Hasil untuk "Petroleum refining. Petroleum products"

Jinyong Li, Hongyu Gong, Qin Qin et al.

Abstract Carbon dioxide (CO2) flooding is an effective method for enhanced oil recovery. However, its application in complex, small-block reservoirs presents significant challenges owing to their limited size and intricate oil–water systems. This study investigates the potential and effectiveness of CO2 huff-and-puff technology for improving oil recovery in such reservoirs, with a focus on identifying key influencing factors. A “toothbrush-shaped” reservoir in the Shulu Sag was selected for a case study. Its geological framework, sand body types, and pore types were characterized, and a three-dimensional geological model was constructed. Based on the CO2 flooding theory, a mathematical model tailored to the study area was developed to simulate CO2 huff-and-puff processes. Numerical simulations were conducted to investigate the impact of various parameters and influencing factors on oil recovery. The predicted oil recovery from CO2 huff-and-puff in the toothbrush-shaped reservoir was then calibrated against production data from existing CO2 huff-and-puff wells. The study found that heterogeneous reservoirs with moderate heterogeneity and oil saturation greater than 0.5 are suitable candidates for CO2 huff-and-puff. Furthermore, a soaking period of 20 days yielded favorable development outcomes. These findings provide valuable insights for enhancing oil recovery in similar reservoirs.

XIONG HANLAN, LUO HONGWEN, LI HAITAO et al.

Distributed temperature sensing (DTS) technology is widely applied in intelligent monitoring of production dynamics in oil and gas wells. To address the challenges in quantitatively analyzing oil-water two-phase flow profile in horizontal wells, a temperature profile prediction model applicable to oil-water two-phase flow in horizontal wells was constructed, comprehensively considering multiple micro-thermal effects, including the Joule-Thomson effect. Simulation and sensitivity analyses of the temperature profile of a reservoir horizontal well were conducted. Meanwhile, the particle swarm optimization (PSO) algorithm was used to establish a DTS data inversion model, innovatively enabling the inversion of multi-dimensional unknown downhole parameters based on a single DTS data source, thereby achieving a quantitative interpretation of the oil-water two-phase flow production profile in horizontal wells. The results showed that: (1) The main influencing factors of the temperature profile in oil-water two-phase horizontal wells, ranked by impact degree from high to low, were single-well production (<italic>Q</italic>)&gt; permeability (<italic>k</italic>)&gt; water cut (<italic>F</italic>_W)&gt; wellbore radius (<italic>R</italic>_w)&gt; crude oil density (<italic>ρ</italic>_o)&gt; damage zone radius (<italic>R</italic>_d)&gt; reservoir thermal conductivity (<italic>K_t</italic>). (2) Single-well production, permeability, and water cut were the key dominant factors affecting the temperature profile. When inverting measured DTS data, formation permeability could be prioritized as the core target parameter for inversion, and secondary factors could be set as fixed values or assigned reasonable ranges to simplify the problem. (3) By using the PSO inversion model to invert the DTS temperature data of the field well, the production positions of the two-phase fluids could be accurately identified. The interpreted liquid production profile obtained from inversion showed high consistency with field production logging tool (PLT) test results, with a mean absolute error of the average liquid production per section of less than 10%, fully verifying the reliability of the PSO inversion model. Future research can focus on enhancing the model's ability to characterize complex flows and expanding its application to multiphase flow scenarios.

Wenzheng Li, Hua Jiang, Xiaodong Fu et al.

Based on the drilling, logging and field analysis, this paper discusses the lithofacies paleogeography of the Ordovician and its petroleum potential in the Middle-Upper Yangtze Area, South China. Results show that Ordovician of the Middle-Upper Yangtze Region can be divided into Tongzi Formation, Honghuayuan Formation, Meitan Formation, Shizipu Formation, Pagoda Formation, Linxiang Formation and Wufeng Formation from bottom to top. During the Early Ordovician Tongzi Period and Honghuayuan Period (Tremadocian Stage), a carbonate rimmed platform developed in the study area with lots of grain shoals in Guangyuan-Weiyuan Areas and Lichuan-Tongzi Areas of Southeastern Sichuan Basin. To the Meitan Period (Floian and Dapingian and Early Darriwilian Stage), a mixed carbonate platform with clastic sedimentary rock deposition developed in study area. In Middle-late Ordovician Shizipu and Linxiang-Pagoda Period (Late Darriwilian and Hirnantian-Sandbian Stage), a carbonate ramp developed in Middle-Upper Yangtze Region. At the end of the Ordovician (Hirnantian Stage), Wufeng Formation deposited in a retention basin due to the restriction of peripheral uplift and paleo-land. Two sets of reservoir-source assemblages developed in the Ordovician, with three sets of source rocks developed in the study area. First, the lower Cambrian Qiongzhusi Formation acted as the main source rock, and the hydrocarbon migrated upward to the Ordovician reservoir along the fault. Second, the Wufeng-Longmaxi Formation acted as source rock, and hydrocarbon migrated to the Lower Ordovician along the karst crust and the fault. Third, the Lower Ordovician Meitan-Shizipu Formation acted as source rock, hydrocarbon can migrate upward to the upper Ordovician reservoir directly, which deserves exploration attention.

Lutfi Mulyadi Surachman, Abdulazeez Abdulraheem, Abdullatif Al-Shuhail et al.

Abstract Acoustic impedance is the product of the density of a material and the speed at which an acoustic wave travels through it. Understanding this relationship is essential because low acoustic impedance values are closely associated with high porosity, facilitating the accumulation of more hydrocarbons. In this study, we estimate the acoustic impedance based on nine different inputs of seismic attributes in addition to depth and two-way travel time using three supervised machine learning models, namely extra tree regression (ETR), random forest regression, and a multilayer perceptron regression algorithm using the scikit-learn library. Our results show that the R 2 of multilayer perceptron regression is 0.85, which is close to what has been reported in recent studies. However, the ETR method outperformed those reported in the literature in terms of the mean absolute error, mean squared error, and root-mean-squared error. The novelty of this study lies in achieving more accurate predictions of acoustic impedance for exploration.

Abed Inan Chowdhury, Md Mostafijul Karim

When pressure in gas reservoirs fall below the dew point, condensate banking occurs around the wellbore which alters the fluid flow behavior. The state of the knowledge on this flow behavior is yet not fully-developed; which leads to severe problems in field. In this study, the Al-Hussainy, Ramey, and Crawford Solution Technique has been modified to accurately resemble the real gas flow behavior for this condition. First, a primary investigation was conducted to observe the severity of the problem in three condensate banked reservoirs. Then this study involved Constant Composition Expansion tests for determining the dew point, Prode Properties software for modeling the reservoir fluid properties, Flowing Material Balance (or Dynamic P/Z Material Balance) for identifying the pressure distribution of the selected reservoirs. The real field data along with the determined (analytical, computational, and experimental) data were incorporated to check the validity of the models. The modification proposes a Dimensionless Correction Factor (CD) for any condensate banked reservoir and identifies parameters such as the Perforation Factor (Pf) and Heterogeneity Factor (n). It is found that the Modified Al-Hussainy, Ramey, and Crawford Solution Technique successfully models the actual flow characteristics of the stated condition.

Huang Peng, Guan Feng, Zheng Liwei et al.

A simplified model of dual-cutter PDC bits was established to model how the PDC bit is being worn when drilling into dense conglomerate. Then the rock breaking process was investigated using an Archard wear model and finite element software, and how the backward inclination, temperature, linear speed and WOB of the PDC bit influence the bit wear was analyzed. The results show that, the wear rate of cutter increases slowly when the backward inclination is between 15° and 20°, and reaches the maximum value at 20°;the wear rate increases rapidly after the temperature reaches 300 ℃;the linear speed and the WOB are proportional to the wear. Finally, sensitivity analysis by orthogonal tests shows that the influence on the bit wear is linear speed, backward inclination, temperature, and WOB in turn. This study is helpful to how to update drilling parameters and extend the service life of a PDC bit when drilling conglomerate layers.

Ehsan Khamehchi, Mohammad Zolfagharroshan, Mohammad Reza Mahdiani

Abstract Flow rate prediction of multiphase flow in the oil and gas wellbores is more complicated than single-phase flow avoiding direct measurements such as using flowmeters or well logging. This study offers an approach to find the accurate two-phase flow rates, applicable in extensive cases of two-phase wells/pipelines. When in a production well, the wellhead data are accessible except for flow rate, and bottom hole conditions, computing the pressure and temperature profiles through the wellbore can be brought about by replacing different values for flow rates, and lead us to probable accurate answers. This aim can be achieved by hiring a heuristic solver to find the most accurate answers as quickly as possible. This approach is flexible and practical depending on the statement of the problem. So, in this study, it has been applied to some vertical two-phase flow wells, which their well survey data was available to avoid future loggings, the wells modeled. Two models were developed, where each one predicted the flow rate by an error of less than 2%. Considering the final results for vertical wells, in this study, the model in which a mechanistic method for predicting pressure gradient applied in proposed compared with experiment-based methods.

Zhu He

Sublevel fracturing with sand of horizontal wells is an important method for the development of CBM. Combined with the fracturing construction examples in Zhijin district, we analyzed the reasons of the sand plug in fracturing and proposed the corresponding measures, thereby, to improve the success rate of the construction and achieve the purpose of reducing the cost and increasing the efficiency. It provided technical guarantee for the development of CBM wells in Zhijin area.

Yaser SALIMIDELSHAD, Ali MORADZADEH, Ezatallah KAZEMZADEH et al.

To examine the effect of pressure on pore structure and petrophysical properties of carbonate rock, the porosity, permeability, CT scanning, SEM and elastic wave velocity of two carbonate core plug samples from an oilfield in Southwest Iran were analyzed under cyclic pressure. One of the plugs was calcite and the other was dolomite with anhydrite nodules. The cyclic pressure exerted on the samples increased from 13.79 MPa to 27.58 MPa in six steps, and the variations in petrophysical properties of the two samples at different pressure loading and unloading steps were counted and analyzed. The results show that the calcite sample decreases in porosity and permeability with the increase of pressure, which is consistent with the results from compression and shear wave velocity tests. In the dolomite sample, the decreasing trend was not observed; fluctuations of compressive and shear velocities were observed during the loading stage, which may be due to different geometries of the pores and the porosity variation in the sample. Understanding the variation of carbonate petrophysical properties with pressure is helpful for optimizing reservoir development scheme. Key words: cyclic pressure loading, petrophysical property, carbonate reservoir, CT scan, rock physical property, structure deformation

W.O. Medjor, O.N. Namessan, Eunice Adebowale Medjor

Fenton oxidation remediation of hydrocarbons contaminated groundwater was investigated for efficiency and effectiveness. 10% pollution was simulated in the laboratory by contaminating groundwater samples with diesel and domestic purpose kerosene (DPK) in two different experimental set ups. Optimum conditions of concentrations of the treatment solutions and pH were established: 300 mg/L (FeSO4), 150,000 mg/L (H2O2) and pH = 3 for the kerosene contaminant; 100 mg/L (FeSO4), 300,000 mg/L (H2O2) and pH = 3 for the diesel contaminant. The results from kinetics study show that the remediation process is pseudo-first order reaction with a rate constant of 8.07 × 104 mgL−1hr−1 and 3.13 × 104 mgL−1hr−1 for the diesel and kerosene contaminants in that order with 95.32% and 79.25% reduction in chemical oxygen demand (COD) for diesel and kerosene contaminated samples at the end of the remediation process respectively indicated that remediation have occurred significantly. Percent reduction in Total Petroleum Hydrocarbon (TPH) as kerosene was 89.84% and that of the diesel contaminant as 91.87% after 6 hours of remediation. The general pollution index (GPI) for the hydrocarbons contaminated samples was in the range of 6.70–7.52 against the background value of 4.39 for the control groundwater sample. After treatment the GPI had dropped to 4.13–4.43 which depicts remarkable remediation although the samples remained impaired. Therefore there is the need of post-treatments to make the groundwater fit for domestic and agricultural uses. The application of the Fenton oxidative process is found to be very efficient, effective and rapid in reducing total petroleum hydrocarbon as kerosene and diesel as target contaminants. Keywords: Post-treatment, Pollution, Optimum, Rate constant, Pseudo-first order kinetics

Guoqi WEI, Wei YANG, Jian ZHANG et al.

Based on the latest seismic data, resistivity profile, outcrop evidence and logging data, the structural features of basement in Sichuan Basin and its control on the hydrocarbon accumulation in the Sinian-Cambrian strata was discussed. It was found that a NE striking pre-Sinian rift was developed across the whole basin. Controlled by a series of rift-parallel normal faults, horst-graben structures were developed inside the rift, large horst-graben structures and later activity of their boundary faults controlled the distribution of beach facies of the overlying strata. The horst-graben structures induced the formation of local highs of ancient landform and controlled the successive development of overlapped bioherm beach facies in long-term marine setting from the Sinian period to the Permian period, and as a result a widely distributed favorable sedimentary facies belt was developed. The pre-Sinian rift and later activities of related normal faults controlled the development of the grain beach and karst reservoirs and the deposition of high quality source rock, which form structural-lithologic traps. Through comprehensive evaluation, two large structural-lithologic composite trap favorable exploration areas in the south and north of the Gaoshiti-Moxi area, were selected. Key words: Sichuan Basin, pre-Sinian, rift, horst-graben structure, Sinian-Cambrian, hydrocarbon accumulation model, structural-lithologic trap

Ren Xuhu, Su Jiannan, Li Xu et al.

In order to deal with the complicated and variable working conditions in the production process of the pumping unit, a multi-mode control system of the beam pumping unit is designed. By obtaining the electrical parameters and position information of the pumping unit, the developed system realizes multiple pumping unit operation modes like the constant speed mode, different speed between upper stroke and lower stroke mode and power servo mode by the frequency conversion technology. Combined with the development of the host computer software, real-time display and storage of the status information of pumping unit has been achieved. The field test showed that the multi-mode control system can effectively eliminate the current shock caused by the start of the pumping unit. A test well operated under the power servo mode has achieved the comprehensive energy saving rate of 10.4%. By changing the operation mode of oil well, the multi-mode control system can realize efficient, stable and economical operation of the pumping unit under several complicated working conditions, presenting high application value.

E.O. Ajala, F. Aberuagba, A.M. Olaniyan et al.

The challenges of biodiesel production from high free fatty acid (FFA) shea butter (SB) necessitated this study. The reduction of %FFA of SB by esterification and its subsequent utilization by transesterification for biodiesel production in a two stage process for optimization studies was investigated using response surface methodology based on a central composite design (CCD). Four operating conditions were investigated to reduce the %FFA of SB and increase the %yield of shea biodiesel (SBD). The operating conditions were temperature (40–60°C), agitation speed (200–1400 rpm), methanol (MeOH): oil mole ratio: 2:1–6:1 (w/w) for esterification and 4:1–8:1 (w/w) for transesterification and catalyst loading: 1–2% (H2SO4, (v/v) for esterification and KOH, (w/w) for transesterification. The significance of the parameters obtained in linear and non-linear form from the models were determined using analysis of variance (ANOVA). The optimal operating conditions that gave minimum FFA of 0.26% were 52.19°C, 200 rpm, 2:1 (w/w) and 1.5% (v/v), while those that gave maximum yield of 92.16% SBD were 40°C, 800 rpm, 7:1 (w/w) and 1% (w/w). The p-value of <0.0001 for each of the stages showed that the models were significant with R2 of 0.96 each. These results indicate the reproducibility of the models and showed that the RSM is suitable to optimize the esterification and transesterification of SB for SBD production. Therefore, RSM is a useful tool that can be employed in industrial scale production of SBD from high FFA SB.

Ali Hossein Kianfar, Roghayeh Hashemi Fath

In this research, structures of M(BAE) (where M = VO(IV), Zn(II), Cu(II) and Ni (II), BAE = bis(acetylacetone)ethylenediimine), [Ni(BFE)], [Ni(BBE)] and [Ni(BCE)] (where BFE = bis(1,1,1-triflouroacetylacetone)ethylenediimine, BBE = bis(benzoylacetone)ethylenediimine and BCE = bis(3-hloroacetylacetone)ethylenediimine) were determined by MP2 theoretical study. The thermodynamics of the tautomerism reactions was studied and the equilibrium constant of the reactions was calculated. The optimized molecular geometry and atomic charges were calculated using MP2 method with 6-31G(d) basis set and compared with the reported X-ray data. Nickel and copper complexes have a planar structure while the zinc structure shows a distorted square-planar N2O2 coordination geometry. The vanadyl structure has a square-pyramide N2O3 coordination geometry. Also the bond lengths and the bond angles were studied and compared.

Lin Kang, Zhang Yiyang, Luo Lei et al.

During domestic development of automated drilling equipment,if the control system software for each device shows error in the protection logic and trajectory solver,safety incident of device could be easily raised in joint debugging test.To address the issue,a virtual driller’s operating system for deepwater drilling rig has been developed.Adopting 3DVIA Virtools as the virtual reality technology development platform,combined with industrial automation,industrial networking communications and large-screen technology,the system could simulate the joint work flow of drilling equipment,thus optimize the rig overall configuration and layout.Before the joint test of newly developed electro-hydraulic device,assist test of control program of each device’s virtual prototype could be conducted to reduce the risk of electro-hydraulic joint test.The field application of the system has achieved good results with shortened test debug time and reduced product development costs.Finally,it is indicated that,the interaction-based virtual driller’s operating system for deepwater drilling is a novel driller training mode.

Qin Haozhi, Chen Yao, Xiao Wensheng

The seal assembly domestically produced is used only under shallow water and low pressure conditions and fails to meet the needs of usage under different water depths and drilling under different pressures.In view of this, this paper studies the series design method and metal sealing mechanism, and analyzes the key factors that influence sealing performance and pressure rating of seal assembly, so as to define the series design principle and evaluation criteria of seal assembly and identify the series design method.The study confirms that the 103.4 MPa wellhead seal assembly system, as the basic type of series design, can achieve the desired sealing effect and ensure safe recovery, works out the structural parameters of seal assembly under three pressure levels of 34.5, 68.9 and 137.9 MPa, and finishes the series design of seal assembly.ANSYS Workbench is used to complete a detailed mechanical analysis of the sealing performance of the basic type seal assembly.The proposed method could provide the theoretical basis and guidance for series design of the entire wellhead system.

Yanli Guo, Baojiang Sun, Keke Zhao et al.

To prevent the deposition of natural gas hydrate in deepwater gas well, the hydrate formation area in wellbore must be predicted. Herein, by comparing four prediction methods of temperature in pipe with field data and comparing five prediction methods of hydrate formation with experiment data, a method based on OLGA & PVTsim for predicting the hydrate formation area in wellbore was proposed. Meanwhile, The hydrate formation under the conditions of steady production, throttling and shut-in was predicted by using this method based on a well data in the South China Sea. The results indicate that the hydrate formation area decreases with the increase of gas production, inhibitor concentrations and the thickness of insulation materials and increases with the increase of thermal conductivity of insulation materials and shutdown time. Throttling effect causes a plunge in temperature and pressure in wellbore, thus leading to an increase of hydrate formation area.

Fu Yue, Ma Weiguo, Wu Qiudong

The WOB during window milling in coil tubing(CT) casing is hardly controlled,so motors might be damaged,and undesirable quality of the window might be caused.With the window milling of whipstock as object,the "vertical and horizontal bending method" was used for programming of computer software to calculate forces and deformation of drilling assemblies with specific structures for windowing in coil tubing in the one-dimensional wellbore.With consideration to cutting conditions similar with those encountered in field,three limiting conditions have been clarified,namely,proper functioning of the motor,drilling in accordance with pre-determined trajectory and generation of high-quality window,to predict range of acceptable WOBs during window milling.Research results show that proper prediction of WOB during window milling in coil tubing may be favorable for protection of drilling tools and generation of high-quality window.Such results may provide necessary guidance for on-site application.Since the motor may stall at the stage of initial window milling,minor drilling pressures shall be deployed.

Ping YANG, Zandong SUN, Xianghao LIANG et al.

Aiming at the problems of “high but unstable production” and low success ratio in highly profitable well prediction of the Ordovician fractured-vuggy carbonate reservoirs of the Tarim Basin, based on their features of small size, huge burial depth and high heterogeneity, and proceeding from the similar bead-like reflections, this study tries to find out and quantify the differences in oil and gas bearing scale between the reservoir units, and accurately works out the reserves in them. An integrated seismic technical strategy was proposed which bases on full-azimuth and high-density acquisition, centers on amplitude-preserved prestack depth migration, and stresses on the quantitative reservoir description. By figuring out the storage spaces of the fractured-vuggy reservoirs, the connection conditions between fracture-cave bodies, and the hydrocarbon bearing conditions of the fracture-cave bodies, the fracture-cave units which have larger reserves are chosen as drilling targets. The application results in Ha 7 area of the Tabei region proved that the fracture-cave bodies can be precisely studied and the fracture-cave units can be accurately delineated by these techniques, and the success ratio of the highly-profitable well prediction can be raised accordingly. Key words: carbonates, full-azimuth and high-density acquisition, prestack depth migration, quantitative reservoir characterization, Tarim Basin