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Summary Monitoring of microbial corrosion is always difficult because of the sessile nature of bacteria and the lack of meaningful correlation between routine bacteria counts and bacterial activity. This problem is further aggravated in a large oilfield water system because of size and sampling difficulties. This paper discusses some monitoring techniques currently used in the oil industry, their limitations, and possible areas for improvement. These improved techniques are in use or will be implemented in the Aramco systems. Introduction Microbial corrosion has caused some failures in seawater injection systems. Whether or not microbial corrosion represents a major corrosion mechanism in the oilfield water system is a controversial question. However, it has certainly become a major concern in recent years. There are two approaches in dealing with microbial corrosion problems in a large oilfield water system. One approach is to start treating the system with bactericide in conjunction with regular scraping when the system is commissioned. The other is to treat the system only when an impending microbial-related problem is clearly defined. in either case, monitoring of microbial corrosion is essential. The first approach is more or less a precautionary measure. The treatment and selection of bactericides is usually based on past experience and laboratory evaluation tests. While the treatment is being implemented, a reliable monitoring program could assess the effectiveness of the current program of microbial corrosion control. In the second case, monitoring of microbial corrosion is even more important. it would provide timely information toward implementation of a treatment program before the system could get out of control. The industry's awareness of microbial corrosion has been indicated by the number of papers published in recent years on this subject. These articles cover a wide spectrum of interest from fundamental corrosion mechanisms to case studies, detection methods, control measures, etc. Although it is not clear to what extent microorganisms are responsible for the observed field corrosion failures, the general consensus still favors early establishment of a routine microbial corrosion monitoring program. The best approach seems to he the establishment of solid baseline data for the system after which any significant future deviation can be interpreted as a sign of a potential problem. The following sections describe the current methods used for routine monitoring, specifically for Aramco's large oilfield water systems. The limitations of these methods, the difficulties encountered, and some suggested studies for modification and improvement are discussed also. Current Monitoring Methods The methods currently used by Aramco can be categorized as (l) cell counts in water, (2) metal surface examination, (3) scraping solids analysis, (4) water quality analysis, and (5) evaluation of current bactericide treatment. Cell Counts in Water. These are used to detect bacterial organisms and their concentrations. it is recognized that confirmation of free-flowing bacteria in the water does not automatically mean trouble. However, if bacteria counts demonstrate a definite increase across the system, or over a period of time, the odds are that bacteria are active and working on the metal somewhere in the system. Cell counts routinely monitored include sulfate-reducing bacteria (SRB), general aerobic bacteria (OAB), iron bacteria, and others. SRB are widely recognized to he primarily responsible for bacteria-induced corrosion in an anaerobic environment. Depending on the nature of the sample to be tested and the types of problems encountered (or expected) in the field, one or several different enumeration techniques are employed. For field work, the method generally used by Aramco is culturing of samples in liquid growth media specifically designed for detecting a certain group of organisms. These laboratory media are prepared using the appropriate field water as a base, with addition of general growth nutrients for the organisms. The use of field water to prepare the media provides a water composition similar to that in which the bacteria originated. The media are supplemented with other ingredients to create an environment conducive to growth of certain bacteria (e.g., certain reducing agents have to he added into the SRB media). The media then are dispensed into serum vials at exactly 9 mL [9 cm3] each and sealed with rubber stoppers and aluminum seals. JPT P. 1171

The cover of a disposal cell is an important element in the long-term stability of a reclaimed uranium tailings site. The cover is generally comprised of a radon barrier, filter, and surface erosion barrier. A study is conducted to investigate the drainage and erosion potential between the filter and radon barrier layer in response to surface water flows over a layer of riprap. A cover system is physically modeled in a hydraulics laboratory. The experimental program evaluated the interstitial velocity potential through four filters, the erosion and sediment transport potential from the radon barrier, and the filter drainage rate after passage of the surface runoff hydrograph. The results indicated that the use of traditional filter criteria to bed riprap is extremely conservative and restricts drainage. The grain size of the filter materials should be increased to enhance drainage when placed on flat (\IS\N ≤\N 5%) slopes. A relationship is presented for estimating the drainage velocity potential through a filter layer as a function of slope and gradation. A new filter criteria should be developed for overtopping flow conditions.

Abstract The Permian Basin in West Texas contains one of the thickest deposits of Permian rocks found anywhere in the world. The Embar-B lease located in southern Andrews County on the Central Basin Platform (a regional structural high in the Permian Basin) has been producing from the Leonardian Clearfork formation for over 70 years. The Clearfork formation is primarily a subtidal and intertidal carbonate rock characterized as moderate quality reservoir. Most Permian Basin fields have multiple stacked reservoirs with varying degrees of reservoir quality and there is typically a need in these maturing fields to increase reservoir contact. In 2009, a drilling campaign was launched in Embar-B with a focus on expanding the completion interval to include what was previously considered marginal pay in the deeper Wichita Albany formation. The Wichita Albany, also Leonardian in age, is composed mostly of marginal quality tidal flat rocks and is characterized by high fracture gradients and low permeability. These characteristics required an advancement in completion practices to achieve a successful stimulation. The combination of improved completions practices and an expanded target interval resulted in production double that of previous wells. This success has driven a need for an innovative development strategy and continued optimization of completion practices. Geomodeling, volumetrics, reservoir simulation, seismic attribute analysis and oil fingerprinting were all used for reservoir characterization and to determine an allocation method for commingled wells. This lead to the identification of several Clearfork/Wichita Albany locations with significant reserves potential. Re-evaluation of the completion strategy using a multidisciplinary approach indicated the need to reduce the number of perforation clusters, add a diversion mechanism, and develop multiple hydraulic fracturing designs based on reservoir quality and presence of natural fractures. Results from recent drilling programs have exceeded expectations bringing lease production up from 200 BOEPD in 2009 to a peak rate of 3153 BOEPD in 2015.

AbstractThe Controlled Freeze Zone™ technology removes CO2 and H2S from natural gas in a single step cryogenic distillation process. Removal and management of acid gas impurities from natural gas pose significant challenges in developing sour gas fields. In many cases CFZ™ is capable of processing sour gases with a wide range of CO2 and H2S compositions at a lower cost than conventional technologies. The acidic components are removed as a high pressure liquid that can be injected into reservoirs for geosequestration or, when of suitable composition, to improve oil recovery. In either case, sulfur production from H2S and release of CO2 to the atmosphere can be eliminated.CFZ™ technology was successfully demonstrated through earlier pilot plant operations. Currently, ExxonMobil Upstream Research Company is advancing CFZ™ to large scale commercial readiness through a commercial demonstration plant in Wyoming, USA. By building the commercial demonstration plant at ExxonMobil’s world-class Shute Creek gas treating and acid gas injection facility, integration of CFZ™ with acid gas injection, will also be demonstrated when the unit is operated in 2010–2011.

Considerable interest is being shown in using biochar production from waste biomass with a variety of disciplines to address the most pressing environmental challenges. Biochar produced by the thermal decomposition of biomass under oxygen-limited conditions is gaining popularity as a low-cost amendment for agro-ecosystems. The efficiency of biochar formation is affected by temperature, heating rate, feedstock type, particle size and reactor conditions. Properties such as pH, surface area and ash content of produced biochar increases with increasing temperatures. Biochar produced at lower heating rates may have high porosity and be beneficial for morphological changes in the soil. Biochar can help to enhance soil health and fertility as well as improve agricultural yield. As a result, biochar can assist in increasing food security by promoting sustainable agricultural systems and preserving an eco-friendly environment. Biochar is also widely being used as a sorbent for organic and inorganic pollutants, owing to its large surface area, allowing it to be immobilized from soil with ease. The functional groups and charges present on the surface of biochar play an important role in pollutants removal. This review focuses on the mechanisms of biochar production using different waste materials as a feed stock, factors that influence biochar quality as well as application of biochar in agricultural soil and their reclamation as well. This article also discusses knowledge gaps and future perspectives in the field of biochar-based toxic-pollution remediation.

The growing population and increasing urbanization have led to a surge in domestic wastewater generation, posing significant challenges for effective and sustainable treatment. The present study demonstrates a novel and sustainable approach for the onsite treatment of domestic wastewater using an integrated settler-based biofilm reactor (ISBR) with efficient biogas generation. The ISBR provides an optimized environment for the growth of biofilm, facilitating the removal of organic pollutants and pathogens. Moreover, the ISBR enables the recovery of a valuable resource in the form of biogas, thus enhancing the overall utility of the treatment process. The performance of the ISBR was comprehensively evaluated at laboratory scale through treating the actual domestic wastewater generated from the hostel of Manipal University Jaipur. The ISBR system was operated under an ambient environment at a hydraulic retention time (HRT) of 24 h. The results demonstrated remarkable efficiency in terms of chemical oxygen demand (COD), total suspended solids (TSS), and coliforms removal, with average removal efficiency being more than 90%. According to the COD mass balance analysis, 48.2% of the influent COD was recovered as bioenergy. The chromatogram revealed a high percentage of methane gas in the collected biogas sample. The field emission scanning electron microscope (FESEM) analysis of the accumulated sludge in the ISBR system depicted the morphology of methanogenic bacteria. Both the experimental and theoretical results confirmed the feasibility and sustainability of the ISBR system at the onsite level.

AbstractThis article shows the results of hydrological studies on the river Don around water-intake facilities in Rostov-on-Don. The factors of wind-surge influencing ecstatic increases in the water level of the receiving basin are presented. The uneven seasonal and long-term flow river regime leading to intensive channel deformations was evaluated. A low water discharge, causing an active rift deformation within the saddle was of a high river-forming significance for the natural water flow due to a high amount of water irrespective of the yearly water content. However, the river reformation occurred mostly during a high water discharge (flooding): the floodplain was subdivided into separate arrays of channels and creeks constituting several branches within the floodplain. These deformations facilitated the formation of the easily washed floodplain alluvium. These deformations occurred mainly during years with the abundant rainfall. For a relatively short period of time (the flood period) the most significant river bed deformation occurred during the natural flow. Hydrographs were drafted according to the results of the studies on the water-level regime.

Abstract Synthetic hyperaccumulator biomass (SHB) impregnated with Ni, Zn, Cu, Co or Cr was used to conduct 11 experiments in a lab-scale fluidized bed reactor. Two runs with blank corn stover, with no metal added, were also conducted. The reactor was operated in an entrained mode in a oxygen-free (N2) environment at 873 K and 1 atm . The apparent gas residence time through the lab-scale reactor was 0.6 s at 873 K . The material balance for the lab-scale experiments on N2-free basis varied between 81% and 98%. The presence of a heavy metal in the SHB decreased the char yield and increased the tar yield, compared to the blank. The char and gas yields appeared to depend on the form of the metal salt used to prepare the SHB. However, the metal distribution in the product streams did not seem to be influenced by the chemical form of the metal salt used to prepare the SHB. Greater than 98.5% of the metal in the product stream was concentrated in the char formed by pyrolyzing and gasifying the SHB in the reactor. The metal concentration in the char varied between 0.7 and 15.3% depending on the type of metal in the SHB. However, the metal concentration was increased 4 to 6 times in the char compared to the feed.