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
Two types of ultra-high-temperature resistant water-based drilling fluid additives were designed and developed:an ultra-high-temperature resistant salt-tolerant polymer fluid loss reducer,and an ultra-high-temperature...Two types of ultra-high-temperature resistant water-based drilling fluid additives were designed and developed:an ultra-high-temperature resistant salt-tolerant polymer fluid loss reducer,and an ultra-high-temperature resistant micro-nano plugging agent.An ultra-high-temperature resistant water-based drilling fluid system meeting the requirements of ultra-deep well drilling was established.Laboratory test and field application were employed for performance evaluation.The ultra-high-temperature and high-salt resistant polymer fluid loss reducer exhibits a mesh-like membrane structure with numerous cross-linking points,and its high-temperature and high-pressure(HTHP)loss was 28.2 m L after aging at 220℃under saturated salt conditions.The ultra-high-temperature resistant micro-nano plugging agent adaptively filled mud cake pores/fractures through deformation,thus reducing the fluid loss.At elevated temperatures,it transitioned to a viscoelastic state to effectively cement the rock on wellbore wall and enhanced wall stability.The ultra-high-temperature resistant water-based drilling fluid system with a density of 1.6 g/cm^(3)exhibits excellent rheological properties at high temperature and high pressure.Its HTHP fluid loss at 220℃was only 9.6 m L.It maintains a stable performance under high-temperature and high-salt conditions,with a sedimentation factor below 0.52 after holding at high temperature for 7 d,and generates no H_(2)S gas after aging,demonstrating good lubricity and safety.This drilling fluid system has been successfully applied in the 10000-meter ultra-deep well of China,Shenditake 1,in Tarim Oilfield,ensuring the well's successful drilling to a depth of 10910 m.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
During drilling process,the water phase in drilling fluids infiltrates rock fractures through capillary action.The surface wettability of dolomite is governed by multiple factors,resulting in an unstable wetting state...During drilling process,the water phase in drilling fluids infiltrates rock fractures through capillary action.The surface wettability of dolomite is governed by multiple factors,resulting in an unstable wetting state.Studies have shown that altering the surface wettability of reservoir rocks to an intermediate wetting state can effectively reduce the damage of drilling fluids to oil and gas reservoirs and improve oil and gas recovery.Therefore,it is necessary to develop a reservoir protectant to prevent the water phase in the drilling fluid from intruding into the oil and gas reservoirs.Given this,a modified polysiloxane was synthesized to alter the surface wettability of dolomite.Tetramethylcyclotetrasiloxane(D^(H)_(4))and octamethylcyclotetrasiloxane(D_(4))were ring-opened copolymerized to obtain the hydrogencontaining polysiloxane,which in turn reacted with unsaturated hydrocarbons to obtain the modified polysiloxane.The ability of reservoir protectants to regulate the surface wettability of dolomite under high-temperature and high-salinity conditions was tested.The experimental results show that the reservoir protectant is able to alter the wettability of the dolomite surface to an intermediate wetting state by adsorption on the rock surface even after 16 h of aging at 240℃ and 15% salt concentration.展开更多
Wellbore stability is crucial for ultra-deep wells operating under high temperature and high stress conditions.To analyze the effects of thermal shock and horizontal stress on wellbore stability,a series of true triax...Wellbore stability is crucial for ultra-deep wells operating under high temperature and high stress conditions.To analyze the effects of thermal shock and horizontal stress on wellbore stability,a series of true triaxial compression experiments and wellbore stability experiments were conducted on dolomite specimens under high temperature and high triaxial stress.In the true triaxial compression experiments,as the horizontal stress increases,the peak strength of the specimen exhibits a nonlinear growth trend.As the intermediate principal stress increases,the peak strength of the specimen first increases and then decreases,with the failure mode transitioning from shear failure to a mixed tensile-shear failure.Thermal shock stimulates the formation of microcracks within the specimen,reducing its peak strength,cohesion,and internal friction angle.In the wellbore stability experiments,the maximum horizontal principal stress that causes wellbore instability increases nonlinearly with the increase in minimum horizontal principal stress.Under the same minimum horizontal principal stress conditions,the specimen after thermal shock exhibits a lower maximum horizontal principal stress that causes wellbore instability.Based on the experimental result,Mohr-Coulomb(M-C)and Mogi-Coulomb(MG-C)criteria incorporating the effects of thermal shock were established to evaluate wellbore stability.Comparing the M-C criterion,the MG-C criterion considers the effect of the intermediate principal stress,thus providing a more accurate prediction of wellbore stability in ultra-deep wells.This study enhances the understanding of the mechanisms underlying wellbore instability and offers valuable insights for managing stability challenges in ultra-deep well environments.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
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
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
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
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.
基金Supported by the CNPC Science and Technology Project(2022ZG06)Xinjiang Uygur Autonomous Region Science and Technology Innovation Talent Project(2024TSYCCX0061)。
文摘Two types of ultra-high-temperature resistant water-based drilling fluid additives were designed and developed:an ultra-high-temperature resistant salt-tolerant polymer fluid loss reducer,and an ultra-high-temperature resistant micro-nano plugging agent.An ultra-high-temperature resistant water-based drilling fluid system meeting the requirements of ultra-deep well drilling was established.Laboratory test and field application were employed for performance evaluation.The ultra-high-temperature and high-salt resistant polymer fluid loss reducer exhibits a mesh-like membrane structure with numerous cross-linking points,and its high-temperature and high-pressure(HTHP)loss was 28.2 m L after aging at 220℃under saturated salt conditions.The ultra-high-temperature resistant micro-nano plugging agent adaptively filled mud cake pores/fractures through deformation,thus reducing the fluid loss.At elevated temperatures,it transitioned to a viscoelastic state to effectively cement the rock on wellbore wall and enhanced wall stability.The ultra-high-temperature resistant water-based drilling fluid system with a density of 1.6 g/cm^(3)exhibits excellent rheological properties at high temperature and high pressure.Its HTHP fluid loss at 220℃was only 9.6 m L.It maintains a stable performance under high-temperature and high-salt conditions,with a sedimentation factor below 0.52 after holding at high temperature for 7 d,and generates no H_(2)S gas after aging,demonstrating good lubricity and safety.This drilling fluid system has been successfully applied in the 10000-meter ultra-deep well of China,Shenditake 1,in Tarim Oilfield,ensuring the well's successful drilling to a depth of 10910 m.
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funded by the Opening Project of Oil&Gas Field Applied Chemistry Key Laboratory of Sichuan Province(YQKF202214)。
文摘During drilling process,the water phase in drilling fluids infiltrates rock fractures through capillary action.The surface wettability of dolomite is governed by multiple factors,resulting in an unstable wetting state.Studies have shown that altering the surface wettability of reservoir rocks to an intermediate wetting state can effectively reduce the damage of drilling fluids to oil and gas reservoirs and improve oil and gas recovery.Therefore,it is necessary to develop a reservoir protectant to prevent the water phase in the drilling fluid from intruding into the oil and gas reservoirs.Given this,a modified polysiloxane was synthesized to alter the surface wettability of dolomite.Tetramethylcyclotetrasiloxane(D^(H)_(4))and octamethylcyclotetrasiloxane(D_(4))were ring-opened copolymerized to obtain the hydrogencontaining polysiloxane,which in turn reacted with unsaturated hydrocarbons to obtain the modified polysiloxane.The ability of reservoir protectants to regulate the surface wettability of dolomite under high-temperature and high-salinity conditions was tested.The experimental results show that the reservoir protectant is able to alter the wettability of the dolomite surface to an intermediate wetting state by adsorption on the rock surface even after 16 h of aging at 240℃ and 15% salt concentration.
基金funding support from Deep Earth Probe and Mineral Resources Exploration,National Science and Technology Major Project(Grant No.2024ZD1003600)Engineering Research Center of Geothermal Resources Development Technology and Equipment,Ministry of Education,Jilin University(Grant No.24013)Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-DQC022).
文摘Wellbore stability is crucial for ultra-deep wells operating under high temperature and high stress conditions.To analyze the effects of thermal shock and horizontal stress on wellbore stability,a series of true triaxial compression experiments and wellbore stability experiments were conducted on dolomite specimens under high temperature and high triaxial stress.In the true triaxial compression experiments,as the horizontal stress increases,the peak strength of the specimen exhibits a nonlinear growth trend.As the intermediate principal stress increases,the peak strength of the specimen first increases and then decreases,with the failure mode transitioning from shear failure to a mixed tensile-shear failure.Thermal shock stimulates the formation of microcracks within the specimen,reducing its peak strength,cohesion,and internal friction angle.In the wellbore stability experiments,the maximum horizontal principal stress that causes wellbore instability increases nonlinearly with the increase in minimum horizontal principal stress.Under the same minimum horizontal principal stress conditions,the specimen after thermal shock exhibits a lower maximum horizontal principal stress that causes wellbore instability.Based on the experimental result,Mohr-Coulomb(M-C)and Mogi-Coulomb(MG-C)criteria incorporating the effects of thermal shock were established to evaluate wellbore stability.Comparing the M-C criterion,the MG-C criterion considers the effect of the intermediate principal stress,thus providing a more accurate prediction of wellbore stability in ultra-deep wells.This study enhances the understanding of the mechanisms underlying wellbore instability and offers valuable insights for managing stability challenges in ultra-deep well environments.
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 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.
