Risk Assessment of Abandoned Radioactive Logging Sources in Oil Wells in Nigeria

An integrated model for the risk assessment is developed for abandoned radioactive logging sources (Am-241 and Cs-137) in oil wells. The model is composed of four components: Source term, Barrier failure model, a geosphere model, a biosphere model, and finally a dose and health effect model to analyse the radionuclide dispersion phenomenon from the abandoned source term to the risk of serious health effects on members of the public (cancer death). In addition to time-dependent annual release rate and dose rate for each radionuclide, the ultimate risk in terms of cancer death rate is estimated.  The results show that the highest value of the annual dose for the abandoned radioactive logging sources is less than the individual dose limit to the human body, and the calculated highest cancer death rate is much lower than that of background radiation but higher than that of low-level waste repository. Subsequently, an abandonment procedure was developed in an effort to manage the risk and reduce it to the barest minimum.  It is concluded that the use of simplified mathematical modelling for the risk assessment of abandoned radioactive sources in oil wells could be an effective tool for development of efficient and acceptable abandonment procedure. Keywords: risk assessment, geosphere model, dose, cancer death, logging sources, low-level repository, radionuclide, abandonment procedur

Impact Of Artificial Intelligence And Big Data On The Oil And Gas Industry In Nigeria

This paper examines the concept of Artificial intelligence and Big Data as a field of study and its Impact on the oil and gas industry. Artificial Intelligence refers to the concept having of Computer systems that can perform tasks that would typically require human intelligence. Some such tasks are visual perception, speech recognition, decision-making and translation between languages, amongst others. “Big data” or Big Data analytics is a term often used to describe a huge or somewhat overwhelming data size that exceeds the capacity of both humans and the traditional software to process within an acceptable time and value. There is a big interface between the two concepts. AI does not stand alone; it requires big data for efficiency. AI and Big Data have brought about great impact across different industries and organizations. In the oil and gas industry, there have been an increasing installation of data recording sensors, hence data acquisition in exploration, drilling and production aspects of the industry. The industry is gradually making use of this huge data set by processing them using AI enabled tools and software to arrive at smart decisions that bring efficiency to operations in the industry. Some of such areas are analysis of seismic and micro-seismic data, improvement in reservoir characterization and simulation, reduction in drilling time and increasing drilling safety, optimization of pump performance, amongst others. Some of the solutions listed above have been successfully implemented in Nigeria, mostly by the international oil companies and some additional areas have also been impacted: managing asset integrity, tubular tally for drilling operations using RFID and the licensing and permit system by DPR. The industry has fully embraced the AI and Big Data concept, the future is very bright for more innovative solutions. However, there are still a few challenges especially in Nigeria. Some of these challenges include lack of local skilled manpower, poor data culture, security challenges in the industry’s operating areas, limited availability of good quality data, and understanding the complexity of the concept

A MODEL TO OPTIMIZE A CRYOGENIC SEPARATION SYSTEM WITH INNOVATIVE HYBRID DISTILLATION MEMBRANE IN SERIES

The study developed a model for hybrid distillation membrane that optimized the energy usage in binary cryogenic separation. In separating air mixture components, distillation columns are often used and these columns consumes very large energy during operation. From analysis, the exergy efficiency and heat transfer of a cryogenic air separation double diabatic column in the distillation process is greater than that of the conventional adiabatic double columns. There is need to discover alternative separation technologies with lesser energy consumption such as membrane separation. However, use of membrane separation alone is constrained to small separation due to large areas needed with the attendant costs. Thus, a hybrid system comprising of distillation column and membrane separator offers the best compromise. To optimize the process, the overhead product from the distillation column was fed to a membrane separator in series in this study. A mathematical Model approach was proposed to improve a hybrid separation system comprising of a distillation column and a Serial novel membrane separation unit. First, a model was introduced that validated if the hybrid system could optimize the process and the order of magnitude of energy that can be expected. Secondly, a superstructure optimization approach was applied and it uses rigorous models for both the column and the membrane. A process simulator, excel and visual basic were used to solve and program the equations. The result showed that significant energy savings was achieved using a novel hybrid separation system with a material membrane

GAS PROCESS SYSTEM EMPIRICAL TOOL FOR PREDICTING HYDRATE FORMATION

The rapid formation of gas hydrates, promoted by typical high pressure/ low temperature operating conditions in deep water installations, is considered one of the most difficult problems with flow assurance. Understanding the conditions for the formation of hydrates is necessary to overcome the problems associated with hydrates. Ideally, the conditions for the formation of gas hydrates are determined experimentally in the laboratory; but this data is not always available. Therefore, correlation is used to determine the conditions for gas hydrate formation. Several models have been proposed that require more complex and longer computations to predict the conditions for the formation of gas hydrate over the years. In this study, it is crucial to develop a reliable and easy-touse method for oil and gas practitioners’. The proposed correlation extends over a wide range of pressure (2000 to 25000kPa) and molecular weights (16 to 27). Consistent and accurate results of the proposed pressure range, temperature, and molecular weight are presented. Statistical error analysis is used to appraise the efficiency and accuracy of the correlation coefficient for estimating the formation of gas hydrate. This will guide designer and operator to select the optimal correlation for a particular application

Data on shale-water based drilling fluid interaction for drilling operation

The shale dispersion test (rolling test) is a common procedure that is used to measure the interactions between drilling fluids and shales. The shale rolling test depends on the moisture content of the shale, the shale composition, the viscosity of the test fluid, the rotation speed of the rollers, and the test temperature. The rheological behavior of the test fluid has the strongest influence on test results. The data was generated experimentally, shale samples from Agbada formation Niger-Delta was used. These shale samples were cored at a depth of 2000ft and 3400ft. Water based mud that will minimize shaledispersionandswellingofshalewasformulated.Thedispersion test was conducted, and it involves exposing a weighted quantity of sized shale to the formulated mud in roller-oven. This test is used to design fluids and screen the effectiveness of inhibitor additives to maintain the integrityof the cuttings and minimize the interaction of fluids with the shale sections during the drilling and completion operations.Theswellingtest wasconductedandthe linearexpansion adopted because it is the most representative of the increase seen by the wellbore but was measured in the direction perpendicular to the bedding plane as this is the direction of swelling into the wellbore

The Chemical Modification of Calophyllum Inophyllum Plant Oil for Potential Base Oil in Drilling Mud Operation

Research on the use of plant oil or ester oil in drilling mud operation is on the increase. The is due to the less toxic and low cost advantage over the commercial synthetic base oil. Despite the attractive physicochemical properties of vegetable oil samples, it deteriorates and becomes unstable under downhole temperature and aging conditions when used directly in mud formulation. Hence, plant oil needs improvement in order to be compared to the conventional base oil. Calophyllum inophyllum oil was extracted and reacted with methano in the presence of catalyst to form biodiesel. The physicochemical properties of the commercial synthetic base oil, extracted Calophyllum inophyllum oil, and biodiesel Calophyllum inophyllum oil were measured and compared to the EN14214 and the ASTM D6751 standards. The commercial synthetic oil, Calophyllum inophyllum oil, and biodiesel Calophyllum inophyllum oil had a flash point of 101 ± 0.1, 164 ± 0.1, and 146 ± 0.1 °C respectively; density of 108, 172, and 152 (kgm3kgm3) respectively; viscosity index of 192, 163, and 282 respectively; acid value of 0.953, 24.24, and 1.0 respectively, and oil yield of NA, 71, and 62 respectively. The result showed that the biodiesel can also serve as alternative to commercial synthetic base oil due to their comparable property to the commercial base oil. The biodiesel Calophullum inophyllum oil is a potential base oil for drilling mud formulation

LIPIDNA PEROKSIDACIJA KOD DIMLJENOG AFRIČKOG SOMA TRETIRANOG MARINADOM Moringa oleifera, SOLJU I BUTIL HIDROKSI ANISOLOM

Smoke-dried fish is vulnerable to lipid peroxidation, which can reduce product quality and pose health risks to consumers. The study examined the antioxidant potency of Moringa oleifera marinade on oxidative stabilityof smoke-dried catfish in comparison with salt and Butylated hydroxyl anisole (BHA), a synthetic antioxidant. Seventy-two catfish (208±6 g) were processed, randomly assigned to six antioxidant treatment groups and hotsmoked. The treatments are the control (0%), 1%, 2% and 3% (w/v) Moringa oleifera marinade (MOM), 5% Brine (w/v) and 0.2% BHA (w/v). Thesmoke-dried fish were stored at room temperature (35±10C) for 8 weeks. Lipid peroxidation was monitored weekly using Thiobarbituric acid (TBA)assay. The results showed that Moringa oleifera marinade and BHA decreased lipid peroxidation more than (p0.05) difference was observedamong all Moringa treated samples and BHA. Moringa oleifera marinade could be used as an alternative to BHA in suppressing lipid peroxidation in smoke-dried African catfish stored for 8 weeks.Sušena dimljena riba izložena je lipidnoj peroksidaciji, što može smanjiti kvalitetu krajnjeg proizvoda, ali i ugroziti zdravlje potrošača. Ovim istraživanjem ispitanoje potencijalno antioksidantsko djelovanje marinade Moringa oleifera na stabilnost oksidacije kod dimljenog soma te je ono uspoređeno s djelovanjem soli i butil hidroksi anisola (BHA), sintetičkog antioksidanta.Obrađeno je 72 primjeraka soma (208 ± 6 g),a ravnomjerno su raspoređeni u 6 skupina tretiranih antioksidansima te izloženih vrućem dimu. Skupine s obzirom na vrstu tretmana i postotak izloženosti bile su sljedeće: kontrolna skupina (0%), 3 skupine somovatretiranih marinadom Moringa oleifera (MOM)(1%, 2% i 3%), somovi u rasolu (w/v) (5%) i somovi u butil hidroksi anisolu (w/v) (0,2%). Dimljena riba bila je pohranjena na sobnoj temperaturi (35 ± 10C)8 tjedana. Peroksidacija lipida tjedno je praćena pomoću ispitivanja tiobarbiturnom kiselinom (TBA). Rezultati su pokazali smanjenje lipidne peroksidacijekod skupina somova u marinadi Moringa oleifera i u butil hidroksi anisolu (p<0,05), za razliku od rezultata povećane lipidne peroksidacije kod somova iz kontrolne skupine (0,94 mg/MDA/kg) i onih tretiranih solju (0,92 mg/MDA/kg). Dakle, reaktivne promjene prilikom ispitivanja tiobarbiturnom kiselinom (TBARS)su kod pojedinih skupina somova bile manje: uzorci tretirani 1% marinadom Moringa oleifera (0,44 mg/MDA/kg), uzorci tretirani 2% i 3% istom marinadom (0,88 mg/MDA/kg; 0,85 mg/MDA/kg) i uzorci tretirani BHA-om (0,80 mg/MDA/kg). Tijekom izloženosti riba prije navedenim uvjetima, praćen je proces kvarenjariba uzrokovan oksidacijom. Prirast je bio intenzivniji u kontrolnoj i skupini riba tretiranih solju (p<0,05). Nema značajne razlike kod skupina riba tretiranih marinadomMoringa oleifera i onih tretiranih butil hidroksi anisolom. Marinada Moringa oleifera mogla bi se u osmotjednom periodu izloženosti dimljenog afričkog soma koristiti kao alternativa za BHA u suzbijanju lipidneperoksidacije

Aerobic and anaerobic biodegradation of synthetic drilling fluids in marine deep-water offshore environments: Process variables and empirical investigations

In this study, the aerobic and anaerobic biodegradation tendencies of a newly developed synthetic ester drilling fluid named “SEEP Mixture synthetic fluid” in marine deep-water environment were experimentally studied. The results were compared with a GTL and LASF synthetic hydrocarbon fluids. A modified Oxygen (O2) Consumption and a gas pressure measurement technique were used for biodegradation evaluation in the aerobic and anaerobic digesters respectively. The tested drilling fluids were exposed to the sea water inoculum for a period of 28 and 60 days in the different digester designs. An empirical investigation of the influence of some paramount biodegradation factors among others such as reaction temperature, dissolved oxygen concentration, time, chemical and inoculum concentrations was conducted.The biodegradation levels in SEEP mixture synthetic fluid and reference chemical sample were already above 60% during the 10-day window period under aerobic condition which shows that the new ester fluid (SEEP mixture) is inherently-readily biodegradable under aerobic condition. The ultimate biodegradability degrees of the new fluid were 81.50% and 76.10 % in aerobic and anaerobic pathways respectively. The rates of biodegradation were higher in the aerobic than in anaerobic medium in all the tested fluid chemicals. However, the GTL and LASF fluids (SHBF &amp; SEBF) were not readily biodegradable in both microbial consortia. The rate of aerobic and anaerobic biodegradation has a positive linear relationship with incubation time and temperature but an inverse relationship with substrate concentration. Finally, Lower oxygen concentration in sea water reduces aerobic biodegradation while anaerobic transformation is grossly dependent on the availability of alternative electron acceptor ions such as NO3−, SO42−, Fe3＋ Mn4+, and CO32−and methanogens in the sea water

Synthesis and characterization of polyvalent high-performance synthetic base oil for drilling operations in recalcitrant and unconventional oil and gas reservoirs

Synthetic ester fluid is one of the most widely recommended drilling fluids for unconventional and recalcitrant reservoirs owing to its numerous technical advantages, high sustainability, non-toxic and inherently biodegradable. However, there are serious concerns about its thermal and hydrolytic stability at high temperatures and pressures (HTHP) as well as its viscosity and flow characteristics in low temperature climates such as deep-water wells. Hence, its inability to maintain stable borehole and flat rheology characteristics may invariably threaten its application under these aforementioned scenarios.In this study, a high-performance ternary mixture of synthetic ethyl esters of plants oil (SEEP mixture) fluid was synthesized by a non-catalyzed supercritical ethanol transesterification process using coconut, castor seed and linseed oil as starting materials. The nature, chemistry and fluid particle interactions of the individual components that make up the synthetic ester fluid were critically studied. The process equipment consists of a continuous flow reactor equipped with a PID controlled furnace as heat source to the reactor and a high- pressure transducer. The conversion efficiency was monitored by an Agilent 5500a FTIR machine with attenuated total reflectance (ATR) system while a GC-EIMSD system was used for fatty acid ester compositional analysis. The oil was extracted by a Soxhlet apparatus mechanism. The extracted Plant oil and the synthetic esters were characterized under standard recommended laboratory procedures by API, ASTM and the European Union (EN) standard protocols. Also, fluid's toxicity and biodegradability tests were conducted according to OECD recommended practices. The results were compared with existing synthetic hydrocarbon fluids (SHFs) for HTHP and deep-water wells.The conversion efficiency of the non-catalyzed transesterification process was 96.50%. The amount of oil yield from the plant oil after Soxhlet extraction is commendable. Hence, synthetic ester fluid raw materials are readily available in large quantities and in a sustainable manner. The GC-MS analysis shows that the coconut oil contains 92% saturated fatty acid. Whereas, the castor seed oil contains 98.31% unsaturated fatty acid with 89.75% of mono-unsaturated ricin-oleic acid (D-12-hydroxyoctadec-cis-9-enoic acid). The linseed oil has high content of linolenic acid with 89.60% unsaturated fatty acid. The designed fluid has excellent lubricity characteristics, extremely low cloud and pour point temperatures, higher oxidative stability, low peroxide value, lower copper strip corrosion value and lower kinematic viscosity and density variations with temperatures which signals flat rheology when used to form a synthetic based mud. Also, its flash point and auto-ignition temperatures are high and thus forestall possible fire hazard in high temperature zones. Finally, the fluid is non-toxic and inherently biodegradable

Analysis of the Collapse Gradient of Deep Water Horizontal Wellbore and the Effects of Mud Chemical Activity and Variation in Water Depth

Wellbore collapse is an instability-event that occurs at low mud density and leads to unfavorable economic project, reaching billions of US dollars. Thus, it is important to accurately determine its value, especially in deepwater horizontal wellbores. The main reasons for nontrivial problems with such wellbores are evident: the shale encountered are anisotropic in nature and possess planes of weakness; they react with water-based mud, generate osmotic stresses, swell, and fall unto the wellbore bottom, thereby increasing the non-productive time. To this end, salts are added to reduce the collapse tendency, but it is not currently known what amount of salt addition maintains stability, and does not lead to wellbore fracture; in deepwater, the current trend in global warming means there is a future concern to the industry. As the climate temperature increases, more ice melts from the polar region, the seawater expands and the sea level rises. How to incorporate the corresponding effect on collapse gradient is scarcely known. This study captures the major concerns stated above into wellbore stability analysis. Following the classical approach for geomechanical analysis, Mogi-Coulomb criterion was combined with a constitutive stress equation comprising contributions from mechanical and osmotic potentials of mud and shale. A sophisticated industry model was used to consider the deepwater effect. The results show significant reduction in collapse gradient as the water depth increases, also, larger difference between the mud and shale chemical activities represents higher complexities in the wellbore. In addition, the reduction in the chemical activities of mud limited to 37.5% of the initial value can be practically safe