石油压裂支撑剂材料开发应用前景分析

正碳化硅半导体器件的迅速发展,给相关研究以水力压裂技术作为油气井增产的主要工艺措施的研究提供了技术支持,主要应用于低渗油气田、高压油气层、中深井和潜井改造,技术核心是利用添加化学物质的高压水流对地层进行压裂(形成高于地层破裂强度的压力),形成足够长度、宽度的高导流能力裂缝(保证导流能力地层导流能力),使得油气在岩层裂缝聚合流出。以页岩水平井为例,压裂工艺利用支撑剂实现油气储层的封隔、分段改造~([1])。     

油田新投井低产低效原因及改造措施探讨

针对低渗透或特低渗透,并且裂缝发育,平面矛盾突出的油田区块新投油井低产低效情况,我们从储层改造角度对油井低产原因进行了分析,采用特殊的措施压裂工艺对储层进行措施改造,有效地提高压裂裂缝在储层平面和纵向的改造程度,为低渗透油田提高低产低效单井产量提供了重要的技术基础。     

长岭深层致密砂岩气藏压裂技术研究

吉林油田长岭D组深层气藏为低孔、低渗、致密砂岩气藏,储层温度高,大多数气井的自然产能达不到工业产能,对储层进行压裂工艺改造是增储上产的主要措施。结合致密砂岩储层特征及压裂技术需求,从压裂液体系优化、支撑剂筛选、施工参数优化等方面进行系统的研究和改进。应用压前裂缝诊断、前置液阶段支撑剂段塞处理和裂缝组合支撑等多项配套压裂工艺技术,对长岭致密砂岩气藏进行压裂改造,提高压裂规模及裂缝导流能力,大幅度提高气藏的产量,取得了很好的效果。     

低压低渗油藏压裂影响因素及施工工艺

随着油气田勘探和开发转移到低压、低渗油藏,压裂改造发现很的问题,本文介绍了地应力、夹层、施工参数对水力压裂影响和油藏改造技术。包括地应力对裂缝高度的影响;夹层对压裂改造的影响,施工排量泵压、液体性能对压裂效果的影响,以及压裂技术。     

探讨底水油藏压裂影响因素及技术措施

随着油气田勘探和开发转移到低压、低渗底水油藏，压裂改造发现很的问题，本文介绍了地应力、夹层、施工参数对水力压裂影响和底水油藏改造技术。包括地应力对裂缝高度的影响；夹层对压裂改造的影响；施工排量泵压、液体性能对压裂效果的影响，以及压裂技术。     

DPH-47大井眼水平井钻井技术浅析

由于大牛地气田地质构造位置处于鄂尔多斯盆地伊陕斜坡东北部,该气田属于低压、低渗、低孔隙度型气田,随着气田的开发,如何继续增产提效是当前面临的关键问题。目前提高"三低"油气层产能、提高经济效益比较成熟的方式是大力发展水平井钻井技术及采用高压压裂的方式扩大储层的裂缝。     

应用压裂技术改善欧利坨油田开发效果

在不断总结以往压裂成功井经验的基础上,进一步细化欧利坨油田选井原则及选井程序,通过对先期压裂井的压裂参数及储层特点研究,改进压裂方案及选井条件,重点对有薄煤夹层的储层压裂方案进行改进,在注水断块油田小井距低渗储层,采用有效控制注水区块裂缝,适当控制加砂规模,改造油层增油效果显著。     

延长油田储层改造技术的发展

对延长油田储层改造技术发展历程进行总结，介绍了各时期油田主要的储层改造技术，主要经历了油井爆炸、清水压裂、清水加砂压裂、冻胶压裂等发展阶段。压裂技术依然是目前特低渗透油田开发核心技术，是延长油由千万吨级产量稳产、上产的技术保障，伴随着油田资源日益减少，储层改造技术的提高和进步，必将在今后油田开发中发挥更加重要的作用。     

提高海拉尔油田压裂施工一次成功率

海拉尔油田地质条件复杂,储层物性差异较大,需要针对不同储层的特点制定出不同的压裂方案,针对一些物性差、埋藏深以及认识不清楚的疑难储层需要进行压前测试压裂,通过测试压裂分析出影响压裂施工成败的五个重要特征参数：停泵压力梯度、近井摩阻、地层滤失情况、天然裂缝发育程度以及裂缝的净压力。复杂的构造和储层类型使压裂施工难度增大,突出的问题反映出砂堵层比较多,影响了压裂改造的效果;其次由于有些目的层储层岩性和物性较差,泥质含量高,裂缝的破裂压力过高,在目前的设备条件下无法压开有效裂缝,一定程度上也影响了压裂改造的效果。针对这些不利的影响因素,我们也制定出了针对不同储层类型条件的压裂改造方案,对于提高海拉尔油田压裂施工一次成功率有重大意义。     

滩坝砂储层压裂液伤害及对策研究

滩坝砂油藏是胜利油田低渗透未动用储量的主体,由于其为低渗乃至特低渗油藏,均需实施压裂改造措施,才能达到工业油流。但岩心实验表明,常用压裂液体系对滩坝砂储层的伤害率达70%左右,一些低伤害压裂液体系伤害率也达到40%,远高于一般低渗透油藏。本文通过对滩坝砂储层地质特征、敏感性特征、压裂液微观伤害特征评价,分析了滩坝砂压裂液伤害的主要机理,优化了滩坝砂储层压裂液体系及压裂规模,降低了压裂液对储层的伤害,提高了滩坝砂储层压裂改造效果。     

Numerical simulation study of shale gas reservoir with stress-dependent fracture conductivity using multiscale discrete fracture network model

The exploitation of shale gas has increasingly become the focus of worldwide energy industry. Due to the existence of natural/hydraulic fractures, most of the shale gas reservoirs exhibit high degree of heterogeneity and complexity which leads to the stress-dependent fracture conductivity of shale gas reservoir. Discrete fracture network (DFN) model is adopted in this research since the conventional continuum model cannot meet the numerical simulation requirements of fractured shale gas reservoir. A series of experiments about the fracture properties stress-dependent have been conducted on some shale core samples, the stress-dependent fracture conductivity correlation is selected and incorporated into the mathematical model to characterize the reduction of fracture conductivity potential with the reservoir pressure drop. The DFN model is applied to a shale gas reservoir with fracture network to study the effect of the stress-dependent fracture conductivity on the shale gas well performance. The results show that the effect of fracture conductivity reduction with pressure drop on the shale gas well performance depends on both the initial fracture conductivity and matrix permeability. The complex interactions between the fracture and matrix permeability should be considered when select the appropriate size of proppants for fracturing.     

定向射孔多缝压裂工艺案例分析

一种新型的压裂工艺在中国长庆油田试验成功,该工艺在层内压裂形成了2条独立裂缝,大幅增加了裂缝与油藏的接触面积,提高了产量。长庆油田开发的超低渗透油藏岩芯分析渗透率一般在0.5 mD以下,且受到储层条件、注采井网、压裂工艺等多重限制,常规压裂工艺改造难以实现该类油藏的有效开发。历经多年研究并结合自身实际,长庆油田于2006年提出了体积压裂的理念,通过在油层内造多缝扩大油藏的泄流体积以提高单井产量。室内物模试验研究射孔对压裂影响时观察到,当射孔方向与最大水平主应力方位存在夹角的情况下裂缝发生转向,即裂缝均先沿射孔孔眼方向起裂,后转向最大主应力方向。在同一油层内上下各射一排孔,两排孔方位与最大主应力方向呈一定夹角,一排偏右,一排偏左。分别对两排孔眼进行压裂,这样由于初始裂缝转向导致两条裂缝在井眼处虚拟相交,但在地层内不会重合,形成近井类似于"X"形4条裂缝,远井形成2条近于平行的裂缝。提出了一种产生多裂缝的新型压裂工艺———定向射孔多裂缝压裂。开展了大量物模试验,证实了思路的可行性,并且长庆油田在A井开展了现场压裂试验。井下微地震裂缝测试表明:形成了"X"形多裂缝;产量数据表明:定向射孔多缝压裂井相比邻井产量提高38.1%。     

Mixed integer simulation optimization for optimal hydraulic fracturing and production of shale gas fields

Optimal development of shale gas fields involves designing a most productive fracturing network for hydraulic stimulation processes and operating wells appropriately throughout the production time. A hydraulic fracturing network design—determining well placement, number of fracturing stages, and fracture lengths—is defined by specifying a set of integer ordered blocks to drill wells and create fractures in a discrete shale gas reservoir model. The well control variables such as bottom hole pressures or production rates for well operations are real valued. Shale gas development problems, therefore, can be mathematically formulated with mixed-integer optimization models. A shale gas reservoir simulator is used to evaluate the production performance for a hydraulic fracturing and well control plan. To find the optimal fracturing design and well operation is challenging because the problem is a mixed integer optimization problem and entails computationally expensive reservoir simulation. A dynamic simplex interpolation-based alternate subspace (DSIAS) search method is applied for mixed integer optimization problems associated with shale gas development projects. The optimization performance is demonstrated with the example case of the development of the Barnett Shale field. The optimization results of DSIAS are compared with those of a pattern search algorithm.     

中国低渗透油气的现状与未来

中国低渗透油气资源丰富,具有很大的勘探开发潜力.近20年来,在低渗透砂岩、海相碳酸盐岩、火山岩勘探方面取得了很大发现,形成了国际一流的开发配套技术,实现了低渗透油气藏的规模有效开发,低渗透油气产量持续上升,其在产量构成中所占比例逐年增加.无论从近几年新增探明储量还是从剩余油气资源量看,低渗透油气都是今后勘探开发的主要对象,低渗透油气是中国未来油气工业的勘探开发主流,对保障国家能源安全具有重要的战略意义.     

低渗油藏裸眼水平井压裂技术及应用

针对大庆外围朝长地区未动用储量属于低渗透扶余油层,采用常规直井开发,单井产能低、开发效益差,为进一步提高低渗透扶余油层开发效果,通过水平井近平衡钻井、裸眼完井,减少了钻井及固井对储层污染,采用打孔管结合油膨胀封隔器工艺进行压裂改造,探索低产低渗透储层有效的开发途径。试油及投产效果表明,低渗透油藏采用近平衡钻井、裸眼完井能有效地保护储层,实施裸眼水平井储层压裂改造能够提高单井日产油,对进一步改善低渗透油藏开发效果有重要意义。     

美国Eagle Ford页岩气开发对我国页岩气勘探开发的启示

据估计,我国的页岩气可采储量高达20万亿～36万亿m3,虽然我国页岩气储量评估处于初级阶段,但仍然可以肯定我国是页岩气资源丰富的国家之一,如果都能开发,按当前的天然气年产量计算,可以开发200多年。目前国内外多家企业聚焦中国,逐鹿页岩气,页岩气有望成为我国常规能源替代品,页岩气的勘探开发必将对我国乃至世界能源格局产生重大影响。但是由于页岩气储层致密,渗透率低至纳达西级,若不采取特殊的增产措施难以实现商业开发。美国是目前唯一实现页岩气商业开采的国家,技术和商业模式都相当成熟,中海石油斥资10多亿美元收购了美国页岩气主产区Eagle Ford 33.3%的股份,该地区页岩气地质储量高达6 000亿m3,开发前景广阔。为提升我国页岩气总体水平,笔者率领技术专家深入考察了美国Eagle Ford页岩气项目,增进了对水平钻井与分段压裂等关键技术的了解,同时分析了相应扶持政策,对中国页岩气的勘探开发具有重要的参考价值。     

低渗油藏人工裂缝监测技术在现河地区的应用

针对高压低渗透油藏渗透率低、孔隙度小的特点,在压裂改造时进行裂缝监测,根据监测出的裂缝方位（方向）、裂缝长度、裂缝的高度（范围）和产状以及地下主应力的方向,为下步布井和井网调整提供了依据。2008年以来,现河地区已成功实施裂缝监测79井次,为低渗透油藏的高效开发提供了有力支持。     

Geomechanical optimization of hydraulic fracturing in unconventional reservoirs: a semi-analytical approach

Unconventional drilling and completion architecture includes drilling multilateral horizontal wells in the direction of minimum horizontal stress and simultaneous multistage fracturing treatments perpendicular to the wellbore. This drilling and stimulation strategy is utilized in order to raise the connectivity of the reservoir to the wellbore, thereby remedying the low permeability problem, increasing reserve per well, enhancing well productivity, and improving project economics in this type of reservoir. However, in order to have the highest production with the least cost, an optimization technique should be used for the fracturing treatment. According to the fact that aperture, propagation direction, and propagation potential of hydraulic fractures are of paramount importance in optimization of the fracking treatment, in this research paper, these three major factors are studied in detail, the control variables on these three factors are examined, and the effect of each factor is quantified by proposing a complete set of equations. Using the proposed set of equations, one can make a good estimate about the fracture aperture (directly controlling the fracture conductivity), the stress shadow size (directly controlling the fracture path), and the change of stress intensity factor (directly controlling the fracture propagation potential). A geomechanical optimization procedure is then presented for toughness-dominated and viscosity-dominated regimes based on the proposed equations that can be used for estimation of different optimal fracturing patterns. The most efficient fracturing pattern can be determined afterward via considering the cumulative production using a reservoir simulator e.g. ECLIPSE, Schlumberger. This procedure is likely to offer an optimal simultaneous multistage hydraulic fracture treatment without deviation or collapse, with no fracture trapping, with the highest possible propagation potential in the hydrocarbon producing shale layer, and a predicted aperture for proppant type/size decision and conductivity of the fractures.     

Interactions between the Design and Operation of Shale Gas Networks,Including CO2 Sequestration

As the demand for energy continues to increase, shale gas, as an unconventional source of methane (CH₄), shows great potential for commercialization. However, due to the ultra-low permeability of shale gas reservoirs, special procedures such as horizontal drilling, hydraulic fracturing, periodic well shut-in, and carbon dioxide (CO₂) injection may be required in order to boost gas production, maximize economic benefits, and ensure safe and environmentally sound operation. Although intensive research is devoted to this emerging technology, many researchers have studied shale gas design and operational decisions only in isolation. In fact, these decisions are highly interactive and should be considered simultaneously. Therefore, the research question addressed in this study includes interactions between design and operational decisions. In this paper, we first establish a full-physics model for a shale gas reservoir. Next, we conduct a sensitivity analysis of important design and operational decisions such as well length, well arrangement, number of fractures, fracture distance, CO₂ injection rate, and shut-in scheduling in order to gain in-depth insights into the complex behavior of shale gas networks. The results suggest that the case with the highest shale gas production may not necessarily be the most profitable design; and that drilling, fracturing, and CO₂ injection have great impacts on the economic viability of this technology. In particular, due to the high costs, enhanced gas recovery (EGR) using CO₂ does not appear to be commercially competitive, unless tax abatements or subsidies are available for CO₂ sequestration. It was also found that the interactions between design and operational decisions are significant and that these decisions should be optimized simultaneously.     

中国石化非常规油气资源潜力及勘探进展

中国石油化工集团有限公司(简称中国石化)矿权区内拥有较为丰富的非常规油气资源,煤层气可勘探面积为10.19万km2,煤层埋深小于2 000 m的煤层气地质资源量为11.02万亿m3。页岩气可供勘探面积为17.5万km2,初步估算页岩气地质资源量为15.9万亿m3。页岩油勘探面积为11.76万km2,具有较大的资源基础及潜力。中国石化自2004年开始关注非常规油气资源,先后启动了页岩油气、煤层气等非常规油气资源的研究和勘探工作。目前在泌阳凹陷页岩油勘探泌页HF-1水平井分段压裂后获日产油23.6 m3;元坝地区多口陆相钻井测试获得高产气流,建南地区建页HF-1井日产气12 300 m3;延川南区块煤层气已探明地质储量为106.47亿m3,多口井排采获工业气流,初步形成了中国石化非常规油气资源多类型、多阶段的勘探开发格局。