Hasil untuk "Petroleum refining. Petroleum products"

Ahmed Zoeir, Najme Talebi, Yousef Kazemzadeh et al.

Abstract Parameters like sediment’s origin, transport distances or next influencing factors such as cementation or dissolution, cause almost all natural porous media to exhibit some degree of anisotropy. Using the X-ray CT scanning approach to provide a virtual environment for the calculation of such properties has its own issues, including its low resolution, which gives an incomplete description of internal structure, along with its relatively high costs. Porous media can be reconstructed with the help of statistical techniques from existing high-resolution thin section images. In this work, in this article, a micro-CT file available on the Imperial College website is first selected, which has been obtained from a disordered anisotropic sandstone core sample. specific statistical algorithms are applied to the top and side images of the core sample, which represent the input images for the Multiple-Point Statistics (MPS) technique. After that, to construct artificial anisotropic media models, Optimization algorithms are used to polarize the phase occurrence potentials in the principal directions, which are obtained from the two thin-section images. Results show that applying optimization algorithms to polarize occurrence potential functions can effectively develop artificial porous media that exhibit tensor properties closely matching those calculated from high-resolution micro-CT images of the actual sandstone core sample, such as permeability and thermal conductivity tensors.

Masud Ramezanian Kaykanloo, Asgar Khademvatani, Hossein Ali Akhlaghi Amiri

Abstract This study investigates the optimization of condensate recovery in a retrograde gas reservoir, where production efficiency is hindered by complex interactions between subsurface and surface processes. Accurate modeling of these interactions is essential for reliable production forecasting and economic assessment. This research compares the efficacy of two simulation methodologies: (1) standalone reservoir modeling and (2) integrated modeling encompassing the reservoir, wells, pipelines, and surface facilities under various gas reinjection and production scenarios. Key economic metrics, including Net Present Value (NPV) and Modified Internal Rate of Return (MIRR), are employed to assess scenario feasibility and identify optimal recovery strategies. The findings demonstrate that integrated modeling significantly enhances production forecasts' accuracy by capturing interdependencies often neglected in standalone models. Specifically, optimized gas reinjection in the integrated model resulted in a 15% increase in condensate recovery and improved reservoir pressure maintenance, thereby facilitating sustained productivity. Economically, integrated simulations yielded an NPV up to 10% higher than the standalone approach under optimal reinjection conditions, indicating enhanced economic resilience to market fluctuations. Through this methodology, the study provides a more comprehensive framework for evaluating technical and economic performance in gas condensate reservoir management, offering refined tools for informed decision-making in complex field operations.

Ruotong Cheng, Azadeh Farzan

We study the problem of automated hypersafety verification of infinite-state recursive programs. We propose an infinite class of product programs, specifically designed with recursion in mind, that reduce the hypersafety verification of a recursive program to standard safety verification. For this, we combine insights from language theory and concurrency theory to propose an algorithmic solution for constructing an infinite class of recursive product programs. One key insight is that, using the simple theory of visibly pushdown languages, one can maintain the recursive structure of syntactic program alignments which is vital to constructing a new product program that can be viewed as a classic recursive program -- that is, one that can be executed on a single stack. Another key insight is that techniques from concurrency theory can be generalized to help define product programs based on the view that the parallel composition of individual recursive programs includes all possible alignments from which a sound set of alignments that faithfully preserve the satisfaction of the hypersafety property can be selected. On the practical side, we formulate a family of parametric canonical product constructions that are intuitive to programmers and can be used as building blocks to specify recursive product programs for the purpose of relational and hypersafety verification, with the idea that the right product program can be verified automatically using existing techniques. We demonstrate the effectiveness of these techniques through an implementation and highly promising experimental results.

NI Xiaoming, FENG Dong, HAO Shaowei, WANG Kai, SU Erlei

Determining the gas source and contribution in coal measure gas commingled production lays the foundation for developing commingled production schemes. Based on coal measure gas exploration and development data from the Wulihu mining area in the Lu’an mining area, carbon and hydrogen isotope tests of CH4 from the No. 3+4 coal measure strata and the No. 15 coal seam were conducted. Using a binary gas source model, the gas source and proportions of six commingled wells were identified. Additionally, considering factors such as gas content, permeability, and desorption capacity, the production contributions of gas from the No. 3+4 coal measure strata and the No. 15 coal seam in three commingled wells were calculated based on catastrophe theory. The results showed that when isotopic differences in carbon and hydrogen values were observed between multiple gas-producing layers, these differences could be used to determine the source and proportion of gas from each layer. When the No. 3+4 coal measure strata consistently produced gas while the No. 15 coal seam did not desorb gas, the produced gas entirely originated from the No. 3+4 coal measure strata. When both the No. 3+4 coal measure strata and the No. 15 coal seam stably produced gas, the gas productions were 42%-45% and 55%-58%, respectively. The production split coefficients calculated based on catastrophe theory closely matched experimental results, confirming the feasibility of this method. This study provides a method and reference for accurately identifying gas sources and contributions in coal measure gas commingled production for this mining area.

Mohammad Abubakr, Suhaib Shahid, Iram Arman

Hydrogen production is a vital process in the quest for decarbonization and a sustainable future. This conversation explores the various technologies used in hydrogen production, such as steam methane reforming, electrolysis, and biomass gasification. These methods have different applications and efficiencies, but all contribute to the production of hydrogen gas. The future of hydrogen production looks promising, as it offers a clean and versatile energy source that can be used in various sectors, including transportation, industry, and power generation. The increasing demand for hydrogen in these sectors, coupled with the global push for decarbonization, highlights the importance of advancing hydrogen production technologies and infrastructure. This paper focuses broadly on different methods of hydrogen production like steam methane reforming, electrolysis, and biomass gasification. Steam methane reforming is currently the most common method, accounting for about 95% of global hydrogen production. Electrolysis is another method that uses electricity to split water into hydrogen and oxygen. Biomass gasification involves converting organic materials into hydrogen gas through a thermochemical process. The renewable energy sources considered are water and biomass and the methods considered are Electrolysis (grid), thermolysis, thermochemical water splitting, photoelectrochemical water splitting, and gasification. Electrolysis of water to produce hydrogen accounts for about 5% of the total hydrogen production. Statistically, global hydrogen production reached about USD 155.35 billion in 2022, with the majority of it being used in the petroleum refining and ammonia production industries. As for applications, hydrogen can be used as a fuel for fuel cell vehicles, as a feedstock for chemical processes, and as a storage medium for renewable energy.

SANG Shuxun,HAN Sijie,ZHOU Xiaozhi,LIU Shiqi,WANG Yuejiang

Deep coalbed methane（CBM） development in East China is of great significance to ensure regional energy demand, optimize regional energy structure and realize the dual carbon goal. Based on the systematic investigation and previous works, the current situations of CBM extraction in East China were summarized, and the gas-bearing attributes and resources potential of deep CBM were analyzed. Then, the applicability of existing deep CBM exploration and development technologies in East China was discussed, and the potential favorable areas of deep CBM exploration and development in East China were discussed and predicted. Finally, the advantages and challenges of deep CBM exploration and development in East China are put forward. Previous results show that: East China has a good CBM development accumulation on the tectonically deformed coal and in the coal mine area, such as “Huainan CBM extraction model” and horizontal well staged fracturing in the roof of the tectonically deformed coal. Deep coal in East China has a high gas content（greater than10 cm3/g） and gas-bearing saturation（greater than 80 %）. The predicted geological resources of deep CBM are 8 984.69×108 m3 in the Huannan-Huanbei mining area, suggesting that Huainan and Huaibei coal field has an attractive deep CBM resources potential. Horizontal well development and hydraulic fracturing techniques for deep CBM have great application prospects in East China. Panxie mine area in Huainan coal field is expected to be a pilot area for deep CBM exploration and development in these areas. However, the overall exploration and development degree of deep CBM is low, so it is necessary to carry out the more detailed resource evaluation and analysis of deep CBM geological accumulation in the type area, like deep Panxie coal mine in Huainan coal field.

Anton Ayzenberg, Dmitry Gugnin

In this paper we study the actions of tori (standard compact tori, as well as their quaternionic analogues) on products of spheres. It is proved that the orbit space of a specific action of a torus on a product of spheres is homeomorphic to a sphere. A similar statement for a real torus $\mathbb{Z}_2^n$ was proved by the second author in 2019. We also provide a statement about arbitrary compact topological groups, generalizing the mentioned results, as well as the results of the first author about the actions of a compact torus of complexity one.

Sajjad Mohammadi

Let $m$ and $n$ be two positive integers such that $m < n$. Let $Q_{n-m+1}$ be the symplectic quasi-projective space of rank $n-m+1$. In this article, we will study the order of the Samelson product $S^{4m-1}\wedge Q_{n-m+1}\rightarrow Sp(n)$.

Marc S. Klinger, Robert G. Leigh

Recent work has highlighted the importance of crossed products in correctly elucidating the operator algebraic approach to quantum field theories. In the gravitational context, the crossed product simultaneously promotes von Neumann algebras associated with subregions in diffeomorphism covariant quantum field theories from type III to type II, and provides the necessary ingredients to gravitationally dress operators, thereby enforcing the constraints of the theory. In this note we enhance the crossed product construction to the context of general gauge theories with arbitrary combinations of internal and spacetime local symmetries. This is done by leveraging the correspondence between the crossed product and the extended phase space. We then undertake a detailed study of constraint quantization from the perspective of a generic crossed product algebra. We study and compare four distinct approaches to constraint quantization from this point of view: refined algebraic quantization, BRST quantization, path integral quantization, and the commutation theorem for crossed products. Far from simply reproducing existing analyses, the operator algebraic viewpoint sheds new light on old problems by reformulating the dressing of operators in terms of conditional expectations and other closely related projection maps. We conclude by applying our approach to the constraint quantization of three distinct gauge theories including a discussion of gravity on null hypersurfaces.

Joav Orovitz, Raz Slutsky, Itamar Vigdorovich

We show that the space of traces of the free group $F_d$ on $2\leq d \leq \infty $ generators is a Poulsen simplex, i.e., every trace is a pointwise limit of extreme traces. This fails for many virtually free groups. The same result holds for free products of the form $C(X_1)*C(X_2)$ where $X_1$ and $X_2$ are compact metrizable spaces without isolated points. Using a similar strategy, we show that the space of traces of the free product of matrix algebras $M_n(\mathbb{C}) * M_n(\mathbb{C})$ is a Poulsen simplex as well, answering a question of Musat and R\ordam for $n \geq 4$. Similar results are shown for certain faces of the simplices above, such as the face of finite-dimensional traces or amenable traces.

Yves Fomatati

An algorithm for matrix factorization of polynomials was proposed in \cite{fomatati2022tensor} and it was shown that this algorithm produces better results than the standard method for factoring polynomials on the class of summand-reducible polynomials. In this paper, we improve this algorithm by refining the construction of one of its two main ingredients, namely the multiplicative tensor product $\widetilde{\otimes}$ of matrix factorizations to obtain another different bifunctorial operation that we call the reduced multiplicative tensor product of matrix factorizations denoted by $\overline{\otimes}$. In fact, we observe that in the algorithm for matrix factorization of polynomials developed in \cite{fomatati2022tensor}, if we replace $\widetilde{\otimes}$ by $\overline{\otimes}$, we obtain better results on the class of summand-reducible polynomials in the sense that the refined algorithm produces matrix factors which are of smaller sizes.

Zhang Min, Jin Xiaowei, Liu Jun et al.

To reduce the risk of severe wear of aluminum alloy oil casing, the 7075 aluminum alloy grinding discs and 40CrNiMo pins are used as friction pairs, and UTM friction tester is used to study the effect of sliding speed on the dry friction properties of aluminum alloy oil casing. The research results show that when the sliding speed is 50～600 mm/s, as the sliding speed increases, the friction factor decreases and fluctuates continuously. The wear rate first increases slowly and then significantly with the sliding speed. At low sliding speeds(50～100 mm/s), the main wear mechanism of 7075 aluminum alloy is slight oxidation wear. At medium sliding speeds(150 mm/s), the main wear mechanism changes to oxidation wear. When the sliding speed is 350 ～600 mm/s, the main wear mechanism of 7075 aluminum alloy changes to adhesion-delamination wear.When air drilling technology is used, under the condition of meeting the drilling requirements, making the linear velocity of the drill pipe rotation lower than 150 mm/s can effectively avoid serious wear of the aluminum alloy casing. The research results can provide certain guidance for the research on anti-wear methods of aluminum alloy casing.

Li Qian, Li Jiaojiao, Zhai Fenlou et al.

Subsea capping stack is a kind of emergency rescue device and it is used for emergency rescue after the failure of underwater well control. In order to understand the wear situations of subsea capping stack under different working conditions, its internal flow under different working conditions was numerically simulated using CFD. The severely worn positions were determined by analyzing the distribution of the wear rate inside the pipeline under five working conditions. In addition, its structure was optimized. The analysis results show that when the main vertical pipe is opened (working condition 1 and 2), the maximum wear rate is lower and the wear is mainly distributed near the diversion hole of the main vertical pipe; when the main vertical pipe is closed, the maximum wear rate is increased obviously and the severely worn positions are located on the outer side wall surface of the downstream of the right angle pipe and the inner corner of the right angle pipe; and replacing the right angle pipe structure with the blind tee can significantly reduce the wear rate there. The research results can provide a reference for the structural design and optimization of the subsea capping stack and are conducive to speed up the research progress of subsea emergency devices in China.

Xinlei SHI, Yunjiang CUI, Wankun XU et al.

Based on the measurement mechanism of mobility in pressure measurement while drilling, through analyzing a large number of mobility data, it is found that under the condition of water-based mud drilling, the product of mobility from pressure measurement while drilling and the viscosity of mud filtrate is infinitely close to the water phase permeability under the residual oil in relative permeability experiment. Based on this, a method converting the mobility from pressure measurement while drilling to core permeability is proposed, and the permeability based on Timur formula has been established. Application of this method in Penglai 19-9 oilfield of Bohai Sea shows: (1) Compared with the permeability calculated by the model of adjacent oilfields, the permeability calculated by this model is more consistent with the permeability calculated by core analysis. (2) Based on the new model, the correlation between the calculated mobility of well logging and the actual drilling specific productivity index bas been established. Compared with the relationship established by using the permeability model of an adjacent oilfield, the correlation of the new model is better. (3) Productivity of four directional wells was predicted, and the prediction results are in good agreement with the actual production after drilling. Key words: mobility from pressure measurement while drilling, permeability, irreducible water saturation, Timur formula, productivity prediction, Penglai 19-9 oilfield

Qin Yanbin, Yao Jie, Dai Zhengyu et al.

The collapse strength of perforating gun is one of the key concerns for perforating equipment manufacturers and users. The three-dimensional model of the perforating gun is established using SolidWorks software, and then imported into ANSYS finite element analysis software to establish its three-dimensional FEA model. Simulations are conducted to analyze the influencing factors and influence laws of perforating gun’s collapse strength. The results show that the collapse strength decreases with the increase of hole density and diameter. Under the same conditions, the collapse strength of the perforating gun is 8.71% smaller when the hole density is increased from 8 holes/m to 24 holes/m. In the common spiral hole phase angle of 30°, 45°, 60°, 90°, 120° and 180°, the perforating gun has the highest collapse strength under the phase angle of 60°. The blind hole depth has the greatest influence on the collapse strength. With the increase of the blind hole depth, the perforating gun’s collapse strength decreases sharply. If the concentricity and cylindricity tolerance is greater than 1 mm, the perforating gun’s collapse strength will be considerably reduced. As the well temperature and the axial tensile force increase, the collapse strength of the perforating gun will also decrease.

Zhenhua XU, Shenghe WU, Zhao LIU et al.

Core, well logging and seismic data were used to investigate sandbody architectural characteristics within Lower Member of Minghuazhen Formation in Neogene, Bohai BZ25 Oilfield, and to analyze the sedimentary microfacies, distribution and internal architecture characteristics of the bar finger within shoal water delta front. The branched sand body within shoal water delta front is the bar finger, consisting of the mouth bar, distributary channel over bar, and levee. The distributary channel cuts through the mouth bar, and the thin levee covers the mouth bar which is located at both sides of distributary channel. The bar finger is commonly sinuous and its sinuosity increases basinward. The distributary channel changes from deeply incising the mouth bar to shallowly incising top of the mouth bar. The aspect ratio ranges from 25 to 50 and there is a double logarithmic linear positive relationship between the width and thickness for the bar finger, which is controlled by base-level changing in study area. For the bar finger, injection and production in the same distributary channel should be avoided during water flooding development. In addition, middle–upper distributary channel and undrilled mouth bar are focus of tapping remaining oil. Key Words: shoal water delta, bar finger, sandbody architecture, Bohai BZ25 Oilfield, Neogene Minghuazhen Formation, remaining oil

Manar Elsayed Abdel-Raouf, Shimaa Mohmaed El-Saeed, Elsayed Gamal Zaki et al.

Two sets of hydrogel materials based on guar gum were prepared by grafting guar gum onto acrylic acid/acrylamide and acrylic acid/N-isopropylacrylamide copolymers by using persulphate radical as an initiator and N,N′ methylenebisacrylamide as a cross linker. The prepared hydrogels were denoted as AA-AcM-GG and AA-NIPAM-GG respectively. They were characterized by FTIR Spectroscopy and SEM. The effect of some composition variables on the swelling performance of PA-GG hydrogel was thoroughly studied. Furthermore, swelling behavior was monitored as a function of temperature and electrolyte concentration. A lab experiment was carried out in order to investigate the effect of the optimum hydrogels on the growth of guava plant. Keywords: Guar gum, Acrylate, N-isopropyl acryl amide, Green hydrogels, Temperature sensitive, Salt sensitive

Stefan Tohaneanu

Let $\mathbb K$ be a field of characteristic 0. Given $n$ linear forms in $R=\mathbb K[x_1,\ldots,x_k]$, with no two proportional, in one of our main results we show that the ideal $I\subset R$ generated by all $(n-2)$-fold products of these linear forms has linear graded free resolution. This result helps determining a complete set of generators of the symmetric ideal of $I$. Via Sylvester forms we can analyze from a different perspective the generators of the presentation ideal of the Orlik-Terao algebra of the second order; this is the algebra generated by the reciprocals of the products of any two (distinct) of the linear forms considered. We also show that when $k=2$, and when the collection of $n$ linear forms may contain proportional linear forms, for any $1\leq a\leq n$, the ideal generated by $a$-fold products of these linear forms has linear graded free resolution.

Cameron Ruether

We extend techniques employed by Garibaldi to construct various new injections involving the half-spin group, $\textbf{HSpin}$, induced by lifting the Kronecker tensor product to simply connected groups. We calculate the Rost multipliers of the maps we have constructed. Furthermore, we utilize our new map $\textbf{PSp}_{2n}\times \textbf{PSp}_{2m} \hookrightarrow \textbf{HSpin}_{4nm}$ to describe the structure of the normalized degree three cohomological invariants of $\textbf{HSpin}_{4n}$.