龙26-平25长水平段水平井钻井技术

为了高效开发低渗透油藏,在大庆油田龙26区块部署了龙26-平25长水平段水平井。介绍了井身结构与井眼轨迹剖面设计特点,分析了钻井施工中的难点,从井眼轨迹控制、旋转地质导向钻井技术、摩阻与扭矩监测、井眼清洁等几个方面对该井采用的技术措施进行了详细阐述。龙26-平25井完钻井深4045.00 m,水平段长2033.00 m,各项指标均符合设计要求,创出了大庆油田应用水基钻井液施工水平井水平段最长的记录,为今后施工同类型长水平段水平井积累了宝贵的施工经验。     

东胜气田钻井液废弃物处理与钻井液技术

东胜气田某水平井钻探过程中应用钻井液不落地技术,通过电化学处理、沉淀、加药调整各项性能之后再次参与循环,岩屑无害化处理以降低废弃物污染。但钻井液中直径＜5 μm的固体颗粒没有完全清除,颗粒累积后会污染钻井液。污染后的钻井液导致各类井下复杂频发。这样会增加钻井成本,甚至使施工井报废。试验应用的氯化钾聚合物钻井液体系解决井壁失稳和井漏问题。对合理应用不落地技术和氯化钾聚合物钻井液体系提供了参考依据。     

延长油田浅层高密井网水平井防碰绕障技术研究

为了经济有效开发浅层（300～600 m）低渗透、低丰度油藏,提高油藏采收率,陕西延长石油（集团）有限责任公司尝试利用旧井场在老井区部署加密浅层水平井进行调整开发,开展了在复杂工程、地质等多种不利限制条件下具有延长油田特色的浅层高密井网水平井防碰绕障技术研究。通过优化井眼轨迹,精细防碰扫描以及配套的现场工程技术措施,有效控制井眼方位,进行主动防碰绕障。现场应用结果表明,在该技术指导下浅层水平井均成功穿越或避开老井网,保证了钻井作业的安全进行,为油田浅层难动用油藏中后期开发提供了一条新的途径。     

控压钻井技术在涪陵页岩气田的实践与认识

随着涪陵页岩气田勘探开发进程的不断深入,长水平段页岩气井在钻井过程中遇到的复杂事故愈发凸显。目的层龙马溪组,裂缝发育、岩性构成复杂且破碎严重,钻井中钻井液密度窗口窄,易发生垮塌、溢漏同存、水平井段漏失大量油基泥浆等问题。为了快速、安全有效地钻穿复杂页岩层段,采用控压钻井技术破解长水平段页岩气井井漏的钻井难题,在焦页33-4HF井应用控压钻井技术,在长水平段钻遇多个不同压力系数的漏失显示层,安全钻达完钻井深,大大减少了油基泥浆的漏失及其不良影响,减小了经济损失,取得了显著应用效果。     

潘庄区块煤层气U型水平井下套管技术探讨

下入生产套管的煤层气U型井具有产气量高、成本低的优点,逐渐成为潘庄区块煤层气开发的主要井型。潘庄区块煤层埋深一般在500 m以浅,同时要求U型井的水平段在1000 m左右,生产套管的下入成为该区块垂深浅、水平段长的煤层气U型井的技术难题,经过多口井试验,优化钻井轨迹的平滑度,采用原钻具、短螺旋扶正器和生产套管内置钻铤3次划眼,以及严格控制下套管程序,可提高套管一次性下入的成功率,并提高生产效率。     

页岩气储层钻井液损害评价研究

延长油田页岩气储层埋藏较深,地质条件复杂,页理构造发育,岩石物性极差,页岩易膨胀、分散。由于孔缝并存,页岩气储层比砂岩油藏具有更严重的微粒运移损害、储层应力敏感损害、水锁损害等特性。鉴于延长页岩储层太过致密,不能用常规方法进行渗透率测定。通过采用人造裂缝法测定钻井液对储层裂缝的污染程度来表征钻井液对储层的损害率。经人造裂缝法测定,延长油田现场使用的白油基钻井液体系对页岩气储层的污染渗透率恢复率达到91.060%,初步证实该体系具有良好的储层保护效果,可在延长油田进一步推广使用并验证。     

Neotectonics of the Eastern Margin of the Tibetan Plateau: New Geological Evidence for the Change from Early Pleistocene Transpression to Late Pleistocene-Holocene Strike-slip Faulting

We present in this paper some new evidence for the change during the Quaternary in kinematics of faults cutting the eastern margin of the Tibetan Plateau. It shows that significant shortening deformation occurred during the Early Pleistocene, evidenced by eastward thrusting of Mesozoic carbonates on the Pliocene lacustrine deposits along the Minjiang upstream fault zone and by development of the transpressional ridges of basement rocks along the Anninghe river valley. The Middle Pleistocene seems to be a relaxant stage with local development of the intra-mountain basins particularly prominent along the Minjiang Upstream and along the southern segment of the Anninghe River Valley. This relaxation may have been duo to a local collapse of the thickened crust attained during the late Neogene to early Pleistocene across this marginal zone. Fault kinematics has been changed since the late Pleistocene, and was predominated by reverse sinistral strike-slip along the Minshan Uplift, reverse dextral strike-slip on the Longmenshan fault zone and pure sinistral strike-slip on the Anninghe fault. This change in fault kinematics during the Quaternary allows a better understanding of the mechanism by which the marginal ranges of the plateau has been built through episodic activities.     

Changes in Relative Plate Motion during the Isan Orogeny (1670-1500 Ma) and Implications for Pre-Rodinia Reconstructions

Foliation inflexion/intersection axes(FIAs)preserved within porphyroblasts that grew throughout Isan orogenesis reveal significant anticlockwise changes in the direction of bulk horizontal shortening between 1670 and 1500 Ma from NE-SW,N-S,E-W to NW-SE.This implies an anticlockwise shift in relative plate motion with time during the Isan orogeny.Dating monazite grains amongst the axial planar foliations defining three of the four FIAs enabled an age for the periods of relative plate motion that produced these structures to be determined.Averaging the ages from monazite grains defining each FIA set revealed 1649±12 Ma for NE-SW shortening,1645±7 Ma for N-S shortening,and 1591±10 Ma for that directed E-W.Inclusion trail asymmetries indicate shear senses of top to the SW for NW-SE FIAs and dominantly top to the N for E-W FIAs,reflecting thrusting towards the SW and N.No evidence for tectonism related to early NE-SW bulk horizontal shortening has previously been detected in the Mount Isa Inlier.Amalgamation of the Broken Hill and possibly the Gawler provinces with the Mount Isa province may have taken place during these periods of NE-SW and N-S-directed thrusting as the ages of tectonism are similar.Overlapping dates,tectonic,metamorphic,and metallogenic similarities between eastern Australia(Mount Isa and Broken Hill terranes)and the southwest part of Laurentia imply a most probable connection between both continental masses.Putting Australia in such position with respect to North America during the Late-Paleo-to-Mesoproterozoic time is consistent with the AUSWUS model of the Rodinia supercontinent.     

Comparison of Constant and Time-variant Optimal Forcing Approaches in El Nio Simulations by Using the Zebiak–Cane Model

Model errors offset by constant and time-variant optimal forcing vector approaches(termed COF and OFV, respectively)are analyzed within the framework of El Nio simulations. Applying the COF and OFV approaches to the well-known Zebiak–Cane model, we re-simulate the 1997 and 2004 El Nio events, both of which were poorly degraded by a certain amount of model error when the initial anomalies were generated by coupling the observed wind forcing to an ocean component. It is found that the Zebiak–Cane model with the COF approach roughly reproduced the 1997 El Nio, but the 2004 El Nio simulated by this approach defied an ENSO classification, i.e., it was hardly distinguishable as CP-El Nio or EP-El Nio. In both El Nio simulations, substituting the COF with the OFV improved the fit between the simulations and observations because the OFV better manages the time-variant errors in the model. Furthermore, the OFV approach effectively corrected the modeled El Nio events even when the observational data(and hence the computational time) were reduced.Such a cost-effective offset of model errors suggests a role for the OFV approach in complicated CGCMs.     

机器学习法在面向对象影像分类中的对比分析

针对如何选择遥感影像面向地理对象分类方法的问题,该文面向地理国情普查中的地表覆盖分类应用,以3个典型区域(山区、平原、城区)的多源高分辨率遥感影像为实验数据,从分类效果、分类精度等方面对比分析3种分类方法(支持向量机、决策树、随机森林)的优劣。在相同影像分割、特征提取、样本采集条件下,通过333组分类实验,得出以下规律:支持向量机分类方法稳定性强,分类速度快,但对特征数的要求高,特征数目与总体精度、地物环境之间的规律性不强,从而增加了特征提取与选择的难度,而随着特征的增加,决策树、随机森林的总体分类精度均为先升高后降低,最后趋于平衡。最后,综合随机森林对特征的优选机制和支持向量机的高分类精度,得到新的组合分类器。