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Petroleum is any hydrocarbon recovered from the subsurface of the earth after drilling such as oil and gas.Oil and gas provide about 60% of all the energy used by the society today. They provide fuel for means of transportation and they are a must for the daily life requirements including: heating, lighting and cooking. They are used in most of manufacturing processes around us such as: synthetic fabrics, plastics, fertilizers, detergent and many other purposes. Briefly, no one can imagine the world without oil and gas. Most people know the source of petroleum is plants and animals that died millions of years ago.
Early U.S. settlements commonly were located near salt lakes that supplied salt to the population. These salt springs were often contaminated with petroleum, and many of the early efforts to acquire salt by digging wells were rewarded by finding unwanted amounts of oil and gas associated with the saline waters. In the Appalachian Mountains, saline water springs commonly occur along the crests of anticlines. In 1855, it was found that petroleum distillation produced light oil that was, as an illuminant, similar to coal oil and better than whale oil. This knowledge spurred the search for saline waters containing oil. With the methods of the salt producers, Colonel Edward Drake drilled a well on Oil Creek, near Titusville, Pennsylvania, in 1859.
Occidental Petroleum (Oxy) said this week it has agreed to sell almost 25,000 net acres in the Permian Basin of Texas to Colgate Energy Partners III for nearly $508 million. Average output of the properties amounts to 10,000 BOE/D from about 360 wells in the southern Delaware Basin, Houston-based Oxy reported in its announcement. The sale, expected to close in the third quarter, will boost Midland-based Colgate's holdings in the Permian to about 83,000 acres with an estimated production of 55,000. Colgate said it plans to run up to six drilling rigs by year's end and boost average production to 75,000 BOE/D by 2022. Proceeds from the sale will be used to pay down Oxy's debt that was around $35.4 billion in March, down slightly from the $36.03-billion debt reported last June.
Liang, Qixuan (China University of Petroleum (East China)) | Zhang, Feng (China University of Petroleum (East China)) | Zhang, Xiaoyang (China University of Petroleum (East China)) | Chen, Qian (China University of Petroleum (East China)) | Fan, Jilin (China University of Petroleum (East China))
Abstract Unconventional oil and gas resources, such as tight oil and gas, have become indispensably succeeding energy sources in nowadays. At the stage of exploration, gas saturation is essential for the evaluation of tight formation, which can provide the key parameters for reserves calculation and development plans making. Conventional logging technologies including acoustic logging and resistivity logging have played a role in gas formation identification and evaluation. Besides, inelastic and capture gamma energy spectrum or time spectrum from pulsed neutron logging tools with NaI, BGO, LaCl3, or LaBr3 detectors are used to realize the quantitative evaluation of gas saturation. With the development of nuclear technology, the new detector, called CLYC (Cs2LiYCl6:Ce), can simultaneously measure the signals of gamma ray and thermal neutron, providing a new mean for gas saturation evaluation use pulsed neutron logging technique. The CLYC scintillation crystal with a density of 3.31g/cm has an energy resolution in the order of 4%-5% (0.662MeV), and its light output efficiency of gamma ray and neutron are 20000 photons/MeV and 70500 photons/MeV. Meanwhile, its excellent temperature characteristics in the range from -30℃ to 180℃ can fit the downhole environment. Consisting of the D-T neutron source and CLYC detector, the pulsed neutron logging system is designed in this paper, in which the burst gate is 0 to 40 microseconds and the capture gate is 50 to 100 microseconds. To evaluate gas saturation, this system combines the inelastic gamma ray and thermal neutron recorded from the burst gate and the capture gate. The new pulsed neutron logging tool consists of two LaBr3 detectors and a CLYC detector, and the spacing of the CLYC detector is 75cm. In addition to the conventional C/O and Sigma measurement functions, the new instrument can also realize the quantitative evaluation of gas saturation by the CLYC detector. The inelastic gamma, capture gamma, and thermal neutron distribution in long-detector are simulated by the Monte Carlo method under the condition of tight gas saturated formation with porosity from 3% to 20%. Based on the spatial flux distribution characteristic of inelastic gamma and thermal neutron, the new parameter (RGTH) is defined as the ratio of inelastic gamma counts to thermal neutron counts from the CLYC detector to calculate gas saturation. The results imply that RGTH is positively correlated with porosity and negatively correlated with gas saturation, and the gas and water dynamic range is about 36% under the condition of a sandstone formation with 10% porosity. Different lithology has different RGTH benchmark values. RGTH is not affected by the yield of the neutron source and water salinity, and the subtract coefficient can be accurately determined by the time spectrum of the thermal neutron to acquire the pure inelastic gamma. A tight lime-bearing sandstone formation with 5% porosity has been set by MCNP to check validity, the absolute error of gas saturation calculated by RGTH is less than 5%.
Chen, Qian (China University of Petroleum (East China)) | Zhang, Feng (China University of Petroleum (East China)) | Tian, Lili (China University of Petroleum (East China)) | Zhang, Xiaoyang (China University of Petroleum (East China)) | Li, Xianghui (Isotope Research Institute of Henan Academy of Sciences Co. Ltd.) | Fang, Qunwei (China University of Petroleum (East China)) | Fan, Junting (China University of Petroleum (East China))
Abstract The evaluation of carbonate rocks with fractures, caves, and pores is of great significance in the search for reservoir sweet spots and the prediction of reservoir productivity. With the advancement of exploration and development technology, the targets of oil and gas exploration move to deep high temperature, high pressure (HPHT) formations drilled with oil-based mud systems. The existing fracture evaluation methods often rely on dipole acoustic logging, electrical or acoustic formation micro-imaging, which utilize the difference of rock and pore fluid petrophysical properties for fracture detection, but the adverse HPHT conditions are a huge challenge to evaluate reservoir structure by such means. The tracer imaging technology (TIT) which utilizes pulsed neutron technology and tagged proppant containing high absorption cross-section element has been proposed for crack evaluation after hydraulic fracturing, but a quantitative evaluation of crack parameters, due to their low sensitivity caused by neutron self-shielding, has not been feasible. In this paper, the combination of the new pulsed neutron tool with multi-detector array design and oil-based mud with high absorption cross-section element is used to achieve the crack parameter evaluation in carbonate reservoirs under oil-based mud invasion condition via tracer element imaging. The special oil-based mud is injected into the carbonate formation through the borehole to enhance the difference of the nuclear properties between crack and rock. A multi-detector array tool that contains four gamma detectors arranged in a ring with 90 degrees between detectors is adopted to acquire capture the gamma spectrum in different orientations. Here, a new crack inversion method adopting a joint of the multi-element characteristic peak is used to eliminate the influence of neutron self-shielding to improve the response sensitivity of crack and calculation accuracy. The new method is suitable for all pore fluid types. Meanwhile, the effect of formation backgrounds which consist of formation matrix, pore fluid, and borehole fluid on the quantitative evaluation is analyzed and discussed for limitations of this method. To improve the recognition accuracy of the parameters in the image, the digital imaging recognition method based on artificial intelligence is applied in crack imaging for the information extraction of crack orientation. The effect of formation background on the quantitative evaluation of crack parameters is analyzed and discussed. Quantitative evaluation of carbonate with fractures, caves, and cavities can be realized with the new tracer imaging technology, which eliminates the saturation effect caused by neutron self-shielding to improve the calculation precision of fracture width. Finally, an example of carbonate formation with multiple cracks and formation background is simulated utilizing a Monte Carlo N-Particle transport model (MCNP). The calculation results of the crack density and crack width are presented and the crack orientation is determined from crack imaging, which is consistent with the model set. The result verifies the feasibility of the method.
Zhang, Feng (China University of Petroleum (East China)) | Qiu, Fei (China University of Petroleum (East China)) | Fang, Qunwei (China University of Petroleum (East China)) | Zhang, Xiaoyang (China University of Petroleum (East China)) | Zhang, Hui (China University of Petroleum (East China)) | Tang, Fangwei (China University of Petroleum (East China)) | Fan, Jilin (China University of Petroleum (East China))
Abstract Unconventional reservoirs have low porosity and complex mineral composition containing quartz, feldspar, calcite, dolomite, pyrite and kerogen, which may seriously reduce the accuracy of the porosity measurement. The multi-detector pulsed neutron logging technique was already used for determining porosity through the combination of inelastic and capture gamma ray information in different spacing. In this paper, the new parameter, which is characterized by thermal neutron count ratio and lithology factor based on element content, is proposed to determine porosity from the three-detector pulsed neutron element logging in unconventional reservoir. To evaluate mineral composition, lithology, and gas/oil/water saturation in unconventional reservoir, a new multi-detector pulsed neutron logging tool was put out. The instrument consists of two He-3 thermal neutron detectors and a LaBr3 gamma detector. Therefore, the combination of thermal neutron count ratio between near detector and long detector with lithology factor of element content can measure neutron porosity and eliminate the influence of complex lithology. Based on some calibration pit data measured in laboratory, as well as the numerical simulation method, the influences of different lithological characters and mineral types on the neutron count ratio were studied. Meanwhile, large numbers of stratigraphic models with different lithological characters and different mineral compositions were established using Monte Carlo simulation method, and the content of silicon, calcium, hydrogen, oxygen, magnesium, aluminum and iron under different stratigraphic conditions was determined by the spectral element solution. A regression analysis was conducted to establish the relationship between the content of elements and the lithologic factor. The count ratio difference stemming from different lithological and mineral compositions was eliminated through a combination of lithological correction factor and thermal neutron count ratio. Different mineral compositions of stratigraphic simulation models were set up for verification. The absolute error of porosity measurement was less than 1.0p.u. in the formations with porosity less than 15p.u., which verified the accuracy of this method for neutron porosity evaluation in complex lithological characters formations. Two field examples were processed by this new parameter which in combination of thermal neutron count ratio and formation elements content information from the three-detector pulsed neutron instrument, which indicated a good accuracy for unconventional oil and gas reservoir evaluation.
The International Organization of Standardization (ISO) has issued a new ISO 15663 containing requirements and guidance on how to apply life cycle costing methodologies to provide decision support for selection between alternative competing options. The document specifies requirements and gives guidance on the application of costing to create value for the development activities and operations associated with drilling, exploitation, processing, and transport of petroleum, petrochemical, and natural gas resources. Life cycle costing is an iterative process of planning, estimating, and monitoring costs and revenue differences throughout an asset's life and is used to support the decision-making process by evaluating alternative options and performing trade-off studies. While the largest benefits are typically achieved in the early life cycle phases, it is equally applicable to all phases and at many levels of detail. Cost management within the petroleum, petrochemical, and natural gas industries will benefit from the adoption of a common and consistent approach to life cycle costing, according to the organization.
Oil and gas producers in the Permian Basin are revealing the extent of their losses from a historic winter storm that caused widespread power outages and wellhead freeze-offs across much of Texas and in other parts of the southern US last week. The figures come as companies begin to issue their fourth-quarter earnings and capital plans for the rest of the year. Analysts are struggling to pin down the exact toll of the storm on US oil production but suggest that between 2 and 4 million B/D were curtailed by the biggest weather-induced disruption to Permian oil fields. Occidental Petroleum, the Permian's second-largest oil producer, informed investors this week that about 25,000 BOE/D of production was shut in during the winter storm. After accounting for the lost production, the operator expects first quarter output in the Permian to be between 450,000 and 460,000 BOE/D.
Outlooks for the oil and gas industry continue to vary along with the supply/demand balance and the continued effects of COVID-19 across the globe. As the outlooks and realities vary, so too do the effects on the global workforce in the energy sector. Last month, Tim Gould, head of energy supply outlooks and investment at the International Energy Agency (IEA), said, “Producers are grappling with huge uncertainty about where this goes from here. That’s not just in terms of economic recovery but indicators we wouldn’t necessarily normally be looking at - levels of trust in different countries about vaccines.” What this may mean, and has meant to date, for the oil and gas industry is reflected in a recent workforce report, “The Global Energy Talent Index 2021,” compiled by Airswift, an international workforce solutions provider that focuses on the energy, process, and infrastructure industries. Based on survey results of 16,000 energy professionals of 151 different nationalities and spread across 166 countries, the 43-question survey was open for 8 weeks and closed in October 2020. Approximately 75% of the respondents were ages 24-54; 90% were male; and employment status was contractor (30%), unemployed (34%), or staff (36%). For the first time in the survey’s 5-year history, more professionals in the oil and gas sector reported a fall in pay (29%) rather than an increase (28%). For about one in four professionals the cut was substantial: 24% said salaries and day rates have fallen by more than 5%. In last year’s survey, only 11% reported a similar drop. However, 49% expect pay to rise in the next 12 months, compared to just 18% who expect further reductions. About 80% of the respondents feel less secure in their jobs than they did a year ago and they indicated a willingness to relocate, if necessary. Nearly 90% of the professionals would consider relocating to another region, with 42% citing career progression as their main reason. Lifestyle and low cost of living and culture now rank higher than remuneration in deciding to relocate. Those who do wish to stay where they are cite family issues as a priority. Nearly half indicate remaining close to family members as their reason to stay, while 13% cite their children’s education. “There’s a clear trend here,” Janette Marx, CEO of Airswift, said in the report. “People are telling us, directly and indirectly, that remuneration is no longer the key consideration. Career progression matters but so too does lifestyle and staying closer to family and friends. This has implications for the way we recruit and retain talent throughout the sector.” A majority remained optimistic about their employers and the industry. Fifty-seven percent believe their employer is resilient to both recent and future change and 64% expect the sector to grow over the next 3 years. Among the factors identified as creating opportunities in the next 3 years, the top-ranked (64%) was advances in engineering techniques and technologies, followed by the economic outlook, transition to cleaner energy, and new digitally enabled skills and competencies.