An overview of CNPC engineering technology service As an important backup and guarantee for CNPC＇s oil and gas business, engineering technology service companies have focused on the goal of building an integrated in...An overview of CNPC engineering technology service As an important backup and guarantee for CNPC＇s oil and gas business, engineering technology service companies have focused on the goal of building an integrated international energy company, and launched new round of specialized restructuring and business integration since the end of 2007, in accordance with the principle of intensification, specialization, and integration.展开更多
On the basis of reviewing the development history of drilling engineering technology over a century, this paper describes the technical and scientific background of downhole control engineering, discusses its basic is...On the basis of reviewing the development history of drilling engineering technology over a century, this paper describes the technical and scientific background of downhole control engineering, discusses its basic issues, discipline frame and main study contents, introduces the research progress of downhole control engineering in China over the past 30 years, and envisions the development direction of downhole control engineering in the future. The author proposed the study subject of well trajectory control theory and technology in 1988, and further proposed the concept of downhole control engineering in 1993. Downhole control engineering is a discipline branch, which applies the perspectives and methods of engineering control theory to solve downhole engineering control issues in oil and gas wells; meanwhile, it is an application technology field with interdisciplinarity. Downhole control engineering consists of four main aspects; primarily, investigations about dynamics of downhole system and analysis methods of control signals; secondly, designs of downhole control mechanisms and systems, research of downhole parameters collections and transmission techniques; thirdly, development of downhole control engineering products; fourthly, development of experimental methods and the laboratories. Over the past 30 years, the author and his research group have achieved a number of progress and accomplishments in the four aspects mentioned above. As a research field and a disciplinary branch of oil and gas engineering, downhole control engineering is stepping into a broader and deeper horizon.展开更多
Petroleum engineering service is one of the pillars that support the petroleum industry in China. Being one of CNPC’s main businesses, the sector has always been escorting the Group to realize its strategic goals. Si...Petroleum engineering service is one of the pillars that support the petroleum industry in China. Being one of CNPC’s main businesses, the sector has always been escorting the Group to realize its strategic goals. Since a new round of specialized re-structuring in 2007, the sector has been promoting all its展开更多
Major bottlenecks in the development of the sector Compared with foreign peers, the sector still lags behind in capacity and performance, reflecting the sector needs to do more in improving technology innovation abili...Major bottlenecks in the development of the sector Compared with foreign peers, the sector still lags behind in capacity and performance, reflecting the sector needs to do more in improving technology innovation ability, setting up favorable mechanism and investing more in technology research. The current situation indicates that the following factors have been affecting the development of the sector.展开更多
Antarctica contains numerous scientific mysteries,and the Antarctic ice sheet and its underlying bedrock contain important information about the geological structure of Antarctica and the evolutionary history of the i...Antarctica contains numerous scientific mysteries,and the Antarctic ice sheet and its underlying bedrock contain important information about the geological structure of Antarctica and the evolutionary history of the ice sheet.In order to obtain the focus of these scientific explorations,the Antarctic drilling engineering is constantly developing.The drilling fluid performance directly determines the success or failure of drilling engineering.In order to enhance the poor performance for drilling fluids due to poor dispersion stability and easy settling of organoclay at ultra-low temperatures,the small-molecule wetting agent(HSR)for drilling fluid suitable for Antarctica was prepared by oleic acid,diethanolamine and benzoic acid as raw materials.Its chemical structure,properties and action mechanism were investigated by various experimental methods.The experimental results showed that 2%HSR could improve the colloidal rate for drilling fluid from 6.4%to 84.8%,and the increase rate of yield point was up to 167%.Meanwhile,it also made the drilling fluid excellent in shear dilution and thixotropy.In addition,2%HSR could increase the density from 0.872 to 0.884 g/cm^(3) at-55 ficial.And the drilling fluid with 2%HSR had a good thermal conductivity of 0.1458 W/(m·K)at-55 ficial.This study gives a new direction for the research of drilling fluid treatment agents suitable for the Antarctic region,which will provide strong support for the scientific exploration of the Antarctic region.展开更多
This paper systematically reviews the advances in shale oil and gas drilling fluid technology,provides an in-depth analysis of the critical bottlenecks in each technology and explores their future development directio...This paper systematically reviews the advances in shale oil and gas drilling fluid technology,provides an in-depth analysis of the critical bottlenecks in each technology and explores their future development directions.Several technologies have been developed for shale oil and gas:water-based drilling fluids with a core emphasis on sealing,inhibition and lubrication;oil-based drilling fluids centered around wellbore strengthening,low-oil-water-ratio emulsions,and synthetic-based systems;drilling fluids for reservoir protection based on clay-free,under-balanced,and interfacial modification;as well as lost circulation control technologies founded on bridging,gelling,responsive,and composite mechanisms.A comprehensive analysis indicates that existing technologies are still plagued by several bottlenecks,including inadequate high-temperature and contamination resistance,prohibitive costs,and poor formation adaptability.Drilling operations still face severe challenges such as wellbore instability,reservoir damage and severe fluid losses.Accordingly,the following prospects for future shale oil and gas drilling fluid technology are proposed:(1)Water-based drilling fluids require a focus on the synergistic effects of nanoscale plugging and chemical inhibition,the development of smart responsive lubricants,and enhanced resistance to high temperatures and acid gas contamination.(2)Oil-based drilling fluids should achieve breakthroughs in novel emulsifiers for cost-effectiveness and high-temperature resistance,alongside intensified research efforts in environmentally friendly technologies.(3)Reservoir protective drilling fluids necessitate the development of a real-time prediction and diagnosis expert system for formation damage,coupled with the advancement and application of high-temperature resistant additives and intelligent integrated pressure control equipment.(4)Lost circulation control technologies should be dedicated to developing smart responsive plugging materials and strengthening their compatibility with fracture networks.展开更多
1.Introduction With the increasing demand for petroleum and natural gas resources,along with technological advancements in exploration and production,the primary frontier of oil and gas resources has shifted from conv...1.Introduction With the increasing demand for petroleum and natural gas resources,along with technological advancements in exploration and production,the primary frontier of oil and gas resources has shifted from conventional oil and gas development to the domains of“Two Deeps,One Unconventional,One Mature,”which include deep onshore,deepwater,unconventional resources,and mature oilfields[1].展开更多
As the well drilling depth has broken through the 10,000 m in China,accurate measurements of downhole engineering parameters,such as annulus temperature and pressure for the whole wellbore,are significant in controlli...As the well drilling depth has broken through the 10,000 m in China,accurate measurements of downhole engineering parameters,such as annulus temperature and pressure for the whole wellbore,are significant in controlling potential downhole complexities.In this present work,a new micro-measurer is developed by integrating measurements of downhole temperature,pressure,magnetic field strength,and its own dynamic signals.The micro-measurer can flow with drilling fluid from the drillstring to the bottomhole and then float up back to the ground via the wellbore annulus.Compared with other downhole measurement tools that are fixedly connected to the drill string,its“measure-and-move-on”approach reduces the residence time in the high-temperature and high-pressure zone at the bottomhole;moreover,both the pressure and temperature at different well depth can be measured,thereby the temperature and pressure profiles of the whole wellbore can be constructed.In addition,the bluetooth low energy(BLE)technique is applied to offer the micro-measurer with the capability of wireless information transmission;while hydrodynamic optimization of the micro-measurer is carried out to design the structure of the micro-measurer,which can promote its recovery rate from downhole.In addition,an intelligent joint for releasing micro-measurers from the wellbore annulus is also proposed,aiming to overcome the limitation imposed by the nozzle on the size of the micro-measurer.Both the indoor experiments and the field tests have verified the feasibility of the newly designed micro-measurer,which is a key step for establishing a complete downhole internet of things(IoT)system to serve the intelligent drilling in the future.展开更多
The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,hi...The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,high pressure and high stress,fracture development,wellbore instability,drilling fluid lost circulation and other problems faced in the process of deep and ultra-deep complex oil and gas drilling,scholars have developed deep and ultra-deep high-temperature and high-salt resistant water-based drilling fluid technology,high-temperature resistant oil-based/synthetic drilling fluid technology,drilling fluid technology for reservoir protection and drilling fluid lost circulation control technology.However,there are still some key problems such as insufficient resistance to high temperature,high pressure and high stress,wellbore instability and serious lost circulation.Therefore,the development direction of deep and ultra-deep drilling fluid technology in the future is proposed:(1)The technology of high-temperature and high-salt resistant water-based drilling fluid should focus on improving high temperature stability,improving rheological properties,strengthening filtration control and improving compatibility with formation.(2)The technology of oil-based/synthetic drilling fluid resistant to high temperature should further study in the aspects of easily degradable environmental protection additives with low toxicity such as high temperature stabilizer,rheological regulator and related supporting technologies.(3)The drilling fluid technology for reservoir protection should be devoted to the development of new high-performance additives and materials,and further improve the real-time monitoring technology by introducing advanced sensor networks and artificial intelligence algorithms.(4)The lost circulation control of drilling fluid should pay more attention to the integration and application of intelligent technology,the research and application of high-performance plugging materials,the exploration of diversified plugging techniques and methods,and the improvement of environmental protection and production safety awareness.展开更多
With further exploration and development of oil and gas fields both at home and abroad, complicated geological conditions, poor quality of reserves and abominable working environment, drilling business, the largest of...With further exploration and development of oil and gas fields both at home and abroad, complicated geological conditions, poor quality of reserves and abominable working environment, drilling business, the largest of upstream petroleum industry in terms of total investment and scale, is facing new challenges.China National Petroleum Corporation (hereinafter referred to as CNPC) is in urgent need of transforming development patterns of drilling, so as to enhance competitiveness, improve production efficiency, and increase economic profits.展开更多
With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind...With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.展开更多
In drilling ultra-deep wells,the drilling fluid circulation usually causes erosion damage to downhole casing and drilling tools.However,the extent and process of this damage to the downhole tools is intricate and less...In drilling ultra-deep wells,the drilling fluid circulation usually causes erosion damage to downhole casing and drilling tools.However,the extent and process of this damage to the downhole tools is intricate and less understood.In order to systematically evaluate and clarify this damage process for different types of drilling fluid contamination,this research uses a high-temperature drilling fluid damage device to simulate the damage caused to the casing/drilling tools by various drilling fluid under a field thermal gradient.The results show that the drilling fluid residues are mainly solid-phase particles and organic components.The degree of casing/tool damage decreases with an increase in bottom hole temperature,and the casing/tool is least damaged within a temperature range of 150–180°C.Moreover,the surface of the casing/tool damaged by different types of drilling fluid shows different roughness,and the wettability of drilling fluid on the casing/tool surface increases with an increase in the degree of roughness.Oil-based drilling fluid have the strongest adhesion contamination on casing/drilling tools.In contrast,polysulfonated potassium drilling fluid and super-micro drilling fluid have the most potent erosion damage on casing/drilling tools.By analyzing the damage mechanism,it was established that the damage was mainly dominated by the abrasive wearing from solid-phase particles in concert with corrosion ions in drilling fluid,with solids producing many abrasion marks and corrosive ions causing a large number of pits.Clarifying drilling fluid's contamination and damage mechanism is significant in guiding the wellbore cleaning process and cutting associated costs.展开更多
Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However...Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However, wellbore instability, caused by the invasion of drilling fluids into shale formations, remains a significant challenge for the safe and efficient extraction of shale oil and gas. This work reports the preparation of mesoporous SiO2nanoparticles with low surface energy, utilized as multifunctional agents to enhance the performance of oil-based drilling fluids aimed at improving wellbore stability. The results indicate that the coating prepared from these nanoparticles exhibit excellent hydrophobicity and antifouling properties, increasing the water contact angle from 32°to 146°and oil contact angle from 24°to134.8°. Additionally, these nanoparticles exhibit exceptional chemical stability and thermal resistance.Incorporating these nanoparticles into oil-based drilling fluids reduced the surface energy of the mud cake from 34.99 to 8.17 m J·m-2and increased the roughness of shale from 0.26 to 2.39 μm. These modifications rendered the mud cake and shale surfaces amphiphobic, effectively mitigating capillary infiltration and delaying the long-term strength degradation of shale in oil-based drilling fluids. After 28days of immersion in oil-based drilling fluid, shale cores treated with MF-SiO2exhibited a 30.5% increase in compressive strength compared to untreated cores. Additionally, these nanoparticles demonstrated the ability to penetrate and seal rock pores, reducing the API filtration volume of the drilling fluid from11.2 to 7.6 m L. This study introduces a novel approach to enhance the development of shale gas and oil resources, offering a promising strategy for wellbore stabilization in oil-based drilling fluid systems.展开更多
Real-time monitoring of wellbore stability during drilling is crucial for the early detection of instability and timely interventions.The cause and type of wellbore instability can be identified by analyzing the dropp...Real-time monitoring of wellbore stability during drilling is crucial for the early detection of instability and timely interventions.The cause and type of wellbore instability can be identified by analyzing the dropped blocks brought to the surface by the drilling fluid,enabling preventive measures to be taken.In this study,an image capture system with fully automated sorting and 3D scanning was developed to obtain the complete 3D point cloud data of dropping blocks.The raw data obtained were preprocessed using methods such as format conversion,down sampling,coordinate transformation,statistical filtering,and clustering.Feature extraction algorithms,including the principal component analysis bounding box method,triangular meshing method,triaxial projection method,local curvature method,and model segmentation projection method,were employed,which resulted in the extraction of 32 feature parameters from the point cloud data.An optimal machine learning algorithm was developed by training it with 10 machine learning algorithms and the block data collected in the field.The XGBoost algorithm was then used to optimize the feature parameters and improve the classification model.An intelligent,fully automated feature parameter extraction and classification system was developed and applied to classify the types of falling blocks in 12 sets of drilling field and laboratory experiments and to identify the causes of wellbore instability.An average accuracy of 93.9%was achieved.This system can thus enable the timely diagnosis and implementation of preventive and control measures for wellbore instability in the field.展开更多
During oilfield development,a comprehensive model for assessing inter-well connectivity and connected volume within reservoirs is crucial.Traditional capacitance(TC)models,widely used in inter-well data analysis,face ...During oilfield development,a comprehensive model for assessing inter-well connectivity and connected volume within reservoirs is crucial.Traditional capacitance(TC)models,widely used in inter-well data analysis,face challenges when dealing with rapidly changing reservoir conditions over time.Additionally,TC models struggle with complex,random noise primarily caused by measurement errors in production and injection rates.To address these challenges,this study introduces a dynamic capacitance(SV-DC)model based on state variables.By integrating the extended Kalman filter(EKF)algorithm,the SV-DC model provides more flexible predictions of inter-well connectivity and time-lag efficiency compared to the TC model.The robustness of the SV-DC model is verified by comparing relative errors between preset and calculated values through Monte Carlo simulations.Sensitivity analysis was performed to compare the model performance with the benchmark,using the Qinhuangdao Oilfield as a case study.The results show that the SV-DC model accurately predicts water breakthrough times.Increases in the liquid production index and water cut in two typical wells indicate the development time of ineffective circulation channels,further confirming the accuracy and reliability of the model.The SV-DC model offers significant advantages in addressing complex,dynamic oilfield production scenarios and serves as a valuable tool for the efficient and precise planning and management of future oilfield developments.展开更多
Ultra-deep and complex formations are characterized by narrow safety density windows and challenging well control.The combined use of multiple well-killing methods or temporary adjustments to well-killing strategies i...Ultra-deep and complex formations are characterized by narrow safety density windows and challenging well control.The combined use of multiple well-killing methods or temporary adjustments to well-killing strategies is becoming common.However,conventional well-killing models often struggle to calculate the parameters required for these special cases.In this paper,a boundary matrix for wellkilling fluid density and volume is proposed to unify the driller's method,the engineer's method,and the weight-while-circulating method.Furthermore,a dynamic unified well-killing model is developed to enable the synergistic regulation of multiple well-killing methods.The model also can be applied with or without accounting for gas dissolution.Using this model,it is able to dynamically track key parameters during well killing and shut in the well at any time to determine the standpipe and casing pressures.The results indicate that the casing pressure drops to zero before the well-killing fluid returns to the annulus wellhead,and continued injection of the fluid leads to a gradual increase in standpipe pressure,a phenomenon not previously accounted for.The discrepancy between the actual and calculated standpipe/casing pressures after shut-in can be utilized to assess whether the downhole gas kick is effectively controlled.Through real-time adjustments to the boundary matrix,updated wellkilling parameters can be derived for conventional method,multi-method combination,temporary strategy modification,and other well-killing scenarios.The model was applied to two field wells under water-and oil-based drilling fluids.No secondary downhole complications occurred during well killing,and the calculated pressure curves closely matched the measured construction pressure curves,confirming the model's reliability and applicability.This study provides valuable theoretical guidance for enhancing well control safety in ultra-deep and complex formations.展开更多
This study aims to eliminate the subjectivity and inconsistency inherent in the traditional International Association of Drilling Contractors(IADC)bit wear rating process,which heavily depends on the experience of dri...This study aims to eliminate the subjectivity and inconsistency inherent in the traditional International Association of Drilling Contractors(IADC)bit wear rating process,which heavily depends on the experience of drilling engineers and often leads to unreliable results.Leveraging advancements in computer vision and deep learning algorithms,this research proposes an automated detection and classification method for polycrystalline diamond compact(PDC)bit damage.YOLOv10 was employed to locate the PDC bit cutters,followed by two SqueezeNet models to perform wear rating and wear type classifications.A comprehensive dataset was created based on the IADC dull bit evaluation standards.Additionally,this study discusses the necessity of data augmentation and finds that certain methods,such as cropping,splicing,and mixing,may reduce the accuracy of cutter detection.The experimental results demonstrate that the proposed method significantly enhances the accuracy of bit damage detection and classification while also providing substantial improvements in processing speed and computational efficiency,offering a valuable tool for optimizing drilling operations and reducing costs.展开更多
Many mature onshore oilfields have entered a high-water-cut stage,with reservoir recovery approaching economic limits.Converting these depleted or nearly depleted reservoirs into underground gas storage(UGS)facilities...Many mature onshore oilfields have entered a high-water-cut stage,with reservoir recovery approaching economic limits.Converting these depleted or nearly depleted reservoirs into underground gas storage(UGS)facilities offers an efficient way to leverage their substantial storage potential.During cyclic gas injection and withdrawal,however,the reservoir experiences complex three-phase flow and repeated stress fluctuations,which can induce rock fatigue,inelastic deformation,and ultimately sand production.This study uses controlled physical experiments to simulate sand production in reservoir rocks subjected to alternating gas injection and production under three-phase conditions.After preparing oil-water-saturated cores through waterflooding,gas is introduced to perform repeated displacement cycles.Polynomial models relating core mass loss to water-oil ratio and cycle number are developed using the Newton interpolation method,enabling prediction of sand production under various operating conditions.Results show that,within the critical pressure-difference range for sand onset,permeability increases with water-oil ratio.When the water-oil ratio lies between 0.3 and 1,sand production decreases progressively;beyond a ratio of 1,sand production increases with further increases in water-oil ratio.The number of displacement cycles exerts a dominant influence:sand production remains relatively stable between 25 and 55 cycles but rises sharply thereafter.Average sand production during cycles 55–100 is 5.27 times higher than during cycles 5–55.These findings indicate that cumulative structural damage to the rock framework intensifies significantly with repeated cycling,making cycle number a critical factor governing sand production in UGS operations.展开更多
Ionic liquids(ILs),recognized for their negligible vapor pressure,thermal stability,and structural tailorability,offer targeted inhibition of clay expansion.Compared to ILs,polyionic liquids(PILs)possess stronger mech...Ionic liquids(ILs),recognized for their negligible vapor pressure,thermal stability,and structural tailorability,offer targeted inhibition of clay expansion.Compared to ILs,polyionic liquids(PILs)possess stronger mechanical properties and adsorption capabilities,showing even greater potential in inhibiting clay swelling.In this work,we synthesized and characterized an imidazole-based ionic liquid(IL-NH_(2)),a polyionic liquid(PIL-ABHIm),and a PIL/IL combination.Their inhibitory performance was rigorously evaluated under simulated drilling conditions through immersion tests,linear swelling tests,among others.Additionally,the mechanisms underlying their interaction with clay minerals were elucidated through contact angle measurements,Fourier-transform infrared spectroscopy,X-ray diffraction(XRD),Zeta potential analysis,and molecular electrostatic potential(MEP)analysis.This work demonstrates that IL-NH_2inhibits osmotic hydration by altering the interlayer structure of the clay,while PIL-ABHIm reduces surface hydration by forming a hydrophobic barrier on the clay surface.PIL/IL combines both mechanisms,significantly enhancing the stability of clay through the dual mechanisms of cation exchange and hydrophobic barriers.These findings reveal an innovative mechanism by which PIL/IL combination inhibits clay hydration and swelling,providing a scientific foundation for their application in drilling fluids.展开更多
文摘An overview of CNPC engineering technology service As an important backup and guarantee for CNPC＇s oil and gas business, engineering technology service companies have focused on the goal of building an integrated international energy company, and launched new round of specialized restructuring and business integration since the end of 2007, in accordance with the principle of intensification, specialization, and integration.
文摘On the basis of reviewing the development history of drilling engineering technology over a century, this paper describes the technical and scientific background of downhole control engineering, discusses its basic issues, discipline frame and main study contents, introduces the research progress of downhole control engineering in China over the past 30 years, and envisions the development direction of downhole control engineering in the future. The author proposed the study subject of well trajectory control theory and technology in 1988, and further proposed the concept of downhole control engineering in 1993. Downhole control engineering is a discipline branch, which applies the perspectives and methods of engineering control theory to solve downhole engineering control issues in oil and gas wells; meanwhile, it is an application technology field with interdisciplinarity. Downhole control engineering consists of four main aspects; primarily, investigations about dynamics of downhole system and analysis methods of control signals; secondly, designs of downhole control mechanisms and systems, research of downhole parameters collections and transmission techniques; thirdly, development of downhole control engineering products; fourthly, development of experimental methods and the laboratories. Over the past 30 years, the author and his research group have achieved a number of progress and accomplishments in the four aspects mentioned above. As a research field and a disciplinary branch of oil and gas engineering, downhole control engineering is stepping into a broader and deeper horizon.
文摘Petroleum engineering service is one of the pillars that support the petroleum industry in China. Being one of CNPC’s main businesses, the sector has always been escorting the Group to realize its strategic goals. Since a new round of specialized re-structuring in 2007, the sector has been promoting all its
文摘Major bottlenecks in the development of the sector Compared with foreign peers, the sector still lags behind in capacity and performance, reflecting the sector needs to do more in improving technology innovation ability, setting up favorable mechanism and investing more in technology research. The current situation indicates that the following factors have been affecting the development of the sector.
基金financially supported by the National Natural Science Foundation of China(No.52274021)the National Key Research and Development Program of China(No.2021YFA0719102)。
文摘Antarctica contains numerous scientific mysteries,and the Antarctic ice sheet and its underlying bedrock contain important information about the geological structure of Antarctica and the evolutionary history of the ice sheet.In order to obtain the focus of these scientific explorations,the Antarctic drilling engineering is constantly developing.The drilling fluid performance directly determines the success or failure of drilling engineering.In order to enhance the poor performance for drilling fluids due to poor dispersion stability and easy settling of organoclay at ultra-low temperatures,the small-molecule wetting agent(HSR)for drilling fluid suitable for Antarctica was prepared by oleic acid,diethanolamine and benzoic acid as raw materials.Its chemical structure,properties and action mechanism were investigated by various experimental methods.The experimental results showed that 2%HSR could improve the colloidal rate for drilling fluid from 6.4%to 84.8%,and the increase rate of yield point was up to 167%.Meanwhile,it also made the drilling fluid excellent in shear dilution and thixotropy.In addition,2%HSR could increase the density from 0.872 to 0.884 g/cm^(3) at-55 ficial.And the drilling fluid with 2%HSR had a good thermal conductivity of 0.1458 W/(m·K)at-55 ficial.This study gives a new direction for the research of drilling fluid treatment agents suitable for the Antarctic region,which will provide strong support for the scientific exploration of the Antarctic region.
基金Supported by the National Natural Science Foundation of China(52288101,52474022)Shandong Provincial Key Research and Development Program(2024CXPT076).
文摘This paper systematically reviews the advances in shale oil and gas drilling fluid technology,provides an in-depth analysis of the critical bottlenecks in each technology and explores their future development directions.Several technologies have been developed for shale oil and gas:water-based drilling fluids with a core emphasis on sealing,inhibition and lubrication;oil-based drilling fluids centered around wellbore strengthening,low-oil-water-ratio emulsions,and synthetic-based systems;drilling fluids for reservoir protection based on clay-free,under-balanced,and interfacial modification;as well as lost circulation control technologies founded on bridging,gelling,responsive,and composite mechanisms.A comprehensive analysis indicates that existing technologies are still plagued by several bottlenecks,including inadequate high-temperature and contamination resistance,prohibitive costs,and poor formation adaptability.Drilling operations still face severe challenges such as wellbore instability,reservoir damage and severe fluid losses.Accordingly,the following prospects for future shale oil and gas drilling fluid technology are proposed:(1)Water-based drilling fluids require a focus on the synergistic effects of nanoscale plugging and chemical inhibition,the development of smart responsive lubricants,and enhanced resistance to high temperatures and acid gas contamination.(2)Oil-based drilling fluids should achieve breakthroughs in novel emulsifiers for cost-effectiveness and high-temperature resistance,alongside intensified research efforts in environmentally friendly technologies.(3)Reservoir protective drilling fluids necessitate the development of a real-time prediction and diagnosis expert system for formation damage,coupled with the advancement and application of high-temperature resistant additives and intelligent integrated pressure control equipment.(4)Lost circulation control technologies should be dedicated to developing smart responsive plugging materials and strengthening their compatibility with fracture networks.
基金the Science Foundation of China University of Petroleum,Beijing(Grant No.2462024YJRC021)the National Natural Science Foundation of China(Grant No.U24B2031 and 52104013).
文摘1.Introduction With the increasing demand for petroleum and natural gas resources,along with technological advancements in exploration and production,the primary frontier of oil and gas resources has shifted from conventional oil and gas development to the domains of“Two Deeps,One Unconventional,One Mature,”which include deep onshore,deepwater,unconventional resources,and mature oilfields[1].
基金supported by the National Natural Science Foundation of China(No.U22B2072)the Research Project of China Petroleum Science and Technology Innovation Fund(No.2025DQ02-0144).
文摘As the well drilling depth has broken through the 10,000 m in China,accurate measurements of downhole engineering parameters,such as annulus temperature and pressure for the whole wellbore,are significant in controlling potential downhole complexities.In this present work,a new micro-measurer is developed by integrating measurements of downhole temperature,pressure,magnetic field strength,and its own dynamic signals.The micro-measurer can flow with drilling fluid from the drillstring to the bottomhole and then float up back to the ground via the wellbore annulus.Compared with other downhole measurement tools that are fixedly connected to the drill string,its“measure-and-move-on”approach reduces the residence time in the high-temperature and high-pressure zone at the bottomhole;moreover,both the pressure and temperature at different well depth can be measured,thereby the temperature and pressure profiles of the whole wellbore can be constructed.In addition,the bluetooth low energy(BLE)technique is applied to offer the micro-measurer with the capability of wireless information transmission;while hydrodynamic optimization of the micro-measurer is carried out to design the structure of the micro-measurer,which can promote its recovery rate from downhole.In addition,an intelligent joint for releasing micro-measurers from the wellbore annulus is also proposed,aiming to overcome the limitation imposed by the nozzle on the size of the micro-measurer.Both the indoor experiments and the field tests have verified the feasibility of the newly designed micro-measurer,which is a key step for establishing a complete downhole internet of things(IoT)system to serve the intelligent drilling in the future.
基金Supported by the Projects of National Natural Science Foundation of China(52288101,52174014,52374023)。
文摘The research progress of deep and ultra-deep drilling fluid technology systematically reviewed,the key problems existing are analyzed,and the future development direction is proposed.In view of the high temperature,high pressure and high stress,fracture development,wellbore instability,drilling fluid lost circulation and other problems faced in the process of deep and ultra-deep complex oil and gas drilling,scholars have developed deep and ultra-deep high-temperature and high-salt resistant water-based drilling fluid technology,high-temperature resistant oil-based/synthetic drilling fluid technology,drilling fluid technology for reservoir protection and drilling fluid lost circulation control technology.However,there are still some key problems such as insufficient resistance to high temperature,high pressure and high stress,wellbore instability and serious lost circulation.Therefore,the development direction of deep and ultra-deep drilling fluid technology in the future is proposed:(1)The technology of high-temperature and high-salt resistant water-based drilling fluid should focus on improving high temperature stability,improving rheological properties,strengthening filtration control and improving compatibility with formation.(2)The technology of oil-based/synthetic drilling fluid resistant to high temperature should further study in the aspects of easily degradable environmental protection additives with low toxicity such as high temperature stabilizer,rheological regulator and related supporting technologies.(3)The drilling fluid technology for reservoir protection should be devoted to the development of new high-performance additives and materials,and further improve the real-time monitoring technology by introducing advanced sensor networks and artificial intelligence algorithms.(4)The lost circulation control of drilling fluid should pay more attention to the integration and application of intelligent technology,the research and application of high-performance plugging materials,the exploration of diversified plugging techniques and methods,and the improvement of environmental protection and production safety awareness.
文摘With further exploration and development of oil and gas fields both at home and abroad, complicated geological conditions, poor quality of reserves and abominable working environment, drilling business, the largest of upstream petroleum industry in terms of total investment and scale, is facing new challenges.China National Petroleum Corporation (hereinafter referred to as CNPC) is in urgent need of transforming development patterns of drilling, so as to enhance competitiveness, improve production efficiency, and increase economic profits.
基金financially supported by the National Natural Science Foundation of China(Grant No.U22B20126)the National Key Research and Development Program of China(Grant No.2022YFC2806100).
文摘With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.
基金support and funding from the CNPC Project(2021ZG10)National Natural Science Foundation of China(No.52174047)Sinopec Project(No.P23138).
文摘In drilling ultra-deep wells,the drilling fluid circulation usually causes erosion damage to downhole casing and drilling tools.However,the extent and process of this damage to the downhole tools is intricate and less understood.In order to systematically evaluate and clarify this damage process for different types of drilling fluid contamination,this research uses a high-temperature drilling fluid damage device to simulate the damage caused to the casing/drilling tools by various drilling fluid under a field thermal gradient.The results show that the drilling fluid residues are mainly solid-phase particles and organic components.The degree of casing/tool damage decreases with an increase in bottom hole temperature,and the casing/tool is least damaged within a temperature range of 150–180°C.Moreover,the surface of the casing/tool damaged by different types of drilling fluid shows different roughness,and the wettability of drilling fluid on the casing/tool surface increases with an increase in the degree of roughness.Oil-based drilling fluid have the strongest adhesion contamination on casing/drilling tools.In contrast,polysulfonated potassium drilling fluid and super-micro drilling fluid have the most potent erosion damage on casing/drilling tools.By analyzing the damage mechanism,it was established that the damage was mainly dominated by the abrasive wearing from solid-phase particles in concert with corrosion ions in drilling fluid,with solids producing many abrasion marks and corrosive ions causing a large number of pits.Clarifying drilling fluid's contamination and damage mechanism is significant in guiding the wellbore cleaning process and cutting associated costs.
基金support from the National Natural:Science Foundation of China(NO.52174014)the National Natural Science Foundation Basic Science Center(NO.52288101).
文摘Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However, wellbore instability, caused by the invasion of drilling fluids into shale formations, remains a significant challenge for the safe and efficient extraction of shale oil and gas. This work reports the preparation of mesoporous SiO2nanoparticles with low surface energy, utilized as multifunctional agents to enhance the performance of oil-based drilling fluids aimed at improving wellbore stability. The results indicate that the coating prepared from these nanoparticles exhibit excellent hydrophobicity and antifouling properties, increasing the water contact angle from 32°to 146°and oil contact angle from 24°to134.8°. Additionally, these nanoparticles exhibit exceptional chemical stability and thermal resistance.Incorporating these nanoparticles into oil-based drilling fluids reduced the surface energy of the mud cake from 34.99 to 8.17 m J·m-2and increased the roughness of shale from 0.26 to 2.39 μm. These modifications rendered the mud cake and shale surfaces amphiphobic, effectively mitigating capillary infiltration and delaying the long-term strength degradation of shale in oil-based drilling fluids. After 28days of immersion in oil-based drilling fluid, shale cores treated with MF-SiO2exhibited a 30.5% increase in compressive strength compared to untreated cores. Additionally, these nanoparticles demonstrated the ability to penetrate and seal rock pores, reducing the API filtration volume of the drilling fluid from11.2 to 7.6 m L. This study introduces a novel approach to enhance the development of shale gas and oil resources, offering a promising strategy for wellbore stabilization in oil-based drilling fluid systems.
基金supported by the Scientific research and technology development projects of CNPC“Research on Key Technologies and Equipment for Drilling and Completion of 10000-m Ultra-deep Oil and Gas Resources”(No.2022ZG06)“Development of a Complete Set of 70 MPa Intelligent Managed Pressure Drilling Equipment”(No.2024ZG35).
文摘Real-time monitoring of wellbore stability during drilling is crucial for the early detection of instability and timely interventions.The cause and type of wellbore instability can be identified by analyzing the dropped blocks brought to the surface by the drilling fluid,enabling preventive measures to be taken.In this study,an image capture system with fully automated sorting and 3D scanning was developed to obtain the complete 3D point cloud data of dropping blocks.The raw data obtained were preprocessed using methods such as format conversion,down sampling,coordinate transformation,statistical filtering,and clustering.Feature extraction algorithms,including the principal component analysis bounding box method,triangular meshing method,triaxial projection method,local curvature method,and model segmentation projection method,were employed,which resulted in the extraction of 32 feature parameters from the point cloud data.An optimal machine learning algorithm was developed by training it with 10 machine learning algorithms and the block data collected in the field.The XGBoost algorithm was then used to optimize the feature parameters and improve the classification model.An intelligent,fully automated feature parameter extraction and classification system was developed and applied to classify the types of falling blocks in 12 sets of drilling field and laboratory experiments and to identify the causes of wellbore instability.An average accuracy of 93.9%was achieved.This system can thus enable the timely diagnosis and implementation of preventive and control measures for wellbore instability in the field.
基金the National Natural Science Foundation of China(Grant No.52374051)the Joint Fund for Enterprise Innovation and Development of NSFC(Grant No.U24B2037).
文摘During oilfield development,a comprehensive model for assessing inter-well connectivity and connected volume within reservoirs is crucial.Traditional capacitance(TC)models,widely used in inter-well data analysis,face challenges when dealing with rapidly changing reservoir conditions over time.Additionally,TC models struggle with complex,random noise primarily caused by measurement errors in production and injection rates.To address these challenges,this study introduces a dynamic capacitance(SV-DC)model based on state variables.By integrating the extended Kalman filter(EKF)algorithm,the SV-DC model provides more flexible predictions of inter-well connectivity and time-lag efficiency compared to the TC model.The robustness of the SV-DC model is verified by comparing relative errors between preset and calculated values through Monte Carlo simulations.Sensitivity analysis was performed to compare the model performance with the benchmark,using the Qinhuangdao Oilfield as a case study.The results show that the SV-DC model accurately predicts water breakthrough times.Increases in the liquid production index and water cut in two typical wells indicate the development time of ineffective circulation channels,further confirming the accuracy and reliability of the model.The SV-DC model offers significant advantages in addressing complex,dynamic oilfield production scenarios and serves as a valuable tool for the efficient and precise planning and management of future oilfield developments.
基金supported by the National Natural Science Foundation of China(52474018,52227804,U22B2072,52404012)the National Key Research and Development Program of China(2023YFC3009200)the Science Foundation of China University of Petroleum,Beijing(2462023BJRC008,2462024XKBH006)。
文摘Ultra-deep and complex formations are characterized by narrow safety density windows and challenging well control.The combined use of multiple well-killing methods or temporary adjustments to well-killing strategies is becoming common.However,conventional well-killing models often struggle to calculate the parameters required for these special cases.In this paper,a boundary matrix for wellkilling fluid density and volume is proposed to unify the driller's method,the engineer's method,and the weight-while-circulating method.Furthermore,a dynamic unified well-killing model is developed to enable the synergistic regulation of multiple well-killing methods.The model also can be applied with or without accounting for gas dissolution.Using this model,it is able to dynamically track key parameters during well killing and shut in the well at any time to determine the standpipe and casing pressures.The results indicate that the casing pressure drops to zero before the well-killing fluid returns to the annulus wellhead,and continued injection of the fluid leads to a gradual increase in standpipe pressure,a phenomenon not previously accounted for.The discrepancy between the actual and calculated standpipe/casing pressures after shut-in can be utilized to assess whether the downhole gas kick is effectively controlled.Through real-time adjustments to the boundary matrix,updated wellkilling parameters can be derived for conventional method,multi-method combination,temporary strategy modification,and other well-killing scenarios.The model was applied to two field wells under water-and oil-based drilling fluids.No secondary downhole complications occurred during well killing,and the calculated pressure curves closely matched the measured construction pressure curves,confirming the model's reliability and applicability.This study provides valuable theoretical guidance for enhancing well control safety in ultra-deep and complex formations.
基金support of the CNPC International Collaborative Research Project(No.2022DQ0410)。
文摘This study aims to eliminate the subjectivity and inconsistency inherent in the traditional International Association of Drilling Contractors(IADC)bit wear rating process,which heavily depends on the experience of drilling engineers and often leads to unreliable results.Leveraging advancements in computer vision and deep learning algorithms,this research proposes an automated detection and classification method for polycrystalline diamond compact(PDC)bit damage.YOLOv10 was employed to locate the PDC bit cutters,followed by two SqueezeNet models to perform wear rating and wear type classifications.A comprehensive dataset was created based on the IADC dull bit evaluation standards.Additionally,this study discusses the necessity of data augmentation and finds that certain methods,such as cropping,splicing,and mixing,may reduce the accuracy of cutter detection.The experimental results demonstrate that the proposed method significantly enhances the accuracy of bit damage detection and classification while also providing substantial improvements in processing speed and computational efficiency,offering a valuable tool for optimizing drilling operations and reducing costs.
基金National Science and Technology Major Project(2025ZD1406805)“Key Technology for Efficient Construction of New Underground Gas Storage”Research Project of CNPC(2023DJ8308)“Research on Wellbore Treatment and Rapid Construction Method of Oil and Gas Reservoir and Thin Salt Layer Storage”National Key Research and Development Program of China(Grant No.2025ZD1406805 and Grant No.2025ZD1011105).
文摘Many mature onshore oilfields have entered a high-water-cut stage,with reservoir recovery approaching economic limits.Converting these depleted or nearly depleted reservoirs into underground gas storage(UGS)facilities offers an efficient way to leverage their substantial storage potential.During cyclic gas injection and withdrawal,however,the reservoir experiences complex three-phase flow and repeated stress fluctuations,which can induce rock fatigue,inelastic deformation,and ultimately sand production.This study uses controlled physical experiments to simulate sand production in reservoir rocks subjected to alternating gas injection and production under three-phase conditions.After preparing oil-water-saturated cores through waterflooding,gas is introduced to perform repeated displacement cycles.Polynomial models relating core mass loss to water-oil ratio and cycle number are developed using the Newton interpolation method,enabling prediction of sand production under various operating conditions.Results show that,within the critical pressure-difference range for sand onset,permeability increases with water-oil ratio.When the water-oil ratio lies between 0.3 and 1,sand production decreases progressively;beyond a ratio of 1,sand production increases with further increases in water-oil ratio.The number of displacement cycles exerts a dominant influence:sand production remains relatively stable between 25 and 55 cycles but rises sharply thereafter.Average sand production during cycles 55–100 is 5.27 times higher than during cycles 5–55.These findings indicate that cumulative structural damage to the rock framework intensifies significantly with repeated cycling,making cycle number a critical factor governing sand production in UGS operations.
基金funding from the National Natural Science Foundation of China(Nos.51991361 and 52288101)the Young Scientists Fund of the National Natural Science Foundation(No.52204023)。
文摘Ionic liquids(ILs),recognized for their negligible vapor pressure,thermal stability,and structural tailorability,offer targeted inhibition of clay expansion.Compared to ILs,polyionic liquids(PILs)possess stronger mechanical properties and adsorption capabilities,showing even greater potential in inhibiting clay swelling.In this work,we synthesized and characterized an imidazole-based ionic liquid(IL-NH_(2)),a polyionic liquid(PIL-ABHIm),and a PIL/IL combination.Their inhibitory performance was rigorously evaluated under simulated drilling conditions through immersion tests,linear swelling tests,among others.Additionally,the mechanisms underlying their interaction with clay minerals were elucidated through contact angle measurements,Fourier-transform infrared spectroscopy,X-ray diffraction(XRD),Zeta potential analysis,and molecular electrostatic potential(MEP)analysis.This work demonstrates that IL-NH_2inhibits osmotic hydration by altering the interlayer structure of the clay,while PIL-ABHIm reduces surface hydration by forming a hydrophobic barrier on the clay surface.PIL/IL combines both mechanisms,significantly enhancing the stability of clay through the dual mechanisms of cation exchange and hydrophobic barriers.These findings reveal an innovative mechanism by which PIL/IL combination inhibits clay hydration and swelling,providing a scientific foundation for their application in drilling fluids.
