页岩气钻探冲洗液体系的研究与应用

中国页岩气资源开发潜力巨大,近年来页岩气勘探开发力度不断加大,对钻探工艺和技术的要求不断提高。页岩气地层岩性主要为泥岩、砂岩、页岩、碳质板岩、灰岩,该类地层胶结性差、破碎、井壁强度低,钻进中易出现孔壁失稳,发生坍塌、卡钻、埋钻等孔内事故,需要研制具有强抑制性、低成本、绿色环保的冲洗液体系来保证施工安全。本文通过对页岩气井壁稳定机理的探究,优选出一种适用于页岩地层双聚防塌和成膜防塌低固相冲洗液体系,该体系由抑制剂、防塌剂、降失水剂、润滑剂、封堵剂、流型调节剂等处理剂组成,具有良好的抑制性和胶结性。现场应用取得了良好的效果,保证了项目的顺利施工。     

固结钻井液对湘西北页岩气储层的护壁机理研究

文中提出了一种液态离子固结剂,该处理剂能够有效提高页岩气井井壁的力学强度。通过开展室内实验以及进行相关分析,初步了解了添加液态离子固结剂的钻井液的基本性能,并探究了该体系钻井液对炭质页岩膨胀的抑制性以及对炭质页岩力学强度的影响。发现钻井液滤失量随液态离子固结剂含量的增加先减小后增大;在各配方钻井液中的压制岩心膨胀率明显低于在清水中的,但液态离子固结剂含量增加使得钻井液中的压制岩心膨胀率越来越高;各钻井液处理的岩粉所制成的剪切试样抗剪强度高于经清水处理的,随着液态离子固结剂含量的增加,试样抗剪强度总体上先升高再下降,且试样单轴抗压强度增大。实验结果表明,在适宜的含量范围内,液态离子固结剂有助于增强钻井液维护井壁稳定的能力。     

油基解卡液处理粘附卡钻事故的分析与应用

深井钻探技术发展到现在有了突飞猛进的提高,而且日趋成熟。但地热井在施工过程中,经常发生一些孔内事故在所难免。发生事故以后需认真分析事故发生的原因,尽快制定针对性的处理方案和程序,科学合理地去处理。以晋中一个经常发生孔内粘附卡钻事故的地热井施工为工程实例,分析了发生粘附卡钻事故的诸多原因,制定出处理粘附卡钻事故的方法。通过解卡机理,设定油基解卡液的性能和配置方法,准确进行注入量计算,在注入时掌握技术工艺要点,获得了良好的处理粘附卡钻事故的效果。     

水力压裂技术在豫西基岩地热井增产中的应用研究

地热资源是清洁能源,其开发利用主要通过钻井工程来实现。地热资源量（水量）大小决定着开发利用的价值。实际中,因地层等条件的复杂和不确定性,导致地热井出水量和温度不能达到预期的目标。特别是在山区基岩缺水地区地热资源开发,由于水量和温度指标偏低,严重影响了清洁能源的开发利用。本文结合工程实例,首次在豫西基岩严重缺水地区通过压裂车和钻井泵分段水力压裂技术,使低产地热井出水量增加3倍,达到了预期的目的。为今后基岩地区地热和地下水资源开发利用增产提供了借鉴。     

山东半岛硅热流值与区域地质条件的关系

据地下水中ＳｉＯ２含量计算山东半岛硅热流值。以此为基础初步探讨本区的地热场特征及其与区域地质条件的关系。指出：１．山东半岛平均热流值与全球平均热流值接近，但比一般古老地块略高。２．划分出三个地热异常区，在大地构造上，两较高热异常区分别对应于胶北和文登隆起；较低热异常区与胶莱盆地相应。３．地热场总特征及其区域热异常的形态主要与近地表的地层岩性、构造形态和断裂发育程度等地质条件有关，而与中生代的岩浆活动无关，但第四纪岩浆活动对胶北隆起局部（蓬莱一带）热异常有重要作用     

Benthic Front and the Yamato Basin Bottom Water in the Japan Sea

Hydrographic observations have revealed detailed structure of the Bottom Water in the Japan Sea. The Yamato Basin Bottom Water (YBBW) exhibits higher temperatures and lower dissolved oxygen concentrations than those found in the Japan Basin Bottom Water (JBBW). Both Bottom Waters meet around the boundary region between the Yamato and the Japan Basins, forming a clear benthic front. The structure of the benthic front suggests an estuary-like water exchange between both Basins, with the inflow from the Japan Basin passing under the outflow from the Yamato Basin. It is inferred from the property distributions that the JBBW flowing into the Yamato Basin is entrained by the cyclonic circulation in the basin, and modified to become the YBBW. Vertical diffusion and thermal balance in the YBBW are examined using a box model. The results show that the effect of geothermal heating has about 70% of the magnitude of the vertical thermal diffusion and both terms cancel the advection term of the cold JBBW from the Japan Basin. The box model also estimates the turnover time and vertical diffusivity for the YBBW as 9.1 years and 3.4 × 10⁻³ m²s^{− 1}, respectively.     

Results from microseismic monitoring,conventional instrumentation,and tomography surveys in the creation and thinning of a burst-prone sill pillar

Located in northern Québec, the Lac Shortt Mine was a small gold mine consisting of a thin subvertical orebody which was mined in three main phases. High stress and rockbursting conditions were experienced when ore was extracted in the upper zone between the surface and a depth of 500 metres during the first two phases of mining. Severe rockbursts were experienced in late 1989 near the shaft and in the footwall development following a deepening of the mine shaft to a depth of 830 m and partial development of footwall drift access for the third phase of mining (the mining of the lower zone starting at a depth of 830 m moving upward toward a depth of 500 m). A 16-channel Electrolab MP250 microseismic system, with a Queen's University Full-Waveform piggy-back system, was installed underground at the site due to these problems.It was expected that the thinning sill would be subjected to an ever-increasing load as the thickness of the 500 m sill pillar decreased in the face of the mining excavation from below. A monitoring program consisting of the microseismic monitoring system, a range of conventional geomechanics monitoring tools as well as the undertaking of periodic seismic tomography surveys to assess the ongoing state of stress and rock mass condition within the sill was therefore warranted.The anomalously high-magnitude stress field and the brittle rockmass created a situation in which rockmass failure was common and violent. In the creation and thinning of the sill pillar, the location of banded microseismic activity was crucial in tracing rockmass failure and the associated ground control problems. Reliable source-location determination enabled the identification of areas of stress increase. The movement of the rockmass failure front could be followed, and was responsible for stope dilution, footwall and orebody development deterioration, and caving.Source-mechanism analyses gave accurate double-couple solutions for approximately forty percent of these events having at least ten recognizable polarities. Results suggested movement along vertical north-south striking or vertical east-west striking features. Underground observation of damaged access points showed that vertical north-south striking joints were experiencing failure.The microseismic activity, which was consistently concentrated close to the southwest and northeast corners of current production stopes, could be explained by a stress field oriented obliquely to the strike of the orebody, as measured prior to shrinkage of the sill pillar byin situ stress measurements and observed borehole overbreaks. The orientations of theP andT axes for the microseismic activity further confirmed that the stress field oriented obliquely to strike.While an increase in compressional-wave velocity of 2.3 percent, corresponding to a measured stress increase of approximately 10 MPa could be measured by repeated tomographic surveys, it was relatively small and only a factor of two or so above the velocity measured uncertainty. The relative insensitivity of thein situ rock mass modulus to the applied stress is believed to be largely due to the rockmass discontinuities being relatively closed prior to stress increase, as substantiated by the small deformations seen by the extensometer and borehole camera. This situation existed because of the very high pre-mining stress level.The experimental demonstration that the rock could not absorb substantially increased load through the mechanism of discontinuity closure or tightening (which would be reflected in the modulus) may be evidence in itself of potentially burst-prone ground, such as encountered at Lac Shortt.     

日照市沿海地区地热资源特征研究

日照市沿海地区位于日照-青岛断裂两侧,区内断裂、构造较发育,成热地质条件良好。为了全面查明日照市沿海地区地热资源特征,该文通过浅层地温测量、物探、测温孔等手段,确定日照街道三柱山村东和南湖镇徐家坪-万家坪一带两处地热异常区,然后分别建立热储概念模型分析研究,采用热储法对两区域地热资源量进行评价。浅层地温测量显示区域恒温带埋深一般在17.84～26.15m,恒温带平均温度15.39℃,地温梯度值平均值为1.46℃/100m;热储概念模型分析显示,地下水受深部热源加热、温度升高,遇构造交会区形成凝滞,与围岩发生溶滤,形成了具有较高温度和矿物质的地热流体,最终沿断裂破碎带传输至地表,形成了地热异常区;热储法计算结果:三柱山区域地热资源量3.07×10~(15)J,可利用地热资源量2.46×10~(14)J,南湖区域地热资源量3.85×10~(15)J,可利用地热资源量3.08×10~(14)J。这对于日照市沿海地区地热资源勘查提供了方向,对我国"断控型"地热资源研究提供了一定的参考价值。     

Hydrochemistry of groundwaters in a spa area of Korea: an implication for water quality degradation by intensive pumping

A geochemical study was carried out in a small spa area (Onyang Spa, Korea) where intensive pumping of deep thermal groundwater (1 300 000 m³ year⁻¹) is taking place. This has caused the deep fractures to lose their artesian pressure and the upper shallow fractures have been encroached by shallow, cold waters. To quantify the influence of long‐term heavy pumping on the quality of the geothermal water, groundwater sampling and chemical analysis, water‐level measurement, and well loggings were performed for the selected deep thermal wells and shallow cold wells. Chemical analysis results indicate a big contrast in water chemistry and origins between the two water types. Shallow groundwater shows a wider concentration ranges in solutes that are closely related to human activity, illustrating the water's vulnerability to contamination near the land surface. Plots of water chemistry as a function of fluoride reveal that the quality of the thermal water was greatly influenced by the shallow, cold groundwater and that intensive pumping of the deep thermal groundwater has caused the introduction of shallow groundwater into the deeper fractures. Although the deep and the shallow fractures were piezometrically separated to some extent, a mixing model based on fluoride and nitrate indicated that the cold‐water fractions in the thermal wells are up to 50%. This suggests that the thermal water is faced with water quality degradation by the downward flow of the shallow, cold water. Restriction on the total of all the pumpage permits per unit area is suggested to restore the artesian pressure of the deep thermal aquifer and to prevent cold‐water intrusion in the study area. Copyright © 2004 John Wiley & Sons, Ltd.