Constructing Calcite Core by Microbially Induced Calcite Precipitation (MICP) Usable in Oil and Gas Tests

Ali Doust Salimi, Nazanin | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54024 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Yaghmaei, Soheila; Bazargan, Mohammad; Ghobadi Nejad, Zahra
  7. Abstract:
  8. Acidizing is the most widely performed job to remove the formation damage, and enhance the oil recovery. Different models have been introduced to design the optimized condition for acidizing. However, none of them are able to predict the optimum injection flow rate in the actual application. As a result, Calcite cores are extracted from reservoirs for conducting experiments and modifying the present models. Nevertheless, acidizing is an intrusive technique destroying the costly extracted cores. Thus, there is a need to construct calcite cores of various porosities and permeabilities to take advantage of them in acidizing modelling.Microbially induced calcite precipitation is a well-known process that has attracted much attention in recent decades for its various biotechnological applications. Despite other studies which mainly introduced this process on soil and sand, this study has seen MICP from a new perspective, and has taken advantage of the MICP to construct calcite cores. To do so, a semi-continuous system consisting of a glass reactor and a peristaltic pump is designed. The MICP process is done inside the reactor in the bed of micronized powder of calcium carbonate with mesh sizes of 40 and 60. The most famous microorganism used in MICP applications is Sporosarcina pasteurii, a gram-positive, ureolytic, and nonpathogenic bacteria capable of hydrolyzing urea in favourable conditions. In this study, the enzyme activity of the bacteria after 40 hours of incubation, was 1.78 mM urea per minute. At the end of the treatment, SEM images indicate that calcite crystals are precipitated both on the particles’ surface and between two adjacent particles. The SEM images of different parts of the specimen (down, middle, and top) showed the produced precipitations act as a bridge to attach the particles. Thus, the MICP process was successful in binding the calcite particles together. The treated samples were such consolidated that it was hard to divide them into smaller parts. In conclusion, this technology has the potential to produce cores of different porosity and permeability, and can be utilized in the acidizing design and modelling
  9. Keywords:
  10. Microbially Induced Calcite Precipitation ; Calcite ; Urease ; Reservoirs Acidizing ; Sporosarcina Pasteurii Bacteria ; Formation Damage ; Enhanced Oil Recovery ; Constructing Calcite Cores

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