microbial method

The lifecycle of any field consists of three main periods; green, plateau and maturity periods. Currently most of GUPCO fields are brown what made us very concerned to sustain and even increase our production. To achieve that, we have looked at new different options to exploit our resources better. Generally, this can be achieved by whether optimizing current system, applying new technology or evaluating unconventional resources.

One of the high-potential resources that we do have in GUPCO is unconventional resources with many tight carbonate formations. Nevertheless, we did not try to appraise it before since most of our reservoirs are clastics that can be easily characterized and evaluated. On the other hand, tight carbonate formations cannot be characterized or appraised utilizing conventional logging tools or even classical reservoir engineering concepts. It always requires unique techniques relevant to its unique complexity degree especially in presence of micro-porosity and unknown fluid content. This paper sheds light on Appraisal Unconventional Resource Study that resulted in the first successful producer in the company.

GUPCO started to appraise tight carbonate rocks (named Thebes in Lower Eocene) and basaltic intrusion in GoS. This study involved high integration between key disciplines; Petrophysics, Petrology and Reservoir Engineering. To manage uncertainty, we have acquired wide range of data types starting from advanced petrophysical logging tools like Magnetic Resonance, Borehole Imaging and spectroscopy, and full petro-graphic description, reaching to predicting reservoir dynamic performance using measured pressure points (RFT), its analysis and fluid characterization. Ultimately, we have succeeded to completely characterize Thebes formation, and proposing its development plan. The first successful well resulted in 300 BOPD gain as the first successful tight carbonate producer in GUPCO. Development plan is being built to drill new wells targeting unconventional resources including a few possible potential in basalt intrusions, as well.

Dealing with unconventional resources is not an easy task. It requires a lot of work and analysis. Having all of your homework done is not always enough, you have to integrate with interrelated disciplines to link dots and complete the picture. In this paper, we have conceived a new approach in evaluating such formations, and it is a very good example of managing uncertainty by integrating different data to convert hypothesis into reality that can be translated ultimately into oil production and revenues.

Globally, most oil fields are on the decline and further production from these fields is addressed to be practical in cost-effectiveness and oil productivity. Most oil companies are adopting two main technologies to address this: artificial intelligence and enhanced oil recovery (EOR). But the cost of some of these EOR methodologies and their subsequent environmental impact is daunting. Herein, the environmental and economic advantage of microbial enhanced oil recovery (MEOR) makes it the point of interest. Since, there is no need to change much-invested technology and infrastructure, amidst complex geology during MEOR application, it is entrusted that MEOR would be the go-to technology for the sustainability of mature fields.

Despite the benefits of MEOR, the absence of a practical numerical simulator for MEOR halts its economic validation and field applicability. Hence, we address this by performing both core and field- scale simulations of MEOR comparing conventional waterflooding. The field scale is a sector model(fluvial sandstone reservoir with 13,440 active grid cells) of a field in Asia - Pacific.

Here we show that pre-flush inorganic ions (Na⁺ and Ca²⁺) affect the mineralization of secondary minerals which influences microbe growth. This further influences carboxylation, which is relevant for oil biodegradation. Also, as per the sensitivity analysis: capillary number, residual oil saturation and relative permeability mainly affect MEOR. Secondary oil recovery assessment showed an incremental 6% OOIP for MEOR comparing conventional water flooding. Also, tertiary MEOR application increased the oil recovery by about 4% OOIP over conventional water flooding. It was established that during tertiary recovery, initiating MEOR after 5years of conventional waterflooding is more advantageous contrasting 10 and 15years. Lastly, per probabilistic estimation, MEOR could sustain already water-flooded wells for a set period, say, a 20% frequency of increasing oil recovery by above 20% for 2 additional years as highlighted in this study.

Microbial-influenced corrosion (MIC) has been implicated in few corrosion-related challenges in the well-service industry in the past. DuPont is ramping up the commercial-scale implementation of its microbial enhanced oil recovery (MEOR) method after nearly a decade of development and testing of what it says is a low-risk way to improve production from mature fields.

Good diagnostic testing is often painstaking, time-consuming, and costly, but recent studies suggest that a lack of knowledge can be even costlier. Tiny soil samples may contain as many as 300,000 species of microbial life, but a Netherlands-based startup has figured out that between 50 and 200 of them can tell an operator if a drilling location will hold oil and gas reserves. For the past 2 decades, the use of DNA sequencing technology has largely been relegated to the domains of criminal forensics and the healthcare industry. One company is betting that the shale industry soon will join that list. DuPont is ramping up the commercial-scale implementation of its microbial enhanced oil recovery (MEOR) method after nearly a decade of development and testing of what it says is a low-risk way to improve production from mature fields.

From the highest courts of the US judicial branch to the C-suite, contests involving patents have recently come to the fore in the innovation hungry US oilfield services industry, even as filings and litigation have declined in recent years. Seeking out, experimenting with, and ultimately embracing technologies from other industries have proven crucial to innovating at oilfield service firms such as Halliburton, which has tried everything from dog food to submarine tech to improve its work downhole. R&D may be the key to the survival of companies as the new economics of the industry take hold. The R&D Technical Section dinner at ATCE drew varying perspectives as the panelists discussed, and sometimes debated, a range of approaches to safeguarding industry viability and growth in the years ahead. Even as the oil and gas industry looks for the next great idea to propel it forward, it should constantly reconsider past innovations for inspiration, the CEO of a major operator said Monday on the opening day of 2017 SPE ATCE.

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Microbial Exploration Technology (MET), also called microbial enhanced oil recovery (MEOR), is a method of enhanced oil recovery (EOR) that identifies microorganism levels in soil near reservoir surfaces to estimate hydrocarbon levels. This method is largely based on the premise that the more microorganisms present, the more hydrocarbons are present for those microorganisms to feed on. Hydrocarbon degrading bacteria can be used to detect migrating hydrocarbon gases from oil and gas deposits. As short chain hydrocarbon gases migrate to the surface, bacterial cells metabolize these gases in the near surface aerobic zone. In the laboratory, EBT measures the response from these hydrocarbon utilizing bacteria and develops their recommendations based on a proprietary data analysis process.

Utilisation of microorganisms as an enhanced oil recovery (EOR) method has attracted much attention in recent years because it is a low-cost and environmentally friendly technology. However, the pore-scale mechanisms involved in MEOR that contribute to an additional oil recovery are not fully understood so far. This work aims to investigate the MEOR mechanisms using microfluidic technology, among others bioplugging and changes in fluid mobilities. Further, the contribution of these mechanisms to additional oil recovery was quantified.

A novel experimental setup that enables investigation of MEOR in micromodels under elevated pressure, reservoir temperature and anaerobic and sterile conditions was developed. Initially, single-phase experiments were performed with fluids from a German high-salinity oil field selected for a potential MEOR application: Brine containing bacteria and nutrients was injected into the micromodel. During ten days of static incubation, bacterial cells and in-situ gas production were visualised and quantified by using an image processing algorithm. After that, injection of tracer particles and particle image velocimetry were performed to evaluate flow diversion in the micromodel due to bioplugging. Differential and absolute pressures were measured throughout the experiments. Further, two-phase flooding experiments were performed in oil wet and water wet micromodels to investigate the effect of in-situ microbial growth on oil recovery.

In-situ bacteria growth was observed in the micromodel for both single and two-phase flooding experiments. During the injection, cells were partly transported through the micromodel but also remained attached to the model surface. The increase in differential pressure confirmed these microscopic observations of bioplugging. Also, the resulting permeability reduction factor correlated with calculations based on the Kozeny-Carman approach using the total number of bacteria attached. The flow diversion of the tracer particles and the differences in velocity field also confirmed that bioplugging occurred in the micromodel may lead to an improved conformance control. Oil viscosity reduction due to gas dissolution as well as changes in the wettability were also identified to contribute on the incremental oil. Two-phase flow experiments in a newly designed heterogeneous micromodel showed a significant effect of bioplugging and improved the macroscopic conformance of oil displacement process.

This work gives new insights into the pore-scale mechanisms of MEOR processes in porous media. The new experimental microfluidic setup enables the investigation of these mechanisms under defined reservoir conditions, i.e., elevated pressure, reservoir temperature and anaerobic conditions.

The PDF file of this paper is in Russian.

The use of strains of bacteria that destroy aluminosilicates leads to a change in the molecular structure of rocks of a low permeable clay-containing oil-bearing layer. In processed samples, the reduction in silicon content makes up one to five and a half percent, aluminum totals up to twelve percent. A high intensity of biogenic leaching of silicates (including quartz) is noted during the destruction of silicate minerals by cultures of silicate bacteria, in comparison with the abiogenic process. Among the layered silicates and aluminosilicates, the most decomposable were aluminosilicates (clay minerals). The results of the research may be relevant for the development of clay containing oil-bearing formations in Western Siberia and Yakutia, for the restoration of the reservoir's filtration capacity after drilling on a clay basis, and geological and technological measures.

There are several self-healing mechanisms, both natural and artificial, applied to cementitious materials. In recent years, microbially induced calcite precipitation (MICP) technology has garnered special attention in the fields of Microbiology and Civil Engineering. The technology involves the synthesis of calcium carbonate crystals at ambient temperatures in calcium rich systems. Biocementation occurs as active microbes diffuse through the cracks and micro-pits generating calcitic deposits owing to their metabolic pathway. The calcifying bacterial cultures produce urease or carbonic anhydrase enzyme which is capable of precipitating calcium in the surrounding micro environment as CaCO₃. The bacterial degradation of urea locally increases the pH and stimulates the microbial deposition of carbonate. The calcium carbonate produced binds the soil particles together, thus cementing and clogging the grains, and hence improves the strength and reduces the hydraulic conductivity of the unconsolidated sands. Moreover, these precipitated crystals can thus fill the cracks and enhance the durability of cement, mortar, and concrete. Incorporating calcifying bacteria is the essence of developing a self-healing material or "bio-cementing" technology as bacteria behaves as a long-lasting healing agent.

The calcifying microbes can be isolated from different sources like water springs, soil, ocean, environments with high pH values or the cement itself. The purified strains can be grown for a 24-hour period in the laboratory and then blended with the cement or other materials depending on the desired application. A cheap carbon source like glycerol/molasses is supplemented to the mixture triggering fast bacterial multiplication. It was found that after the curing time of 28 days, tensile strength, micro-crack healing capacity, and durability increased significantly. The process is as simple as mixing bacteria into a cement paste. The technique for creating a high strength cement in a permeable starting material involves combining the starting material with effective amounts of (1) a urease producing micro-organism with a high urea hydrolysis rate; (2) urea; and (3) calcium ions, under standard conditions of 0.5-50 mM urea hydrolyzed min^-1. Scientists found that after injecting the bacterial cementitious solution for a period of one month, the spores of three particular bacteria where still viable. Harmless bacteria such as Bacillus genus remains dormant until water enters the cracks. In this case, formation water, or water from fracturing fluids or any source can be used to trigger the bacteria. Moreover, the process does not require oxygenation.

In this paper, self-healing approaches based on bacteria will be thoroughly reviewed. The concept of biomineralization, bioclogging, and biorepair and its applications in improving the engineering properties of sands and cement is tackled. Based on the aforementioned aspects of self-healing in cementitious materials, recommendations for further research in self-healing engineering applications are proposed. This method is a green and eco-friendly way and the use of bacteria can lead to substantial savings. The following presents major practical applications for the oil and gas industry. Via the microbial calcification theory, solidifying the sea beds before drilling for oil, preventing hole cavings and wellbore enlargements or washouts, sealing undesirable leakage pathways near wellbores to achieve fracture plugging and permeability reduction, plugging sands to diminish water absorption and porosity are all lucrative potential applications the industry is in dire need of.