Hasil untuk "Petroleum refining. Petroleum products"

Zhe Ban, Carlos Pfeiffer

Abstract Data reconciliation techniques have been the subject of many classic studies in the data conditioning process. By reconciling the measurements, accurate estimation of the system output and unmeasured variables is provided. However, accurately determining measurement noise and parameter uncertainty in real time remains a significant challenge. How to simultaneously estimate parameters in the system has been attracting considerable interest. So far, very little attention has been paid to time-varying parameter estimation in oil production systems. In particular, estimation of parameter dynamics and the corresponding uncertainty without prior knowledge remains challenging. This work extends a previous study on dynamic parameter estimation by considering scenarios where parameters change both gradually and abruptly. To address these dynamics, nonlinear filtering methods are employed and compared. A comparative analysis was conducted using both quantitative metrics and visualization plots to evaluate the performance of various approaches. Under the same abrupt parameter change scenario, nonlinear filter-based methods demonstrated superior performance in parameter estimation, achieving a root mean square error of $$6.56 \times 10^{-11}$$ , compared to $$7.84 \times 10^{-11}$$ for the MCMC-based method-even without the use of prior information. Additionally, nonlinear filters showed a significant advantage in simultaneous state estimation, with a root mean square error of $$1.94 \times 10^{4}$$ , markedly lower than the $$1.47 \times 10^{6}$$ observed with the MCMC-based approach. The effectiveness of nonlinear filtering methods was further validated in scenarios involving gradual parameter changes, again without relying on prior knowledge. This work provides an important opportunity to advance the understanding of dynamic parameter estimation in the gas and oil industry, and the improved model can possibly be applied to real-time optimization and model-based control. Graphical abstract

Liu Qi, Wang Gang, Li Xiaogang et al.

The buried-hill basement reservoirs of oilfields in Chad demonstrate low pressure and low production of oil production wells.To improve the well production,gas injection is required to replenish the formation energy.However,the reservoirs are filled due to sand production in upper layers after the open-hole development wells are converted to gas injection wells.A lower completion string consisting of an expandable tube hanger and an open-hole packer was run in Well BX20 in buried-hill reservoir of Block B,Chad,for a pilot test of recompletion technology.The test results show that the designed recompletion string is set successfully in one trip,with the entire operation period of 10 d,which is 7 d less than the average operation period of traditional recompletion technology,corresponding to US$200 000 of workover costs or more saved.After the recompletion,the casing is effectively sealed and protected from damage caused by high-pressure gas injection,ensuring the wellbore integrity of the open-hole gas injection wells.The gas injection pressure reaches 20 MPa,and the daily gas injection rate reaches 2 000 m³/h.The proposed recompletion technology is proved suitable for gas injection wells in basement reservoirs in Chad,and has a demonstration effect on the development of similar oilfields.

XU Yandong, TAO Shan, HE Hui, WAN Xiaoyong, ZOU Ning, YUAN Hongfei

The fault-affected karst system in the north of Shuntuoguole low uplift, Tarim basin, Shunbei oilfield has obvious vertical development and heterogeneity. Due to the large vertical depth of the reservoir, the influence of gravity can not be ignored in the process of fluid flow. Considering that the reservoir is composed of small-scale fracture, large-scale cavity and large-scale channeling path, and the initial pressure at different depths varies with the depth, a large-scale fracture-vuggy well test model considering gravity is established combined with the principle of seepage mechanics and the equipotential body theory. The Laplace transform method was used to address this issue and the typical model plate and parameter sensitivity analysis plate were drawn. The results show that the fluid flow needs to overcome more resistance when gravity is taken into account, and the positions of dimensionless pressure and its derivative curves are higher in the middle and later stages. When accounting for the seepage effect in small-scale fractured reservoirs, distinct flow characteristics emerge: Linear flow in channeling paths, Transitional flow in large cavities, Quasi-steady flow in large cavities, and Radial flow in fractured reservoirs. The slope of the dimensionless pressure and its derivative curve of the former is between 0 and 0.5. The dimensionless pressure derivative curves of the latter two decrease slowly and then rise slowly. The applicability and validity of the model are further corroborated through case studies. This research not only enriches the fracture-vuggy well test model literature but also provides a solid theoretical foundation for interpreting well test data in vertical fracture-vuggy reservoirs with significant depth.

Yupeng Li, Rashid S. Mohammad

The inter-well connectivity calculated from reservoir dynamic production data reflects formation heterogeneity quantitatively. Currently, the calculated inter-well connectivity between pair wells is mainly used as a tool for water flood management but not for quantitative reservoir characterization. This study proposes an innovative, dynamic data integration workflow that can integrate inter-well connectivity with a static reservoir model. In the workflow, the first step is calculating the inter-well connectivity vectors from the reservoir pairwise injector and producer wells. The second step covers interpolation in the domain of interest. The third step is to update the permeability model based on the Bayesian updating method. The result of this study shows that integrating the calculated inter-well connectivity with the static models enhances model reliability and it also provides an insight to deeper geological understanding reflected from dynamic data integration in reservoir modeling.

Lei Tian, Jun Liu, Qingzhou Yao

There is a close relationship between the evolution of the Cambrian–Ordovician paleo-uplifts and their hydrocarbon accumulation in the Southwest Tarim Depression. Using regional 2D seismic data interpretation, the structural morphology of the top of the Ordovician carbonate rocks in the Southwest Tarim Depression at different historical geologic stages is mapped. Combined with analysis of the discovered oil and gas reservoirs, the regularity of the hydrocarbon distribution in the Southwest Tarim Depression is investigated. Research shows that the evolution of the Cambrian-Ordovician paleo-uplifts in the Southwest Tarim Depression can be divided into four stages: (1) formation of the paleo-uplifts, (2) steady subsidence of the eastern paleo-uplift, (3) migration and adjustment of the western paleo-uplift and (4) strong subsidence and extinction of the paleo-uplifts. The Cambrian-Ordovician strata in the Southwest Tarim Depression experienced a seesaw-like structural reconstruction from an early north-dipping slope to a late south-dipping slope. During the structural reconstruction process, a pivot zone was located at the position of the current Maigaiti Slope, proving favorable for hydrocarbon accumulation and preservation. The fault zones in the eastern and western paleo-uplifts of the Maigaiti slope finalized during the Late Hercynian Period were favorable to preserving paleo-oil reservoirs. In contrast, the fault zones in the northern margin of the Maigaiti Slope, where the current tectonic uplift is located, were favorable for the accumulation of gas reservoirs.

Inna N. Ponomareva, Vladislav I. Galkin, Dmitriy A. Martyushev

One of the major tasks of monitoring production well operations is to determine bottom-hole flowing pressure. The overwhelming majority of wells in the Perm Krai are serviced using borehole pumps, which makes it difficult to take direct bottom-hole flowing pressure measurements. The bottomhole filtration pressure (BHFP) in these wells is very often determined by recalculating the parameters measured at the well mouth (annulus pressure, dynamic fluid level depth). The recalculation is done by procedures based on analytically determining the characteristics of the gas-liquid mixture in the wellbore, which is very inconsistent to perform due to the mixture's complex behavior. This article proposes an essentially different approach to BHFP measurements that relies on the mathematical processing of the findings of more than 4000 parallel mouth and deep investigations of the oil production wells of a large oil-production region. As a result, multivariate mathematical models are elaborated that allow reliably determining the BHFP of oil-production wells in operation.

石磊, 尹汉军, 琚选择 et al.

The PLET is the core product of deep-water oil and gas field development, whose technologies have long been monopolized by foreign countries. To master the key technologies for the design, manufacture, testing and installation of deep-water PLET and realize the complete localization of the product, according to the application characteristics of deep-water PLET, relying on the trial project of a gas field in the South Sea of China, a split PLET engineering prototype for water depth 500 m is designed and developed. After completing the conventional land test, considering the environmental conditions of China's South Sea area, offshore installation and function test are carried out in the 330 m water depth of Lufeng sea area. The test results show that the ROV can clearly read the numbers, letters and valve switch position indications on the engineering prototype. The underwater valve is smoothly operated by ROV. The switch position indication is accurate, and the overall valve function is complete. The switch pins of the lock arms on both sides of the deep-water PLET engineering prototype are easy to operate. The lock arms on both sides are normally opened and closed. The PLET body can be correctly located in the anti-sinking board foundation, and the pipeline part does not tilt. The separation from the anti-sinking board foundation and recovery to the deck of the PLET body is smooth. All test results meet the design index requirements. The research results have important reference significance for the technical research and product development of deep-water PLET and other deep-water production facilities.

Fangzheng JIAO

Taking the Wufeng–Longmaxi shale gas in the Sichuan Basin as a typical example, based on the new progress in exploration and development, this study re-examines the “unconventional” of unconventional oil and gas from two aspects: oil and gas formation and accumulation mechanisms, and main features of oil and gas layers. The oil and gas of continuous accumulation and distribution from integrated source and reservoir is unconventional oil and gas, and the study focusing on shale oil and gas in comparison with conventional oil and gas has made progress in five aspects: (1) Unconventional oil and gas have source-reservoir-in-one and in-situ accumulation; according to the theory of continuous oil and gas accumulation, the accumulation power of oil and gas is overpressure and diffusion; for conventional oil and gas, the source and reservoir are different formations, the trapping accumulation is its theoretical foundation, and the accumulation power is characterized by buoyancy and capillary force. (2) The unconventional oil and gas reservoirs are mainly formed in the low-energy oxygen-anaerobic environment, dominantly semi-deep to deep shelf facies and the semi-deep to deep lake facies, simple in lithology, rich in organic matter and clay minerals; conventional oil and gas mainly occur in coarse-grained sedimentary rocks formed in high-energy waters with complex lithology. (3) The unconventional oil and gas reservoirs have mainly nano-scale pores, of which organic matter pores take a considerable proportion; conventional oil and gas reservoirs mainly have micron-millimeter pores and no organic matter pores. (4) Unconventional shale oil and gas reservoirs have oil and gas in uniform distribution, high oil and gas saturation, low or no water content, and no obvious oil and gas water boundary; conventional oil and gas reservoirs have oil and gas of complex properties, moderate oil and gas saturation, slightly higher water content, and obvious oil, gas and water boundaries. (5) Organic-rich shale is the main target of unconventional oil and gas exploration; the sedimentary environment controls high organic matter abundance zone and organic matter content controls oil and gas abundance; positive structure and high porosity control the yields of shale wells; bedding and fracture development are important factors deciding high yield. Key words: unconventional oil and gas, theoretical connotation, shale oil and gas, hydrocarbon accumulation dynamics, organic matter, fine grain deposition, Wufeng–Longmaxi Formations, Sichuan Basin

Miao Zhipeng, Xia Hongnan, Nan Lihua et al.

Because the coiled tubing is not rotatable, the coiled tubing orientation tool becomes an indispensable device for coiled tubing drilling. However, the existing hydraulic ratchet-type orientation tool has such defects as high single turning angle, inferior orientation accuracy and unadjustable single turning angle. To address the problem, a coiled tubing drilling hydraulic orientation tool was designed. This tool executes the orienting and resetting action by controlling the displacement and pressure of the ground pump, thus realizes the adjustment of the tool face angle. The length of the turning angle control mechanism can be changed before run-in-hole to control the single orienting angle. The working displacement and output torque of the orientation tool are calculated to determine the working parameters:the adjustable angle range is 5°~30°, the working displacement is 8.02~12.74 L/s, and the maximum torque is 89.46~125.37 N·m. The rationality of the tool structure design was verified by stress check of the key components. The ground test results showed that the hydraulic orientation tool can control the orienting action by controlling the displacement, and consequently achieve the purpose of adjusting the tool face angle.

Wang Yuhai, Xia Haibang, Bao Kai et al.

Pengshui block is a typical shale gas reservoir at atmospheric pressure which has lower coefficient of original formation pressure, and usually needs artificial lift recovery after fracturing. In the initial stage, we optimized the electric submersible pump for the drainage gas recovery. This technology was simple, meanwhile, the formation energy declined gradually, the formation liquid supply gradually decreased and the recovered fluid contained impurities such as sand and clay particle, so that it was hard to realize the stable continuous drainage and recovery, and had complex operation precess and high production cost. In order to solve these problems, we researched and applied the jet pump, and optimized the technology parameters and matching technology. At last, we formed a set of jet pump technology suitable for the drainage gas recovery of shale gas at atmospheric pressure to effectively guide the pressure of shale gas recovery.

Wenzhi ZHAO, Suyun HU, Xujie GUO et al.

The Junggar Basin is one of the major petroliferous basins with abundant oil and gas resources in onshore China. Around 2010 and thereafter, the hydrocarbon exploration for finding giant fields in the basin faced tough difficulties: in the northwestern margin area, no significant breakthrough has been made for long since seeking to “escape from the step-fault zone and extend to the slope area”; in the central part, the exploration for large lithologic-stratigraphic reservoirs stood still; since the discovery of the Kelameili gas field, no important achievement has been made in gas exploration. Under the guidance of “whole sag-oil-bearing” theory in the petroliferous basin, and based on the long-term study and thinking of the petroleum accumulation conditions and characteristics, the authors proposed several new concepts, i.e., a “thrust-induced second-order fault step” hiding under the northwestern slope area; six “hydrocarbon migrationward surfaces” favorable for hydrocarbon accumulation; promising natural gas resource. These concepts have played an important role in the discoveries of Wells Mahu1 and Yanbei1 as well as the confirmation and expansion of Permian-Triassic billion-ton-scale petroliferous areas in Mahu. The fairway of new discoveries has also appeared for natural gas exploration in Wells Fu26, Gaotan1 and Qianshao2, suggesting that the surrounding regions of the highly matured source kitchen are of high possibility to form gas accumulations. Key words: second-order fault step, hydrocarbon migrationward surface, favorable facies belt, lithologic-stratigraphic reservoir, whole sag-oil-bearing, natural gas, potential and direction, Junggar Basin

Ali K. Darwesh, Thorkild M. Rasmussen, Nadhir Al-Ansari

Abstract Oil well drilling data from 23 oil wells in northern Iraq are analyzed and optimized controllable drilling parameters are found. The most widely used Bourgoyne and Young (BY) penetration rate model have been chosen for roller cone bits, and parameters were extracted to adjust for other bit types. In this regard, the collected data from real drilling operation have initially been averaged in short clusters based on changes in both lithology and bottom hole assemblies. The averaging was performed to overcome the issues related to noisy data negative effect and the lithological homogeneity assumption. Second, the Dmitriy Belozerov modifications for polycrystalline diamond bits compacts have been utilized to correct the model to the bit weight. The drilling formulas were used to calculate other required parameters for the BYM. Third, threshold weight for each cluster was determined through the relationship between bit weight and depth instead of the usual Drill of Test. Fourth, coefficients of the BYM were calculated for each cluster using multilinear regression. Fifth, a new model was developed to find the optimum drill string rotation based on changes in torque and bit diameter with depth. The above-developed approach has been implemented successfully on 23 oil wells field data to find optimum penetration rate, weight on bit and string rotation.

Yu Xiong, Hongguang Xu, Yongqing Wang et al.

The fluid flow of unconsolidated sandstone reservoir can be affected by compaction and sand production which will damage the reservoir and affect oil well productivity. This study aims to measure how the two factors affect the fluid flow. Firstly, single-phase displacement test was applied to investigate how the permeability changed with compaction. Then two-phase displacement test assessed the influence of compaction on oil production. Finally, the characteristics of fluid flow with compaction and sand production were studied under different water content. The results demonstrate that the reduction of permeability with compaction is irreversible, which will result in lower productivity. In contrast, sand production can increase the permeability at mid and high water content, which slows down the decline of oil production. Generally, the oil well productivity is reduced because of compaction even with sand production, especially when the formation pressure drop varies from 2 MPa to 4 MPa. Consequently, advance water injection is necessary to keep the formation pressure and oil production during oilfield development of unconsolidated sandstone reservoir. Simultaneously, the study can provide theoretical basis and references for the similar reservoirs. Keywords: Compaction, Sand production, Seepage, Unconsolidated sandstone

Mohammad Reza Talaghat, Ahmad Reza Bahmani

In this work, a mathematical model is established to describe the removal of CO₂ from gaseous mixtures including CH₄ and CO₂ in a polypropylene hollow fiber membrane contactor in the presence of conventional absorbents such as monoethanolamine (MEA), methyldiethanolamine (MDEA), and a blend of them. Modeling was performed in axial and radial directions under the fully-wet condition for countercurrent gas-liquid flow arrangement. Both of axial and radial diffusions have been considered in three segments, including shell, membrane, and tube. To evaluate the model, the results of this model were compared with the experimental data and the results of COMSOL software and the results were in agreement with the experimental data and COMSOL outputs. In addition, the effect of various parameters on the removal percentage of carbon dioxide from gas mixtures was studied. It was found out that the CO₂ removal percentage is the best by using MEA solution as the absorbent. This modeling shows that the removal of CO₂increases by adding MEA into MDEA solution. In this study, the factors that influence the removal percentage of CO₂ from gaseous mixture were investigated. The CO₂ removal efficiency increased with an increase in the liquid flow rate, number of fibers, membrane length, porosity-to-tortuosity ratio, and solvent concentration. The results show that increasing gas flow rate reduces CO₂removal due to decreasing the contact time. Finally, the performance of this membrane was compared with other membranes such as polyvinyl difluoride (PVDF) and polytetrafluoroethylene (PTFE). The results show that the percentage of CO₂ removal by the polypropylene HFM is higher than that of the PVDF and PTFE hollow fiber membranes in the presence of MEA as the absorbent.

S. Roby, M. Dutta, Ya-Kun Zhu et al.

B. Sarup

Pankaj K. Kanaujia