Water Production In Reservoirs Research Articles

Simulating Oil and Water Production in Reservoirs with Generative Deep Learning

Summary This study investigated the ability to produce accurate multiphase flow profiles simulating the response of producing reservoirs, using generative deep learning (GDL) methods. Historical production data from numerical simulators were used to train a variational autoencoder (VAE) algorithm that was then used to predict the output of new wells in unseen locations. This work describes a procedure in which data analysis techniques can be applied to existing historical production profiles to gain insight into field-level reservoir flow behavior. The procedure includes clustering, dimensionality reduction, correlation, in addition to novel interpretation methodologies that synthesize the results from reservoir simulation output, characterizing flow conditions. The insight was then used to build and select samples to train a VAE algorithm that reproduces the multiphase reservoir behavior for unseen operational conditions with high accuracy. Furthermore, using deep feature space interpolation, the trained algorithm can be used to further generate new predictions of the reservoir response under operational conditions for which we do not have previous examples in the training data set. It is found that VAE can be used as a robust multiphase flow simulator. Applying the methodology to the problem of determining multiphase production rate from new producing wells in undrilled locations showed positive results. The methodology was tested successfully in predicting multiphase production under different scenarios including multiwell channelized and heterogeneous reservoirs. Comparison with other shallow supervised algorithms demonstrated improvements realized by the proposed methodology. The study developed a novel methodology to interpret both data and GDL algorithms, geared toward improving reservoir management. The method was able to predict the performance of new wells in previously undrilled locations, potentially without using a reservoir simulator.

Some polymeric imidazolates from alkylimidazolium as corrosion inhibitors of API 5L X52 steel in production water

In this work, the synthesis route and evaluation of two poly(ionic liquids) (PolyILs) derived from alkylimidazolium imidazolate to be used as corrosion inhibitors (CIs) of API 5L X52 steel exposed to oil reservoir production water (PW) are discussed. The corrosion inhibition performance of the PolyILs was investigated by potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). According to the PDP analysis, it was concluded that the PolyILs could be classified as mixed-type CIs with anodic tendency, featuring maximal inhibition efficiency (η) of 80%. The adsorption mechanism occurred through the blocking of active sites by means of electrostatic attraction forces and formation of chemical bonds. The SEM and AFM surface analyses evidenced that the metal surface in the presence of the PolyILs was less damaged by steel corrosion. Finally, the XPS studies confirmed that the CI interaction with the steel surface reduced the amount of produced corrosion products such as FeOOH and/or FeCO3.

Long-chain n-alkane biodegradation coupling to methane production in an enriched culture from production water of a high-temperature oil reservoir

Paraffinic n-alkanes (C22–C30), crucial portions of residual oil, are generally considered to be difficult to be biodegraded owing to their general solidity at ambient temperatures and low water solubility, rendering relatively little known about metabolic processes in different methanogenic hydrocarbon-contaminated environments. Here, we established a methanogenic C22–C30 n-alkane-degrading enrichment culture derived from a high-temperature oil reservoir production water. During two-year incubation (736 days), unexpectedly significant methane production was observed. The measured maximum methane yield rate (164.40 μmol L−1 d−1) occurred during the incubation period from day 351 to 513. The nearly complete consumption (> 97%) of paraffinic n-alkanes and the detection of dicarboxylic acids in n-alkane-amended cultures indicated the biotransformation of paraffin to methane under anoxic condition. 16S rRNA gene analysis suggested that the dominant methanogen in n-alkane-degrading cultures shifted from Methanothermobacter on day 322 to Thermoplasmatales on day 736. Bacterial community analysis based on high-throughput sequencing revealed that members of Proteobacteria and Firmicutes exhibiting predominant in control cultures, while microorganisms affiliated with Actinobacteria turned into the most dominant phylum in n-alkane-dependent cultures. Additionally, the relative abundance of mcrA gene based on genomic DNA significantly increased over the incubation time, suggesting an important role of methanogens in these consortia. This work extends our understanding of methanogenic paraffinic n-alkanes conversion and has biotechnological implications for microbial enhanced recovery of residual hydrocarbons and effective bioremediation of hydrocarbon-containing biospheres.

Bioconversion Pathway of CO2 in the Presence of Ethanol by Methanogenic Enrichments from Production Water of a High-Temperature Petroleum Reservoir

Transformation of CO2 in both carbon capture and storage (CCS) to biogenic methane in petroleum reservoirs is an attractive and promising strategy for not only mitigating the greenhouse impact but also facilitating energy recovery in order to meet societal needs for energy. Available sources of petroleum in the reservoirs reduction play an essential role in the biotransformation of CO2 stored in petroleum reservoirs into clean energy methane. Here, the feasibility and potential on the reduction of CO2 injected into methane as bioenergy by indigenous microorganisms residing in oilfields in the presence of the fermentative metabolite ethanol were assessed in high-temperature petroleum reservoir production water. The bio-methane production from CO2 was achieved in enrichment with ethanol as the hydrogen source by syntrophic cooperation between the fermentative bacterium Synergistetes and CO2-reducing Methanothermobacter via interspecies hydrogen transfer based upon analyses of molecular microbiology and stable carbon isotope labeling. The thermodynamic analysis shows that CO2-reducing methanogenesis and the methanogenic metabolism of ethanol are mutually beneficial at a low concentration of injected CO2 but inhibited by the high partial pressure of CO2. Our results offer a potentially valuable opportunity for clean bioenergy recovery from CCS in oilfields.

Shifts of the indigenous microbial communities from reservoir production water in crude oil- and asphaltene-degrading microcosms

Microbial metabolism of crude oil is an important process in both microbial enhanced oil recovery and bioremediation. Recently, diverse microorganisms have been detected and isolated from oil reservoirs. In this work, crude oil- and asphaltene-degrading microcosms were constructed using two different reservoir production water samples, which had distinct bacterial communities. After two three-week enrichments culture, GC-MS and FT-IR analysis showed that crude oil and asphaltene were biodegraded. Microbial communities in microcosms using the same carbon source showed high similarity, which suggested similar processes of microbial succession in both crude oil- and asphaltene-degrading consortia. Parvibaculum, Pseudomonas, Alcanivorax, Devosia, Hydrogenophaga and Dietzia were found in all crude oil degrading microcosms and Parvibaculum, Alcanivorax, Hyphomonas, Flavobacterium and Reyranella were found in all asphaltene degrading microcosms, which might play important roles in crude oil or asphaltene degradation. The results indicated that reservoir production water might serve as a microbial species pool which contained the indigenous core microbiomes for crude oil degradation. This work provided new insights into the understanding of microbial diversity in reservoir production water and the potential role of reservoir production water as a microbial species pool for oil degrading microorganisms.

Biodegradation of Heavy Oil in Oilfield Wastewater by Bacteria Isolated from Heavy Oil Reservoir Production Water

Biodegradation of Heavy Oil in Oilfield Wastewater by Bacteria Isolated from Heavy Oil Reservoir Production Water

The diversity of hydrogen-producing microorganisms in a high temperature oil reservoir and its potential role in promoting the in situ bioprocess

Hydrogen-producing microorganisms are believed to play an important role in energy metabolism of micro-organisms in anaerobic environments and hence are one of the crucial factors for influencing the activity and develop-ment of these microorganisms. Consequently, they provide the biological foundation for the biotechnology such as MEOR (Microbial Enhanced Oil Recovery) and microbial fixation of CO2 and conversion of it into CH4 and etc. How-ever, knowledge on the community of hydrogen-producing microorganisms and their potential in subsurface formations are still limited. In this study, hydrogen-producing microorganisms in the production water from an oilfield as well as enrichment cultures were analyzed with clone library analysis of [FeFe]-hydrogenase encoding genes. The results show that [FeFe]-hydrogenase genes in production water are diverse and related to Bacteroidetes, Firmicutes, Spirochaetes and uncultured. Anaerobic incubations established within the oil reservoir production water and generating 202 mmol H2/mol glucose during 7-day incubation at 55°C indicate a high frequency of members of the Firmicutes. This study implies that hydrogen-producing microorganisms in oil reservoir may play a positive role in promoting the in situ bio-process via hydrogen production once common nutrients are available. These data are helpful for evaluating, developing, and utilizing hydrogen-producing microorganisms in oil reservoirs for biological fixation and conversion of CO2 into CH4 as well as MEOR.

Preparation and performance of fluorescent polyacrylamide microspheres as a profile control and tracer agent

Polyacrylamide microspheres have been successfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir produced fluid, fluorescent polyacrylamide microspheres P(AM-BA-AMCO), which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribution in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, Na2CO3, and dispersant. The bonding characteristics of microspheres were determined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultraviolet irradiation in the produced fluid, even though they had experienced extrusion and deformation in the sand pack.

Analyses of n-alkanes degrading community dynamics of a high-temperature methanogenic consortium enriched from production water of a petroleum reservoir by a combination of molecular techniques

Despite the knowledge on anaerobic degradation of hydrocarbons and signature metabolites in the oil reservoirs, little is known about the functioning microbes and the related biochemical pathways involved, especially about the methanogenic communities. In the present study, a methanogenic consortium enriched from high-temperature oil reservoir production water and incubated at 55 °C with a mixture of long chain n-alkanes (C(15)-C(20)) as the sole carbon and energy sources was characterized. Biodegradation of n-alkanes was observed as methane production in the alkanes-amended methanogenic enrichment reached 141.47 μmol above the controls after 749 days of incubation, corresponding to 17 % of the theoretical total. GC-MS analysis confirmed the presence of putative downstream metabolites probably from the anaerobic biodegradation of n-alkanes and indicating an incomplete conversion of the n-alkanes to methane. Enrichment cultures taken at different incubation times were subjected to microbial community analysis. Both 16S rRNA gene clone libraries and DGGE profiles showed that alkanes-degrading community was dynamic during incubation. The dominant bacterial species in the enrichment cultures were affiliated with Firmicutes members clustering with thermophilic syntrophic bacteria of the genera Moorella sp. and Gelria sp. Other represented within the bacterial community were members of the Leptospiraceae, Thermodesulfobiaceae, Thermotogaceae, Chloroflexi, Bacteroidetes and Candidate Division OP1. The archaeal community was predominantly represented by members of the phyla Crenarchaeota and Euryarchaeota. Corresponding sequences within the Euryarchaeota were associated with methanogens clustering with orders Methanomicrobiales, Methanosarcinales and Methanobacteriales. On the other hand, PCR amplification for detection of functional genes encoding the alkylsuccinate synthase α-subunit (assA) was positive in the enrichment cultures. Moreover, the appearance of a new assA gene sequence identified in day 749 supported the establishment of a functioning microbial species in the enrichment. Our results indicate that n-alkanes are converted to methane slowly by a microbial community enriched from oilfield production water and fumarate addition is most likely the initial activation step of n-alkanes degradation under thermophilic methanogenic conditions.

Microbial community characteristics of petroleum reservoir production water amended with n-alkanes and incubated under nitrate-, sulfate-reducing and methanogenic conditions

Methanogenic, sulfate- and nitrate-reducing enrichment cultures amended with long-chain n-alkanes (C15–C20) were established with production water from Huabei oilfield in China in the present study. Chemical analyses indicated that degradation of n-alkanes was evident under all three conditions after 356 days of incubation. Phylogenetic analyses based on 16S rRNA gene amplification indicated that α-, β-, γ-Proteobacteria and Bacteroidetes were detected in the nitrate-reducing enrichment; Actinobacteria, Nitrospira and δ-Proteobacteria were recovered from both the sulfate-reducing and methanogenic enrichments. Actinobacteria and Nitrospira were the most abundant in methanogenic and sulfate-reducing enrichment, respectively. The archaeal clone libraries showed that the order Methanomicrobiales within the phylum Euryarchaeota predominated methanogenic enrichment; whereas the unclassified class Thermoprotei within the phylum Crenarchaeota prevailed in sulfate-reducing enrichment. Comparison of 16S rRNA gene sequences from genomic DNA extracted directly from the petroleum reservoir production water with those from the three active enrichments showed that the available electron acceptors had a strong influence on the microbial community composition. In addition, genes encoding the alkylsuccinate synthase (assA) and methyl coenzyme-M reductase (mcrA) were amplified from the methanogenic enrichment and the results suggested that fumarate addition was probably involved in the degradation of n-alkanes. These results shed light on the potential utilization of microbial metabolism in remediation of hydrocarbon contamination or in enhancing the recovery of residual oil for energy.