The uncertainty of geological composition,the invisibility of the under-well real-time working conditions,and the complexity of the engineering simulation in the oil and gas field drilling and production process have hindered its scientific and efficient design and construction.The digital twin technology can bring up real-time,intelligent,and visualized project design and decision-making but has yet to lack a systematic method for modeling oil and gas field drilling and production.In this regard,the article first explored the current levels of investigation and implementation both domestically and abroad,based on that the level of development by applying the maturity index was quantified.It then proposed the digital twin modeling approach for drill-ing and production in the oil and gas field,which encompassed the modeling workflow,model division strategies,architecture for model assembly and integration,and modeling tools for constructing the digital twin.Also,two case were studied for drilling and production,using wellbore stability while drilling and offshore gas well production system as two examples,respectively.Finally,the difficulties and challenges related to the digital twin deployment in the field were analyzed,based on which the suggestions for its future development are proposed.It is found that the digital twin for drilling and production has stayed at the visualization level and at a relatively low degree of maturity compared to the manufacturing field on digital twin.The complex demand for oil and gas drilling and production systems can be divided into several clear and easy realized sub-demands.Based on requirement analysis,the modeled object can be separated to be various sub-models based on the granularity,dimension,and lifecycle.The sub-models are then assembled layer by layer across the model,function,and demand layers so that the multi-dimension and multi-field models can be integrated.Meanwhile,an improvement of their methods and an increase in efficiency for the model administration,data management,and engineering simulation ae desired.Moreover,the digital twin faces the problems such as difficulty in selection and fusion of multi-source heterogeneous data,vagueness in the sub-model definition,and ambiguity in the model validation,as well as the challenges such as the complicated kinetics processes,multi-division and multi-task collaboration,and development of domestic software tools.In summary,the digital twin modeling approach and the case studies in this article can provide a methodological guidance and practical reference for oil and gas drilling and production practices.

暂堵转向压裂是非常规油气资源开发过程中的重要增产改造手段之一.通过对国内外暂堵转向压裂技术文献的整理,从暂堵转向压裂机理、材料和工艺3个方面对暂堵转向压裂技术的发展进行了总结.首先,暂堵转向压裂过程包括3个关键步骤:暂堵剂运移、封堵、裂缝转向.不同暂堵剂颗粒的运移分异行为影响了其后续的封堵过程,进而影响新缝的开启,三者紧密相连.其次,在现场应用的暂堵剂种类繁多,包括固体颗粒、纤维、凝胶、泡沫等类型,需要根据储层特征优选适合的暂堵剂,特别是考虑其耐温性、降解性以及承压能力.目前,可降解颗粒和纤维暂堵剂是主流的发展趋势.最后,暂堵转向压裂技术具有广泛的应用场景,其效果得到多种监测手段的证实.在作业过程中需要根据暂堵剂类型的差异采用不同的加注方式,暂堵剂用量和加入时机可根据管外光纤、高频压力监测等多种先进技术手段进行优化设计.随着这些先进技术的应用与推广,暂堵转向压裂作业终将实现实时调控与优化.

To address the challenges of the oil-based drilling fluid system's deteriorating rheological properties and insufficient plugging pressure resistance under high-low temperature cycling conditions in the Yaha gas storage reservoir drilling,a tempera-ture-sensitive high-temperature thickener,RHT,was developed.Optimized plugging materials and supporting agents were selected to construct a high-temperature resistant oil-based drilling fluid system.Characterization methods,including infrared spectroscopy,nuclear magnetic resonance hydrogen spectra,thermogravimetric analysis,and differential scanning calorimetry(DSC),were used to analyze RHT's molecular structure,thermal stability,and temperature-sensitive characteristics in depth.The systematic evaluation of its rheological control in emulsions and oil-based drilling fluids was conducted.Experimental results showed that RHT significantly improved the shear-thinning and thixotropic properties of the emulsion,demonstrating excellent rheological control capabilities under high-low temperature cycling conditions.At 80℃,the dynamic yield stress increased by 87%without any increase in plastic viscosity;at 220℃,the dynamic yield stress increased by 220%,with a dynamic plastic ratio of 0.49 Pa/(mPa·s).The drilling fluid system maintained strong rock-carrying capacity after aging at 220℃and effectively sealed 20～40 mesh sand beds and 1～3 mm cracks,achieving a maximum pressure resistance of 8 MPa.In the field application of the Yaha gas storage reservoir well X,this system significantly enhanced the rock-carrying and plugging performance of the drilling fluid,reducing complexities such as fluid loss and stuck pipe incidents,thereby providing strong technical support for the efficient development of the Yaha gas storage reservoir.

With the exploration and development of oil and gas into the ultra-deep reservoir,hydraulic fracture propagation under the condition of high stress difference is prone to occur large curvature deflection,leading to wellhead overpressure,sand plugging and other problems occur frequently.It is of great significance to clarify the mechanism and main control factors of hydraulic fracture propagation and deflection near wellbore in ultra-deep and high stress difference reservoir for safe and efficient develop-ment.Under the constraint of the continuity framework of classical thermodynamics,the sharp fracture on the discrete interface is smoothly described as a continuous damage dispersion fracture,and the Lagrange Energy Functional is constructed based on Griffith energy balance relation and fracture variational principle,and then the phase field hydraulic fracturing model of perforated well in anisotropic reservoir is established based on the principle of energy minimization.The validity of the phase-field model presented in this paper is verified by comparing with the classical Griffith crack opening profile equation.It is found that the hydraulic fracture starts to crack along an approximate straight line between perforation and maximum horizontal principal stress,and then deflects to the maximum horizontal principal stress direction.The specific direction of crack initiation is affected by in-situ stress difference,displacement and perforation angle.The increase of the in-situ stress difference will promote the hydraulic fracture deflection propagation near the wellbore,make the deflection angle increase and the deflection radius decrease;increasing the displacement can weaken the hydraulic fracture deflection,and making the deflection angle decrease and the deflection radius increase;with the increase of perforation angle,the angle between perforation and the maximum horizontal principal stress increases,which will aggravate the deflection degree of crack propagation so that the flow friction of fracturing fluid increases and the risk of sand plugging increases;the anisotropy characteristics of the reservoir can also significantly affect the deflection and propagation process of hydraulic fractures.In the model,the critical energy release rate in different directions is taken as the anisotropic parameter of fracture resistance.The results show that fractures tend to propagate in the direction of low resistance.The stronger the anisotropy of fracture resistance,the greater the deflection degree of hydraulic fractures.The anisotropic characteristics of reservoir fractures significantly affect the turning behavior of fractures.The phase-field hydraulic fracturing model in this paper provides a convenient method to study the propagation and steering behavior of hydraulic fractures without any fracture criteria,which is helpful to improve the understanding of near-well fracture steering in ultra-deep and high stress difference reservoirs,help to understand the fracture mechanism and fracture deflection behavior under different geological environments and fracturing conditions,and provide reference and suggestions for fracturing technology design and perforation scheme optimization.

The fault-controlled fracture-cavity type oil and gas reservoir plays an important role in the exploration and develop-ment of oil and gas in the carbonate rocks of the Tarim Basin.Research shows that there are significant differences in the oil and gas development effects in different fractures or different segments of the same fracture in the Fuman Oilfield,leading to unclear oil and gas accumulation characteristics and affecting the efficient development of ultra-deep layers.This paper takes the strata from the Yijianfang Group to the Yingshan Group in the Fuman Oilfield of the Tarim Basin as an example,using drilling data,high-quality 3D seismic data,and production dynamic data to study the control effect of ultra-deep strike-slip faults on the degree of oil and gas accumulation.The results show that:(1)The oil and gas accumulation in the fault zone is mainly controlled by three factors:the contact relationship between the fault and the source rock,the fault's role as a migration pathway,and the size of the reservoir.(2)By comparing and analyzing the drilling production results,the paper establishes a quantitative relationship between the connectivity of the source,the fault's guiding role,the scale of the reservoir,and oil and gas accumulation,improving a set of evaluation and calculation methods for the differentiated accumulation degree of ultra-deep fault-controlled oil and gas reservoirs.(3)The source connectivity of deep and large faults is an important factor affecting the accumulation degree of fault-controlled oil and gas reservoirs.The higher the oil and gas accumulation,the better the contact between the fault and the source rock,the better the vertical connectivity of the migration pathway,and the larger the effective reservoir scale. This paper proposes a new understanding of the"source connectivity"analysis of fractures in fault-controlled fracture-cav-ity reservoirs and develops an evaluation technique for ultra-deep carbonate"fault-controlled oil and gas reservoir formation".Using this method,the oil and gas accumulation degree of the FI 19 fault zone in the Fuman Oilfield was analyzed,with a match rate of 92%to the well data.This method has good reference value for the further development practice of other oilfields in the Tarim Basin.

Unconventional oil and gas resources serve as vital replacement energy in China's hydrocarbon portfolio,and their efficient development is of great significance for safeguarding national energy security.The implementation of staged multi-clus-ter hydraulic fracturing in horizontal wells,along with the optimization of intra-stage cluster design parameters,is critical to maximizing the production potential of unconventional reservoirs.Clarifying fracture propagation mechanisms and quantifying the relationship between fracture geometry and well productivity is key to optimize intra-stage multi-cluster fracturing strategies.In this study,a phase-field method is employed to simulate the competitive propagation morphology of multiple fractures within a fracturing stage.A fracture morphology identification technique is integrated to construct a two-dimensional equivalent fracture model,which can characterize the stimulated flow pathways.Equivalent physical parameters after stimulation are extracted and transferred-together with geometric descriptors-as input for a discrete fracture flow model.This enables automatic coupling and data transfer between the geometric and flow models,thereby facilitating quantitative evaluation of production performance under different fracturing scenarios and ultimately achieving fully coupled fracture propagation-fluid flow simulation.The accuracy and feasibility of the dual-model coupling method are verified through comparison with laboratory-scale physical simulation experiments and field fracturing data.On this basis,the effects of intra-stage cluster number and cluster spacing on fracture morphology and production response are further investigated.The results show that,as the cluster spacing increases from 15 m to 25 m,the fracture deflection point shifts farther from the wellbore,and the tip deflection angle decreases from 30° to 24°.Meanwhile,the pressure gradient around the fracture tip is reduced,weakening the fluid driving force and significantly diminishing inter-fracture fluid interference.This change leads to a decline in peak daily oil production and stabilized production rate,with daily and cumulative oil output decreasing by 35.88%and 35.89%,respectively.In contrast,when the number of clusters per stage increases from 3 to 5,the deflection angle at the tip of the outer fractures increases from 30° to 34°,while the coverage of the induced stress field expands from 36.74%to 42.46%.This results in a higher pressure gradient surrounding the fractures,enhancing the fluid driving force and significantly improving oil mobilization.Consequently,peak daily and cumulative oil production increased by 40.49%and 45.467%,respectively.Therefore,optimizing the intra-stage cluster spacing and cluster number can effectively balance the degree of fracture interference and enhance single-well productivity,thereby improving the overall effectiveness of staged multi-cluster hydraulic fracturing in horizontal wells.

In the process of fracturing in tight reservoirs,the imbibition and displacement of crude oil in reservoir pores by fracturing fluids has gradually become a key research field of enhanced oil recovery technology.However,the production characteristics and mechanism of pore crude oil at different scales in the process of imbibition are still unclear,which seriously restricts the optimal design of fracturing fluid system and the reasonable selection of mining technology.Taking the Chang 7 member tight reservoir in the Ordos Basin as the research object,the amphoteric surfactant(EAB-40)was used as the main agent of the clean fracturing fluid system,combined with T1-T2 two-dimensional nuclear magnetic resonance and wettability test,the influence of surfactant concentration on reservoir interface properties and fracturing fluid imbibition and displacement efficiency was systematically studied,and its microscopic mechanism was revealed.The experimental results show that EAB-40 signifi-cantly enhances the capillary driving force and crude oil desorption efficiency by synergistically reducing the oil-water interfacial tension(up to the order of 10-2 mN/m)and inducing the wettability reversal(the contact angle is reduced from 147° to 57.34°).The comprehensive oil displacement effect of the fracturing fluid system is optimal when the concentration of surfactant is 0.1 wt%.During the imbibibibition process,the wettability inversion is caused by the concentration of water-wet minerals in the small pores,and the diffusion of surfactants causes the wetting inversion,which drives the crude oil to migrate efficiently from the small pores T2<1 ms to the middle(T2 is between 1 and 100 ms)and large pores T2>100 ms.Polymer molecules improve the rheological properties of the fracturing fluid system and promote the deep utilization of residual oil in bound oil and blind end pores.Realize the triple synergistic imbibibibibition mechanism of"IFT reduction-wetting inversion-viscoelastic flow control".

Geothermal energy in hot dry rock formations is an important component of China's geothermal resources,and its development is of significant importance for achieving the"dual carbon"goals.The reservoir rocks of hot dry rock formations are mainly granites.The lithology of granites is dense and is usually developed by Enhanced Geothermal System(EGS).As the main pathways for fluid flow and heat transfer in the circulation process,both artificial and natural fractures deformation can lead to the evolution of conductivity,thereby influencing the heat extraction performance of the thermal reservoir.Existing studies on conductivity mostly focus on artificial fractures,often centered around matrix elastic deformation,without considering the impact of natural fractures damage.To reveal the effects of natural fractures damage,a high-temperature and high-pressure rock core injection and extraction multi-field coupling experimental platform is independently developed and designed.The reliability of the experimental system was analyzed and verified,corresponding experimental schemes and procedures are designed.Natural fractures were used to penetrate the rock samples,study the variations of injection and extraction differential pressure with injec-tion flow and confining pressure at room temperature.The characteristics of natural fractures damage at high temperatures were analyzed,and the impact of natural fractures damage on the evolution of conductivity under different injection flow,temperature difference and injection modes were compared.The experiments demonstrated that injecting cold fluid resulted in a significant increase in the volume of natural fractures compared to the initial state,primarily through weak cementation failure damage.Un-der no confining pressure conditions,damage caused an increase in fracture aperture and length,enhancing fracture connectivity and altering fracture conductivity.Therefore,natural fractures should be considered in the design of fracturing and heat extraction schemes.The injection and extraction differential pressure increased with increasing confining pressure and injection flow,with a maximum increase of up to 0.6 MPa.During high-temperature production,the maximum changes in injection and extraction differential pressure and conductivity evolution rate reached 1.11 MPa and 26.59%,respectively.Characteristics of fracture damage are more pronounced under higher injection flows and temperature differentials.Fracture damage is more significant under intermittent injection compared to continuous injection.Grey relational analysis identified the primary controlling factor as the temperature differential,indicating that thermal stress is the main cause of additional conductivity evolution due to fracture damage.This study highlights the necessity of analyzing natural fractures damage in the long-term production process of hot dry rock formations,providing valuable guidance for engineering field construction.

China is rich in shale oil resources.By the end of 2022,the predicted reserves of continental shale oil in China have reached 3 billion tonnes,but only recoverable shale oil has economic value under such reserves.The shale oil reservoirs of the Lucaogou For-mation in the Jimusar Sag can be divided into three types:interlayer type,lamina type and block type according to mineral composition and source-reservoir ratio.However,due to the large difference in pore structure characteristics and fluid occurrence state of the three types of reservoirs,the productivity difference is high using the same fracturing method.In order to clarify the pore structure character-istics of the Lucaogou interlayer and laminated reservoirs in the Jimusar sag and the difference of fluid mobility under their constraints,this paper studies the pore structure characteristics by means of XRD,casting thin sections,scanning electron microscopy and nitrogen adsorption.Nuclear magnetic resonance centrifugation technology was used to quantitatively evaluate the mobility of shale oil in laminated and laminated reservoir samples.The T1-T2 spectrum method was used to clarify the occurrence state of shale oil in different reservoir types.Finally,the main controlling factors of fluid mobility in shale oil reservoirs were analyzed by combining characteristic pore structure parameters.The results show that the carbonate content of laminated reservoirs is high,and the reservoir space is domi-nated by carbonate intergranular pores,clay mineral interlayer fractures and organic matter pores.The fluid component is dominated by kerogen,and the free oil component content is extremely low.The average value of movable fluid saturation is only 7.97%.The felsic content of the interlayer type is higher,the reservoir space is mainly composed of intercrystalline pores and dissolved pores in feldspar grains,the fluid composition is mainly movable oil,followed by bound oil and kerogen,and there is no movable water.The average saturation of movable fluid is 29.3%.The pore throat radius in the characteristic pore structure parameters is the main factor controlling the movable fluid saturation of shale oil reservoirs.The two are exponentially correlated,and the correlation coefficient can reach 0.95.Through the study,the main reservoir space types of the intergranular pores and intra-granular pores in the Lucaogou Formation and the laminar shale oil reservoirs in the Jimsal Depression are determined.The mobile fluid saturation decreases gradually from unimodal interlayer reservoirs to bimodal laminated reservoirs,but increases exponentially with the increase of the maximum pore throat radius.The results show that the maximum pore throat radius has a great influence on the mobile fluid saturation of shale oil reservoir.

油气藏流体运移及地层岩石形变贯穿油气开发始终,是油气开发的核心科学问题.页岩储层天然裂缝发育、地层流体流动机理多样、岩石力学参数呈现非均质性和各向异性等特征,致使页岩气储层气藏渗流—地质力学耦合问题异常复杂.页岩气井生产过程中井筒周围储层产生不同程度的压降,扰动压降区的原地应力,储层应力随开采时间不断演化,即四维动态地应力.准确预测页岩气储层四维动态地应力场是页岩气加密井压裂和重复压裂设计的前提.因此,本文系统总结了油气藏渗流—地质力学耦合及加密井裂缝扩展的数值模拟方法,深入讨论了页岩气藏多场耦合模拟进展和最新研究成果.目前油气藏渗流—地质力学耦合模型多种多样,按照耦合求解形式可划分为全耦合、顺序耦合、单向耦合及拟耦合,通过一种或多种软件结合实现复杂的耦合计算,但各类计算方法的计算时效性及适用性存在差异.由于页岩储层地质特征复杂,目前四维地应力演化模型在传统模型基础上进行了改进,其主要为基于全耦合方法的连续介质模型和离散裂缝模型,以及迭代耦合模型.页岩气开发过程中,三向地应力随孔隙压力的减小而降低,应力方向也会随之发生偏转.相对于连续介质,裂缝会影响储层地应力分布规律和变化趋势.这种地应力状态演化会使加密井裂缝扩展发生偏转及产生"Frac-hit"现象,并引起"微地震屏障"效应.页岩气藏开发过程中的储层渗流—地质力学耦合及裂缝扩展研究是多物理场、多维度、多尺度的耦合问题,本文建议深入研究地质工程一体化的解决方案,开展四维地应力演化条件下页岩气藏水平井重复压裂及加密井压裂过程中复杂裂缝扩展机理研究、页岩气储层立体化开发复杂裂缝空间干扰机理研究、重复压裂及加密井压裂时间优化研究,以及水平井压裂套管损伤机理研究等,为我国页岩气藏的持续高效开发提供理论支撑.

Low salinity water flooding is a new technology for enhancing oil recovery by adjusting the ion composition or con-centration of injected water.However,the applicable reservoir conditions and enhanced oil recovery mechanism of low salinity water flooding have not yet reached a consensus.In this paper,a series of laboratory experiments of wettability control-based low salinity flooding are carried out with plunger rock samples from marine carbonate reservoirs in the Middle East as the research object.Based on the theory of Derjaguin-Landau-Verwey-Overbeek theory(DLVO),an interfacial reaction model of a typical crude oil/brine/rock system is established,and the contact angle and total separation pressure are calculated simultaneously with the augmented Young-Laplace formula.The reliability of the model is verified by the literature experimental data,and the effects of ion concentration and ion type on the separation pressure curve and contact angle are clarified.The results show that in low salinity environments,the pore surface of carbonate rock is more water-wet under the action of fluid flushing,the oil displacement efficiency is higher,and the low salinity water improves the crude oil recovery by 3.2%;under the assumption of constant charge,the mathematical model established based on the DLVO theory for the crude oil/brine/rock system can accurately predict the change of contact angle;compared with the ion concentration,ion type has a greater impact on separation pressure and contact angle.Among divalent ions,Mg2+ions exhibit a more pronounced influence on wettability control compared to Ca2+ions.When the water film thickness is minimal,van der Waals force is the main force affecting the separation pressure.As the thickness of water film increases,the electric double layer force gradually becomes the main force.This study contributes to a deeper understanding of the wettability control mechanism of low salinity water flooding for enhanced oil recovery.

The technology of producing chemicals directly from crude oil involves the direct catalytic cracking of crude oil into chemical raw materials.This innovative process bypasses traditional atmospheric and vacuum distillation units and hydrogenation units,directly reducing both equipment investment and energy consumption.Consequently,this leads to lower production costs and brings significant economic benefits.The direct conversion method not only streamlines the production process but also minimizes the need for complex infrastructure,making it a more efficient alternative to conventional methods.With the continuous advancement of the national dual carbon goals-aiming to peak carbon dioxide emissions and achieve carbon neutrality-accelerating the development of technology for direct catalytic cracking of crude oil to produce chemicals is of paramount importance.This technology holds the potential to significantly reduce process energy consumption and contribute to carbon emission reduction efforts.By optimizing the cracking process,it is possible to achieve higher yields of desirable chemicals while minimizing the formation of by-products like coke,which are less valuable and contribute to increased emissions.As research on the modeling of technology for producing chemicals directly from crude oil deepens,establishing intelligent models to guide process production becomes increasingly crucial.These models can optimize process operations by fine-tuning parameters in real-time,thereby achieving a balance between economic benefits and environmental sustainability.Intelligent models leverage data-driven insights to predict outcomes and adjust variables dynamically,ensuring that the production process remains efficient and aligned with both economic and environmental targets.This study established a robust process simulation model in Aspen HYSYS based on industrial trial data from direct catalytic cracking of crude oil.Through detailed case analysis,single-factor analysis was conducted on four critical process parameters:preheating temperature,reaction temperature,regeneration temperature,and catalyst equilibrium activity.Each of these parameters played a vital role in determining the efficiency and yield of the cracking process.By systematically varyied these factors,researchers can identify optimal conditions that maximize the production of key chemicals such as ethylene and propylene while minimizing unwanted by-products like coke.To enhance the predictive capabilities of the model,a neural network was implemented using Python programming.This neural network model was trained on a comprehensive dataset derived from the process simulations.The model's ability to predict product distribution under different operating conditions was rigorously tested and validated.Furthermore,a multi-objective optimization algorithm,NSGA-II,was integrated into the deep learning framework.This algorithm focuses on maximizing the yield of low-carbon olefins while minimizing coke production,providing a balanced approach to optimizing the overall process.Compared to traditional optimization methods,the established surrogate model offers higher computational efficiency and faster optimization solution times.It enables the decoupling of multiple operational variables,allowing for more precise control over the process.This real-time optimization capability is particularly beneficial in dynamic production environments where conditions can change rapidly.The optimization results demonstrated notable improvements:coke yield decreased by 0.23%,while the yields of ethylene and propylene increased by 1%.In conclusion,the intelligent agent model developed in this study not only enhances solution efficiency and prediction accuracy but also provides valuable insights for guiding process production.Its application could lead to more sustainable and cost-effective chemical manufacturing processes,aligning with both economic and environmental objectives.

水力压裂过程中,暂堵剂在缝内形成架桥封堵,提升缝内净压力,转向激活天然裂缝,增大储层改造体积.本文介绍了水力压裂物理过程及基本控制方程,基于该方程建立了二维流固全耦合相交裂缝扩展模型,实现缝内暂堵转向过程的模拟.利用黏结单元指定水力裂缝与天然裂缝扩展路径,基于内聚区模型控制裂缝单元的起裂与扩展.基于达西方程和润滑方程,令流体在暂堵体内流动的压降,与流体在无暂堵体缝内流动的压降相等,通过改变润滑方程中的等效黏度项来模拟暂堵体对缝内流体流动的影响.模型模拟结果与已发表的数值模拟结果吻合,证明了模型的可靠性.基于该模型研究了缝内暂堵转向动态过程,模拟结果表明,流体压力在暂堵体内部迅速降低,缝内净压力及裂缝开度显著增大,转向激活天然裂缝.整个缝内暂堵转向过程分为5个阶段:(1)水力裂缝起裂并扩展至相交点;(2)水力裂缝由相交点扩展至暂堵体;(3)水力裂缝停止扩展及天然裂缝上分支扩展结束;(4)天然裂缝上分支扩展结束至下分支扩展结束;(5)裂缝体积持续膨胀.本文工作为后续系统开展缝内暂堵转向规律研究提供了方法与模型基础.

面临日益复杂的化工过程生产装置,提高化工过程报警系统的性能有着重要的指导意义.传统的化工过程参数报警阈值设置方法一般只考虑误报警,并没有同时考虑误报警和漏报警,导致报警系统产生大量的错误报警.针对上述问题,提出自适应综合指标的报警阈值优化方法.采用核密度估计方法、基于历史数据对过程报警状态进行估计,综合考虑误报警率和漏报警率,从而建立优化报警阈值的目标函数,将数值优化算法内嵌于粒子群算法形成新的算法进行求解.案例分析中将此方法应用于TE过程,结果表明,用此方法设置的报警阈值监测误报率为0,漏报率为0.78％.与传统的3σ-法相比,此方法能够在保证低漏报率的条件下有效降低误报警率,提高化工过程报警系统的性能,减轻现场操作人员的工作压力,减少人员生命财产损失.

水力压裂过程中为了提高缝网的复杂程度,常在压裂过程中注入可降解的纤维和颗粒,通过对已有裂缝的暂时封堵迫使新裂缝开启并在延伸过程中转向.但是由于目前对纤维与颗粒在水力裂缝内的封堵形成机理仍不明确,制约了暂堵转向压裂效果的进一步提升.因此,本文建立了水力裂缝内封堵的可视化实验系统,对纤维与颗粒在5 mm宽裂缝内的封堵过程进行了直接观测.实验发现封堵过程起始于纤维在裂缝壁面上的吸附,吸附的纤维不断聚集形成封堵带,封堵带膨胀到一定程度后开始捕捉流过的颗粒并填充到纤维的孔隙中,封堵带在扩张的同时变得均匀密实,从而加速了封堵形成过程,最终形成全面封堵.实验结果说明纤维开启了封堵过程,仅仅依靠2 mm粒径的颗粒是无法形成封堵的,但是颗粒可以在封堵后期大幅度加快封堵进程并承担缝内的压差,因此建议在实际的暂堵过程中应该先加入纤维,待到压力明显升高后再加入颗粒.最后,分别固定颗粒和纤维的浓度为1％,考察了另一组分浓度变化时5 mm宽裂缝中的封堵表现,发现封堵形成时间随着暂堵剂浓度的增加而减少,但是当纤维和颗粒的浓度高于1.0％时,其浓度的提高对封堵效率的影响变得十分有限.因此,综合考虑封堵效率和材料成本,对于5 mm宽的水力裂缝,颗粒和纤维的最优质量浓度建议均取为1.0％.

疏松砂岩储层在改造及注水施工中表现出与致密储层压裂迥异的力学变形特征,亟需特定的力学机理解释其宏微观变形行为,从而为现场施工提供理论指导.针对疏松砂岩质地松软、塑性强、渗透率高的岩土力学性质,本文引入土力学的理念,介绍微压裂这一储层改造与增注技术,深入分析该类储层在微压裂过程中的扩容及微裂缝起裂机理.在理清微压裂力学机理的基础上,总结归纳已有的储层微压裂效果评价方法,包括室内实验、解析分析和数值计算方法,阐明各类方法的必要性和优缺点.基于力学机理和计算方法,讨论了微压裂技术在超稠油储层改造、井筒解堵和人工干预地应力场中的应用方法和工程案例.最后,以超稠油储层改造为例,提出微压裂效果自动化评价技术.研究发现微压裂为综合孔隙弹性、塑性和断裂多种力学变形的复杂力学机制,在不同的应用场合实现的功能各异,但普遍体现为扩容至微裂缝起裂这一过程的局部至全部特征;分析微压裂作用效果应当考虑多尺度效应,结合多类数值计算方法开展实际工程案例评价.超稠油储层微压裂改造以井周产生微裂缝、井间储层发生孔隙扩容为主,加强井间热对流效应,加速井间连通.微压裂应用于井筒解堵时提供了反洗冲砂、井周扩容与造微裂缝恢复流体通道的作用,从而延长解堵效果.此外,微压裂亦可应用于致密储层,通过人工干预井周、井间、段簇间有效地应力场,使其利于预期造缝目标.未来的技术攻关应集中在完善自动化、进而发展智能化的微压裂技术,逐步取代人工决策及控制.

非常规油气藏具有岩石致密、孔隙度和渗透率极低、孔隙类型具有多尺度性、强非均质性以及储量丰度低等地质特征,通常采用水平井和大规模"超级"分段压裂的井工厂模式再造一个缝网发育的"人工油气藏"而实现集约化高效开发.本文从高效开发的角度阐述了非常规油气藏开发过程中的工程科学问题:(1)考虑应力场和储层孔隙类型多尺度的地质建模问题(初始建模和压后二次建模);(2)非常规油气藏的裂缝扩展数值模拟问题;(3)非常规油气藏的生产数值模拟及其大规模数值计算;(4)井工厂中水平井和压裂裂缝空间位置的优化设计方法.结合课题组(中国石油大学油气渗流中心)的研究特色.综述了这些工程科学问题的发展现状和趋势,提出了基于非常规油气藏地质模型和数值模拟的井工厂开发模式工程参数的优化设计方法,对非常规油气藏的科学高效开发具有重要的意义.

连续管钻井完井技术是上世纪90年代初迅速发展起来的新技术,它具有作业效率高、成本低、安全可靠等优点.本文回顾世界连续管技术的发展概况,分析国内外连续管钻井和完井的技术现状;阐述连续管寿命及可靠性、变形伸长量、管内流体摩擦压降、钻井携岩和水平井冲砂洗井等连续管钻井完井相关基础理论研究进展;探讨连续管超临界CO2钻井、连续管非接触式破岩钻井、连续管无水压裂、连续管无限级压裂和连续管钻井与压裂改造一体化等前沿技术可行性与发展趋势;最后,展望连续管钻井和完井技术的发展前景.

西湖凹陷平湖斜坡带北部孔雀亭含油构造油气资源丰富,但成藏过程复杂,其油气来源和充注过程尚不明确.通过油源对比及流体包裹体岩相学、均一温度、盐度、结合激光拉曼测试等多种方法,对孔雀亭构造油气来源、油气充注期次和成藏时间进行了分析.研究表明孔雀亭地区烃源岩主要分布在古近系始新统沉积的平湖组、宝石组地层,烃源岩类型包括煤、碳质泥岩和泥岩,有机质类型为Ⅱ1—Ⅱ2型;平湖组上、中、下段和宝石组烃源岩总有机碳含量(TOC)、生烃潜力(S1+S2)、氢指数(HI)等指标有所差异,其中平下段烃源岩有着较高的总有机碳含量;平湖组、花港组砂体多层系含油,油气地球化学性质均有差异,油源对比显示该区油气可划分为2类,Ⅰ类较低成熟度的油气来源于孔雀亭地区中低带平湖组下段烃源岩,Ⅱ类较高成熟度的油气可能来源于中低带宝石组烃源岩;平湖组储层发育2期流体包裹体,第1期气液两相包裹体发黄色、黄绿色、蓝绿色荧光,因经历再平衡作用,认为其捕获均一温度为130～140°C,成藏时期为5～2 Ma,以轻质油和凝析油充注为主;第Ⅱ期天然气包裹体呈灰色,无荧光显示,未经历再平衡作用,结合主峰均一温度140～150°C,认为成藏时期为2 Ma至今,以天然气充注为主,呈现晚期充注特征.激光拉曼检测到包裹体中含有沥青质,推测晚期可能伴有气洗作用.研究认为孔雀亭构造油气主要成藏时间为三潭组沉积至今,具备优良的储盖组合与构造演化的时空配置,具有"早油晚气,晚期成藏"的充注特点.

Considering that the current fiber optic signal interpretation models are based on vertical fractures,and the influence of natural fractures and bedding planes makes hydraulic fractures tilted during its propagation process.What's more,its optical fiber monitoring signals will also differ from those produced by vertical fractures,rendering existing optical fiber signal inter-pretation models inapplicable.Therefore,a three-dimensional inclined fracture propagation model is established in this paper,considering the tensile and shear mechanical behaviors during crack extension,and solved by the finite element method.The model in this paper simulates the fiber optic signal characteristics under vertical crack extension conditions has good agreement with the discontinuous displacement method of Liu and Wu,which verifies the correctness of the numerical model in this paper.After that,we build the geometry model of inclined fractures,the effects of different inclination angles,tilt directions,fracture heights,fiber-optic monitoring distances,and in-situ stress states on fiber-optic strains and strain rates are investigated during the propagation of hydraulic fractures with inclination angles.Some conclusions can be drawn from the simulation results:red and blue bands appear on strain rate waterfall plots monitored by fiber optics in neighboring wells during inclined hydraulic fracture propagation.Symmetrical red and blue strain ellipses and strain rate bands appear when the hydraulic fracture inclination is at 30° to 55°.As the inclined hydraulic fracture continues to propagate,when the inclined fracture hits the fiber,multiple heart-shaped zones appear on the strain rate waterfall map.The fiber-optic-monitored strain and strain-rate waterfall maps are also able to reflect the tilt direction of the hydraulic fracture.The width of the red bands of the strain rate waterfall plot increases with increasing hydraulic fracture height,which provides us with a way of interpreting the height of fractures based on the optical fiber monitoring.For hydraulic fractures of the same morphology and size,the optical fiber monitoring signals under different initial stress states exhibit significant differences,among which,the optical fiber monitoring signals under the normal fault stress state have the most distinct band characteristics.Under the simulation conditions of this paper,with each 100 m increase in fiber-optic monitoring distance,the intensity of the fiber-optic-monitored strain and strain-rate signals decreases by one order of magnitude.The research in this paper is of great significance in guiding the interpretation of hydraulic fracture morphology and size through neighboring well fiber-optic signals and guiding the placement of fiber optics in neighboring wells.

管道输氢是实现氢气大规模、长距离运输的有效方式,然而受高投资和运行成本影响,实现管道输送氢气并非易事.现阶段,技术经济模型可对管道的各个阶段进行预可行性和可行性评估,并描述管道的技术内容和特点,而对于氢气管道,已有国内外氢气管道研究通常将氢气管道视为氢供应链流程中运输环节的一种运输方式进行宏观供应链系统优化,而无法反映管道的详细技术特征和市场变化,导致氢气管道成本的大幅度变化.为此,本文结合现有管道的技术特征与成本分析法,建立了氢气管道的预算型技术经济模型,分析了氢气管道的主要构成成本、氢气管道平准化成本与运输规模之间的关系,并采用氢气平准化成本为分析指标进行氢气管道运输与长管拖车、天然气掺氢管道和液氢槽车运输方式的对比,最终获取国内纯氢管道的投资建设成本范围和平准化成本范围.此外,本文提出降低氢气管道运输成本的主要方式为提高氢气输送规模、改造现有油气管道与优化包含氢气管道的运输方式布局.研究结果显示:①当设计输量为2040年的需求量时,氢气管道运行结果为选取管径为DN500的氢气管道进行运输,沿线站场压力满足要求且管线流速均在安全范围内.②对于给定的150～550 km管道,当设计输量为2040年的需求量时,总建设投资范围为9.66×108～35.43×108 CNY.③氢气管道运输平准化成本随运输距离增加而增加,当运输规模一定时,平准化成本最高不超过10.12 CNY/kg.④在给定运输规模和不同的运输距离下,氢气管道运输成本较长管拖车和液氢槽车具有价格优势,价格范围在2.76～10.12 CNY/kg.研究成果可为纯氢管道的成本估算提供依据,对合理选择氢气管道工程投资和经济效益评价对比分析具有重要意义,为管道建设提供参考.

The heterogeneity of Ordovician carbonate reservoirs in the Halahatang Oilfield,Tarim Basin is complex,so it is important to carry out evaluation and prediction research.Based on geological and seismic data from the Halahatang Oilfield,this paper studies carbonate fracture-vuggy reservoir location,reservoir spatial distribution,reservoir and fault matching relationship,and inter-well connectivity.On this basis,according to the actual drilling,logging data and production dynamic analysis,the fracture-cavity carving of carbonate reservoirs in the fault-controlled area is carried out.The results show that the fault system evolution of the Halahatang oilfield includes four stages:Early Caledonian to Middle Caledonian,Late Caledonian to Early Hercynian,Late Hercynian and Yanshan.Fault trends and multiple stages of fault development are the main controlling factors for the generation of the fault systems.The increase of the horizontal slip of the fault block will give the strike-slip faults better connectivity.The plane diffusing width of the fault is controlled by the intensity of fault activity and the development degree of deep through-source branch faults.In addition,in order to clarify the spatial morphology and distribution characteristics of carbonate reservoirs in buried hill karst areas,interlayer karst areas and fault-controlled karst areas,targeted reservoir prediction is carried out.Based on inversion results,multi-attribute comprehensive prediction is carried out by combining the data such as attributes,sedimentation and drilling.The prediction results show that the fracture zone in the buried-hill karst area of the Tahebei block of the Halahatang Oilfield has good overall source permeability,connectivity and diffusion-solubility,which is conducive to the formation of large-scale solution pore-fracture-cave reservoirs,and the plane distribution of the reservoirs is continuous with the best reservoir quality,which is the key area of oil and gas exploration and development in the future.The study reveals the development characteristics of Ordovician faults and the distribution areas of favorable reservoirs in the fault-controlled area of the Tahebei Block,Halahatang Oilfield,in order to provide a basis for effectively guiding carbonate oil and gas exploration and development in the deep-ultra-deep fault-controlled areas.

西江30洼位于惠州凹陷西南部,由于前期深层地震资料差、钻井少等原因,研究区地质研究及油气发现主要集中在浅层,而对深层文昌组关注相对较少,缺少系统的源汇体系分析及有利砂体预测,制约了该区勘探进程.利用最新三维地震资料和钻井资料,在"源-汇"理论指导下对西江30洼陡坡带文昌组沉积体系进行了系统研究.结果表明:惠西低凸起中生界花岗岩为西江30洼提供物源,源区发育6个汇水单元,对应6个沟谷通道,并定量统计了汇水面积、集水高差、搬运距离、沟谷类型、宽深比等参数.基于地震沉积学及构造背景分析,认为西江30洼陡坡带垂向上发生了由扇三角洲向辫状河三角洲沉积体系的转换,文四段发育扇三角洲沉积,可识别出5个扇体,文三段发育辫状河三角洲沉积,可识别出3个朵叶体.惠州运动所引起的裂陷迁移和古地理格局的变化是西江30洼陡坡带发生扇-辫沉积体系转换的主要原因.通过源汇各要素相关性分析,明确汇水面积和搬运距离是控制西江30洼陡坡带砂体发育规模的主控因素,并指出F汇水单元输砂能力最强,其对应的文四段扇体4和文三段朵叶体3,展布规模最大,地震相特征最优,有利于优质储层发育,是下步勘探的有利区带.通过以上分析指明了西江30洼陡坡带文昌组勘探的有利方向,并且对陡坡型源汇体系研究提供了独特案例.

缝洞型碳酸盐岩储层中分布有形态和尺寸各异的缝洞体,是主要储集体.由于缝洞体的不均匀分布,当前主要采用压裂改造的方式,通过人工裂缝沟通缝洞体,建立缝洞体与井筒之间的流动通道.明确人工裂缝在缝洞体储层中的扩展规律,有利于提升缝洞体储层改造的效果.本文建立了基于非连续离散裂缝模型的缝洞型碳酸盐岩储层人工裂缝扩展数值模型.首先建立缝洞体储层流固耦合应力模型,然后采用离散裂缝模型构建人工裂缝,该模型允许人工裂缝沿着初始划分的网格进行扩展,并采用最小应变能密度准则判定扩展路径.根据缝洞分布规律的不同,本文建立了 3 种缝洞特征的缝洞体储层.通过对具有不同缝洞特征的缝洞体储层模拟研究结果发现:洞体扰动局部应力场,使人工裂缝扩展路径偏转,而洞体越大,扰动作用越明显;根据人工裂缝和洞体相对位置不同,可分为正面排斥作用和侧面吸引作用,而这 2 种作用皆不利于人工裂缝与洞体沟通;但当洞周存在天然裂缝时,人工裂缝可以通过与洞周缝相交,提升沟通缝洞体的概率;增加人工裂缝内净压力,可提升人工裂缝与缝洞体相交时的主导作用,使其偏转程度降低,有利于突破洞体的排斥,与主应力方向缝洞体沟通;人工裂缝穿透缝洞体时的注液点压力主要受人工裂缝内流动能量损失和缝洞体漏失速率控制,优化压裂液性能可以降低穿透压,提升人工裂缝扩展范围.本文研究结果为缝洞型碳酸盐岩储层压裂改造评价提供参考.

我国部分含天然裂缝的混合岩性致密油储层受岩石非均质性的影响,压裂裂缝起裂与延伸规律复杂,裂缝形态认识不清,采用北美缝网压裂思路进行增产改造后产量差异较大.为此,本文采用岩性复杂、天然裂缝发育的大港油田沧东孔二段致密油储层井下岩样,进行三轴力学测试、矿物组分测试和CT扫描,对储层岩样的力学参数、矿物组分和天然裂缝展布情况进行了分析,选取其中含有水平、低角度、高角度和复杂天然裂缝的井下岩样进行真三轴压裂实验,并采用CT扫描对压裂裂缝进行监测,以研究含天然裂缝的混合岩性致密油储层压裂裂缝起裂与扩展规律.实验结果表明:(1)根据对压裂效果的有利程度,可将压后裂缝形态分为以下3类:水力单缝、沿天然裂缝开启和复杂裂缝;(2)天然裂缝是压后裂缝形态的主要控制因素;(3)实验中,水力裂缝遭遇天然裂缝时出现3种延伸模式:沿天然裂缝张开、穿过天然裂缝(直接穿过、转向后穿过)、被天然裂缝阻断,应力差大小决定了以上3种延伸模式;(4)天然裂缝发育程度严重影响破裂压力和压裂液滤失量.实验结果对认识含天然裂缝的混合岩性致密油储层压裂裂缝形态,评价此类储层缝网压裂效果提供了依据.

我国 83%深层油气有待开发,向深层进军获取油气资源是保障国家能源安全的重大战略任务.而裂缝性地层井漏是制约超深层油气钻井的关键"卡脖子"难题.研发专用堵漏材料形成高效堵漏技术,提高深层裂缝性地层一次堵漏成功率,是钻井工程领域当前研究和实践的重点之一.桥接堵漏是裂缝性漏失地层最常用的堵漏技术之一.因此,本文对裂缝性地层桥接堵漏技术进行了详细的综述,概括了桥接堵漏材料的分类、作用机理以及桥接堵漏配方的设计方法和组成,阐述了提高裂缝性地层桥接封堵层稳定性的机制和承压堵漏机理,厘清了桥接封堵层的形成、破坏和结构演化机制.同时,展望了裂缝性地层桥接堵漏技术的发展前景,对于实现高效安全钻井、加快超深层油气开发进程、保障国家能源安全具有重要意义.

There are significant differences in the structural characteristics of conglomerate reservoirs,among which the presence of gravel not only leads to strong heterogeneity of conglomerate,but also has a significant impact on the mechanical properties and fracture development of conglomerate.At present,the influence of the composition of different particle sizes of gravel on the mechanical properties and crack development of conglomerate is still unclear.This article cites the concept of inter-mediate gradation in soil mechanics to characterize the composition of different particle sizes of gravel,and quantifies the grading characteristics using the curvature coefficient Cc and non-uniformity coefficient Cu as grading parameters.A numerical model of conglomerate based on particle flow PFC2D simulation software is established.The influence of gravel gradation parameters on the mechanical properties and crack propagation of conglomerate is investigated by analyzing the stress-strain curve,compressive strength,elastic modulus,and crack development status.The findings reveal that the compressive strength of conglomerates is primarily influenced by the non-uniformity coefficient Cu and the average particle size of gravel,exhibiting a negative correlation with Cu.Similarly,the elastic modulus of conglomerates correlates with the average particle size of gravel.The number of cracks is affected by both the curvature coefficient Cc and the average particle size of gravel,demonstrating a negative correlation with Cc.Conversely,the number of cracks positively correlates with the complexity of the fractures.These research findings offer novel insights into exploring the mechanical properties and fracture propagation patterns of conglomerate reservoirs.

Sedimentary and diagenetic processes usually make reservoirs anisotropic.The existing anisotropy studies mainly focus on the absolute permeability of reservoirs,but lack of studies on relative permeability anisotropy,which cannot reflect the difference of interference degree between fluid phases in different directions.In order to study the effect of an anisotropic structure on oil-water two-phase seepage,a three-dimensional staggered coring method was designed to reduce the influence of end effects in conventional cubic core anisotropy relative permeability experiments,and a method to obtain an anisotropic relative permeability curve was established.On this basis,an anisotropy experiment of oil-water relative permeability of natural sandstone is carried out,which proves the existence of anisotropy of relative permeability of sandstone reservoirs.The generation mechanism and tensor expression of anisotropic relative permeability are analyzed.The effect of relative permeability anisotropy on seepage processes is studied.The results show that bedding structure is the main cause of relative permeability anisotropy of sedimentary reservoirs.Relative permeability anisotropy quantifies the difference of water-phase coning ability and water-oil fluidity ratio in different directions.The relative permeability curve in the high permeability direction is characterized by high residual oil saturation,a narrow two-phase seepage zone,low water saturation and low relative permeability at the isotonic point.Relative permeability anisotropy will lead to oil and water seepage,which will have a significant impact on reservoir development.As the development process progresses,oil and water seepage directions will gradually show obvious differences,and one-way dead oil zones and plane dead oil zones appear successively,resulting in a more complex distribution of remaining oil.

The extraction of shale oil and gas is confronted with numerous complex geomechanical issues. As a core factor determining extraction efficiency and safety, the mechanical properties of shale urgently require in-depth research and exploration. Against this backdrop, machine learning, with its powerful capabilities in data processing and pattern recognition, has opened up new avenues for research on shale mechanical properties. This paper focuses on the application of machine learning in the study of shale mechanical properties, systematically elaborating on the current status, challenges, and prospects in this field. Firstly, it details the application achievements of current machine learning algorithms in the prediction of shale mechanical parameters and the recognition of failure modes, demonstrating their significant advantages over traditional research methods in processing complex data and mining potential patterns. Subsequently, it summarizes the multiple challenges faced in the application of machine learning to the study of shale mechanical properties. Shale sample data exhibits high-dimensional and small-sample characteristics, which easily lead to overfitting in models. Meanwhile, the internal operating mechanisms of most machine learning models are difficult to interpret, restricting their popularization and application. In addition, the geological conditions of shale are complex and variable, with significant differences in mineral composition and pore structure of shale in different regions. The existing models show obviously insufficient universality when applied across regions and geological conditions. Finally, the future is prospected based on the development trends of cutting-edge technologies. Machine learning has broad prospects in the field of shale mechanical properties research. By integrating multi-source data such as geological, geophysical, and logging data, it can provide more abundant information for models and reduce the negative impact caused by data dimensionality. Optimizing algorithm architectures and combining technologies such as transfer learning and ensemble learning can improve the generalization ability of models. Constructing physics-constrained machine learning models can not only enhance the interpretability of models but also improve their adaptability under complex geological conditions. These strategies are expected to break through existing bottlenecks, promote the in-depth application of machine learning in the study of shale mechanical properties, and provide solid theoretical and technical support for the efficient development of shale oil and gas resources.

Unconventional oil and gas,represented by shale oil and gas and low-permeability tight oil and gas,are important replace-ment resources in China.Due to their poor reservoir properties,effective exploitation is difficult.Currently,reservoir transformation is mainly carried out through horizontal well volume fracturing technology.However,there are still problems such as water resource waste,reservoir damage,and poor increasing production.Because of the the low viscosity,high density,and high diffusivity,super-critical/liquid CO2 can quickly enter reservoir micropores and microfracture.CO2 fracturing can effectively reduce fracture pressure,form complex fracture networks,increase formation energy,improve backflow rate,reduce reservoir damage,and achieve single well production increase.It is suitable for efficient and green exploitation of unconventional oil and gas resources.This paper introduces the basic research progress of CO2 fracturing from the aspects of the mechanism of rock breaking and fracture making by CO2 fracturing,the mechanism of influence of CO2 on rock properties,the flow characteristics of CO2 fracturing wellbore,CO2 fracturing stimulation and geological storage,and briefly describes the development and application of several main fracturing technologies,including CO2 foam fracturing,CO2 dry fracturing,CO2 acid fracturing,and CO2 mixed fracturing.Against the background of China's current"dual carbon"goals and increased exploration and development efforts for unconventional oil and gas resources such as shale oil and gas,CO2 fracturing technology is one of the key core technologies for building a clean,environmentally friendly,low-carbon,and efficient energy security and development technology system,with great potential for development and promotion.

炼油工业是中国国民经济发展的基础和支柱产业.2016年中国新增炼油能力2110万t.然而在世界经济增长放缓的背景下,中国炼油工业进入油价低迷、油品需求增长缓慢、炼油产业产能过剩阶段,中国炼油企业必须寻求降低成本的途径以使其健康发展.本文运用生命周期成本理论,确定了地方炼油企业生命周期的边界,划分了生命周期阶段,分析了生命周期过程中的内外部成本构成,进而构建了一套地方炼油企业生命周期成本估算模型,并以山东某地方炼油企业为例进行实证研究.在识别影响成本的关键因素的基础上,引入绿色因子,评价关键因素变化对实证企业生命周期成本的影响程度.最后根据生命周期成本分析结果,结合地方炼油企业实际,从内部成本控制和外部成本管理两方面得到了一系列降低内外部成本、提高企业经营效益的启示与建议.

Reservoir fracability evaluation is one of the prerequisites to improve the effect of balanced fracturing of uncon-ventional oil and gas fields.At present,reservoir fracability evaluation mainly depends on logging data theory to explain rock mechanics parameters,and the application effect on fracturing is uneven.In this paper,the characteristics of rock mechanical parameters are directly reflected by the bit rock breaking data and the reservoir fracability is clustered by drilling and logging data.We established a reservoir fracability clustering model based on a self-organizing map(SOM)unsupervised clustering algorithm.The elbow method is used to determine the optimal clustering number,and the parameter optimization method of fracture placement is formed.The optimal design of three-cluster perforation placement is carried out for typical vertical wells in the Tarim Basin with large thickness reservoirs.The results show that the drilling time,dc-exponent,weight on bit,torque,true formation resistivity,acoustic and neutron data are significantly correlated with reservoir fracability and can be used as character-istic parameters.The established model can effectively distinguish the difference of reservoir fracability along the wellbore axis,and select the fractures in the fracturable well section of the same type of reservoir,which is expected to improve the effect of balanced fracturing.

Low-frequency distributed acoustic sensing in adjacent wells, a recently emerged fracturing monitoring technology, enables detailed diagnosis of hydraulic fractures. To promote industry understanding of recent advances in low-frequency distributed acoustic sensing technology for hydraulic fracture monitoring and facilitate its large-scale field application, this paper begins with the principles of distributed acoustic sensing. It briefly explains the sensing mechanism and well deployment methods, systematically summarizes research progress in numerical simulation, physical modeling, and field applications during hydraulic fracturing, and concludes by outlining future development directions for low-frequency distributed acoustic sensing technology. Research findings indicate that: ①Low-frequency fiber-optic acoustic sensing technology for hydraulic fracturing delivers high precision and real-time monitoring capabilities. This technology is increasingly being deployed for field fracture monitoring and has garnered significant attention from researchers worldwide. Disposable fiber optic systems offer distinct advantages including simplified deployment, low cost, compact footprint, and excellent value proposition. They represent a promising primary solution for future offset-well fracturing monitoring. Mitigating fiber slippage artifacts’ impact on strain response is therefore paramount for enhancing strain data fidelity in fiber optic sensing applications. ②Forward modeling primarily involves comparative analysis of simulated fiber optic strain fields with actual monitoring data to qualitatively characterize strain patterns. This establishes correlations between distinct fracture propagation types and their corresponding strain signatures, enabling interpretation of hydraulic fracture geometry and growth modes in offset wells. Current strain interpretation models predominantly consider two monitoring configurations: horizontal and vertical offset wells. However, these models fail to characterize fracture deflection induced by stress shadowing, resulting in discrepancies with field monitoring observations. Future work urgently requires developing sophisticated multi-fracture forward models that incorporate stress interference effects and fluid partitioning mechanisms to provide reliable guidance for field data interpretation. ③Inversion modeling primarily utilizes the Displacement Discontinuity Method(DDM) to construct fracture propagation models and solve for fracture dimensions. Current solution approaches include Least Squares, Picard iteration, Levenberg-Marquardt (L-M) method, and the Delayed Rejection Adaptive Metropolis (DRAM) algorithm. However, none can simultaneously invert fracture geometric parameters in all three spatial dimensions. Future inversion research must focus on optimizing solution algorithms, where effectively mitigating the impact of solution non-uniqueness will be the primary research focus for subsequent algorithmic enhancements. ④Physical simulation experiments primarily integrate distributed optical fiber interrogators based on Optical Frequency Domain Reflectometry (OFDR) technology with True Triaxial fracturing apparatuses to monitor fracture propagation. However, current experimental parameter configurations still fall short of fully replicating field conditions. Optimizing fiber deployment methodologies across diverse rock specimens and advancing the interpretation of laboratory-derived fiber optic data represent critical research priorities for future physical simulation studies. The study concludes that offset-well fiber optic monitoring demonstrates significant potential for interpreting hydraulic fracture dimensions. This technology holds considerable promise as a key enabling technology for addressing critical bottlenecks in unconventional resource development.