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Microbial enhanced treatment of carbonate reservoirs for in situ hydrocarbon recovery

a carbonate reservoir and in situ hydrocarbon technology, applied in the field of in situ hydrocarbon recovery, can solve the problems of difficult hydrocarbon recovery efficiency of carbonate reservoirs, complex bitumen production from this formation, and difficult recovery of heavy hydrocarbons from carbonate reservoirs, so as to promote the dissolution of carbonate compounds, enhance hydrocarbon recovery, and increase the porosity and permeability of carbonate reservoirs

Inactive Publication Date: 2015-02-26
UTI LLP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent describes a technique for improving the recovery of oil from carbonate reservoirs by using a microbial stimulation fluid containing hydrogen gas (H2). The H2 is converted by microbes into a byproduct that promotes the dissolution of carbonate compounds, increasing the porosity and permeability of the reservoir. This helps to enhance the recovery of oil from the reservoir.

Problems solved by technology

While oil sands reservoirs have been commercially exploited for several decades, carbonate reservoirs have been challenging in terms of efficiently recovering hydrocarbons due to particular characteristics of carbonate reservoirs.
Heavy hydrocarbon recovery from carbonate reservoirs is particularly challenging due to the high viscosity of such heavy hydrocarbons combined with the properties of the carbonate reservoirs.
Bitumen production from this formation is complicated by carbonate reservoir characteristics such as fractures, low permeability and low porosity.
In addition, production may also be challenging where carbonate rock is oil-wet.
The fractures and holes may also contain bitumen, which is difficult to access due to the low permeability and porosity of surrounding carbonate rock.
However, in carbonate formations in situ recovery is particularly challenging due to the nature of such reservoirs, in particular the low permeability and low porosity typical of such formations.
The low permeability and porosity of carbonate reservoirs creates challenges for the injection of mobilizing fluids, such as steam and solvents.
Impaired injectivity, in turn, reduces the ability of the injected mobilizing fluid to access and mobilize the heavy hydrocarbons and therefore reduces the efficiency and productivity of the recovery process.

Method used

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  • Microbial enhanced treatment of carbonate reservoirs for in situ hydrocarbon recovery
  • Microbial enhanced treatment of carbonate reservoirs for in situ hydrocarbon recovery
  • Microbial enhanced treatment of carbonate reservoirs for in situ hydrocarbon recovery

Examples

Experimental program
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examples & experimentation

Example 1

Production of Acetic Acid from Carbon Dioxide and Hydrogen Diffusing Through Oil

[0183]Samples were obtained from the Medicine Hat Glauconitic C (MHGC) field near Medicine Hat, Alberta. This is a shallow (850 m), low temperature (30° C.) field that produces heavy oil (API of 16°) from pre dominantly sandstone reservoir rock by water injection (Voordouw, G., et al. (2009) Environmental Science and Technology, Vol. 43, pp. 9512-9518; Agrawal, A. et al. (2012) Environmental Science and Technology, Vol. 46, pp. 1285-1292, 2012). Produced waters from producing wells 5 and 16 (5-PW and 16-PW) were collected in a 1 L Nalgene bottle that was filled to the brim to exclude air. Upon arrival in the lab these samples were stored in a Coy anaerobic hood with an atmosphere of 90% N2 and 10% CO2. To 159 mL serum bottles, 5 mL of sample (5-PW or 16-PW) and 45 mL of acetogen medium were added. A layer of 10 mL of heavy oil (HO, 2300 cP at 20° C.) or light oil (LO, 3.5 cP at 20° C.) was then ...

example 2

Dissolution of Carbonate Minerals with Acetic Acid

[0185]In order to demonstrate dissolution of carbonate minerals with acetic acid, a sample of calcium carbonate and a sample of oilfield core material were incubated with acetic acid. The experiment was performed by adding 100 μl amounts of 4 or 17.5 M acetic acid to a mixture of 10 mL deionized water and 0.50 g of calcium carbonate (CaCO3; 500 mM) and sample crushed core in a glass vial under stirring. The chemical reaction was monitored by measuring pH as a function of time. Following completion of the reaction, vacuum filtration was used to collect undissolved CaCO3 on an 0.2 μm Millipore filter. The resulting solid was dried at 100° C. for 2 hours, allowed to cool down to room temperature and then weighed.

[0186]The results of the experiment with CaCO3 are shown in FIG. 12. The suspension of CaCO3 in water had a pH of 10, decreasing to 9.2 over 102 minutes of monitoring. The pH decreased to 5.8 following addition 40 mM acetic acid...

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Abstract

Techniques for hydrocarbon recovery from a carbonate reservoir include injecting a microbial stimulation fluid including H2 which enters a region of the reservoir that includes CO2 and a microbial culture which converts at least a portion of the H2 and CO2 into a byproduct to promote dissolution of carbonate compounds in the region of the reservoir, thereby increasing porosity of the region to promote hydrocarbon recovery.

Description

FIELD OF THE INVENTION[0001]The present invention generally relates to the field of in situ hydrocarbon recovery and more particularly to techniques for microbial enhanced treatment of a carbonate reservoir for in situ heavy hydrocarbon recovery.BACKGROUND[0002]While oil sands reservoirs have been commercially exploited for several decades, carbonate reservoirs have been challenging in terms of efficiently recovering hydrocarbons due to particular characteristics of carbonate reservoirs.[0003]Oil sands reservoirs, on the one hand, are primarily composed of a matrix of unconsolidated sand, which is a naturally occurring granular material mainly composed of silica (SiO2), with hydrocarbons occurring in the sand matrix. Oil sands reservoirs also tend to display water-wet conditions, meaning that a thin film of water coats the surface of the sand particles and hydrocarbons surround the inner water coating.[0004]Carbonate reservoirs, on the other hand, are primarily composed of carbonate...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): E21B43/16E21B43/24
CPCE21B43/164E21B43/2406E21B43/24E21B43/16
Inventor VOORDOUW, GERRITFOLARIN, YETUNDENATHOO, SAFIADIAZ-GOANO, CAROLINA
Owner UTI LLP