Hasil untuk "Petroleum refining. Petroleum products"

Kozhevnikova E.E., Bashkova S.E.

In the Perm region, the south and the central part have been exhaustively studied and as a result, it is here that most of the oil and gas fields have been discovered and developed, while less attention has been paid to the north of the region. The article briefly examines the history of the sedimentary cover in the northern Perm region, and evaluates the prospects for oil and gas potential based on the ranking of objects using the de Borda method. The parameters reflecting the conditions of hydrocarbon generation and accumulation are chosen as the basis for the ranking. As a result of this work, a map of the most promising areas for oil and gas exploration has been compiled.

Gao Yunwei, Luo Limin, Xue Fenglong et al.

Rate of penetration(ROP)is an important indicator to evaluate the petroleum drilling performance.To accurately predict the ROP at an oilfield in the Xinjiang work area,the historical drilling data from the area were processed using the local outlier factor(LOF)algorithm,and an ROP prediction model based on Stacking ensemble learning was established.The model integrated by Stacking strategy with the K-nearest neighbor(KNN),support vector machine(SVM)or random forest(RF)algorithm showed inaccurate classification in the verification.The genetic algorithm was then adopted to optimize the parameters of the basic models.The optimized models integrating KNN,SVM,RF and Stacking algorithms yielded the prediction results with accuracy of 73.7%,78.9%,81.6%,and 97.4%,respectively.Clearly,the Stacking-based model gets the highest accuracy.Thus,a software was developed using the Stacking-based model.It was applied to predict the ROP under two sets of parameters.The results show that the predicted ROP matches well with the actual ROP,and the software works stable.This proves the generalization and accuracy of the Stacking-based model.This intelligent algorithm has provided a new means to predict ROP and optimize drilling parameters at the oilfield of Xinjing work area.

Nengwu ZHOU, Shuangfang LU, Pengfei ZHANG et al.

The gas-water distribution and production heterogeneity of tight gas reservoirs have been summarized from experimental and geological observations, but the charging and accumulation mechanisms have not been examined quantitatively by mathematical model. The tight gas charging and accumulation mechanisms were revealed from a combination of physical simulation of nuclear magnetic resonance coupling displacement, numerical simulation considering material and mechanical equilibria, as well as actual geological observation. The results show that gas migrates into tight rocks to preferentially form a gas saturation stabilization zone near the source-reservoir interface. When the gas source is insufficient, gas saturation reduction zone and uncharged zone are formed in sequence from the source-reservoir interface. The better the source rock conditions with more gas expulsion volume and higher overpressure, the thicker the gas saturation stabilization and reduction zones, and the higher the overall gas saturation. When the source rock conditions are limited, the better the tight reservoir conditions with higher porosity and permeability as well as larger pore throat, the thinner the gas saturation stabilization and reduction zones, but the gas saturation is high. The sweet spot of tight gas is developed in the high-quality reservoir near the source rock, which often corresponds to the gas saturation stabilization zone. The numerical simulation results by mathematical model agree well with the physical simulation results by nuclear magnetic resonance coupling displacement, and reasonably explain the gas-water distribution and production pattern of deep reservoirs in the Xujiaweizi fault depression of the Songliao Basin and tight gas reservoirs in the Linxing–Huangfu area of the Ordos Basin.

Shuqin Wen, Bing Wei, Junyu You et al.

Production prediction is crucial for the recovery of hydrocarbon resources. However, accurate and rapid production forecasting remains challenging for unconventional reservoirs due to the complexity of the percolation process and the scarcity of available data. To address this problem, a novel model combining a long short-term memory network (LSTM) and support vector regression (SVR) was proposed to forecast tight oil production. Three variables, the tubing head pressure, nozzle size, and water rate were utilized as the inputs of the presented machine-learning workflow to account for the influence of operational parameters. The time-series response of tight oil production was the output and was predicted by the optimized LSTM model. An SVR-based residual correction model was constructed and embedded with LSTM to increase the prediction accuracy. Case studies were carried out to verify the feasibility of the proposed method using data from two wells in the Ma-18 block of the Xinjiang oilfield. Decline curve analysis (DCA) methods, LSTM and artificial neural network (ANN) models were also applied in this study and compared with the LSTM-SVR model to prove its superiority. It was demonstrated that introducing residual correction with the newly proposed LSTM-SVR model can effectively improve prediction performance. The LSTM-SVR model of Well A produced the lowest prediction root mean square error (RMSE) of 5.42, while the RMSE of Arps, PLE Duong, ANN, and LSTM were 5.84, 6.65, 5.85, 8.16, and 7.70, respectively. The RMSE of Well B of LSTM-SVR model is 0.94, while the RMSE of ANN, and LSTM were 1.48, and 2.32.

Junfeng ZHANG, Xingyou XU, Jing BAI et al.

Distribution characteristics, organic matter development characteristics, gas-bearing characteristics, reservoir characteristics, and preservation conditions of the Shahezi Formation shale of Lower Cretaceous in the Lishu fault depression, Songliao Basin, NE China, are analyzed using organic geochemical, whole rock, and SEM analysis data, and CO2 and N2 adsorption and high-pressure mercury injection experiment data in combination with the tectonic and sedimentation evolution of the region to reveal the geological conditions for enrichment and resource potential of continental shale gas. The organic-rich shale in the Lower Cretaceous of the Lishu fault depression is mainly developed in the lower submember of the second member of the Shahezi Formation (K1sh21 Fm.) and is thick and stable in distribution. The shale has high TOC, mainly types II1 and II2 organic matter, and is in the mature to the over-mature stage. The volcanic activity, salinization, and reduction of the water environment are conducive to the formation of the organic-rich shale. The shale reservoirs have mainly clay mineral intergranular pores, organic matter pores, carbonate mineral dissolution pores, and foliated microfractures as storage space. The pores are in the mesopore range of 10–50 nm, and the microfractures are mostly 5–10 μm wide. Massive argillaceous rocks of lowland and highstand domains are deposited above and below the gas-bearing shale separately in the lower submember of the K1sh21 Fm., act as the natural roof and floor in the process of shale gas accumulation and preservation, and control the shale gas enrichment. Based on the above understandings, the first shale gas exploration well in Shahezi Formation was drilled in the Lishu fault depression of Songliao Basin. After fracturing, the well tested a daily gas production of 7.6×104 m3 marking a breakthrough in continental shale gas exploration in the Shahezi Formation (K1sh Fm.) of the Lishu fault depression in Songliao Basin. The exploration practice has reference significance for the exploration of continental shale gas in the Lower Cretaceous of Songliao Basin and its periphery.

Zhouhua WANG, Tao WANG, Hui LIU et al.

Based on the oil, gas and water distribution characteristics of Khasib reservoir in Halfaya oilfield, Iraq, a core displacement experiment is designed to evaluate the influence of different displacement methods and displacement parameters on oil displacement efficiency. The research shows that, in the displacement method with water injected from the edge of the reservoir, early depletion production is conducive to the elastic expansion of the gas cap, forming the three-dimensional displacement of “upper pressure and lower pushing”, and the oil displacement effect is good. When gas injection at the top and water injection at the edge are used for synergistic displacement, the injection timing has different influences on the oil displacement effects of high and low parts. Considering the overall oil displacement efficiency, the injection pressure should be greater than the bubble point pressure of crude oil. Two displacement methods are recommended with the reasonable injection time at 20–25 MPa. The injection speed has the same influence on different injection media. Appropriately reducing the injection speed is conducive to the stability of the displacement front, delaying the breakthrough of injection media and improving the oil displacement effect. The reasonable injection rate of water flooding is 0.075 mL/min, the reasonable injection rates of water and gas are 0.15 mL/min and 0.10 mL/min, respectively in gas-water synergistic displacement. Gas-water synergistic displacement is conducive to the production of crude oil at high position, and has crude oil recovery 5.0%–14.8% higher than water flooding from the edge, so it is recommended as the development mode of Khasib reservoir at the middle and late stages.

Abzalov A.P.

Taking into account new data on features of the geological structure of petroleum bearing areas and oil and gas promising strata of the Ustyurt petroleum region, the results of constructing structural maps are presented. They were the basis for the development of a structural geological model of the Shege field by identifying and tracing tectonic faults, zones of local subsidence and uplifts that control oil and gas manifestations and hydrocarbon accumulations in the Jurassic strata.

刘统亮, 施建国, 冯 et al.

As the length of the horizontal section of oil and gas wells increases, traditional drillable bridge plugs become more difficult to drill. The dissoluble bridge plugs are more in line with the production needs of oil and gas wells. The role and mechanism of dissoluble bridge plugs in horizontal well fracturing operations are introduced. The research status, technical characteristics and actual operation performances of dissoluble bridge plugs in horizontal wells at home and abroad are systematically investigated and analyzed. The analysis results show that the staged fracturing technology using dissoluble bridge plugs in horizontal wells is an emerging technology in the field of shale gas reservoir development. There is a big gap between China and foreign countries, and it is urgent to explore technologies that meet the actual conditions of China. The dissoluble bridge plugs have the advantages of high strength, high pressure resistance and stable temperature resistance. After the fracturing operation is completed, it can dissolve in the flowback fluid by itself without drilling and milling, allowing full bore completion and direct putting into production. The dissoluble bridge plugs have good safety and practicability, presenting good research value and broad application prospects. The study can provide technical references for the development and application of dissoluble bridge plugs and dissoluble downhole tools in our country.

Wu Han

Drilling rig derricks often have problems like corrosion, wear and sudden increase of load. Therefore, it is necessary to integrate the automatic detection of derrick load capacity with the hook-load monitoring to improve the safety of drilling and workover operations. By analyzing the calculation method of derrick capacity and the existing hook-load detection technology, an integrated technical solution is proposed. The proposed solution, taking computer as the core, collects strain data with single-chip microcomputer and transmits data by wireless Wifi to evaluate the derrick capacity, and simultaneously control the hook load by monitoring real-time hook load data. The key technologies of derrick capacity detection and calculation, wireless node design and hook-load monitoring are discussed in detail. The hardware and software systems and micro-well derricks are established according to the design scheme. Simulation tests are carried out on the universal testing machine. The test results show that the designed hardware and software systems are running normally, the coordination between the subsystems is good, and the design scheme is feasible. The study has practical significance for the safety of drilling rig.

Cheng Xinping, Xue Dedong, Zhang Fenghui

In order to solve the difficulties in the process of downhole gas flow test, the V-cone flowmeter was placed in an intelligent gas lift valve to test the gas flow. In order to avoid damage to the flowmeter by the fluctuation of downhole gas displacement, a V-cone buffer device was designed. The finite element analysis and test method were used to simulate and optimize the equivalent diameter ratio <i>β</i> of V cone. The research results show that the test accuracy of the V-cone flowmeter is closely related to the equivalent diameter ratio of V-cone and flow channel. When the maximum throttling diameter of the cone is 23.5 mm, the optimal equivalent diameter ratio (<i>β</i>=0.341) suitable for the intelligent gas lift valve can be obtained. When the flow rate of the gas lift valve is in the range of 10~40 m³/h, the test error is less than 1.000%, which can satisfy the needs of downhole test. The successful application of the V-cone flowmeter in the intelligent gas lift valve provides technical support for oil and gas production wells, and is of great significance for improving the lift efficiency and ultimate recovery rate of such wells.

Uyiosa Omoregie

Nigeria is generally referred to as an ‘oil economy’ because of the country’s large amount of oil reserves Yet, the petroleum sector in Nigeria currently contributes less than 10 percent of the country’s gross domestic product (GDP). In comparison, some Gulf states petroleum sector’s GDP contribution is usually more than 30 percent. A fundamental reappraisal of the Nigeria’s petroleum sector’s relationship with the economy is required. This paper posits that the missing link between the petroleum sector and Nigeria’s GDP growth is the country’s petroleum refining capacity. Capacity utilization of Nigeria’s refineries dropped to 14 percent in 2014 against a global average refining capacity utilization of 90 percent. The constraints of crude oil supply to Nigeria’s refineries are revealed as well as policy interventions by the Federal Government of Nigeria aimed to increase in-country oil refining capacity. Refining capacity is suggested as an antidote to Nigeria’s so-called ‘resource curse’.

Ma Weiguo, Lu Lei, Wang Gang et al.

Many problems occur in the coiled tubing operation in oil and gas wells, including coiled tubing slipping, slippage and tubing bite, which seriously threaten the safety of the operation and the life of the coiled tubing. From the aspect of the pressure oscillation of the hydraulic cylinder on the gripping system, the influence of the coiled tubing vibration on the gripping force of the injector head gripping system is studied. The dynamic behavior of the gripping force is attained. According to the structure and working principle of the gripping system, the mechanical model of the gripping system and the simplified two-degree-of-freedom physical system are established. The main factors influencing the dynamic behavior of the gripping force and the influence rules are obtained using the AMESim software simulation method. The study shows that the gripping force vibration has a positive correlation with the pressure oscillation of hydraulic cylinder. When the pressure vibration frequency of hydraulic cylinder is high, the vibration amplitude of gripping force decreases with the increase of frequency. The equivalent stiffness of gripping system has a great influence on the gripping force vibration amplitude. The results of the simulation analysis could provide references for the structural design of the coiled tubing gripping system and coiled tubing operation.

Wang Yanzhe, Xu Xingping, Liu Guangdou et al.

To study the effect of the heave plate on the heaving performance of the Truss Spar platform, based on the establishment of calculation model of the vertical wave load of the Truss Spar platform, the viscous damping of the Truss Spar platform has been calculated based on the Keulegan-Carpenter number <i>Kc</i>. The theoretical calculation method of the heave response amplitude has been proposed. The theoretical results were compared with the simulation results of AQWA software. The analysis results show that the two analytical methods have the same trend of heaving response amplitude with close peak value. The calculation speed of the theoretical calculation method is faster than that of the simulation analysis method. The <i>Kc</i>-based calculation method for heaving response amplitude could be used to quickly and effectively analyze the heaving response of the offshore platform with heave plate. The viscous damping can effectively suppress the heaving response of the Truss Spar platform, which could not be ignored in the analysis of heaving response. The viscous damping contributed by the heaving plate is the main component of total viscous damping. The conclusion could provide references for reasonably determining the heaving response amplitude of the Truss Spar platform.

Xiao Guo, Pengbin Du, Peng Wang et al.

Abstract The water coning phenomenon leads to decrease the wellhead pressure with moving of water into gas production zone, which is regarded as one of most serious problems during gas production. It has been shown that water breakthrough time plays an important role in analyzing the water coning phenomenon and production of water. However, the existing prediction models of water breakthrough time are very scarce and need to be discussed. In this work, a novel model for water breakthrough time in high-sulfur gas reservoir with edge water is developed based on flow law and sulfur precipitation model in porous media. The effect of irreducible water saturation, residual gas saturation, and the distance between gas well and edge water, sulfur saturation and gas non-Darcy flow on water breakthrough time was involved in this model. The validity of the proposed model is verified by comparing the existing models available. A good trend is found between them. In addition, the influence of the distance between gas well and edge water, sulfur saturation and gas non-Darcy flow on water breakthrough time was detail discussed further.

Anjiang SHEN, Jianfeng ZHENG, Yongquan CHEN et al.

Based on cores, thin sections and drilling data of 18 wells and two outcrop profiles of the Lower-Middle Cambrian in the Tarim Basin, geochemical analysis of multi-parameters in micro-area (the micro-carbonate fabric which is formed under the same diagenetic event or has the same genesis) and reservoir dissolution modeling were carried out to find out the types, origin and distribution of Lower-Middle Cambrian dolomite reservoirs. There develop three types of dolomite reservoirs, margin reef-shoal reservoir, platform interior mound-shoal reservoir and platform interior gypsodolomite reservoir. The rock types include algae dolomite, grain dolomite, and gypsodolomite; the pore types in them include algae framework pores in algae dolomite; intergranular pores, intra-granular dissolved pores, inter-crystalline dissolved pores in grain dolomite and gypsum-dissolved pore gypsodolomite. The primary pores in sediments of reef-shoal facies and gypsodolomite flat are the key to the development of the dolomite reservoirs, some aragonite and calcite are the material basis of dissolution in early supergene stage, and the dolomite formed in penecontemporaneous dolomitization acts as strong rock skeleton to protect the primary pores from destructive effect in burial stage. The margin reef-shoal reservoirs, large in scale and good in physical properties, are the most practical exploration targets; furthermore, the platform interior reef-shoal reservoirs in Lower Cambrian Xiaoerbulake Formation and platform interior gypsodolomite reservoir in the Middle-Lower Cambrian have higher oil and gas potential. Key words: Tarim Basin, Lower-Middle Cambrian, dolomite reservoir, margin reef-shoal, platform interior reef-shoal, platform interior gypsodolomite

Huiliang ZHANG, Ronghu ZHANG, Haijun YANG et al.

Taking the Cretaceous Basijiqike Formation sandstone reservoirs in the Kuqa foreland basin as an example, this paper studies the characterization and evaluation methods of fracture-pore (fracture-primary pore and fracture-dissolution pore) ultra-deep reservoirs under the double effects of diagenetic compaction and tectonic compression. Buried over 6 000 m deep, the sandstone reservoirs of Basijiqike Formation are ultra-deep reservoirs, aimed at which, an ultra-deep fracture tight sandstone reservoir characterization technique is built, which integrates macroscopic microfacies-lithofacies identification, centimeter-micron scale fracture description, micron pore depiction and nano-throat characterization. The research indicates that the effective reservoir space consists of structural fractures, micron pores and nano-pore throats. The main radius of matrix pores is 2–100 μm, that of matrix throats is 10–500 nm and the main area of fracture opening degree is 100–300 μm. Effective reservoirs are mainly controlled by microfacies-lithofacies, tectonic compression and erosion. Relatively high-quality reservoir spaces consist of fractures, residual intergranular pores and dissolution pores, developed in weak compacted structure zone and stacked underwater distributary channel zone. Favourable reservoirs over 7 000 m deep can be in continuous band distribution, there still could be effective reservoirs in formations over 8 000 m deep. Key words: Kuqa foreland basin, Bashijiqike Formation, ultra-deep formation, fracture, dissolution pore, primary pore, reservoir characterization

L.S. Nasrat, A.F. Hamed, M.A. Hamid et al.

This work presents a study of flashover voltage for outdoor polyester and composite insulators under some desert climatic conditions. Cylindrical polyester composite samples have been prepared after incorporated with different concentrations of inorganic fillers e.g., alumina trihydrate [ATH], boric acid [H3BO3] and magnesium hydroxide [Mg(OH)2] to improve the electrical, mechanical and thermal properties in addition to maximize the surface flashover voltage and decrease the tracking phenomena. Results showed that flashover voltage reaches to 38 kV for samples without filler and 47 kV for samples containing 50% of ATH filler in dry condition. A comparison between inorganic fillers under various environmental conditions showed higher flashover voltage values for samples containing ATH filler than that of samples containing H3BO3 and Mg(OH)2 fillers at all filler concentrations. Flashover voltage increases 24% by adding ATH filler for polyester samples under sandstorm conditions. Also, in this study, the effects of sandstorm, ultra violet (UV) radiation, mechanical strength (compressive and tensile strengths) and thermal performance with respect to surface of the sample under test have been investigated in detail.