formulation stimulates desirable resident microorganisms and suppress undesirable resident microorganisms. 
     
     
         9 . The method of  claim 1  wherein the delivery of the specific nutrient formulation is selected from a group consisting of water injection wells, producing wells, and disposal wells. 
     
     
         10 . The method of  claim 1  further comprising the step of conducting genetic analysis of the resident microorganisms to determine whether oil interactive microorganisms capable of altering wettability are present.