Prediction Model of Drilling Costs for Ultra-Deep Wells Based on GA-BP Neural Network

Drilling costs of ultra-deepwell is the significant part of development investment,and accurate prediction of drilling costs plays an important role in reasonable budgeting and overall control of development cost.In order to improve the prediction accuracy of ultra-deep well drilling costs,the item and the dominant factors of drilling costs in Tarim oilfield are analyzed.Then,those factors of drilling costs are separated into categorical variables and numerous variables.Finally,a BP neural networkmodel with drilling costs as the output is established,and hyper-parameters(initial weights and bias)of the BP neural network is optimized by genetic algorithm(GA).Through training and validation of themodel,a reliable prediction model of ultra-deep well drilling costs is achieved.The average relative error between prediction and actual values is 3.26%.Compared with other models,the root mean square error is reduced by 25.38%.The prediction results of the proposed model are reliable,and the model is efficient,which can provide supporting for the drilling costs control and budget planning of ultra-deep wells.

Characteristics of helical flow in slim holes and calculation of hydraulics for ultra-deep wells

Due to the slim hole at the lower part of the ultra-deep and deep wells, the eccentricity and rotation of drill string and drilling fluid properties have great effects on the annular pressure drop. This leads to the fact that conventional computational models for predicting circulating pressure drop are inapplicable to hydraulics design of deep wells. With the adoption of helical flow theory and H-B rheological model, a computational model of velocity and pressure drop of non-Newtonian fluid flow in the eccentric annulus was established for the cases where the drill string rotates. The effects of eccentricity, rotation of the drill string and the dimensions of annulus on pressure drop in the annulus were analyzed. Drilling hydraulics was given for an ultra-deep well. The results show that the annular pressure drop decreases with an increase in eccentricity and rotary speed, and increases with a decrease in annular flow area. There is a great difference between static mud density and equivalent circulating density during deep well drilling.

Uncertainty Analysis Method of Casing Extrusion Load for Ultra-Deep Wells

With the consideration of the randomness of complex geologic parameters for ultra-deep wells,an uncertainty analysis method is presented for the extrusion load on casing in ultra-deep wells through complex formation at a certain confidence level.Based on the extrusion load model for casing in ultra-deep wells and the prerequisite of integrity of formation-cement ring-casing,the probability and statistics theory are introduced and the sensitivity analysis on the uncertainty of extrusion load on casing is conducted.The distribution types of each formation parameters are determined statistically.The distribution type and distribution function of the extrusion load on casing are derived.Then,the uncertainty analysis of the extrusion load on casing is carried out on several ultra-deep wells in Shanqian block as case study.Several conclusions are made regarding to the field trial result.The randomness of formation elasticity modulus and formation Poisson’s ratio are the main influence factors.The equivalent density profile of extrusion load on casing in ultra-deep wells is a confidence interval with a certain confidence level,rather than a single curve;the higher the confidence level is,the larger the bandwidth of the confidence interval of equivalent density profile becomes,and the larger the range of uncertainty interval becomes.Compared with the result of uncertainty analysis,an error exists in the result of traditional single valued calculation method.The error varies with different casing program and can be either positive or negative.The application of uncertainty analysis of extrusion load on casing provides proof for the accurate determination of casing collapse safety factor.Thus,the over engineering design or under engineering design as a result of tradition casing design will be avoided.

Mechanism and prevention method of drill string uplift during shut-in after overflow in an ultra-deep well

Drill string will sustain large uplift force during the shut-in period after gas overflow in an ultra-deep well, and in serious case, it will run out of the wellhead. A calculation model of uplift force was established to analyze dynamic change characteristics of the uplift force of drill string during the shut-in period, and then a management procedure for the uplift risk during the shut-in period after gas overflow in the ultra-deep well was formed. Cross section method and pressure area method were used to analyze the force on drill string after shut-in of well, it was found that the source of uplift force was the "fictitious force" caused by the hydrostatic pressure in the well. When the fictitious force is in the opposite direction to the gravity, it is the uplift force. By adopting the theory of annular multiphase flow, considering the effects of wellbore afterflow and gas slippage, the dynamic change of the pressure and fluid in the wellbore and the uplift force of drill string during the shut-in period were analyzed. The magnitude and direction of uplift force are related to the length of drill string in the wellbore and shut-in time, and there is the risk of uplift of drill string when the length of drill string in the wellbore is smaller than the critical drill string length or the shut in time exceeds the critical shut in time. A set of treatment method and process to prevent the uplift of drill string is advanced during the shut-in period after overflow in the ultra-deep well, which makes the risk management of the drill string uplift in the ultra-deep well more rigorous and scientific.

A review of reservoir damage during hydraulic fracturing of deep and ultra-deep reservoirs

Deep and ultra-deep reservoirs have gradually become the primary focus of hydrocarbon exploration as a result of a series of significant discoveries in deep hydrocarbon exploration worldwide.These reservoirs present unique challenges due to their deep burial depth(4500-8882 m),low matrix permeability,complex crustal stress conditions,high temperature and pressure(HTHP,150-200℃,105-155 MPa),coupled with high salinity of formation water.Consequently,the costs associated with their exploitation and development are exceptionally high.In deep and ultra-deep reservoirs,hydraulic fracturing is commonly used to achieve high and stable production.During hydraulic fracturing,a substantial volume of fluid is injected into the reservoir.However,statistical analysis reveals that the flowback rate is typically less than 30%,leaving the majority of the fluid trapped within the reservoir.Therefore,hydraulic fracturing in deep reservoirs not only enhances the reservoir permeability by creating artificial fractures but also damages reservoirs due to the fracturing fluids involved.The challenging“three-high”environment of a deep reservoir,characterized by high temperature,high pressure,and high salinity,exacerbates conventional forms of damage,including water sensitivity,retention of fracturing fluids,rock creep,and proppant breakage.In addition,specific damage mechanisms come into play,such as fracturing fluid decomposition at elevated temperatures and proppant diagenetic reactions at HTHP conditions.Presently,the foremost concern in deep oil and gas development lies in effectively assessing the damage inflicted on these reservoirs by hydraulic fracturing,comprehending the underlying mechanisms,and selecting appropriate solutions.It's noteworthy that the majority of existing studies on reservoir damage primarily focus on conventional reservoirs,with limited attention given to deep reservoirs and a lack of systematic summaries.In light of this,our approach entails initially summarizing the current knowledge pertaining to the types of fracturing fluids employed in deep and ultra-deep reservoirs.Subsequently,we delve into a systematic examination of the damage processes and mechanisms caused by fracturing fluids within the context of hydraulic fracturing in deep reservoirs,taking into account the unique reservoir characteristics of high temperature,high pressure,and high in-situ stress.In addition,we provide an overview of research progress related to high-temperature deep reservoir fracturing fluid and the damage of aqueous fracturing fluids to rock matrix,both artificial and natural fractures,and sand-packed fractures.We conclude by offering a summary of current research advancements and future directions,which hold significant potential for facilitating the efficient development of deep oil and gas reservoirs while effectively mitigating reservoir damage.

Drill string dynamic characteristics simulation for the ultra-deep well drilling on the south margins of Junggar Basin

Improper drilling parameters may cause severe vibration of drill string which leads to reduce the rate of penetration and drilling tool premature failure accidents in the drilling process of ultra-deep well.The study on dynamic characteristics of drill string plays an important role in increasing the safety of drilling tool and optimizing the drilling parameters.Considering the influences of real borehole trajectory,interaction between bit and formation,contact between drill string and borehole wall,stiction of drilling fluid and other factors,a comprehensive drill string dynamic model was established to simulate the changes of wellhead hook load,torque,equivalent stress of drill string and BHA(bottomhole assembly)section acceleration and motion trajectory with time at different WOBs(weights on bit)and rotary speeds.The safety factor and overpull margin of wellhead drill string were calculated and the strength of drilling tool in ultra-deep well was checked using the fourth strength theory.The analysis results show that,in the drilling process of ultra-deep well,the transverse motion amplitude of the drill string near the wellhead is relatively small and vibration of drill string mainly occurs in the lower well section.As the rotary speed increases,the number of collision between lower drilling tool and borehole wall increases,wellhead transverse stress increases,change in torque is not large and change in wellhead equivalent stress is relatively small.As the WOB increases,wellhead torque will increase,axial load and equivalent stress will decrease and vibration acceleration of BHA will increase sharply.Wellhead overpull margin and safety factor will decrease with the increase of rotary speed and increase with the increase of WOB.Wellhead safety factor of S135 drilling tool in an F190.5 mm ultra-deep well on the south margins of Junggar basin changes around 1.8.The drilling tool is safe and has relatively sufficient ability to deal with the downhole accidents if a large size high steel grade drill string(F139.7 mm S135)is used.However,in view of BHA safety,neither rotary speed shall be too high nor WOB shall be too large.

Research progress and key issues of ultra-deep oil and gas exploration in China

Based on the recent oil and gas discoveries and geological understandings on the ultra-deep strata of sedimentary basins, the formation and occurrence of hydrocarbons in the ultra-deep strata were investigated with respect to the processes of basin formation, hydrocarbon generation, reservoir formation and hydrocarbon accumulation, and key issues in ultra-deep oil and gas exploration were discussed. The ultra-deep strata in China underwent two extensional-convergent cycles in the Meso-Neoproterozoic Era and the Early Paleozoic Era respectively, with the tectonic-sedimentary differentiation producing the spatially adjacent source-reservoir assemblages. There are diverse large-scale carbonate reservoirs such as mound-beach, dolomite, karst fracture-vug, fractured karst and faulted zone, as well as over-pressured clastic rock and fractured bedrock reservoirs. Hydrocarbons were accumulated in multiple stages, accompanied by adjusting and finalizing in the late stage. The distribution of hydrocarbons is controlled by high-energy beach zone, regional unconformity, paleo-high and large-scale fault zone. The ultra-deep strata endow oil and gas resources as 33% of the remaining total resources, suggesting an important successive domain for hydrocarbon development in China. The large-scale pool-forming geologic units and giant hydrocarbon enrichment zones in ultra-deep strata are key and promising prospects for delivering successive discoveries. The geological conditions and enrichment zone prediction of ultra-deep oil and gas are key issues of petroleum geology.

万米深井上部大尺寸井眼钻柱动力学特性研究

油气勘探已向更深、更复杂的超深层的万米勘探新领域推进,但上部大尺寸井眼给万米深井的钻井提出了巨大挑战:岩石硬和返速低导致钻速慢,大尺寸井眼内剧烈振动导致钻具裂纹多发,钻压小则钻速慢,钻压稍大则下部振动快速加剧从而导致大尺寸钻具使用寿命远低于预期。为此,在对比研究了深地川科1井(以下简称SDCK-1井)和毗邻8000 m超深井上部井段钻柱振动问题基础上,基于全井钻柱系统动力学模型和数值仿真方法,针对性研究了大尺寸井眼中的钻柱动力学特性。研究结果表明:①井眼尺寸越大,钻头和下部钻具的振动越剧烈,SDCK-1井二开大尺寸井眼与邻井中等尺寸井眼相比(井深500 m处),其钻头及下部钻具振动强度均值分别增加了48.0%和41.5%,比SDCK-1井三开中等尺寸3000 m井深的钻头及下部钻具振动强度均值分别高了29.0%和2.9%;②相同井眼尺寸和岩石特性情况下,下部钻具组合比钻柱整体长度对钻头振动的影响更大,优化下部钻具组合能够明显改善钻头振动,保护钻头,同时还可以提高钻头破岩能量利用效率实现钻井提速;③在大尺寸井眼中钻头破岩激励向上传播,横向振动衰减慢于轴向振动衰减,大尺寸钻头扭矩更大且钻压和扭矩波动更加明显,因此从保护下部钻具的角度出发,大尺寸井眼钻具组合对抑制横振更加有效;④大尺寸井眼中下部钻具弯矩和弯矩波动更大,现场频繁出现的钻具裂纹除受控于整体振动强度较大以外,交变弯矩是裂纹发生的重要原因。结论认为,该研究成果揭示了超深井大尺寸井眼中钻柱的动力学特性,指出了应着重控制横振和交变弯矩,该认识可以为超深井上部大尺寸井眼钻井提供技术指导。

超深井钻柱动态疲劳失效特征及参数优选

随着油气勘探深度不断增大,超深井钻柱井下振动更加复杂,应力状态随时间变化显著,为保障超深井钻柱的安全性,开展了受空间挠曲井筒约束超细长钻柱的动态疲劳失效特征研究,并进行钻柱结构及工作参数优选。基于实际井眼轨迹,考虑钻柱与井壁的碰撞特征,通过有限元仿真分析,得到全井钻柱动力学特性;根据疲劳损伤累积理论,研究了超深井全井钻柱在非对称循环变幅应力状态下的疲劳强度;结合现场实例,研究了超深井钻柱的危险截面,分析了钻柱疲劳强度随转速、钻压和稳定器安装位置的变化规律。研究表明:钻压和高转速对钻柱疲劳强度的影响较大,低转速对钻柱疲劳强度的影响较小;稳定器可以大幅降低底部钻具组合疲劳失效的概率,而且稳定器安装位置对钻柱疲劳强度的影响较为显著。研究结果为超深井钻柱组合结构参数和钻井参数优选提供了理论依据。

井深随钻测量误差校正与井眼位置不确定性计算方法

深井和超深井钻井过程中井下温度高、井内钻具承受的拉力大,导致随钻测量的井深误差较大。为此,考虑不同井深处井内温度、热膨胀系数、钻具轴向力和钻具规格等因素的影响,在测点处对井内钻具分段,结合井下温度随钻测量结果和井内钻具受力分析结果,建立了随钻测量井深的热膨胀校正模型和弹性拉伸校正模型,以及计算热膨胀校正误差限和弹性拉伸校正误差限的模型,并给出了随钻测量井深热膨胀和弹性拉伸校正后的井眼位置不确定性计算方法。实例计算表明,超深井钻井过程中由热膨胀和弹性拉伸导致的井内钻具伸长量可达10 m以上;随钻测量井深进行热膨胀和弹性拉伸校正后,可以显著减小测点垂深误差和误差椭球的大小。研究结果为提高井深随钻测量精度与科学计算井眼位置不确定性提供了理论依据。

基于管柱动力学的特深井通井组合刚度评价方法与应用

我国特深井钻井正处于快速发展阶段,受井眼尺寸大和深度深的影响,钻井过程中极易出现微井斜、扩径缩径和井壁台阶等,导致套管下入困难,因此通井钻具组合评价尤为重要。目前,现场使用的评价方法常忽略了管柱下入过程中与井壁的碰撞和变形,导致通井效果时好时坏。为了辅助现场施工,文章基于全井管柱动力学模型和HHT-α数值计算方法提出了一种能够模拟管柱下入的动态过程的通井钻具组合的评价方法,该方法考虑了实测井眼轨迹、井眼扩大率和下入阻力等要素。通过某特深井三开下套管前的钻具组合进行实例计算分析,表明井眼扩大率和套管串下入阻力对通井能力和套管下入影响较大,当井眼扩大率较小且套管串下入阻力较大时,需要使用刚度较大的多扶正器通井钻具组合。本方法可以实现实测井况条件下比较精准的刚度对比模拟,也成功指导了案例井?486 mm套管的安全下入。

超深井套管卡瓦效应的拉伸极限载荷理论计算

针对新疆某油田超深井井口套管悬重过大,造成卡瓦牙对套管外壁齿入损伤,且累计损伤导致卡瓦悬挂器套管断裂失效的事故频繁,提出了“卡瓦效应的拉伸极限载荷”来评价井口卡瓦悬挂器夹持部分套管的强度设计,具体为基于第三强度理论和第四强度理论,分别建立了井口卡瓦悬挂器夹持套管的“卡瓦效应拉伸极限载荷”计算模型。计算结果表明,从安全角度评价套管强度,采用第三强度理论计算卡瓦悬挂器套管的卡瓦效应拉伸极限载荷更合理,但为更充分利用材料的力学性能,应采用第四强度理论进行评价,还得到在四通有限空间内,可以保证有较大的卡瓦效应拉伸极限载荷的最佳卡瓦半锥角为23°~25°,最佳卡瓦有效接触长度为135~145 mm。研究方法和结果将为卡瓦悬挂器井口套管的强度设计、各种安全施工作业等提供理论依据。

超深井自动控制压井室内物理模拟试验及结果分析

现有超深井溢流压井技术依靠手动控制节流管汇,响应速度慢,井筒压力波动大,容易引发二次溢流、漏失等复杂情况,而自动控制压井技术可实现钻井时溢流压井作业稳定控制。为此,设计了比例–积分–微分(PID)与位移双层协同反馈的自动控制方法,开发了超深井自动控制压井系统,建立了自动控制压井物理模拟试验装置,开展了恒定目标压力、连续变化目标压力、压力突变干扰等条件下的自动控制压井试验。试验结果表明,自动控制压井系统能够在30 s左右完成节流阀开度的调节,节流压力波动范围小于0.02 MPa,与手动控制压井相比,自动控制压井系统具有良好的稳定性、准确性、反应速度和抗干扰能力。研究结果为超深井复杂地层安全压井提供了理论依据。

增效型无土相仿生油基钻井液技术的研究与应用

针对深井超深井钻井过程中钻遇高温高压、井壁失稳及井下复杂情况的难题,基于仿生学、超分子化学以及岩石表面润湿性理论,通过优选仿生增效剂、仿生提切剂及仿生降滤失剂,配套相关处理剂,最终形成了一套适用于深井、超深井地层钻探的增效型无土相仿生油基钻井液体系。研究发现,建立的增效型无土相仿生油基钻井液体系可抗220℃高温,配制密度为2.4 g/cm^(3),破乳电压大于400 V,高温高压滤失量为3.2 mL,人造岩心在该体系中220℃下老化后的抗压强度达到7.1 MPa,平均渗透率恢复值为93.9%。现场应用情况表明,体系流变性能稳定,平均机械钻速比邻井提高16%,平均井径扩大率仅为1.25%,可有效解决深井超深井钻井过程中出现的井壁失稳难题,为我国深井超深井的钻探提供了技术保障。

超深井工程理论与技术若干研究进展及发展建议

超深井工程受到高温高压、复杂地层、超长井眼和腐蚀介质等多重因素约束,其安全高效作业面临全方位的技术挑战。为此,针对超深井工程的安全高效设计控制问题,介绍了该工程的发展概况与技术特点;选取井眼轨迹预测与防斜打快、钻柱振动特性分析与减振控制、钻井延伸极限预测与设计控制,以及套管失效风险评估与安全控制等几个重要理论与技术问题,介绍了国内外的相关研究进展及笔者团队的最新研究成果;然后,针对超深井工程提出了若干创新发展建议。研究结果表明,超深井工程理论与技术的发展整体呈现出体系化、科学化、多学科交叉、地质与工程一体化等基本特点。建议在基础理论问题、关键核心技术、技术协同关系、技术迭代模式和多学科交叉融合等方面加强创新研究,以持续推进超深井工程基础理论与关键技术创新发展。

超深井控温钻井隔热涂层参数影响机制研究

为揭示隔热涂层对超深井井筒温度场的影响规律,针对隔热涂层与钻杆的导热特点,采用传热热阻形式计算钻杆的综合传热系数,构建了考虑钻杆内隔热涂层影响的超深井井筒–地层瞬态传热模型,并采用有限差分法对模型进行离散,利用高斯–赛德尔算法进行迭代求解。通过理论分析和现场数据验证了模型的准确性。研究发现,钻杆内隔热涂层的导热系数对井底循环温度影响显著,随着导热系数减小,井筒环空温度迅速降低,出口温度升高;隔热涂层的厚度和长度对井筒温度也有重要影响,隔热涂层厚度越大,井底循环温度越低。这些发现为超深井钻井过程中井筒温度的调控和隔热钻杆参数的优选提供了重要理论依据。

四川盆地超深井钻井关键技术及发展方向

四川盆地海相碳酸盐岩油气资源丰富,但构造地层条件复杂,井筒环境苛刻。近年来,盆地深井超深井钻井关键技术的形成,支撑了油气的增储上产,为特深层油气资源勘探开发奠定了技术基础。特深层油气资源的开发需持续开展地质工程一体化设计技术攻关,通过精细刻画复杂地质体建立三维地质力学模型,指导井身结构和井眼轨道设计,同时开展基于膨胀管、随钻扩眼技术的井身结构拓展研究,并通过岩石可钻性剖面指导钻头及提速工具设计。针对深井超深井井口溢流异常监测识别滞后及钻柱振动剧烈的问题,持续研发基于大数据分析的复杂防控技术。深入开展适用于超高温超高压环境的工具、钻井液研发,研发攻关110钢级及以上膨胀管管材、抗220℃的高密度水基钻井液、抗260℃的油基钻井液体系、抗温240℃以上的水泥浆体系、高性能固井材料以及抗高温堵漏材料。同时,应紧密结合物联网、新型通信、大数据等智能技术,实现钻井全过程运算分析及管理。

塔里木盆地顺北地区顺北84X井超千米含油气重大发现及其意义

塔里木盆地顺北中部北东向走滑断裂带长期处于油气运聚富集的优势区,顺北8号走滑断裂带实钻揭示沿断裂带发育断控缝洞型油气藏,顺北84X井纵向上沿断裂带含油气高度高达1088 m,揭示断控缝洞型油气藏含油气高度大、不受现今构造高低控制。为查明断控缝洞型油气藏含油气高度的主控因素,立足顺北中部奥陶系碳酸盐岩油气藏的成藏地质条件和钻探成果,开展顺北84X井的储层、圈闭及成藏特征等石油地质条件分析,为深化断控缝洞型油气藏认识和向深层评价拓展提供支撑。研究表明:①走滑构造破碎是致密碳酸盐岩成储的关键,其储层发育深度不受碳酸盐岩地层埋深的控制,在近9000 m的埋深条件下仍发育断控缝洞型储集体;②上覆巨厚泥岩盖层顶封、两侧致密灰岩侧封、走滑断裂平面分段和纵向分层变形是形成断控缝洞型圈闭的关键;③油-源对比分析表明油气来自寒武系玉尔吐斯组烃源岩,证实了前期顺北中、东部“寒武多期供烃、构造破裂成储、原地垂向输导、晚期成藏为主、走滑断裂控富”的成藏模式的合理性。顺北84X井的发现揭示塔里木盆地超深层致密碳酸盐岩发育受走滑断裂控制,储层纵向深度大,油气充注足,超深层勘探潜力巨大。

准噶尔盆地沙湾凹陷二叠系上乌尔禾组流体相态及油气藏类型

准噶尔盆地腹部地区沙湾凹陷超深层蕴含丰富的油气资源。根据烃源岩热演化模拟实验分析了沙湾凹陷二叠系上乌尔禾组烃源岩生烃产物类型,结合地层流体高温高压物性实验数据,运用相图判别法和经验参数法对沙湾凹陷征10井地层流体相态进行深入研究。研究结果表明:①沙湾凹陷征10井上乌尔禾组油气主要来自于下乌尔禾组泥质烃源岩,其有机质类型为Ⅱ1型,镜质体反射率(Ro)为1.05%~1.46%,岩石热解峰温(T_(max))为433~446℃,处于成熟—高成熟演化阶段,目前处于生轻质油阶段。②上乌尔禾组地层流体成分表现为凝析气藏的流体组成,地层温度为166.0℃,介于临界温度和临界凝析温度之间,地层压力为155MPa,远高于露点压力,地-露压差大,表明地层条件下流体呈凝析气相特征,但地下油气相态与地表采出流体相态具有一定差异。相图判别法和经验参数法烃类流体相态分析结果均显示,征10井上乌尔禾组气藏为含大油环的凝析气藏。③沙湾凹陷上乌尔禾组具有优越的成藏条件,紧邻下乌尔禾组烃源岩,油气近源垂向输导,向局部隆起区运聚,巨厚的三叠系及上乌尔禾组中上部区域盖层起到重要的封盖作用,最终在局部隆起区形成岩性-构造凝析气藏。

超深特深油气井固井关键技术进展

深层超深层是油气增储上产重要接替领域,正向9000 m及以上特深层迈进。针对超深特深井上部大尺寸井眼固井面临的大尺寸套管安全下入及大排量施工等技术难题,下部深层井段固井面临的高温、高压、窄安全密度窗口、窄环空间隙等技术难题,经过持续技术攻关与实践,超深特深井固井技术取得显著进步,尤其在大尺寸大吨位套管安全下入技术、大排量固井施工技术、窄安全密度窗口精细控压固井工艺技术、抗高温固井水泥浆与前置液技术、高温高压固井配套工具、提高固井密封质量配套技术等方面均取得重要进展。该套固井技术在四川、塔里木、准噶尔、渤海湾、柴达木等盆地的超深、特深井固井中进行了应用,在亚洲最深直井PS6井、亚洲最深水平井GL3C井、国内首口“八开八完”HX1井、中国石油近年最高温度井JT1井等应用效果显著。随着油气勘探开发目标日趋复杂,超深特深井固井仍面临诸多新的挑战,需持续加强超深特深井固井基础理论、超高温固井关键材料及工作液体系、高温高压固井工具及配套固井工艺等研究,为超深特深层油气勘探开发提供更强有力的技术支撑。