Processes

Research

16 pages, 9971 KiB

Open AccessArticle

The Saturation Calculation of NMR Logging Based on Constructing Water Spectrum Function

by Yongfu Liu, Rui Deng, Shenchao Luo, Hong Li, Lei Zhang and Lixiong Gan

Processes 2024, 12(11), 2518; https://doi.org/10.3390/pr12112518 - 12 Nov 2024

Viewed by 429

Tight sandstone oil reservoirs are characterized by complex structures, poor pore connectivity, and strong heterogeneity, with features such as low porosity and ultra-low permeability. Conventional methods for calculating saturation cannot accurately evaluate the hydrocarbon saturation of these reservoirs. To address this, a study [...] Read more.

Tight sandstone oil reservoirs are characterized by complex structures, poor pore connectivity, and strong heterogeneity, with features such as low porosity and ultra-low permeability. Conventional methods for calculating saturation cannot accurately evaluate the hydrocarbon saturation of these reservoirs. To address this, a study was conducted from the perspective of non-electrical logging methods, focusing on the inherent nuclear magnetic resonance (NMR) characteristics of different fluids to develop a saturation calculation method that avoids the influence of the rock matrix, thus enabling precise saturation measurement in tight sandstone oil reservoirs. The traditional NMR porosity model was modified by segmenting it using the clay-bound water cutoff value, aiming to identify the distribution pattern of fluids in pores outside the clay-bound water zone. Through theoretical derivation and water spectrum function simulation, a water spectrum function and its parameter range suitable for the NMR T2 distribution in tight sandstone reservoirs were determined. Using core-sealed core saturation as a reference, the particle swarm optimization (PSO) algorithm was applied to optimize the parameter range and construct the final water spectrum function tailored to tight sandstone oil reservoirs. The accuracy and practicality of this method were validated by applying the derived water spectrum function to NMR logging in the exploration block, allowing for precise saturation calculations and the accurate evaluation of tight reservoir saturation. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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16 pages, 5289 KiB

Open AccessArticle

Numerical Modeling of Hydraulic Fracturing Interference in Multi-Layer Shale Oil Wells

by Xinwei Guo, Abulimiti Aibaibu, Yuezhong Wu, Bo Chen, Hua Zhou, Bolong Zhu and Xiangyun Zhao

Processes 2024, 12(11), 2370; https://doi.org/10.3390/pr12112370 - 29 Oct 2024

Viewed by 521

Abstract

Multi-layer horizontal well development and hydraulic fracturing are key techniques for enhancing production from shale oil reservoirs. During well development, the fracturing performance and well-pad production are affected by depletion-induced stress changes. Previous studies generally focused on the stress and fracturing interference within [...] Read more.

Multi-layer horizontal well development and hydraulic fracturing are key techniques for enhancing production from shale oil reservoirs. During well development, the fracturing performance and well-pad production are affected by depletion-induced stress changes. Previous studies generally focused on the stress and fracturing interference within the horizontal layers, and the infilled multi-layer development was not thoroughly investigated. This study introduces a modeling workflow based on finite element and displacement discontinuity methods that accounts for dynamic porous media flow, geomechanics, and hydraulic fracturing modeling. It quantitatively characterizes the in situ stress alteration in various layers caused by the historical production of parent wells and quantifies the hydraulic fracturing interference in infill wells. In situ stress changes and reorientation and the non-planar propagation of hydraulic fractures were simulated. Thus, the workflow characterizes infill-well fracturing interferences in shale oil reservoirs developed by multi-layer horizontal wells. Non-planar fracturing in infill wells is affected by the parent-well history production, infilling layers, and cluster number. They also affect principal stress reorientations and reversal of the fracturing paths. Interwell interference can be decreased by optimizing the infilling layer, infill-well fracturing timing, and cluster numbers. This study extends the numerical investigation of interwell fracturing interference to multi-layer development. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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18 pages, 5027 KiB

Open AccessArticle

Research on Erosion Damage Laws and Structural Optimization of Bypass Valve for Positive Displacement Motors

by Yanbo Zhang, Lei Zhang, Yulin Gao, Ping Shi, Yu Wang and Lingrong Kong

Processes 2024, 12(9), 1953; https://doi.org/10.3390/pr12091953 - 11 Sep 2024

Viewed by 685

Abstract

The bypass valve of a positive displacement motor is a key component for regulating the bottom hole pressure and ensuring the normal circulation of drilling fluid during the drilling process. Severe erosion damage to the bypass valve significantly affects the service life of [...] Read more.

The bypass valve of a positive displacement motor is a key component for regulating the bottom hole pressure and ensuring the normal circulation of drilling fluid during the drilling process. Severe erosion damage to the bypass valve significantly affects the service life of the positive displacement motor, yet there is currently a lack of related research. In this research, the flow characteristics of drilling fluid inside the valve core were analyzed through flow field simulation, and the main factors influencing erosion damage to the valve core were investigated. The results indicate that the side holes and flow channel structure of the valve core are the main causes of erosion. Based on this, two optimization schemes are proposed, namely, reducing the number of bypass side holes to 4 and optimizing the flow channel cone angle to 45°. The simulation results show that the erosion rate of the optimized valve core is significantly reduced, and the service life is effectively improved. Finally, a valve core life prediction model is established using a back propagation (BP) neural network to evaluate the optimization effect. The results show that the applicable flow range and maximum service life of the optimized valve core are increased by approximately 60% and 75.4%, respectively, validating the effectiveness of the optimization scheme. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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20 pages, 11503 KiB

Open AccessArticle

Combined Deep-Fill and Histogram Equalization Algorithm for Full-Borehole Electrical Logging Image Restoration

by Junhua Wang, Zhenxue Hou, Zhiqiang Zhang, Meng Wang and Haoran Cheng

Processes 2024, 12(8), 1568; https://doi.org/10.3390/pr12081568 - 26 Jul 2024

Viewed by 590

Abstract

Electrical borehole imaging tools cannot achieve full-borehole images due to their structure limitation. Gaps always occur between pads, and it is necessary to fill in the gaps for subsequent interpretation. In this paper, an improved model for borehole image restoration and enhancement is [...] Read more.

Electrical borehole imaging tools cannot achieve full-borehole images due to their structure limitation. Gaps always occur between pads, and it is necessary to fill in the gaps for subsequent interpretation. In this paper, an improved model for borehole image restoration and enhancement is established by combining a “Deep-Fill” image repair algorithm based on generative adversarial networks (GANs) with histogram equalization principles. Firstly, resistivity data is converted into images, and the anomalous areas are manually repaired. Then, the manually repaired images undergo iterative training using the “Deep-Fill” model. Finally, the repaired images are further enhanced through histogram equalization principles. Results show the overall restoration quality of the model surpasses that of the original GAN-based restoration model, particularly in terms of texture coherence at junctions. This approach not only enhances the quality of repaired images but also improves the interpretability of geological features of the electrical imaging logs. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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18 pages, 5455 KiB

Open AccessArticle

Research on Operation Optimization of Fluid Sampling in Wireline Formation Testing with Finite Volume Method

by Lejun Wu, Junhua Wang, Haibo Liu, Rui Huang, Huizhuo Xie, Xiaodong Li, Xuan Li, Jinhuan Liu and Changjie Zhao

Processes 2024, 12(7), 1515; https://doi.org/10.3390/pr12071515 - 19 Jul 2024

Viewed by 644

Abstract

Wireline formation testing is an important technique in the exploration and development of oil fields. Not only can real fluid samples be prepared from the formation directly obtained to know exactly whether the oil existed in the formation or not, but it can [...] Read more.

Wireline formation testing is an important technique in the exploration and development of oil fields. Not only can real fluid samples be prepared from the formation directly obtained to know exactly whether the oil existed in the formation or not, but it can also show flowing pressure change to determine the production capacity of the formation. So, it is an important measurement method for formation evaluation during the drilling process and supports activities related to the exploration and development of oil fields. A numerical simulation model in this article is researched and established based on the finite volume method considering the influence of sensitive parameters such as reservoir heterogeneity, probe suction area, and mud-filtrate invasion depth during the drilling. The model is capable of designing and evaluating formation fluid sampling operations by calculating hydrocarbon content and flowing pressure. Furthermore, through case application, the performance and effect of the process of wireline formation testing were investigated. The results indicate that this technology can serve as an effective auxiliary tool for fluid sampling operations with the function of optimizing fluid sampling measures. It can improve the accuracy of predicting indicators such as hydrocarbon content and breakthrough time during the sampling process. This study provides important supporting evidence and technical guidance for professionals in geological exploration and oil field development. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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16 pages, 8150 KiB

Open AccessArticle

Modeling Surface Roughness and Flow of Gases in Threaded Connections to Analyze Sealing Performance

by Wenqi Zhu, Yu Liang and Lv Zhao

Processes 2024, 12(3), 574; https://doi.org/10.3390/pr12030574 - 14 Mar 2024

Viewed by 1019

Abstract

Oil casings and premium threaded connections play vital roles in the oil and gas extraction industry. The present work establishes an integrated modeling framework for the sealability assessment of premium threaded connections which can be easily implemented and employed by engineers. The framework [...] Read more.

Oil casings and premium threaded connections play vital roles in the oil and gas extraction industry. The present work establishes an integrated modeling framework for the sealability assessment of premium threaded connections which can be easily implemented and employed by engineers. The framework incorporates a part-scale finite element analysis of the make-up process, a micro-scale simulation of the contact behavior, and a mechanism-informed gap flow model. It is found that complete sealing can be achieved when the contact pressure exceeds 1540 MPa for Gaussian rough surfaces presenting a roughness of 1.6 μm. The seal surface fit is revealed to be critical for sealing performance, as it slightly changes the optimum make-up torque (up to 4%) but significantly changes contact pressure (up to 22%). At an optimum make-up torque, the connection with the loosest seal surface tolerance fit is prone to gas leakage when considering an inlet pressure of 110 MPa. The proposed modeling framework can be extended to other types of threaded connections with metal–metal contact sealing. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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18 pages, 20806 KiB

Open AccessArticle

Corrosion Behavior and Mechanical Performance of Drill Pipe Steel in a CO₂/H₂S-Drilling-Fluid Environment

by Yushan Zheng, Yuhan Zhang, Bingcai Sun, Bo Zhang, Sixi Zhang, Shuli Jin, Zhongling Xiao, Shengli Chu, Yinghua Jing and Zhi Zhang

Processes 2024, 12(3), 502; https://doi.org/10.3390/pr12030502 - 29 Feb 2024

Cited by 1 | Viewed by 1446

Abstract

Objectives: This article investigates the corrosion behavior and mechanical-property changes of S135, G105, and V150 drill pipe materials in a high-temperature-resistant, potassium amino poly-sulfonate drilling fluid, which has good lubrication performance and contains CO₂/H₂S, by applying an 80% yield-limit-load [...] Read more.

Objectives: This article investigates the corrosion behavior and mechanical-property changes of S135, G105, and V150 drill pipe materials in a high-temperature-resistant, potassium amino poly-sulfonate drilling fluid, which has good lubrication performance and contains CO₂/H₂S, by applying an 80% yield-limit-load simulation. The results show that the CO₂-corrosion behavior of G105, S135, and V150 drill pipes are obvious under the simulated constant-load-stress-corrosion environments at the wellhead, well-middle, and bottomhole positions. Compared to uncorroded drill pipes, S135 and V150 drill pipes have increased strength and yield ratios, decreased fracture elongation, and increased sensitivity to hydrogen embrittlement under H₂S action, and V150 has a greater risk of stress-hydrogen embrittlement. The strength and yield ratios of G105-material drill pipes decrease, while the fracture elongation increases; the intensity-change amplitude levels are ranked V150 > G105 > S135, and the fracture-elongation-change amplitude is ranked G105 > S135 > V150. The tensile-performance-change amplitude and the SSCC (Sulfide-Stress-Corrosion Cracking) sensitivity of G105 and V150 drill pipes were the highest at the bottomhole. S135 drill pipe materials were most affected by pitting and tensile action at the wellhead, and they had the with the largest SSCC sensitivity. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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17 pages, 9788 KiB

Open AccessArticle

Numerical Simulation Study on the Damage Mechanism of the Combined Perforating Well Testing Tubing in Ultra-Deep Wells

by Jiadong Jiang, Qiao Deng, Dong Yang, Guilin Qi, Fan Zhang and Leichuan Tan

Processes 2024, 12(2), 380; https://doi.org/10.3390/pr12020380 - 14 Feb 2024

Cited by 1 | Viewed by 1428

Abstract

During perforation in ultra-deep wells, the blast shock wave can induce dynamic responses of the perforating tubing, leading to potential downhole accidents such as vibration, deformation, and even fracture of the perforating tubing. To comprehend the dynamic response characteristics of the perforating tubing [...] Read more.

During perforation in ultra-deep wells, the blast shock wave can induce dynamic responses of the perforating tubing, leading to potential downhole accidents such as vibration, deformation, and even fracture of the perforating tubing. To comprehend the dynamic response characteristics of the perforating tubing under blast impact load, we conducted a joint finite element simulation using SolidWorks, Hypermesh, and LS-DYNA. The simulation included deformation analysis, motion analysis, and strength analysis of the perforating tubing. By analyzing these factors, we obtained the change in velocity, acceleration, and equivalent stress of the perforating tubing over time under the blast load. The finite element analysis indicates the following: (a) the bottom of the perforating tubing is susceptible to significant tension compression cycle; (b) the velocity amplitude variation is smallest at the top of the perforating tubing, while the frequency and peak values of velocity changes are maximal at the bottom of the perforating tubing; and (c) the top and bottom of the tubing string are the vulnerable parts of the perforating tubing system. Full article

(This article belongs to the Special Issue Oil and Gas Drilling Processes: Control and Optimization)

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