Pile driving formulas based on pile wave equation analyses     

《Computers and Geotechnics》2017

Pile driving formulas, which directly relate the pile set resulting from a hammer blow to the static load capacity of the pile, are often used to decide whether a pile will have the required design capacity. However, existing formulas do not consider soil or pile type, and do not, in general, reliably predict pile capacity. In this paper, an advanced model for dynamic pile driving analysis was used to develop accurate pile driving formulas. The proposed driving formulas are validated through well-documented case histories. Comparisons of predictions from the proposed formulas with results from static and dynamic load tests show that they produce reasonably accurate predictions of pile capacity based on pile set observations.  相似文献   

Method of deformation analysis for composite structures of soils and masonry stones     

《Computers and Geotechnics》2017

The coupled numerical manifold method (NMM) and discontinuous deformation analysis (DDA) are enhanced to simulate deformations of continuous soil and discontinuous masonry structures. An elasto-plastic NMM-DDA is formulated that incorporates elasto-plastic constitutive laws into incremental forms of the equation of motion. A node-based uniform strain element is applied to avoid volumetric locking, which often occurs in conventional NMM-DDA. The proposed method is applied to three fundamental boundary value problems: a beam bending problem, a bearing capacity problem of a footing, and a bearing capacity problem of a masonry structure. The method is verified through comparisons with conventional solutions.  相似文献   

Numerical simulation of fracture path and nonlinear closure for simultaneous and sequential fracturing in a horizontal well     

《Computers and Geotechnics》2017

Reservoir stimulation requires a model to evaluate the fracture path and closure for the simultaneous or sequential propagation of the hydraulic fracture (HF). This paper presents a fluid-solid coupled model to simulate multi-stage HF propagation. A non-linear joint model is proposed to evaluate the fracture closure when the created fractures are elastically propped. HF closure continues until the balance of external stress matches the proppant's resistance. The reservoir along the horizontal wellbore is not stimulated equally by the multi-stage fracturing. The HFs in the subsequent stage are ‘repelled’ and restrained by the HFs in the previous stage.  相似文献   

Reliability bearing capacity analysis of footings on cohesive soil slopes using RFEM     

《Computers and Geotechnics》2017

Reliability analysis of bearing capacity of a strip footing at the crest of a simple slope with cohesive soil was carried out using the random finite element method (RFEM). Analyses showed that the coefficient of variation and the spatial correlation length of soil cohesion can have a large influence on footing bearing capacity, particularly for slopes with large height to footing width ratios. The paper demonstrates cases where a footing satisfies a deterministic design factor of safety of 3 but the probability of design failure is unacceptably high. Isotropic and anisotropic spatial variability of the soil strength was also considered.  相似文献   

贵州毕节市CK1地热勘探井钻井技术分析     

杨风良 《地质与勘探》2017,53(5):1017-1024

本文通过对贵州毕节市CK1地热井的特点及施工的研究,有效解决了高陡构造地层钻进问题。该井开孔即见基岩,常规工艺加压困难,难以保证孔斜;下部钻孔岩石硬度大,研磨性较强,可钻性差。通过分阶段变化钻进工艺,上部开孔使用空气潜孔锤吊打,后期采用牙轮钻头加螺杆钻具组合,在钻井效率过低的复杂地层则简化钻具组合,使用牙轮正循环工艺钻进,合理调整钻进参数可迅速建井。通过使用有准对性的洗井方法可迅速成井。本文通过对地热井多工艺钻进及完井工序的要求及改进,并针对现地勘单位对地热资源开发的实际情况进行了总结和分析,找出存在的问题及解决办法。本次研究为地热田的开发总结了经验。  相似文献   

基于BP神经网络的底水油藏控水压裂选段新方法     

杨志浩 《地质与勘探》2017,53(4):818-824

随着水平井压裂技术的普遍应用,压裂段的选择成为影响增产效果的主要因素之一,但针对底水油气藏,在压裂时同时考虑控水同样重要。影响底水油气藏压裂效果的因素很多,因素之间具有高度不确定的非线性关系,给控水压裂选段分析带来了诸多不便。利用传统的单因素回归等方法,显然不能满足底水油藏多种影响因素下水平压裂段的选择。针对此问题,通过油藏工程理论和现场经验,确定了避水高度、地层各向异性、天然裂缝发育程度、地应力差值、水平井曲直偏差、储层与水层之间隔层发育程度六个参数作为影响控水压裂段选择的主要因素,建立定性分析方法。通过底水脊进模型确定了参数界限,结合BP神经网络系统的原理,建立定量分析。利用计算机语言编制底水油气藏水平井压裂段控水选择软件,通过实际应用,表明其对现场施工具有一定的指导作用。  相似文献   

废弃井改造为地热井工艺技术研究     

王培义 《地质与勘探》2017,53(4):788-793

中原油田区域内废弃井共2090口,经筛选可利用井有355口。根据这些废弃井不同的井身结构、水层位置、水泥返高等条件,确定了针对性的选井选层方法和废弃井改造工艺方案。配套研发优选了新型套管端部密封止水工具、套管鱼顶修复专用工具、套管切割方案和热储层酸洗方案,形成了废弃井改造的完井工艺系列技术和产能测试工艺技术。开展了马古6井现场改造实验,成功实施了井口恢复、储层解堵和试水测试,验证了改造方案和工艺配套技术的可行性和可靠性。  相似文献   

SAGD技术应用于陆域冻土天然气水合物开采中的理论研究          下载免费PDF全文

王志刚  张永勤  梁健  王汉宝  吴纪修  李宽  李鑫淼  尹浩  李小洋 《探矿工程》2017,44(5):14-18

天然气水合物被誉为最有研究价值和开采价值的清洁能源,已经成为当今世界能源研究的热点。但到目前为止还未形成成熟稳定的天然气水合物开采技术体系,仍处于研究和试采阶段。陆域冻土天然气水合物开采与海域天然气水合物开采相比相对比较容易,在钻进过程中能够形成较稳定的孔壁。天然气水合物开采的主要方法有热激法、降压法、置换法和化学抑制剂法。SAGD（Steam Assisted Gravity Drainage）技术也叫蒸汽辅助重力驱油技术,在重油、油砂开采中得到了迅速发展,取得了非常有效的成果,被认为是目前重油开采最有效的方法。对SAGD技术应用到陆域冻土天然气水合物开采中进行理论分析研究,经过分析发现将SAGD技术应用到天然气水合物开采中是可行的,但确定两口水平井之间的距离是关键,且在应用时要将上部井变为生产井,下部井变为注汽井。  相似文献   

延长油田西部区域水平井固井水泥浆体系优化技术          下载免费PDF全文

刘云 《探矿工程》2017,44(2):17-22

分析了目前延长油田西部区域固井现状及造成固井质量差的原因,据此提出了适合延长油田西部地区水平井固井水泥浆性能的要求,优选出了适合该地区水平井固井的水泥浆体系。该水泥浆体系具有低滤失、零自由液、高沉降稳定性、好流变性,有利于提高浆液顶替效率。形成的水泥石具有不收缩、微膨胀、早强的特点,满足水平井射孔、后期压裂改造等工程施工的要求。最终形成了一整套适合延长油田西部地区水平井固井的水泥浆体系。  相似文献   

沙漠地区页岩气地质调查井施工技术          下载免费PDF全文

尹亮先  李得新  田小林  谢治国 《探矿工程》2017,44(3):17-20

武威盆地儿马湖凹陷地质调查井武地1井钻井工程位于内蒙古自治区腾格里沙漠腹地,施工条件恶劣。上部第四系覆盖层主要岩性为黄色砂土和红色细砂,厚度大,松散易垮塌。针对武地1井钻井难点,从井场建设、钻井设备的选择、井身结构、钻井液优化等方面采取措施,为沙漠地区钻井施工积累了经验。  相似文献