浅谈如何提高挤水泥的成功率.docx

浅谈如何提高挤水泥成功率2016年12月目录1 挤水泥的应用现状11.1 挤水泥作业特点11.2 挤水泥应用领域11.3 挤水泥应用面临的尴尬局面22 提高挤水泥成功率的主要对策和思路22.1 准确分析井筒状况22.2 选择合适的挤水泥技术22.3 合理选择、优化水泥浆体系32.4 加强挤水泥设计计算的研究32.5 开发挤水泥设计模拟软件32.6 采用合理的挤水泥施工措施33 认识与建议4英文翻译5浅谈如何提高挤水泥成功率摘 要：挤水泥的应用面很广，覆盖了钻井、固井、完井和修井作业等诸多环节。到目前为止，石油业界已经进行了大量的挤水泥施工。然而，相比于常规的注水泥，挤水泥失效的情况时有发生，导致作业成本增加。为指导挤水泥作业，提高挤水泥的成功率，在分析国内外近年来有关的挤水泥理论和施工技术方面的文献基础上，对国内外在挤水泥设计方面的主要思路和对策进行梳理和总结。最后，结合我国挤水泥的现状，提出了在挤水泥方面的几点建议。关键词：挤水泥；成功率；思路；对策挤水泥是在一定的液体压力作用下挤压水泥浆，使水泥浆在地层表面脱水、造壁、硬化并封堵射孔、裂缝、窜槽或者空隙的过程。挤水泥应用相当普遍，但由于挤水泥多是在复杂不利情况下进行的作业，挤注成功率较低。如何克服挤水泥所遭遇的挑战，提高挤水泥的成功率，一直以来都是个难点。目前，国内挤水泥理论方面的参考资料相对较少，而国外则对挤水泥进行了持续不断的研究。因此，重点对近年来国外挤水泥理论和成功实践进行分析，从中总结提炼出有助于提高挤水泥成功率的思路、对策，对以后的挤水泥作业提供一定的指导。1 挤水泥的应用现状1.1 挤水泥作业特点挤水泥是一种特殊的固井作业，不利因素较多，挤水泥所遭遇的不利因素包括：井底情况不明、作业工况复杂。与一次注水泥作业相比，挤水泥作业的危险性和复杂性均较大，除要求足够的水泥石强度和良好胶结外，挤水泥对水泥浆密度、流变性能、失水控制、稠化时间都有较高的要求。例如，挤水泥多是把水泥浆挤入到窜槽、孔隙、裂缝等相对较狭窄的空隙，这些狭小空隙的容积比一次注水泥封固段的环空容积小得多，水泥浆通过时的阻力比较大，为此对水泥浆失水流变性能的控制比一次注水泥要求严格，否则可能造成水泥浆过早脱水发生桥堵。1.2 挤水泥应用领域挤水泥的用途很广，常见用途如下：（1）弥补固井时因泥浆造成的窜槽或环空水泥返高不够等缺陷。（2）处理来自油、气产层中、或产层上下的水侵问题。（3）从相邻油层封堵产层，以减小采油过程中的气、油比。（4）弥补由于腐蚀或裂缝造成的套管漏失。（5）封堵没有开采价值或枯竭的地层。（6）在多层系注水（汽）井中，堵塞全部或部分，一层或多层地层，以便直接在所希望的地层注水或注汽。（7）封堵漏失层。1.3 挤水泥应用面临的尴尬局面挤水泥作业已相当普遍，但始终面临着一个尴尬的局面：挤水泥花费的成本巨大，而成功率比较低。国内长庆油田陇东地区的油井，挤水泥作业费用占钻井成本的比例为15%20%。国外同样遭遇类似的窘境，美国田纳西州西部油区在19921994三年间共对137口井实施挤水泥作业，结果只有47口井在第一次挤水泥完成后达到了挤注目的，一次挤水泥成功率仅为34%，作业成本大幅度增加。2 提高挤水泥成功率的主要对策和思路2.1 准确分析井筒状况准确分析挤水泥井段的井筒情况、明确挤水泥的技术难点是提高挤水泥成功率的先决条件。为此，在挤水泥作业之前必须及时测井来认识待挤井段的地层类型、渗透率、孔隙度、孔隙压力、破裂压力、流体流动情况等影响因素。不同的地层类型、渗透率、孔隙度等对挤水泥的水泥浆量、水泥浆性能和材料会有不同的要求，如在碳酸盐岩这种通常含有天然裂缝的地层中挤水泥，就要考虑加入堵漏材料来封堵裂缝。挤水泥最终压力是挤水泥结束的标识，而地层孔隙压力和破裂压力是确定挤水泥最终压力的重要参考依据。因此，通过这些关键参数信息来准确分析井筒状况是挤水泥成功的前提。2.2 选择合适的挤水泥技术基于对挤水泥待挤井段的了解以及每种挤水泥技术适用范围的全面认识，合理选择挤水泥施工技术。常规的挤水泥施工技术具体包括以下3大类：（1）按施工压力的情况分为低压挤水泥、高压挤水泥；（2）按是否使用工具的情况分为井口法挤水泥、可回收式封隔器挤水泥、可钻式承留器挤水泥；（3）按泵送水泥浆方式分为连续挤水泥、间歇挤水泥。2.3 合理选择、优化水泥浆体系在综合考虑挤水泥地层特性和挤水泥技术后，合理选择水泥浆体系相当关键。人们普遍认为，设计的水泥浆应具备如下的几点特性：（1）低粘度，以便使水泥浆能进入裂缝；（2）低切力；（3）零自由水；（4）适当控制失水，保证孔隙和射孔充填最佳；（5）稠化时间适当，保证施工安全。2.4 加强挤水泥设计计算的研究在现场，为满足挤水泥过程中流体用量和安全压力的要求，设计挤水泥作业时要根据所用的挤水泥方法来对水泥浆用量、替浆量和施工作业过程中相关的压力等重要参数进行正确估算。流体用量估算不准确，可能会造成超量顶替或顶替不到位。挤水泥最终压力是挤水泥作业施工完成的一个标志，具有重要的指示意义。若未能正确估算该压力值，则在施工过程中可能由于过高的压力而压裂地层产生次生裂缝，增大水泥浆的使用量。另一方面，在采用高的挤注压力时还必须考虑承转器（采用工具来挤水泥的条件下）的承压情况，结合工具的承压能力采取适当的措施，如考虑是否调整环空以上钻井液密度或者在环空施加平衡压力，否则会造成承转器失效，进而引发挤水泥事故。为此，加强挤水泥计算的研究，正确估算、量化挤水泥作业过程中的相关参数，有助于挤水泥作业的顺利进行。2.5 开发挤水泥设计模拟软件计算机在固井方面的应用已经得到了广泛的重视和认可，通过编制的软件可将相关设计理论方法直接应用于现场实际。挤水泥作为一种特殊的固井方式，需要考虑的因素较多。挤水泥设计评价技术的进步、流体和力学知识的不断完善以及室内和施工现场挤水泥研究给挤水泥作业软件的编制提供了丰富的理论和实践基础，使得在挤水泥之前可以进行施工模拟，预见及预防有关问题，每次挤水泥作业之后，又可用这些计算机程序进行系统评价，提高挤水泥设计的科学性、挤水泥质量评价的准确性。2.6 采用合理的挤水泥施工措施前面部分的思路更多的是针对挤水泥设计过程。而事实上除进行合理的设计外，任何挤水泥作业的成功与否很大程度上依赖于在现场上是否采取了合理有效的施工措施。如果挤水泥时施工不到位，那么即使在设计时考虑的因素很全面也无法保证作业能达到预期的目的。3 认识与建议（1）挤水泥是应用普遍的一种补注水泥作业，作业花费巨大而成功率却较低。为从根本上提高挤水泥的成功率，需更为细致地对挤水泥理论或施工技术进行研究，强化挤水泥作业的设计过程，调研的文献中所提出的思路值得在挤水泥的前期设计中加以借鉴和完善。（2）挤水泥作业的成功不仅在于可行、科学的挤水泥设计，还有赖于具体的施工措施，其应当加以重视、不可忽略。（3）在挤水泥理论技术和施工实践方面，国内与国外还存在一定的差距，国内要动态跟踪国外的先进技术和经验，同时针对我国挤水泥的实际来研究相应的技术方法。目前，国内缺乏对特定区域挤水泥作业数据的分析和总结，建议各个油田对相应区域的现场数据进行综合分析，及早建立挤水泥的经验标准和作业数据库。（4）国外早就开发了挤水泥作业软件来指导挤水泥的现场施工，但考虑到昂贵的服务费用，不能大范围地在国内推广使用。国内近几年意识到计算机在指导挤水泥作业上的重要性，并编制了简单的挤水泥作业程序，但其应用效果有待更多的现场验证。为此，国内亟需开发出更为系统和完善的挤水泥设计模拟软件来填补空白，最好开发出的挤水泥设计模拟软件能与国内已经比较成熟的固井软件在信息资源上进行配套和整合。当然，在该过程中，不能忽视对挤水泥设计计算的研究，这是编制科学、可靠的作业软件的前提。英文翻译Discussion on how to improve the success rate of cement extrusionAbstract: the application of cement is very wide, covering many aspects of drilling, cementing, well completion and repair operations, and so on. So far, the oil industry has been carried out a lot of squeezing cement construction. However, compared to the conventional cement injection, the failure of the extrusion of cement has occurred, resulting in increased operating costs. Squeeze cement job guidance, improve the success rate of cement squeeze, in the analysis of domestic and foreign literature in recent years based on the theory and construction technology of cement squeeze, squeeze on domestic and international main ideas and Countermeasures for cement design review and summary. Finally, according to the present situation of our country, some suggestions are put forward.Key words: squeeze cement; success rate; ideas; CountermeasuresSqueezing cement is the process of squeezing cement slurry under a certain liquid pressure, making cement slurry dewatering, forming wall, hardening and plugging perforation, fracture, channeling or void in formation surface. It is quite common to squeeze cement, but the success rate is low due to the extrusion of cement and the operation under the complicated condition. How to overcome the challenges encountered by the extrusion of cement, improve the success rate of cement squeezing, has always been a difficult point. At present, there are relatively few references about the theory of the cement squeezing in the country, but the research on the cement has been carried on. Therefore, the focus of foreign countries in recent years cement squeezing theory and successful practice from the analysis, summed up is helpful to improve the success rate of cement squeeze ideas and countermeasures, provide some guidance for future operation of cement squeeze.1 current situation of application of squeezing cement1.1 characteristics of squeezing cementCement squeezing is a kind of special cementing operation, which has many disadvantages, such as: the bottom hole is unknown and the working condition is complicated. Compared with a cementing operation, the risk and complexity of cement squeeze works are large, in addition to the requirements of the strength of cement and cement is good enough, squeeze cement to the cement slurry density, rheological properties, filtration control, thickening time have higher requirements. For example, cement squeeze is to cement slurry into channeling, pores, cracks and other relatively narrow gap annular volume of these small voids than the first injection cementing section is much smaller, the cement slurry through the resistance is relatively large, so the control on the rheological properties of cement slurry water loss ratio a cement strict, otherwise it may cause premature occurrence of bridge plug of cement slurry dewatering.1.2 extrusion cement application fieldCement is widely used, and the common use is as follows:(1) to make up for the defects such as the channeling caused by mud or the return of annular cement to the cement.(2) treatment of water from the oil, gas production, or the upper and lower water.(3) the production layer is sealed off from the adjacent layers to reduce the gas and oil ratio in the process of oil production.(4) to make up for casing leakage caused by corrosion or crack.(5) the formation of no mining value or depletion.(6) in a multilayer system of water injection (steam) wells, blocking all or part of a layer or multilayer formation, so as to directly in the desired formation water injection or steam injection.(7) lost circulation.1.3 squeeze cement application facing the embarrassing situationCement extrusion operations have been quite common, but always faced with an embarrassing situation: the cost of cement to spend huge, and the success rate is relatively low. In Longdong area, Changqing Oilfield domestic wells, cement squeeze costs accounted for the proportion of the cost of drilling operations for 15%20%. Foreign also suffered a similar dilemma, western states in 19921994 oilfield in Tennessee a total of three years of the implementation of 137 wells cement squeeze work, only 47 wells in the first time after the completion of cement squeeze to squeeze a squeeze, the success rate is only 34%, a substantial increase in operating costs.2 main countermeasures and ideas to improve the success rate of the extrusion of cement2.1 accurate analysis of the condition of the shaftAccurate analysis of the wellbore condition and the technical difficulty of the cement squeezing is a prerequisite to improve the success rate of cement squeezing. Therefore, it is necessary to know the formation types, permeability, porosity, pore pressure, fracture pressure and fluid flow in the well to be packed well before the cement operation. The formation of different types, such as permeability and porosity have different requirements on the volume of cement slurry, cement squeeze cement slurry properties and materials, such as cement squeeze usually contain natural fractures in carbonate rocks of this formation, we should consider adding plugging material to block crack. The final pressure is the sign of the end of cement squeezing, and the formation pore pressure and fracture pressure are important references to determine the final pressure. Therefore, it is a prerequisite to accurately analyze the condition of the shaft through the information of the key parameters.2.2 to select the appropriate extrusion technologyBased on the understanding of the well section of squeezing cement and the comprehensive understanding of the applicable scope of each kind of extrusion technology, the construction technology of extruding cement. The construction technology of cement squeeze routine includes the following 3 categories: (1) according to the construction situation is divided into low pressure and high pressure squeeze cementing cement squeeze; (2) according to whether the use of tools for wellhead squeeze, Recyclable packer, drillable cement squeeze cement retainer; (3) by pumping cement into continuous cement squeeze, intermittent cement squeeze.2.3 reasonable selection and optimization of the cement slurry systemAfter the comprehensive consideration of the characteristics of the squeezing cement formation and the compaction technology, the reasonable selection of the cement slurry system is very important. It is generally believed that the cement slurry design should have some characteristics as follows: (1) low viscosity, so that the cement slurry can enter the crack; (2) low shearing force; (3) zero free water; (4) to ensure proper control of water loss, and perforation pore filling best; (5) thickening time. When, ensure the safety of construction.2.4 Study on the design and calculation of reinforced concreteAt the scene, to meet in the process of cement squeeze fluid dosage and safety pressure requirements, the design of cement squeeze operations to correct estimation according to the important parameters of cement squeeze method used to cement dosage, the pressure for grouting volume and construction process etc. Estimate the amount of fluid is not accurate, may cause excessive displacement or displacement is not in place. The final pressure is a sign of the completion of the construction of the cement operation, which is of great significance. If the pressure value is not correctly estimated, the formation of secondary fractures may be caused by the high pressure in the construction process, and the use of cement slurry can be increased. On the other hand, in the squeeze pressure high must also be considered the retainer (using a tool to squeeze under the pressure, combined with) the bearing capacity of tools to take appropriate measures, such as considering whether to adjust the annulus above the density of drilling fluid in the annulus pressure or applying balance, otherwise it will cause the retainer failure, which caused the accident of cement squeeze. To this end, to strengthen the study of the calculation of squeezing cement, correctly estimate and quantify the relevant parameters in the process of squeezing the cement, which is helpful to the smooth operation of the.2.5 development of simulation softwareThe application of computer in cementing has received extensive attention and recognition, and the relevant design theory and method can be directly applied to the field practice through the preparation of the software. As a kind of special cementing method, the squeezing cement needs to be considered. Cement squeeze design evaluation of technological progress, and constantly improve the fluid mechanics and the interior and the construction site of cement squeeze research provides a rich theoretical and practical basis for the preparation of cement squeeze operating software, the cement squeeze can be carried out before construction simulation, issues related to anti foresight and pre, after each cement squeeze homework system the assessment of these available computer programs, improve the scientificalness and accuracy of design of cement squeeze cementing quality evaluation.2.6 the reasonable construction measures are adopted.The front part of the train of thought is more aimed at squeezing cement design process. In fact, in addition to the reasonable design, the success of any of the cement operations is largely dependent on whether or not to take a reasonable and effective construction measures on the scene. If the cement is not in place when the construction, then even in the design considerations are very comprehensive and can not guarantee the job can achieve the desired purpose.3 knowledge and advice(1) squeeze cement is a kind of common cementing operation, the operation cost is huge, but the success rate is low. To fundamentally improve the success rate of cement squeeze, need more detailed research on the theory of cement squeeze or construction technology, strengthen the design process of squeezing cement work, the proposed research in the literature ideas worthy of reference and improvement in the design stage of cement squeeze.(2) the success of squeezing cement works not only in the feasible and scientific design, but also depends on the concrete construction measures, which should be paid attention to, can not be ignored.(3) in the theory of cement squeez