Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.06.010
Pu Wang , Yi-An Cui , Lin Zhou , Jing-Ye Li , Xin-Peng Pan , Ya Sun , Jian-Xin Liu
Pre-stack seismic inversion is an effective way to investigate the characteristics of hydrocarbon-bearing reservoirs. Multi-parameter application is the key to identifying reservoir lithology and fluid in pre-stack inversion. However, multi-parameter inversion may bring coupling effects on the parameters and destabilize the inversion. In addition, the lateral recognition accuracy of geological structures receives great attention. To address these challenges, a multi-task learning network considering the angle-gather difference is proposed in this work. The deep learning network is usually assumed as a black box and it is unclear what it can learn. However, the introduction of angle-gather difference can force the deep learning network to focus on the lateral differences, thus improving the lateral accuracy of the prediction profile. The proposed deep learning network includes input and output blocks. First, angle gathers and the angle-gather difference are fed into two separate input blocks with ResNet architecture and Unet architecture, respectively. Then, three elastic parameters, including P- and S-wave velocities and density, are simultaneously predicted based on the idea of multi-task learning by using three separate output blocks with the same convolutional network layers. Experimental and field data tests demonstrate the effectiveness of the proposed method in improving the prediction accuracy of seismic elastic parameters.
叠前地震反演是研究含油气储层特征的有效方法。在叠前反演中，多参数应用是确定储层岩性和流体的关键。然而，多参数反演可能会带来参数耦合效应，破坏反演的稳定性。此外，地质结构的横向识别精度也备受关注。为应对这些挑战，本研究提出了一种考虑角-集差的多任务学习网络。深度学习网络通常被认为是一个黑盒子，不清楚它能学到什么。然而，引入角度聚集差可以迫使深度学习网络关注横向差异，从而提高预测剖面的横向精度。拟议的深度学习网络包括输入和输出块。首先，角度采集和角度采集差值分别被输入到两个独立的输入块中，这两个输入块分别采用 ResNet 架构和 Unet 架构。然后，基于多任务学习的思想，使用具有相同卷积网络层的三个独立输出块，同时预测三个弹性参数，包括 P 波和 S 波速度以及密度。实验和现场数据测试证明了所提方法在提高地震弹性参数预测精度方面的有效性。
{"title":"Multi-task learning for seismic elastic parameter inversion with the lateral constraint of angle-gather difference","authors":"Pu Wang , Yi-An Cui , Lin Zhou , Jing-Ye Li , Xin-Peng Pan , Ya Sun , Jian-Xin Liu","doi":"10.1016/j.petsci.2024.06.010","DOIUrl":"10.1016/j.petsci.2024.06.010","url":null,"abstract":"<div><div>Pre-stack seismic inversion is an effective way to investigate the characteristics of hydrocarbon-bearing reservoirs. Multi-parameter application is the key to identifying reservoir lithology and fluid in pre-stack inversion. However, multi-parameter inversion may bring coupling effects on the parameters and destabilize the inversion. In addition, the lateral recognition accuracy of geological structures receives great attention. To address these challenges, a multi-task learning network considering the angle-gather difference is proposed in this work. The deep learning network is usually assumed as a black box and it is unclear what it can learn. However, the introduction of angle-gather difference can force the deep learning network to focus on the lateral differences, thus improving the lateral accuracy of the prediction profile. The proposed deep learning network includes input and output blocks. First, angle gathers and the angle-gather difference are fed into two separate input blocks with ResNet architecture and Unet architecture, respectively. Then, three elastic parameters, including P- and S-wave velocities and density, are simultaneously predicted based on the idea of multi-task learning by using three separate output blocks with the same convolutional network layers. Experimental and field data tests demonstrate the effectiveness of the proposed method in improving the prediction accuracy of seismic elastic parameters.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 4001-4009"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141936579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.04.007
Peng-Fei Zhang , Shuang-Fang Lu , Jun-Jie Wang , Wen-Biao Li , Ya-Jie Yin , Guo-Hui Chen , Neng-Wu Zhou , Han Wu
Characterizing the microscopic occurrence and distribution of in-situ pore water and oil is crucial for resource estimation and development method selection of shale oil. In this paper, a series of nuclear magnetic resonance (NMR) experiments were conducted on shales from the Gulong Sag, Songliao Basin, China, at AR, WR-AR, WOR-AR, Dry, SO, and WR states. In-situ pore water and oil were reconstructed after WOR-AR. An improved T1–T2 pattern for shale oil reservoirs comprising water and oil was proposed to classify and quantitatively detect pore fluids at different occurrence states. The total and free oil contents derived from NMR T1–T2 spectra at AR states were found to correlate well with those from multistage Rock-Eval. Moreover, the NMR-calculated total and free oil are generally larger than those measured from multistage Rock-Eval, whereas adsorbed oil is the opposite, which implies that adsorbed, bound, and movable oils in shale pores can be accurately and quantitatively detected via NMR, without absorbed hydrocarbons in kerogen. As per the NMR T2 and T1–T2 spectra at WOR-AR state, the microdistributions of in-situ pore water and oil were clearly demonstrated. Adsorbed, bound, and movable oils primarily occur in the micropores (<100 nm), mesopores (100–1000 nm), and macropores (>1000 nm), respectively, whereas capillary-bound water is primarily correlated with micropores. Thus, the microscopic occurrence and distribution of adsorbed oil are remarkably affected by pore water, followed by bound oil, and movable oil is hardly affected. This study would be helpful in further understanding the microscopic occurrence characteristics of pore fluids in-situ shale oil reservoirs.
{"title":"Microscopic occurrence and distribution of oil and water in situ shale: Evidence from nuclear magnetic resonance","authors":"Peng-Fei Zhang , Shuang-Fang Lu , Jun-Jie Wang , Wen-Biao Li , Ya-Jie Yin , Guo-Hui Chen , Neng-Wu Zhou , Han Wu","doi":"10.1016/j.petsci.2024.04.007","DOIUrl":"10.1016/j.petsci.2024.04.007","url":null,"abstract":"<div><div>Characterizing the microscopic occurrence and distribution of in-situ pore water and oil is crucial for resource estimation and development method selection of shale oil. In this paper, a series of nuclear magnetic resonance (NMR) experiments were conducted on shales from the Gulong Sag, Songliao Basin, China, at AR, WR-AR, WOR-AR, Dry, SO, and WR states. In-situ pore water and oil were reconstructed after WOR-AR. An improved T<sub>1</sub>–T<sub>2</sub> pattern for shale oil reservoirs comprising water and oil was proposed to classify and quantitatively detect pore fluids at different occurrence states. The total and free oil contents derived from NMR T<sub>1</sub>–T<sub>2</sub> spectra at AR states were found to correlate well with those from multistage Rock-Eval. Moreover, the NMR-calculated total and free oil are generally larger than those measured from multistage Rock-Eval, whereas adsorbed oil is the opposite, which implies that adsorbed, bound, and movable oils in shale pores can be accurately and quantitatively detected via NMR, without absorbed hydrocarbons in kerogen. As per the NMR T<sub>2</sub> and T<sub>1</sub>–T<sub>2</sub> spectra at WOR-AR state, the microdistributions of in-situ pore water and oil were clearly demonstrated. Adsorbed, bound, and movable oils primarily occur in the micropores (<100 nm), mesopores (100–1000 nm), and macropores (>1000 nm), respectively, whereas capillary-bound water is primarily correlated with micropores. Thus, the microscopic occurrence and distribution of adsorbed oil are remarkably affected by pore water, followed by bound oil, and movable oil is hardly affected. This study would be helpful in further understanding the microscopic occurrence characteristics of pore fluids in-situ shale oil reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 3675-3691"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140771147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Inadequate strength and stability of active crude oil emulsions stabilized by conventional surfactants always lead to a limited plugging rate of plugging agents. Thus, to address this issue, the synthesis of amphiphilic Janus nanosheets was effectively carried out for enhancing the system performances and subsequently characterized. Based on the outcomes of orthogonal tests, an assessment was conducted on the nanosheet and surfactant formulations to optimize the enhancement of emulsion properties. The experimental demonstration of the complex system has revealed its remarkable emulsifying capability, ability to decrease interfacial tension and improve rheological behavior at high temperature (80 °C) and high salinity (35,000 ppm) conditions. Involving probable mechanism of the system performance enhancement is elucidated by considering the synergistic effect between surfactants and nanosheets. Furthermore, variables including water-to-oil ratio, salinity, temperature and stirring intensity during operation, which affect the properties of prepared emulsions, were investigated in detail. The efficacy and stability of the complex system in obstructing medium and high permeability cores were demonstrated. Notably, the core with a high permeability of 913.58 mD exhibited a plugging rate of 98.55%. This study establishes the foundations of medium and high permeability reservoirs plugging with novel active crude oil plugging agents in severe environments.
{"title":"Emulsion properties and plugging performances of active crude oil enhanced by amphiphilic Janus nanosheets","authors":"Hai-Rong Wu , Geng-Lin Li , Guo-Rui Xu , Jia-Wei Chang , Kun-Peng Hou , Wen-Hao Shao , Ji-Rui Hou","doi":"10.1016/j.petsci.2024.07.026","DOIUrl":"10.1016/j.petsci.2024.07.026","url":null,"abstract":"<div><div>Inadequate strength and stability of active crude oil emulsions stabilized by conventional surfactants always lead to a limited plugging rate of plugging agents. Thus, to address this issue, the synthesis of amphiphilic Janus nanosheets was effectively carried out for enhancing the system performances and subsequently characterized. Based on the outcomes of orthogonal tests, an assessment was conducted on the nanosheet and surfactant formulations to optimize the enhancement of emulsion properties. The experimental demonstration of the complex system has revealed its remarkable emulsifying capability, ability to decrease interfacial tension and improve rheological behavior at high temperature (80 °C) and high salinity (35,000 ppm) conditions. Involving probable mechanism of the system performance enhancement is elucidated by considering the synergistic effect between surfactants and nanosheets. Furthermore, variables including water-to-oil ratio, salinity, temperature and stirring intensity during operation, which affect the properties of prepared emulsions, were investigated in detail. The efficacy and stability of the complex system in obstructing medium and high permeability cores were demonstrated. Notably, the core with a high permeability of 913.58 mD exhibited a plugging rate of 98.55%. This study establishes the foundations of medium and high permeability reservoirs plugging with novel active crude oil plugging agents in severe environments.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 4141-4152"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141851105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.08.002
Xin Liu , Jin-Qiang Tian , Fang Hao , Ze Zhang , Xian-Zhang Yang , Yong-Quan Chen , Ke Zhang , Xiao-Xue Wang , Fu-Yun Cong
The natural gas heavy carbon isotope and high dryness coefficients genesis in Tabei uplift, Tarim Basin has been highly controversial. To investigate the generation mechanisms of natural gas in the Tabei Uplift. Natural gas chemical composition, carbon isotopes were used to analyze the genesis of natural gas, source rock maturity, and basin modeling were conducted to reconstruct the natural gas generation process, and the influences of instantaneous and cumulative effects on natural gas properties was discussed. The results show that the dryness coefficients of natural gas range from 0.62 to 0.99 (average: 0.92), the methane contents range from 30.42% to 96.4% (average: 85.10%), ethane contents from 0.43% to 15.58% (average: 3.39%), propane contents from 0.11% to 11.43% (average: 1.78%), and the methane carbon isotopes range from −47.30‰ to −33.80‰ (average: −36.96‰), ethane carbon isotopes range from −39.60‰ to −33.20‰ (average: −35.57‰), propane carbon isotopes range from −36.90‰ to −28.50‰ (average: −35.49‰). Compared with the actual regional thermal evolution of the source rock (Ro% range from 1.4%–1.7%), the natural gas exhibits excessively high dryness coefficients and heavy methane carbon isotope characteristics. The natural gas is primary cracking gas and sourced from marine type II kerogen. The dryness coefficient, methane carbon isotopes, and source rock maturity gradually increases from the west to the east. Instantaneous effects and leakage led to the dry gas and relative heavy methane carbon isotopes generated at a low maturity level. The current natural gas in the Ordovician reservoirs was all generated during the Himalayan orogeny. Long period pause of the gas generation between the two hydrocarbon generation phases is the main cause for the instantaneous effects.
{"title":"The generation mechanism of deep natural gas in Tabei uplift, Tarim Basin, Northwest China: Insights from instantaneous and accumulative effects","authors":"Xin Liu , Jin-Qiang Tian , Fang Hao , Ze Zhang , Xian-Zhang Yang , Yong-Quan Chen , Ke Zhang , Xiao-Xue Wang , Fu-Yun Cong","doi":"10.1016/j.petsci.2024.08.002","DOIUrl":"10.1016/j.petsci.2024.08.002","url":null,"abstract":"<div><div>The natural gas heavy carbon isotope and high dryness coefficients genesis in Tabei uplift, Tarim Basin has been highly controversial. To investigate the generation mechanisms of natural gas in the Tabei Uplift. Natural gas chemical composition, carbon isotopes were used to analyze the genesis of natural gas, source rock maturity, and basin modeling were conducted to reconstruct the natural gas generation process, and the influences of instantaneous and cumulative effects on natural gas properties was discussed. The results show that the dryness coefficients of natural gas range from 0.62 to 0.99 (average: 0.92), the methane contents range from 30.42% to 96.4% (average: 85.10%), ethane contents from 0.43% to 15.58% (average: 3.39%), propane contents from 0.11% to 11.43% (average: 1.78%), and the methane carbon isotopes range from −47.30‰ to −33.80‰ (average: −36.96‰), ethane carbon isotopes range from −39.60‰ to −33.20‰ (average: −35.57‰), propane carbon isotopes range from −36.90‰ to −28.50‰ (average: −35.49‰). Compared with the actual regional thermal evolution of the source rock (<em>R</em><sub>o</sub>% range from 1.4%–1.7%), the natural gas exhibits excessively high dryness coefficients and heavy methane carbon isotope characteristics. The natural gas is primary cracking gas and sourced from marine type II kerogen. The dryness coefficient, methane carbon isotopes, and source rock maturity gradually increases from the west to the east. Instantaneous effects and leakage led to the dry gas and relative heavy methane carbon isotopes generated at a low maturity level. The current natural gas in the Ordovician reservoirs was all generated during the Himalayan orogeny. Long period pause of the gas generation between the two hydrocarbon generation phases is the main cause for the instantaneous effects.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 3804-3814"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.11.017
Li-Rong Dou , Kun-Ye Xiao , Ye-Bo Du , Sheng-Qiang Yuan , Li Wang , Xin-Shun Zhang , Tong-Fei Huang , Yi-Fan Song
It is essential to intensify research on the strike-slip tectonic system in West and Central Africa to better understand regional tectonic evolution and achieve future breakthroughs in oil and gas exploration. Based on the structural interpretation of extensive seismic data and stratigraphic paleontological analysis of more than 50 wells, this study investigated the tectonic history, sedimentary filling, and evolution of the rift basins in the West and Central Africa, and identified a novel type of intraplate strike-slip tectonic system. It exhibits the following characteristics: (i) the strike-slip tectonic system in the West and Central Africa consists of the Central African Shear Zone (CASZ) and two rift branches, manifesting as an N-shape; (ii) most of basins and rifts are characterized by rapid subsidence at one end and substantial sedimentary thickness; (iii) two types of strike-slip basins are developed, namely the transform-normal extensional basin (TEB) along CASZ and the strike-slip-induced extensional basin (SEB) at each end of CASZ; (iv) two types of basins display their own temporal and spatial evolution history. TEBs underwent two rifting stages during the Early and Late Cretaceous, with a strong inversion at the end of the Late Cretaceous. SEBs experienced three rifting stages, i.e., the Early Cretaceous, Late Cretaceous, and Paleogene, with a weak inversion; and (v) this strike-slip tectonic system was formed under intraplate divergent field, indicating a new type of system. This discovery enhances understanding of the breakup of Gondwana and provides valuable guidance for future oil and gas exploration.
{"title":"Tectonics of the West and Central African strike-slip rift system","authors":"Li-Rong Dou , Kun-Ye Xiao , Ye-Bo Du , Sheng-Qiang Yuan , Li Wang , Xin-Shun Zhang , Tong-Fei Huang , Yi-Fan Song","doi":"10.1016/j.petsci.2024.11.017","DOIUrl":"10.1016/j.petsci.2024.11.017","url":null,"abstract":"<div><div>It is essential to intensify research on the strike-slip tectonic system in West and Central Africa to better understand regional tectonic evolution and achieve future breakthroughs in oil and gas exploration. Based on the structural interpretation of extensive seismic data and stratigraphic paleontological analysis of more than 50 wells, this study investigated the tectonic history, sedimentary filling, and evolution of the rift basins in the West and Central Africa, and identified a novel type of intraplate strike-slip tectonic system. It exhibits the following characteristics: (i) the strike-slip tectonic system in the West and Central Africa consists of the Central African Shear Zone (CASZ) and two rift branches, manifesting as an N-shape; (ii) most of basins and rifts are characterized by rapid subsidence at one end and substantial sedimentary thickness; (iii) two types of strike-slip basins are developed, namely the transform-normal extensional basin (TEB) along CASZ and the strike-slip-induced extensional basin (SEB) at each end of CASZ; (iv) two types of basins display their own temporal and spatial evolution history. TEBs underwent two rifting stages during the Early and Late Cretaceous, with a strong inversion at the end of the Late Cretaceous. SEBs experienced three rifting stages, i.e., the Early Cretaceous, Late Cretaceous, and Paleogene, with a weak inversion; and (v) this strike-slip tectonic system was formed under intraplate divergent field, indicating a new type of system. This discovery enhances understanding of the breakup of Gondwana and provides valuable guidance for future oil and gas exploration.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 3742-3753"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.12.013
Shu-Heng Du , Yong-Min Shi
{"title":"Corrigendum to ‘Concise extraction and characterization of the pore-throat network in unconventional hydrocarbon reservoirs: A new perspective’ [Petrol. Sci. 21 (2024) 1474–1487]","authors":"Shu-Heng Du , Yong-Min Shi","doi":"10.1016/j.petsci.2024.12.013","DOIUrl":"10.1016/j.petsci.2024.12.013","url":null,"abstract":"","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Page 4522"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.09.004
Qi-Qiang Ren , Li-Fei Li , Jin Wang , Rong-Tao Jiang , Meng-Ping Li , Jian-Wei Feng
This study aims to elucidate the dynamic evolution mechanism of the fracturing fracture system during the exploration and development of complex oil and gas reservoirs. By integrating methods of rock mechanical testing, logging calculation, and seismic inversion technology, we obtained the current in-situ stress characteristics of a single well and rock mechanical parameters. Simultaneously, significant controlling factors of rock mechanical properties were analyzed. Subsequently, by coupling hydraulic fracturing physical experiments with finite element numerical simulation, three different fracturing models were configured: single-cluster, double-cluster, and triple-cluster perforations. Combined with acoustic emission technology, the fracture initiation mode and evolution characteristics during the loading process were determined. The results indicate the following findings: (1) The extension direction and length of the fracture are significantly controlled by the direction of the maximum horizontal principal stress. (2) Areas with poor cementation and compactness exhibit complex fracture morphology, prone to generating network fractures. (3) The interlayer development of fracturing fractures is controlled by the strata occurrence. (4) Increasing the displacement of fracturing fluid enlarges the fracturing fracture length and height. This research provides theoretical support and effective guidance for hydraulic fracturing design in tight oil and gas reservoirs.
{"title":"Dynamic evolution mechanism of the fracturing fracture system—Enlightenments from hydraulic fracturing physical experiments and finite element numerical simulation","authors":"Qi-Qiang Ren , Li-Fei Li , Jin Wang , Rong-Tao Jiang , Meng-Ping Li , Jian-Wei Feng","doi":"10.1016/j.petsci.2024.09.004","DOIUrl":"10.1016/j.petsci.2024.09.004","url":null,"abstract":"<div><div>This study aims to elucidate the dynamic evolution mechanism of the fracturing fracture system during the exploration and development of complex oil and gas reservoirs. By integrating methods of rock mechanical testing, logging calculation, and seismic inversion technology, we obtained the current in-situ stress characteristics of a single well and rock mechanical parameters. Simultaneously, significant controlling factors of rock mechanical properties were analyzed. Subsequently, by coupling hydraulic fracturing physical experiments with finite element numerical simulation, three different fracturing models were configured: single-cluster, double-cluster, and triple-cluster perforations. Combined with acoustic emission technology, the fracture initiation mode and evolution characteristics during the loading process were determined. The results indicate the following findings: (1) The extension direction and length of the fracture are significantly controlled by the direction of the maximum horizontal principal stress. (2) Areas with poor cementation and compactness exhibit complex fracture morphology, prone to generating network fractures. (3) The interlayer development of fracturing fractures is controlled by the strata occurrence. (4) Increasing the displacement of fracturing fluid enlarges the fracturing fracture length and height. This research provides theoretical support and effective guidance for hydraulic fracturing design in tight oil and gas reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 3839-3866"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.11.014
Yurany Villada , Lady Johana Giraldo , Carlos Cardona , Diana Estenoz , Gustavo Rosero , Betiana Lerner , Maximiliano S. Pérez , Masoud Riazi , Camilo A. Franco , Farid B. Córtes
The conservation of rheological and filtration properties of drilling fluids is essential during drilling operations. However, high-pressure and high-temperature conditions may affect drilling fluid additives, leading to their degradation and reduced performance during operation. Hence, the main objective of this study is to formulate and evaluate a viscoelastic surfactant (VES) to design water-based drilling nanofluids (DNF). Silica nanomaterials are also incorporated into fluids to improve their main functional characteristics under harsh conditions. The investigation included: i) synthesis and characterization of VES through zeta potential, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and rheological behavior; ii) the effect of the presence of VES combined with silica nanoparticles on the rheological, filtration, thermal, and structural properties by steady and dynamic shear rheological, filter press, thermal aging assays, and SEM (SEM) assays, respectively; and iii) evaluation of filtration properties at the pore scale through a microfluidic approach. The rheological results showed that water-based muds (WBMs) in the presence of VES exhibited shear-thinning and viscoelastic behavior slightly higher than that of WBMs with xanthan gum (XGD). Furthermore, the filtration and thermal properties of the drilling fluid improved in the presence of VES and silica nanoparticles at 0.1 wt%. Compared to the WBMs based on XGD, the 30-min filtrate volume for DNF was reduced by 75%. Moreover, the Herschel-Bulkley model was employed to represent the rheological behavior of fluids with an R2 of approximately 0.99. According to SEM, laminar and spherical microstructures were observed for the WBMs based on VES and XGD, respectively. A uniform distribution of the nanoparticles was observed in the WBMs. The results obtained from microfluidic experiments indicated low dynamic filtration for fluids containing VES and silica nanoparticles. Specifically, the filtrate volume of fluids containing VES and VES with silica nanoparticles at 281 min was 0.35 and 0.04 mL, respectively. The differences in the rheological, filtration, thermal, and structural results were mainly associated with the morphological structure of VES or XGD and surface interactions with other WBMs additives.
{"title":"Synergistic effect of nanoparticles and viscoelastic surfactants to improve properties of drilling fluids","authors":"Yurany Villada , Lady Johana Giraldo , Carlos Cardona , Diana Estenoz , Gustavo Rosero , Betiana Lerner , Maximiliano S. Pérez , Masoud Riazi , Camilo A. Franco , Farid B. Córtes","doi":"10.1016/j.petsci.2024.11.014","DOIUrl":"10.1016/j.petsci.2024.11.014","url":null,"abstract":"<div><div>The conservation of rheological and filtration properties of drilling fluids is essential during drilling operations. However, high-pressure and high-temperature conditions may affect drilling fluid additives, leading to their degradation and reduced performance during operation. Hence, the main objective of this study is to formulate and evaluate a viscoelastic surfactant (VES) to design water-based drilling nanofluids (DNF). Silica nanomaterials are also incorporated into fluids to improve their main functional characteristics under harsh conditions. The investigation included: i) synthesis and characterization of VES through zeta potential, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and rheological behavior; ii) the effect of the presence of VES combined with silica nanoparticles on the rheological, filtration, thermal, and structural properties by steady and dynamic shear rheological, filter press, thermal aging assays, and SEM (SEM) assays, respectively; and iii) evaluation of filtration properties at the pore scale through a microfluidic approach. The rheological results showed that water-based muds (WBMs) in the presence of VES exhibited shear-thinning and viscoelastic behavior slightly higher than that of WBMs with xanthan gum (XGD). Furthermore, the filtration and thermal properties of the drilling fluid improved in the presence of VES and silica nanoparticles at 0.1 wt%. Compared to the WBMs based on XGD, the 30-min filtrate volume for DNF was reduced by 75%. Moreover, the Herschel-Bulkley model was employed to represent the rheological behavior of fluids with an <em>R</em><sup>2</sup> of approximately 0.99. According to SEM, laminar and spherical microstructures were observed for the WBMs based on VES and XGD, respectively. A uniform distribution of the nanoparticles was observed in the WBMs. The results obtained from microfluidic experiments indicated low dynamic filtration for fluids containing VES and silica nanoparticles. Specifically, the filtrate volume of fluids containing VES and VES with silica nanoparticles at 281 min was 0.35 and 0.04 mL, respectively. The differences in the rheological, filtration, thermal, and structural results were mainly associated with the morphological structure of VES or XGD and surface interactions with other WBMs additives.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 4391-4404"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.05.016
Yang Bai , Jian-Fa Chen , Wen-Zhe Gang , Xin-Jian Zhu , Václav Suchý , Shuai-Qi Tang , Jin Wu , Min Li , Sheng-Bao Shi
Nitrogen isotope compositions (δ15N) of sedimentary rocks are usually used to reconstruct the paleoenvironment and nitrogen (N) biogeochemical cycle. The δ15N values of crude oils inherit the characteristics of relevant source rocks and can well reflect the information of hydrocarbon-forming organisms and environment in ancient water column. However, studies on the δ15N of crude oils are limited due to the low N content. In this study, a new efficient method is applied to the marine oils from the Bashituo (BST) and Halahatang (HLHT) areas of the Tarim Basin to obtain the nitrogenous components (i.e., nonhydrocarbons and asphaltenes) for the achievement of N concentration. The carbon and nitrogen isotopes of these components and the biomarkers of oils were measured. The δ15N values in asphaltenes (δ15NAsp) are significantly heavier than those in nonhydrocarbons (δ15NNSOs) in these oils, which are attributed to the potential directional N transfer and kinetic isotope fractionation during the thermal evolution of organic matters (OM). The δ15NAsp values have significant correlations with OM origin associated parameters and weak correlations with environmental parameters, suggesting that the difference in δ15NAsp values is mainly resulted from biological source rather than redox conditions. The δ15NNSOs values have a closer relationship with the redox condition than biological characteristics, indicating that they have a good response to paleoenvironmental variation in the water column, which is not completely overprinted by the difference of OM origin. Different redox conditions give rise to distinct nitrogen cycles, resulting in various δ15N values. Anammox occurs in the water column of the Early Cambrian dominated by physically stratified conditions with significant isotope fractionation, resulting in relatively heavier δ15N of OM in the BST area. In the Middle–Late Ordovician period, the limited suboxic zone leads to an insignificant positive bias of δ15N caused by partial denitrification in the HLHT oils. The evaluation of δ15N in nitrogenous fractions enables a more comprehensive reconstruction of N cycle for ancient oceans.
{"title":"Nitrogen isotopes of marine oils in the Tarim Basin, China: Implications for the origin of organic matters and the paleoenvironment","authors":"Yang Bai , Jian-Fa Chen , Wen-Zhe Gang , Xin-Jian Zhu , Václav Suchý , Shuai-Qi Tang , Jin Wu , Min Li , Sheng-Bao Shi","doi":"10.1016/j.petsci.2024.05.016","DOIUrl":"10.1016/j.petsci.2024.05.016","url":null,"abstract":"<div><div>Nitrogen isotope compositions (δ<sup>15</sup>N) of sedimentary rocks are usually used to reconstruct the paleoenvironment and nitrogen (N) biogeochemical cycle. The δ<sup>15</sup>N values of crude oils inherit the characteristics of relevant source rocks and can well reflect the information of hydrocarbon-forming organisms and environment in ancient water column. However, studies on the δ<sup>15</sup>N of crude oils are limited due to the low N content. In this study, a new efficient method is applied to the marine oils from the Bashituo (BST) and Halahatang (HLHT) areas of the Tarim Basin to obtain the nitrogenous components (i.e., nonhydrocarbons and asphaltenes) for the achievement of N concentration. The carbon and nitrogen isotopes of these components and the biomarkers of oils were measured. The δ<sup>15</sup>N values in asphaltenes (δ<sup>15</sup>N<sub>Asp</sub>) are significantly heavier than those in nonhydrocarbons (δ<sup>15</sup>N<sub>NSOs</sub>) in these oils, which are attributed to the potential directional N transfer and kinetic isotope fractionation during the thermal evolution of organic matters (OM). The δ<sup>15</sup>N<sub>Asp</sub> values have significant correlations with OM origin associated parameters and weak correlations with environmental parameters, suggesting that the difference in δ<sup>15</sup>N<sub>Asp</sub> values is mainly resulted from biological source rather than redox conditions. The δ<sup>15</sup>N<sub>NSOs</sub> values have a closer relationship with the redox condition than biological characteristics, indicating that they have a good response to paleoenvironmental variation in the water column, which is not completely overprinted by the difference of OM origin. Different redox conditions give rise to distinct nitrogen cycles, resulting in various δ<sup>15</sup>N values. Anammox occurs in the water column of the Early Cambrian dominated by physically stratified conditions with significant isotope fractionation, resulting in relatively heavier δ<sup>15</sup>N of OM in the BST area. In the Middle–Late Ordovician period, the limited suboxic zone leads to an insignificant positive bias of δ<sup>15</sup>N caused by partial denitrification in the HLHT oils. The evaluation of δ<sup>15</sup>N in nitrogenous fractions enables a more comprehensive reconstruction of N cycle for ancient oceans.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 3692-3705"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141136318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.petsci.2024.05.002
Mahdi Saadat, Hosein Hashemi, Majid Nabi-Bidhendi
Traditionally, simplification has been used in scientific modeling practices. However, recent advancements in deep learning techniques have provided a means to represent complex models. As a result, deep neural networks should be able to approximate the complex models, with a high degree of generalization. To achieve generalization, it is necessary to have a diverse range of examples in the training of the neural network, for example in data-driven FWI, training data should cover the expected subsurface models. To meet this requirement, we porposed a method to create geologically meaningful velocity models with complex structures and severe topography. However, it is important to note that generalization comes with its own set of challenges.
Because of significant variation in topography of the generated velocity models, we need to include this information as an additional input data in training of the network. Therefore, we have transformed the seismic data to a fixed datum to incorporate geometric information. Additionally, we have enhanced the network's performance by introducing a term in the network loss function. Multiple metrics have been employed to evaluate the performance of the network. The results indicate that by providing the necessary information to the network and employing computational techniques to refine the model's accuracy, deep neural networks are capable of accurately estimating velocity models in complex environments characterized by extreme topography.
{"title":"Generalizable data driven full waveform inversion for complex structures and severe topographies","authors":"Mahdi Saadat, Hosein Hashemi, Majid Nabi-Bidhendi","doi":"10.1016/j.petsci.2024.05.002","DOIUrl":"10.1016/j.petsci.2024.05.002","url":null,"abstract":"<div><div>Traditionally, simplification has been used in scientific modeling practices. However, recent advancements in deep learning techniques have provided a means to represent complex models. As a result, deep neural networks should be able to approximate the complex models, with a high degree of generalization. To achieve generalization, it is necessary to have a diverse range of examples in the training of the neural network, for example in data-driven FWI, training data should cover the expected subsurface models. To meet this requirement, we porposed a method to create geologically meaningful velocity models with complex structures and severe topography. However, it is important to note that generalization comes with its own set of challenges.</div><div>Because of significant variation in topography of the generated velocity models, we need to include this information as an additional input data in training of the network. Therefore, we have transformed the seismic data to a fixed datum to incorporate geometric information. Additionally, we have enhanced the network's performance by introducing a term in the network loss function. Multiple metrics have been employed to evaluate the performance of the network. The results indicate that by providing the necessary information to the network and employing computational techniques to refine the model's accuracy, deep neural networks are capable of accurately estimating velocity models in complex environments characterized by extreme topography.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 6","pages":"Pages 4025-4033"},"PeriodicalIF":6.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141048116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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