SPE Journal最新文献

{"title":"Environmentally Friendly Rosin-Modified Silica Nanocomposite as High-Performance Plugging Agent for Drilling in Nano-Microporous Formations","authors":"Ming Lei, Jinsheng Sun, Weian Huang, Haiyan Zhu","doi":"10.2118/218407-pa","DOIUrl":"https://doi.org/10.2118/218407-pa","url":null,"abstract":"<p>The increasingly severe wellbore instability problem and the intensified environmental requirements necessitate the development of high-performance and environmentally friendly plugging materials for drilling fluid. In this work, a novel core-shell nanocomposite (PDSA) with nano-silica (nano-SiO₂) as the rigid core and hydrophobic resin derived from dehydroabietic acid (DHAA) of pine rosin and crosslinked hydrophilic layer of 2-acrylamido-2-methyl-1-propanesulfonic acid and <em>N</em>, <em>N</em>-dimethylacrylamide (DMA) as the polymer shell was synthesized through semi-continuous emulsion polymerization. The molecular structure of PDSA was confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectra analysis. Particle-size distribution and morphology measured by dynamic light scattering, scanning electron microscopy, and transmission electron microscopy revealed that PDSA was a monodisperse nanosphere with a particle size of around 98 nm, with a core-shell structure and possessed excellent long-term colloidal dispersion stability. The nano-microporous plugging performance of PDSA was evaluated using tight sandstone cores, shale cuttings, and filter membranes (200–400 nm) as plugging media. The results showed that PDSA could form effective aggregated plugging zones in nano-micropores and fractures in sandstone core and shale samples, lowering the core permeability by 78% and improving the shale recovery to above 80%, superior to conventional plugging agents of nano-polyester (NP) and sulfonated asphalt. PDSA also effectively minimized the nano-micropore fluid loss for filter membranes under high-temperature and high-pressure (HTHP) conditions. Furthermore, based on the response surface methodology (RSM) design, the established statistical significant prediction model for HTHP nano-microporous fluid loss indicated the main controlling factor of temperature and its interactive effects with PDSA dosage and membrane size. The high-temperature-induced deformation of PDSA in conjunction with the rigid core was conducive to enhancing and maintaining the HTHP plugging effect within 180°C. The plugging mechanism of PDSA was revealed to be the core-shell synergistic plugging effects of the interparticle bridging and gap filling of the rigid core and the adhesive film forming of the rosin resin shell. The study might provide a novel strategy for preparing high-performance and eco-friendly nano-plugging agents from natural rosin to maintain wellbore stability and relieve environmental pressure, especially for applications in the deep shale and tight formations associated with high-temperature and nano-microporous harsh conditions and the environmentally sensitive areas.</p>","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"2015 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140581200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interpretable Lost Circulation Analysis: Labeled, Identified, and Analyzed Lost Circulation in Drilling Operations","authors":"Yongcun Feng, Heng Yang, Xiaorong Li, Shuai Zhang, Han Hu, Jinshu Wang","doi":"10.2118/218380-pa","DOIUrl":"https://doi.org/10.2118/218380-pa","url":null,"abstract":"\u0000 Lost circulation (LC) is a serious problem in drilling operations, as it increases nonproductive time and costs. It can occur due to various complex factors, such as geological parameters, drilling fluid properties, and operational drilling parameters, either individually or in combination. Therefore, studying the types, influencing factors, and causes of LC is crucial for effectively improving prevention and plugging techniques. Currently, the expert diagnosis of LC types relies heavily on the experience and judgment of experts, which may lead to inconsistencies and biases. Additionally, difficulties in obtaining data or missing important data can affect the efficiency and timeliness of diagnosis. Traditional physical modeling methods struggle to analyze complex factor correlations, and conventional machine learning techniques have limited interpretability. In this paper, we propose an interpretable lost circulation analysis (ILCA) framework that provides a new method for analyzing LC. First, we use Gaussian mixture model (GMM) clustering to analyze the LC characteristics of regional case data, efficiently and accurately labeling 296 LC events. Second, we establish the relationship between geological features, drilling fluid properties, operational drilling parameters, and LC types using the XGBoost algorithm. This enables timely identification of LC types during drilling operations using real-time data, with a precision greater than 85%. Finally, we use interpretable machine learning techniques to conduct a comprehensive quantitative analysis of influencing factors based on the established XGBoost model, providing a clear explanation for the identification model. This enables drilling engineers to gain deeper insights into the factors influencing LC events. In summary, the proposed ILCA framework is capable of efficiently labeling LC types based on regional case data, identifying LC types in a timely manner using real-time data, and conducting quantitative analysis of the factors and causes of LC. This approach addresses the limitations of traditional methods and offers valuable insights for drilling engineers.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"14 19","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139457403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study of Seismic Wave Attenuation in Carbonate Rocks","authors":"F. Bouchaala, Mohammed Y. Ali, Jun Matsushima, Mohamed Soufiane Jouini, A. A. Mohamed, Syed Nizamudin","doi":"10.2118/218406-pa","DOIUrl":"https://doi.org/10.2118/218406-pa","url":null,"abstract":"\u0000 Seismic wave attenuation has a great potential for studying saturated and fractured media, due to its high sensitivity to the physical properties of geological media. However, accurately estimating this parameter can be challenging due to its sensitivity to signal noise, particularly in heterogeneous media such as carbonate rocks. This explains the paucity of attenuation studies carried out in carbonate rocks compared with sandstones, and the ambiguity around its mechanisms and its relationship with petrophysical properties. To investigate further, we conducted an experimental study of ultrasonic waveform signals (0.5–3 MHz) reordered under dry and fully saturation conditions in 13 samples covering a wide range of petrophysical values and subjected them to differential pressure reaching reservoir pressure. The resulting increase in attenuation magnitudes and their variation with pressure due to brine saturation were more pronounced than in velocity magnitudes, confirming the higher sensitivity of attenuation to fluid content. However, understanding the relationship between attenuation and petrophysical properties required a careful examination of the results and more elucidation about attenuation mechanisms. We suggested that multiple attenuation mechanisms coexist, including scattering, cracks slipping, solid frictional relative motion, and global and squirt flow. This explains the frequency dependence of attenuation, with higher magnitudes at sonic frequencies, where the squirt flow mechanism may be dominant. In contrast to sandstone, the magnitude of compressional to shear attenuation ratio (QP−1/QS−1) was found to be greater than unity in both dry and brine fully saturated carbonate samples at ultrasonic frequencies. This result may be due to the complex porosity structure of carbonate rocks, which makes it not appropriate to the sandstone rock physics models.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"12 12","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139457118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Design of Hydrogen Saline Aquifer Storage Processes Using a Machine-Learning Assisted Multiobjective Optimization Protocol","authors":"Qian Sun, Miao Zhang, Turgay Ertekin","doi":"10.2118/218405-pa","DOIUrl":"https://doi.org/10.2118/218405-pa","url":null,"abstract":"\u0000 The global effort toward decarbonization has intensified the drive for low-carbon fuels. Green hydrogen, harnessed from renewable sources such as solar, wind, and hydropower, is emerging as a clean substitute. Challenges due to the variable needs and instable green hydrogen production highlight the necessity for secure and large-scale storage solutions. Among the geological formations, deep saline aquifers are noteworthy due to their abundant capacity and ease of access. Addressing technical hurdles related to low working gas recovery rates and excessive water production requires well-designed structures and optimized cushion gas volume. A notable contribution of this study is the development of a multiobjective optimization (MOO) protocol using a Kalman filter-based approach for early stopping. This method maintains solution accuracy while employing the MOO protocol to design the horizontal wellbore length and cushion gas volume in an aquifer hydrogen storage project and accounting for multiple techno-economic goals. Optimization outcomes indicate that the proposed multiobjective particle swarm (MOPSO) protocol effectively identifies the Pareto optimal sets (POSs) in both two- and three-objective scenarios, requiring fewer iterations. Results from the two-objective optimization study, considering working gas recovery efficacy and project cost, highlight that extending the horizontal wellbore improves hydrogen productivity but may lead to unexpected fluid extraction. The three-objective optimized hydrogen storage design achieves a remarkable 94.36% working gas recovery efficacy and a 59.59% reduction in water extraction. The latter represents a significant improvement compared to the reported literature data.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"22 5","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139455237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Investigation of Solids Production Mechanisms in a Hydraulic Screen-Through Fracturing Well in a Loose Reservoir and Its Control","authors":"Saifula Dilimulati, Changyin Dong, Xinjie Zhan, Jingwei Li, Guoliang Cui, Quangang Liu, Haobin Bai","doi":"10.2118/218414-pa","DOIUrl":"https://doi.org/10.2118/218414-pa","url":null,"abstract":"\u0000 Successful cases of hydraulic screen-through fracturing (HSTF) in the Bohai oil field highlight the possibility that hydraulic fracturing can be an alternative method for enhancing the productivity of loose reservoirs. However, a portion of the HSTF wells in the Bohai oil field suffer from severe solids production, meaning that proppants and stratum sands are produced in the wellbore during production and cause wellbore plugging and ensuing debilitation of productivity. In this study, fluid flow amid the stratum, fracture, and HSTF well is simulated experimentally, and pressure drop, flow rate of the fracture, and stratum are monitored to investigate mechanisms and influencing factors of solids production from HSTF wells. Perspectives on solids control optimization are put forward for the Bohai oil field. Results indicate that the formation of an erosion cavity on lip-sealing in fracture and a dominant fluid channel near the wellbore in the stratum are two main mechanisms of solids production. The higher the flow rate and fluid viscosity are, the more severe solids production can be. For the Bohai oil field, with 725-psi-strength resin-coated proppant, the minimum proportion of resin-coated proppant in fractures to prevent solids production can be reduced from the previous 65% to 30%. With 1,073-psi-strength resin-coated proppant, it can be further reduced to 20%. Reducing the proportion of resin-coated proppant can help optimize the conductivity of fractures. This study aims to provide preliminary insight on solving the solids production problem of an HSTF well, thus enhancing the applicability of hydraulic stimulation in loose reservoirs.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"121 49","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Physics-Informed Neural Networks for Estimation of Saturation Functions from Countercurrent Spontaneous Imbibition Tests","authors":"J. Abbasi, P. Andersen","doi":"10.2118/218402-pa","DOIUrl":"https://doi.org/10.2118/218402-pa","url":null,"abstract":"\u0000 In this work, physics-informed neural networks (PINNs) are used for history matching data from core-scale countercurrent spontaneous imbibition (COUCSI) tests. To our knowledge, this is the first work exploring the variation in saturation function solutions from COUCSI tests. 1D flow was considered, in which two phases flow in opposite directions driven by capillary forces with one boundary open to flow.\u0000 The partial differential equation (PDE) depends only on a saturation-dependent capillary diffusion coefficient (CDC). Static properties such as porosity, permeability, interfacial tension, and fluid viscosities are considered known. In contrast, the CDC or its components [relative permeability (RP) and capillary pressure (PC)], are considered unknown. We investigate the range of functions (CDCs or RP/PC combinations) that explain different (synthetic or real) experimental COUCSI data: recovery from varying extents of early-time and late-time periods, pressure transducers, and in-situ saturation profiles.\u0000 History matching was performed by training a PINN to minimize a loss function based on observational data and terms related to the PDE, boundary, and initial conditions. The PINN model was generated with feedforward neural networks, Fourier/inverse-Fourier transformation, and an adaptive tanh activation function, and trained using full batching. The trainable parameters of both the neural networks and saturation functions (parameters in RP and PC correlations) were initialized randomly.\u0000 The PINN method successfully matched the observed data and returned a range of possible saturation function solutions. When a full observed recovery curve was provided (recovery data reaching close to its final value), unique and correct CDC functions and correct spatial saturation profiles were obtained. However, different RP/PC combinations composing the CDC were calculated. For limited amounts of recovery data, different CDCs matched the observations equally well but predicted different recovery behavior beyond the collected data period. With limited recovery data, when all points were still following a square root of time trend, a CDC with a low magnitude and peak shifted to high saturations gave the same match as a CDC with a high magnitude and peak shifted to low saturations. Recovery data with sufficient points not being proportional to the square root of time strongly constrained how future recovery would behave and thus which CDCs could explain the results. Limited recovery data combined with an observed in-situ profile of saturations allowed for accurate determination of CDC and prediction of future recovery, suggesting in-situ data allowed for shortened experiments. With full recovery data, in-situ PC data calibrated the PC toward unique solutions matching the input. The RPs were determined, where their phase had much lower mobility than the others. The CDC is virtually independent of the highest fluid mobility, and RPs could not be matched at thei","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"2 5","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139457019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study on Permeability and Gas Production Characteristics of Montmorillonite Hydrate Sediments Considering the Effective Stress and Gas Slippage Effect","authors":"Zhaoran Wu, Qing Gu, Lei Wang, Guijing Li, Cheng Shi, Yufa He, Qingping Li, Yanghui Li","doi":"10.2118/218385-pa","DOIUrl":"https://doi.org/10.2118/218385-pa","url":null,"abstract":"\u0000 Gas permeability in hydrate reservoirs is the decisive parameter in determining the gas production efficiency and gas production of hydrate. In the South China Sea (SCS), the gas flow in tight natural gas hydrate (NGH) silty clay reservoirs is significantly affected by the gas slippage effect and the effective stress (ES) of overlying rock. To improve the effectiveness of hydrate exploitation, it is necessary to understand the influence of gas slippage in hydrate reservoirs on the permeability evolution law. For this paper, the gas permeability characteristics and methane production of hydrate montmorillonite sediments were studied at different pore pressures and ESs. Experimental data revealed that the gas permeability of montmorillonite samples before methane hydrate (MH) formation is seriously affected by the Klinkenberg effect. The gas permeability of montmorillonite sediments before hydrate formation is generally smaller than that after hydrate formation, and the gas slippage effect in the sediments after hydrate formation is weaker than that before hydrate formation. With the change in ES, the intrinsic permeability of sediment has a power law relationship with the simple ES. The ES law coefficient n was determined using the response surface method to eliminate the influence of gas slip on gas permeability. As pore pressure decreases and MH decomposes, montmorillonite swelling seriously affects gas permeability. However, the gas slippage effect has a good compensation effect on the permeability of montmorillonite sediments after MH decomposition under low pore pressure. The multistage depressurization-producing process of MH in montmorillonite sediments is mainly 3 MPa depressurization-producing stage and 2 MPa depressurization-producing stage. In this paper, the influence mechanism of gas slippage effect of hydrate reservoir is studied, which is conducive to improving the prediction accuracy of gas content in the process of hydrate exploitation and exploring the best pressure reduction method to increase the gas production of hydrate in the process of exploitation.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"80 10","pages":""},"PeriodicalIF":3.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139458262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feature Extraction in Time-Lapse Seismic Using Deep Learning for Data Assimilation","authors":"Rodrigo Exterkoetter, Gustavo R. Dutra, Leandro P. de Figueiredo, Fernando Bordignon, Gilson M. S. Neto, Alexandre A. Emerick","doi":"10.2118/212196-pa","DOIUrl":"https://doi.org/10.2118/212196-pa","url":null,"abstract":"<p>Assimilation of time-lapse (4D) seismic data with ensemble-based methods is challenging because of the massive number of data points. This situation requires excessive computational time and memory usage during the model updating step. We addressed this problem using a deep convolutional autoencoder to extract the relevant features of 4D images and generate a reduced representation of the data. The architecture of the autoencoder is based on the VGG-19 network, a deep convolutional architecture with 19 layers well-known for its effectiveness in image classification and object recognition. Some advantages of VGG-19 are the possibility of using some pretrained convolutional layers to create a feature extractor and taking advantage of the transfer learning technique to address other related problem domains. Using a pretrained model bypasses the need for large training data sets and avoids the high computational demand to train a deep network. For further improvements in the reconstruction of the seismic images, we apply a fine-tuning of the weights of the latent convolutional layer. We propose to use a fully convolutional architecture, which allows the application of distance-based localization during data assimilation with the ensemble smoother with multiple data assimilation (ES-MDA). The performance of the proposed method is investigated in a synthetic benchmark problem with realistic settings. We evaluate the methodology with three variants of the autoencoder, each one with a different level of data reduction. The experiments indicate that it is possible to use latent representations with major data reductions without impairing the quality of the data assimilation. Additionally, we compare central processing unit (CPU) and graphics processing unit (GPU) implementations of the ES-MDA update step and show in another synthetic problem that the reduction in the number of data points obtained with the application of the deep autoencoder may provide a substantial improvement in the overall computation cost of the data assimilation for large reservoir models.</p>","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"35 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140581288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Flow Units and Capillary Pressures of the Giant Chicontepec Tight Oil Paleochannel in Mexico and a Fresh Look at Drilling and Completions","authors":"Alejandra Gutierrez Oseguera, Roberto Aguilera","doi":"10.2118/212745-pa","DOIUrl":"https://doi.org/10.2118/212745-pa","url":null,"abstract":"&lt;p&gt;The Chicontepec Paleochannel in Mexico is a giant shaly sandstone reservoir with volumes of original oil in place (OOIP) ranging between 137 and 59 billion STB (Guzmán 2022). However, the oil recoveries are very small, ranging between 0.32% and 0.75% of the OOIP. Under these conditions, consistent interpretation of flow units and mercury injection capillary pressures up to 55,000 psi provide useful information that helps in deciphering the rock quality and pore sizes at levels that might not be reached by thin-section petrography. This is important because the Chicontepec Paleochannel (Misantla-Tampico Basin) has been recently equated to the Permian Basin in the United States and has been termed by Guzman (2022) “a premier super basin in waiting.”&lt;/p&gt;&lt;p&gt;The current cumulative oil production of Chicontepec is 440 million STB. Although it is a significant volume, it represents a very small percentage of recovery from the reservoir (0.32–0.75% of the OOIP). To help improve recovery, a method is developed for characterizing the tight Chicontepec Paleochannel using flow units and capillary pressures. Like in the case of many tight unconventional reservoirs, the capillary pressures can go to very high values, reaching 55,000 psi in the Chicontepec case. Therefore, a special procedure is developed to generate a consistent interpretation of all the available capillary pressure curves for the entire range of pressures.&lt;/p&gt;&lt;p&gt;The results highlight the important oil recovery potential. The assessment is supported by quantitative formation evaluation work performed by Gutierrez Oseguera and Aguilera (2023). Although natural fractures are present, most wells must be hydraulically fractured to achieve commercial success.&lt;/p&gt;&lt;p&gt;Process or delivery speed (the ratio of permeability and porosity) for the Chicontepec samples used in the capillary pressure experimental work range between 159.1 md and 0.17 md (porosity in the denominator is a fraction). Flow units show pore throat radii (&lt;em&gt;r&lt;sub&gt;p&lt;/sub&gt;&lt;/em&gt;&lt;sub&gt;35&lt;/sub&gt;) range from less than 0.1 µm to about 4.5 µm. These values and flow units compare well with data available for prolific unconventional reservoirs such as the Cardium sandstone in Canada and the giant Permian Basin in the United States. The radius &lt;em&gt;r&lt;sub&gt;p&lt;/sub&gt;&lt;/em&gt;&lt;sub&gt;35&lt;/sub&gt; refers to the pore throat radius at 35% cumulative pore volume (PV) of injected mercury. This is different from &lt;em&gt;r&lt;sub&gt;p&lt;/sub&gt;&lt;/em&gt; also discussed in this paper, which is the pore throat radius at any water saturation (for example, at 40% water saturation). Thus, in the case where water saturation is 65%, &lt;em&gt;r&lt;sub&gt;p&lt;/sub&gt;&lt;/em&gt; is equal to &lt;em&gt;r&lt;sub&gt;p&lt;/sub&gt;&lt;/em&gt;&lt;sub&gt;35&lt;/sub&gt;.&lt;/p&gt;&lt;p&gt;The novelty of this study is the development of a consistent procedure for interpreting the entire range of pressures measured during mercury injection capillary pressures. Such pressures go up to 55,000 psi for the core samples considered in this study. The integration with flow units a","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"159 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140581206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bi-Objective Optimization of Subsurface CO2 Storage with Nonlinear Constraints Using Sequential Quadratic Programming with Stochastic Gradients","authors":"Quang Minh Nguyen, Mustafa Onur, Faruk Omer Alpak","doi":"10.2118/214363-pa","DOIUrl":"https://doi.org/10.2118/214363-pa","url":null,"abstract":"<p>This study focuses on carbon capture, utilization, and sequestration (CCUS) via the means of nonlinearly constrained production optimization workflow for a CO₂-enhanced oil recovery (EOR) process, in which both the net present value (NPV) and the net present carbon tax credits (NPCTC) are bi-objectively maximized, with the emphasis on the consideration of injection bottomhole pressure (IBHP) constraints on the injectors, in addition to field liquid production rate (FLPR) and field water production rate (FWPR), to ensure the integrity of the formation and to prevent any potential damage during the life cycle injection/production process. The main optimization framework used in this work is a lexicographic method based on the line-search sequential quadratic programming (LS-SQP) coupled with stochastic simplex approximate gradients (StoSAG). We demonstrate the performance of the optimization algorithm and results in a field-scale realistic problem, simulated using a commercial compositional reservoir simulator. Results show that the workflow can solve the single-objective and bi-objective optimization problems computationally efficiently and effectively, especially in handling and honoring nonlinear state constraints imposed onto the problem. Various numerical settings have been experimented with to estimate the Pareto front for the bi-objective optimization problem, showing the trade-off between the two objectives of NPV and NPCTC. We also perform a single-objective optimization on the total life cycle cash flow, which is the aggregated quantity of NPV and NPCTC, and quantify the results to further emphasize the necessity of performing bi-objective production optimization, especially when used in conjunction with commercial flow simulators that lack the capability of computing adjoint-based gradients.</p>","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"47 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140581285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}