SPE Journal最新文献

{"title":"Experimental and Simulation Investigation on Ball-Sealer Transport and Diversion Performance Aided by Machine Learning Method","authors":"Hai Qu, Ying Liu, Chengying Li, Zhijun Zeng, Xu Liu, Zhelun Li","doi":"10.2118/218010-pa","DOIUrl":"https://doi.org/10.2118/218010-pa","url":null,"abstract":"Summary Ball-sealer diversion has been proven to be an effective and economical way to increase fractures and fracturing volume in multistage hydraulic fracturing and matrix acidizing treatments. However, designing and implementing a successful ball-sealer diversion treatment is still challenging. Typically, operators rely on empirical data to determine diversion parameters and need an understanding of accurate ball transport and diversion behaviors. A model for optimizing operating parameters, including fluid and ball properties, and predicting the diversion performance of ball sealers before treatment is needed for designing the fracturing process. In this work, we systematically investigated ball-sealer diversion using experimental and numerical methods. The resolved model of computational fluid dynamics (CFD) and discrete element method (DEM) is first developed to simulate the transport of a large ball in a horizontal wellbore with side holes. The experimental results validated the numerical model. The effects of the ball position in the pipe, flow ratio of the hole to pipe, injection flow rate, and ball density on the diversion performance were studied under field parameters. The results show that the ball sealer easily misses the heel-side perforation due to the inertial effect and travels to the toe side due to the large inertia and turbulent flow. The ball position and flow rate ratio are crucial for the diversion performance. There is a threshold value of the ball position under the specific condition, and the ball successfully turns to the perforation only when the threshold distance is met. A ball sealer closer to the perforation will have a larger probability of blocking the hole than the ball at the other side of the wellbore. The larger the flow rate ratio, the more the drag force on the ball, and the ball can successfully divert to the perforation despite the ball being far from the hole. The injection flow rate and ball density negatively correlate with the diversion performance due to the large inertia and gravity. The best classification result with the F1 score of 87.0% in the prediction set was achieved using the random forest (RF) algorithm. It provides new insight into developing ball sealers and adjusting fracturing parameters based on machine learning (ML) methods.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"8 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371877","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":"Fabrication and Release Mechanism Study of a Nanocapsule Breaker for Controlling Degradation Rate of Insoluble Residue in Slickwater at Moderate-Temperature Reservoirs","authors":"Jingyang Pu, Ming-liang Luo, Kai Wang, Xu Li, Jin-bo Wu, Na Zhang, Yang Zhao, Mingjing Lu","doi":"10.2118/217981-pa","DOIUrl":"https://doi.org/10.2118/217981-pa","url":null,"abstract":"Summary In an ideal hydraulic fracturing project, the viscosity of hydraulic fracturing fluid (HFF) should drop to facilitate an efficient and quick fracture cleanup once proppants have been placed. Ammonium persulfate (APS) is widely used as an oxidizer breaker to degrade the insoluble residue of the HFF. However, a complex network of artificial fractures with sizes ranging from millimeters to micrometers restricts the transportation application and reaction time of standard breakers and current millimeter-sized capsule breakers. In this study, we introduce an APS nanocapsule (APS-NC) breaker, fabricated via a simple miniemulsion technique, that is capable of addressing the degradation of insoluble residue of the HFF in deep fractures. The nanocapsules are produced through precise control of the nanoprecipitation of poly(methyl methacrylate) (PMMA) onto aqueous APS nanodroplets. Stable aqueous nanodroplets are generated by means of an inverse miniemulsion using Pluronic P-123 as a specific surfactant to form a large and stable water-oil internal surface referring to the long chain and amphipathic property of Pluronic P-123 molecule. Pluronic P-123 is included in the process not only to stabilize the miniemulsion and increase the precipitation efficiency of PMMA but also to function as a thermo-responsive switch for the delayed burst release of APS. The size of the resulting nanocapsules can be controlled within the 207 and 821 nm range, yielding APS up to 92%. The release rate of APS can be controlled by the initial amount of PMMA (150–300 mg), environmental temperature (40–80°C), and environmental pH (3.4–7). When the temperature was 80℃, the initial amount of Pluronic P-123 dominated the release dynamic of APS. Compared with the APS breaker in a dynamic degradation experiment, the APS-NC had a more controllable degradation profile that could cause hydrolyzed polyacrylamide (HPAM) to burst degrade after 6 hours of heating at 80°C.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134937296","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":"Development and Optimization of a High-Frequency Axial-Torsional Composite Percussion Drilling Tool for Enhanced Impact Technology","authors":"Haili Yang, Yinglin Yang, YueXiang Huang, Hengjing Zhang, Liangliang Xie","doi":"10.2118/218006-pa","DOIUrl":"https://doi.org/10.2118/218006-pa","url":null,"abstract":"Summary A high-frequency axial-torsional composite percussion drilling tool is designed to enhance the drilling efficiency by delivering high-frequency axial and torsional impact loads directly to the drill bit. The impact performance and influencing factors of the tool are analyzed via the large eddy simulation method, and a scaled-down experiment on the pulse nozzle structure is conducted. The analysis reveals that after design optimization, the tool achieves high-frequency axial and torsional impacts of 421 and 284 Hz, respectively, at an inlet flow rate of 30 kg/s. Additionally, the unilateral amplitudes of the axial and torsional impact loads reach 1511 N and 19.3 N·m, respectively, with a pressure drop of 2.998 MPa. Furthermore, the similarity degree between the parameters derived from the experiment and numerical analysis is close to or exceeds 70%, demonstrating the reliability and precision of the numerical analysis results. Overall, this study sets a baseline for high-frequency impact technology, paving the way for further advancements in drilling efficiency.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136153898","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":"Solution Gas/Oil Ratio Prediction from Pressure/Volume/Temperature Data Using Machine Learning Algorithms","authors":"Asia Majid, Grant Charles Mwakipunda, Chaohua Guo","doi":"10.2118/217979-pa","DOIUrl":"https://doi.org/10.2118/217979-pa","url":null,"abstract":"Summary Many methods have been developed to determine the solution gas/oil ratio (Rs), starting with experiments, followed by empirical correlations establishments, and recently with machine learning applications receiving much interest due to their ability to produce precise results compared with empirical correlations. In this paper, the group method of data handling (GMDH) and the enhanced GMDH based on discrete differential evolution (GMDH-DDE) are used for the first time to estimate the Rs and to provide a correlation to the laboratory measured Rs from bubblepoint pressure (Pb), oil API gravity (API), gas-specific gravity (γg), and reservoir temperature (T) without crude oil properties. These two methods are compared with backpropagation neural networks (BPNN). The reason for using the hybrid GMDH (GMDH-DDE) is to overcome the drawbacks of the GMDH, such as the method used to calculate neuron weights (i.e., quadratic polynomial transfer function), which seems to have inaccuracies. Also, in selecting model inputs, the GMDH tends to choose the most appropriate inputs for the model; however, the selection criteria are not straightforward and may affect the final results. Furthermore, the GMDH has a multicollinearity problem, affecting model coefficient stability and overfitting problems, etc. A total of 420 data sets from the Mpyo oil field were used, with 70% used for training and 30% used for testing. According to the findings, the GMDH-DDE outperformed both the GMDH and BPNN. In comparison with the GMDH and BPNN, the GMDH-DDE has a higher correlation coefficient (R), lower root-mean-square error (RMSE), and lower mean absolute error (MAE). During training, R, RMSE, and MAE were 0.9849, 0.090, and 0.010, respectively, and during testing, R = 0.9603, RMSE = 0.290, and MAE = 0.017. The second-best technique (GMDH) produces R, RMSE, and MAE values of 0.9611, 0.122, and 0.032 in training, and R = 0.9438, RMSE = 0.349, and MAE = 0.055 in testing. Furthermore, the GMDH-DDE used less computational time (1.32 seconds) compared with the GMDH (2.01 seconds) and BPNN (4.96 seconds), proving that the GMDH-DDE has accurate and fast convergence compared with the GMDH and BPNN. These findings show that the GMDH-DDE and GMDH can be adopted as alternative methods for predicting the Rs.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135762424","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":"Effect of Polishing on Cutting Efficiency and Mechanical Properties of PDC Cutters","authors":"Jiusen Wei, Wei Liu, Deli Gao, Dameng Guo","doi":"10.2118/217997-pa","DOIUrl":"https://doi.org/10.2118/217997-pa","url":null,"abstract":"Summary Polycrystalline diamond compact (PDC) bits equipped with polished cutters have shown improvements in drilling performance compared to the bits using nonpolished cutters. Despite the positive feedback from numerous global field runs, the merits of polished cutters are still not fully studied and not taken seriously, for example, by the bit manufacturers and drilling engineers in China. In this work, the effect of polishing on the rock-cutting efficiency and mechanical properties of PDC cutters was comprehensively analyzed through laboratory tests and field trials. The underlying mechanism was also investigated through theoretical modeling and experimental results. A rock-cutting force model of a single PDC cutter was developed to elucidate the effect of polishing on the rock-cutter interaction considering the friction between the cutter surface and rock cuttings. The results revealed that the polished cutter has better rock-cutting efficiency because the polishing reduces the friction on the cutter surface. This reduction in friction facilitates the evacuation of rock cuttings from the crushing zone and plastic flow zone, leading to lower mechanical specific energy (MSE) compared to the nonpolished diamond surface. Moreover, the polished cutters exhibit improved thermal stability and better impact fatigue resistance while maintaining comparable wear and impact resistance to nonpolished cutters. To further validate the findings, two field trials were conducted in Sinopec Shengli Oilfield. The first field trial using four PDC bits with polished cutters and one bit with nonpolished cutters found that the bits with polished cutters obtained a higher rate of penetration (ROP) in drilling hard and plastic mudstone, which agreed well with the theoretical and experimental results. In the second field trial, it was noted that the polished cutters presented comparable mechanical properties to nonpolished cutters, which was also consistent with experimental results. However, the advantages of polished cutters in thermal stability and impact fatigue resistance were not distinguished in the field trials. This work elucidated the beneficial effect of polishing in enhancing the drilling efficiency of PDC cutters and, more meaningfully, without sacrificing the mechanical properties of PDC cutters, which provided solid evidence to convince bit manufacturers and drilling engineers for the broader adoption of polished cutters.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"153 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135810748","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":"Prediction of the Maximum Horizontal Principal Stress from Breakout Data Using Generative Adversarial Networks and Backpropagation Neural Network","authors":"Bisheng Wu, Haoze Zhang, Shengshen Wu, Yuanxun Nie, Xi Zhang, Robert G. Jeffrey","doi":"10.2118/217970-pa","DOIUrl":"https://doi.org/10.2118/217970-pa","url":null,"abstract":"Summary A good understanding of the magnitude and direction of in-situ stresses is very important for oil and gas exploration. The conventional wellbore breakout method directly uses information about rock strength and wellbore shape (i.e., depth and width of breakout) to predict the in-situ stresses, but it is difficult to accurately describe the relationship between the breakout shape and the in-situ stresses. This paper presents a deep learning model, combining the generative adversarial networks (GAN) and backpropagation neural network (BPNN) to predict the maximum horizontal principal stress (MHPS) from breakout data. First, a GAN is used to effectively improve the quantity and quality of training data by generating a certain number of new training data that approximate the original data. Second, the training data enhanced by the GAN are used to train the BPNN, which predicts the MHPS based on wellbore breakout geometries. The two independent modules, the GAN and BPNN, use the training data to train themselves, respectively. This dual deep learning pattern ensures that the potential relationship between the in-situ stresses and wellbore breakout shape can be found. To examine the reliability of this technique, 86 sets of laboratory data from published literature are used to train the model, and 19 sets of laboratory data from other published literature are used to test the prediction performance of the trained model. The results show that the proposed model has good accuracy with an average relative error of 4.76% when predicting the MHPS. In addition, this deep learning model combining the GAN and BPNN requires only a few seconds to run on a laptop computer, thus providing an effective and efficient tool for predicting the MHPS.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135567686","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":"Pore-Scale Characterization of CO2 Trapping and Oil Displacement in Three-Phase Flow in a Heterogeneous Layered Sandstone","authors":"Yingwen Li, Yongfei Yang, Mingzhe Dong, Gloire Imani, Jun Yao, Kai Zhang, Hai Sun, Junjie Zhong, Lei Zhang","doi":"10.2118/217996-pa","DOIUrl":"https://doi.org/10.2118/217996-pa","url":null,"abstract":"Summary Permeability variation in the vertical direction, a typical sandstone reservoir heterogeneity, can trap a large amount of oil in the low-permeability layer. We performed water-alternating-gas (WAG) injection and CO2 foam flooding on a specially constructed millimeter-sized layered sandstone and investigated fluid distribution using high-resolution X-ray microtomography. Based on the segmented images, CO2 capillary-trapping capacity, oil recovery, Euler number, shaper factor, capillary pressure, and fluid flow conductivity were calculated. Our results show that increasing the number of WAG cycles favored CO2 capillary trapping, and oil recovery was enhanced by the WAG strategy. However, there was still a significant amount of oil trapped in the low-permeability layer. After the WAG injection, the connectivity of the residual oil clusters decreased, the capillary pressure of the oil clusters increased, and oil flow conductivity decreased. This was not conducive to further oil recovery. The subsequent injection of CO2 foam effectively recovered the oil in the low-permeability layer. During the no-injection period, we observed a crossflow phenomenon caused by gravity segregation (the high-permeability layer was located below the low-permeability layer), i.e., oil in the low-permeability layer decreased while oil in the high-permeability layer increased, which is beneficial for subsequent oil production. Furthermore, CO2 moved upward driven by gravity, and although capillary barriers could prevent CO2 from escaping, subsequent water injection was essential to improve the stability of CO2 capillary trapping. This work accurately quantifies the distribution of oil and gas in high- and low-permeability layers, thus providing fundamental data for oil recovery and CO2 trapping in reservoirs with vertical heterogeneity. Although the sample used in the experiment was not natural reservoir rock, our results imply that when the permeability ratio between the two layers is greater than 2, sufficient attention must be paid to the fluid distribution differences caused by this layered heterogeneity. Different displacement strategies, such as WAG and CO2 foam flooding, or gravity differences between oil and gas can be used to enhance oil recovery.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135811826","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":"A Pore-to-Process Digital Design Methodology to Evaluate Efficiency of Geothermal Power Plants","authors":"Arash Behrang, Hicham Abbas, Chris Istchenko, Angela Solano","doi":"10.2118/217976-pa","DOIUrl":"https://doi.org/10.2118/217976-pa","url":null,"abstract":"Summary The development and operation of geothermal plants play a crucial role in the transition to sustainable and low-carbon energy systems. In this paper, we have presented a seamless and flexible pore-to-process digital solution for the design and assessment of geothermal systems, encompassing the geothermal reservoir, gathering network, and geothermal power plant. Our primary focus in this study centers on the geothermal power plant with a detailed analysis of the functionality and performance of two commonly used configurations—a single-flash power plant and a double-flash geothermal power plant. Our work highlights that overall exergy efficiency of the studied geothermal power plants declines over time, primarily due to a decrease in the quality of the geothermal reservoir. Additionally, our analysis demonstrated that variations in the inlet separator pressure have a notable impact on the overall behavior of the power plant. Parametric studies also reveal that increasing the inlet separator pressure leads to decreased overall exergy efficiency and turbine power, resulting from less efficient conversion of available exergy into useful work. Our studies showed that a substantial portion of the available exergy in the geothermal fluid is being dissipated in the condenser. Consequently, optimizing the design and operation of the condenser emerges as a crucial factor in enhancing the overall efficiency of geothermal power plants.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134979056","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 Dynamic Barite Sag and Effects of Inclination and Pipe Rotation","authors":"Muili F. Fakoya, Ramadan Ahmed","doi":"10.2118/217987-pa","DOIUrl":"https://doi.org/10.2118/217987-pa","url":null,"abstract":"Summary Barite sag causes pressure fluctuations in the wellbore, which is undesirable. These problems usually occur with oil-based muds (OBMs; invert emulsion muds) and are associated with fluid properties and operation parameters. Drilling issues related to this undesirable phenomenon include wellbore instability, lost circulation, and stuck pipes. As barite sagging is a complex phenomenon, the mechanisms that cause and aggravate it still need to be fully understood to mitigate these problems. This study examines barite sagging in the wellbore with inner pipe rotation to understand the process and develop prevention strategies. Thus, a flow loop study with OBM is conducted in a concentric annular test section with varying inner pipe rotation and inclination angles. The tests were performed at an elevated temperature (49°C) to simulate borehole conditions. By measuring the pressure profile in a mud sample trapped in the test section, barite sagging was evaluated. Using the data, we calculated the density difference between the top and bottom sections of the column. The novelty of the work lies in continuous monitoring of the density profile of the mud column, which is sheared between two coaxial cylinders to simulate drillstring rotation in the wellbore, and utilizing the data for evaluating barite sag. The results show the evolution of the pressure profile with time, indicating the sagging of barite particles at the bottom of the test section. Due to barite sagging, the density of the top portion of the mud column decreased over time, while the density of the bottom part increased. The lateral sedimentation of barite particles toward the annulus outer wall enhances barite sag in inclined configurations. The sedimentation creates two suspension layers with different densities, leading to secondary flow, which enhances sagging. Hence, the primary factor driving barite sagging is inclination. An increase in inclination angle from 0° to 50° resulted in a significant (more than twofold) increase in mud density difference. Also, the rotation of the pipe delayed sagging during the early phases of the testing process (less than 20 minutes). However, it did not have much effect as the sagging progressed, resulting in approximately the same density difference in both cases (i.e., with and without rotation).","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135762252","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":"Mechanism Analysis and Mathematical Modeling of Brittle Failure in Rock Cutting with a Single Sharp Cylinder-Shaped PDC Cutter","authors":"Jiusen Wei, Wei Liu, Deli Gao","doi":"10.2118/217988-pa","DOIUrl":"https://doi.org/10.2118/217988-pa","url":null,"abstract":"Summary The drilling efficiency of a polycrystalline diamond compact (PDC) bit plays a vital role in oil and gas exploration, which is greatly affected by the rock-cutting performance of a single PDC cutter. Although many research efforts have been put in, the rock-cutting mechanism of a single PDC cutter is still indistinct. In this work, the rock-cutting process of a single sharp cylinder-shaped PDC cutter was captured using a high-speed camera. The brittle failure mode mechanism in the rock cutting of the PDC cutter was thus revealed by this real-time observation combined with the findings in previous publications. The brittle rock-cutting failure zones in front of the cutter were separated into three different zones: crushing zone, plastic flow zone, and rock chipping zone. The crushing zone grew while the cutter cut forward and generated a plastic flow zone. When the crushing zone was large enough, a tensile crack would tear apart the rock, forming the rock chip. Based on this rock-cutting mechanism, a new mathematical model of brittle failure in rock cutting of PDC cutter was developed, considering the rock properties and cutting parameters. The boundary geometry of the crushing zone was calculated using elastoplastic theory and the Mohr-Coulomb criterion. All forces on the boundaries of these three failure zones were calculated and combined into the tangential and normal forces in the 3D mathematical model. Furthermore, a new parameter, named as crescent area, was proposed in the mathematical model. When compared to previous publications, the newly developed mathematical model had no variables that needed to be calibrated with experimental data fitting. Moreover, a series of single PDC cutter cutting tests were carried out at various depths of cut (DOCs) and backrake angles to validate the mathematical model. The results showed that the model-predicted forces basically matched the experimental data. The modeling and experimental results shared the same trend for both tangential and normal cutting forces. The experimental phenomena could be well explained by the developed mathematical model. For example, the cutting forces increase with increasing DOC and backrake angle, which is caused by the changing of the crescent area of the rock-cutter interaction. All resultant forces have almost the same inclination angle to the horizontal plane because of the almost constant boundary shape of the crushing zone. The differences between modeling and experimental results could be attributed to several reasons, one of which was the oversimplified plastic flow zone. This work presents a mathematical model that can guide the PDC bit design at different formation properties.","PeriodicalId":22252,"journal":{"name":"SPE Journal","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135811301","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}