Method for evaluation of geological strength index of carbonate cliff rocks:Coupled hyperspectral-digital borehole image technique

The deterioration of unstable rock mass raised interest in evaluating rock mass quality.However,the traditional evaluation method for the geological strength index(GSI)primarily emphasizes the rock structure and characteristics of discontinuities.It ignores the influence of mineral composition and shows a deficiency in assessing the integrity coefficient.In this context,hyperspectral imaging and digital panoramic borehole camera technologies are applied to analyze the mineral content and integrity of rock mass.Based on the carbonate mineral content and fissure area ratio,the strength reduction factor and integrity coefficient are calculated to improve the GSI evaluation method.According to the results of mineral classification and fissure identification,the strength reduction factor and integrity coefficient increase with the depth of rock mass.The rock mass GSI calculated by the improved method is mainly concentrated between 40 and 60,which is close to the calculation results of the traditional method.The GSI error rates obtained by the two methods are mostly less than 10%,indicating the rationality of the hyperspectral-digital borehole image coupled evaluation method.Moreover,the sensitivity of the fissure area ratio(Sr)to GSI is greater than that of the strength reduction factor(a),which means the proposed GSI is suitable for rocks with significant fissure development.The improved method reduces the influence of subjective factors and provides a reliable index for the deterioration evaluation of rock mass.

Automatic discrimination of sedimentary facies and lithologies in reef-bank reservoirs using borehole image logs

Reef-bank reservoirs are an important target for petroleum exploration in marine carbonates and also an essential supplemental area for oil and gas production in China. Due to the diversity of reservoirs and the extreme heterogeneity of reef-banks, it is very difficult to discriminate the sedimentary facies and lithologies in reef-bank reservoirs using conventional well logs. The borehole image log provides clear identification of sedimentary structures and textures and is an ideal tool for discriminating sedimentary facies and lithologies. After examining a large number of borehole images and cores, we propose nine typical patterns for borehole image interpretation and a method that uses these patterns to discriminate sedimentary facies and lithologies in reeI^bank reservoirs automatically. We also develop software with user-friendly interface. The results of applications in reef-bank reservoirs in the middle Tarim Basin and northeast Sichuan have proved that the proposed method and the corresponding software are quite effective.

Acoustic Borehole Images for Fracture Extraction and Analysis in Second Pre-pilot Drillhole of CCSD

Ultrasonic imaging logging provides continuous and oriented images of structures vs. depth. In the Chinese Continental Scientific Drilling (CCSD) Project, acoustic borehole images were recorded in the second pre-pilot drillhole which penetrates the metamorphic rocks. This paper focuses on fracture evaluation of the drillhole with these images. Both least square fit and a modified Hough transform are used for fracture extraction, and 269 fractures were mapped in the interval from 69.5 to 1 020 m. Most fractures dip steeply, with an average angle of 54°. Fracture dip directions are dominantly in the range of 220°-280° above the depth of 267 m, but 80°-120° in the lower zones. These observations may indicate the differences in structural movements or in-situ stress fields between the upper and lower zones in the drillhole.

Groundwater Exploration Using 2-D Geoelectrical Resistivity Imaging Technique at Sungai. Udang, Melaka

Electrical resistivity imaging surveys have been conducted in order to locate, delineate subsurface water resource and estimate its reserve. The resistivity imaging surveys carried out basically measure and map the resistivity of subsurface materials. Electrical imaging is an appropriate survey technique for areas with complex geology where the use of resistivity sounding and other techniques are unsuitable to provide detailed subsurface information. The purpose of electrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. The resistivity imaging measurement employing Wenner electrode configuration was carried out using an ABEM SAS 1000 terrameter and electrode selector system ES464. The field survey was conducted along four profiles which provide a continuous coverage of the resistivity imaging below surface. The surface soil material is mainly clayey silt. The results showed that the layers associated with the low resistivities （Ωm） are located at depth ranging from 2 m to 28 m. This low resistivity values are associated with zone of water saturated weathered layer and fractures. The results showed that the thickness of residual soil is about 0.5-2.55 m. Borehole data indicated that the depth of bedrock is about 10 m and the groundwater level is ranging from 8.73 m to 8.54 m.

露天潜孔钻机随钻测量系统研发与应用研究

露天采矿随钻测量技术研究目前尚处于初期阶段,研发随钻参数测量系统是实现随钻测量技术服务于采矿工程行业的首要任务。基于TAIYE-390-Ⅱ潜孔钻机工作原理,确定了随钻参数,提出了一套通用的测量方法,并研发了测量装置。装置主要由数据采集系统、数据转换系统和数据处理系统组成,可实现对钻进时间、钻进深度、钻进速度、钻杆轴压、回转力矩、回转速度、冲击风压和冲击风量等参数的实时准确测量、采集、计算、存储、显示和远程传输。结合某石灰岩矿钻孔数据,提出了一种反映岩性变化的数据整合方法,并借助钻孔成像试验分析了随钻测量技术在岩体结构面识别中的可行性。结果表明钻进速度和回转力矩对岩体结构响应最为灵敏,冲击风量和冲击风压在钻凿含孔洞的破碎岩体时表现突出,而钻杆轴压和回转速度在岩体结构识别中作用较小。研究成果在潜孔钻机随钻测量系统研发和随钻岩性识别等方面具有重要的理论意义和应用价值。

A study on the discrete image method for calculation of transient electromagnetic fields in geological media

We conducted a study on the numerical calculation and response analysis of a transient electromagnetic field generated by a ground source in geological media. One solution method, the traditional discrete image method, involves complex operation, and its digital filtering algorithm requires a large number of calculations. To solve these problems, we proposed an improved discrete image method, where the following are realized： the real number of the electromagnetic field solution based on the Gaver-Stehfest algorithm for approximate inversion, the exponential approximation of the objective kernel function using the Prony method, the transient electromagnetic field according to discrete image theory, and closed-form solution of the approximate coefficients. To verify the method, we tentatively calculated the transient electromagnetic field in a homogeneous model and compared it with the results obtained from the Hankel transform digital filtering method. The results show that the method has considerable accuracy and good applicability. We then used this method to calculate the transient electromagnetic field generated by a ground magnetic dipole source in a typical geoelectric model and analyzed the horizontal component response of the induced magnetic field obtained from the ＂ground excitation-stratum measurement method. We reached the conclusion that the horizontal component response of a transient field is related to the geoelectric structure, observation time, spatial location, and others. The horizontal component response of the induced magnetic field reflects the eddy current field distribution and its vertical gradient variation. During the detection of abnormal objects, positions with a zero or comparatively large offset were selected for the drill- hole measurements or a comparatively long observation delay was adopted to reduce the influence of the ambient field on the survey results. The discrete image method and forward calculation results in this paper can be used as references for relevant research.

基于穿层钻孔声波远探测有限元方法的煤岩界面成像

小型地质构造是造成煤与瓦斯突出事故的主要因素,小构造的精准探测是亟需解决的关键问题。煤岩界面高精度探测是查明小构造,实现透明工作面的基础。声波远探测技术具有探测范围大、分辨率高、可成像等优点,能够实现对煤岩界面的精准识别。为此,提出了基于穿层钻孔声波远探测的煤岩界面探测技术,通过在井下穿层钻孔内布置声波远探测仪,采集孔周煤岩分界面产生的阵列波形,并利用反射波信息反演获得煤岩界面成像图,进一步结合钻孔群,实现工作面的整体勘察。首先,利用COMSOL Multiphysics软件构建出煤系单极远探测数值模型;然后通过模型正演分析全波信号与波场快照的全时空变化规律;最后对远探测声波数据进行反演实现煤岩界面的偏移成像。正演结果表明:模型中煤层的纵波波速比顶底板岩层慢1.2 km/s左右,声波在煤层中传播时能量衰减得更快,同时声波穿过煤岩界面时会出现主频的漂移;当测点趋近于仪器从底板岩层向煤层过渡的位置时,直达波的变化特征为幅度的骤降与声时的增大,而界面反射波的特征为时间-深度域中倾斜同相轴的斜率改变。对采集到的波形数据进行滤波、波场分离、反射波增强、偏移成像四个步骤完成模型反演,成像结果与原始模型相似度高,煤岩界面倾角误差0.6°、煤厚误差0.212 m,穿层钻孔远探测声波有限元方法可以有效地反演出煤岩界面的位置和形态特征。该研究可为声波远探测技术应用于穿层钻孔煤岩界面识别提供基础理论支撑。

多层系复杂水体下开采界限确定的工程实践

车集煤矿二2煤层开采受上覆地表水、新生界底部松散孔隙承压水、砂岩裂隙水等多层系复杂水体影响。为了评价各含水体对二2煤层的影响,并以此确定二2煤层的开采界限,采用现场实测、数值模拟、理论计算等方法对二2煤层“两带”发育规律进行研究。结果表明:二2煤层导水裂隙带发育高度在42.25~47 m,垮落带发育高度约为10.53 m;顶板塑性区基本呈“蘑菇形”,采空区四周塑性区为剪切塑性区,中间为拉张塑性区;上覆地表水、新生界底部松散孔隙承压含水层、砂岩裂隙水对二2煤层开采影响较小,确定二2煤层可以全厚开采。该研究可为车集煤矿二2煤层和其他相类似条件煤层开采“两带”发育规律及开采界限研究提供参考。

高性能井筒超声脉冲回波扫描成像测井仪研制

多功能超声成像测井仪采用超声脉冲反射法对套管腐蚀及固井质量做定量评价。利用从井眼内壁反射波形提取的幅度及到时实现井眼内壁高分辨率成像;提取套管共振波的共振频率计算套管厚度;采用全波反演方法反演套管后环空介质的声阻抗。通过优化采集模式、研制高性能换能器并建立固井质量评价模版确保仪器性能优于同类产品。现场实测资料表明,仪器可准确测量套管壁厚,识别射孔层段和射孔孔眼,识别套损缺陷,为套管找漏及侧钻点选择提供重要的决策依据,并准确评价双层套管情况下的内层套管固井质量,同时还可以在裸眼井中获取井壁表面裂缝、层理、孔洞等地质构造信息。

川南大安龙马溪组电成像测井资料中大型滑塌体的发现及地质意义

应用高分辨率电成像测井资料,首次在川南大安地区下志留统龙马溪组泥页岩中发现了大型滑塌体。滑塌体分布在龙一2亚段—龙二段内,岩性主要为灰黑色泥页岩,在常规测井曲线和岩心上与正常页岩特征一致、难以区分,但在电成像图像上可见滑塌构造和滑动构造,与正常页岩呈现的水平层理特征迥异、界面截然。大安地区1000 km^(2)范围内的6口钻井中均发现有多层滑塌体,滑塌体层之间为正常的页岩,不同井中滑塌体的层数、厚度明显不同,在横向上缺乏对比性,总体表现为北厚南薄、北强南弱的趋势。单井中最多发育有35层滑塌体,最少为9层;单层滑塌体厚度最大为32.4 m,最小为0.5 m;单井滑塌体层累计厚度最大为194.5 m,最小为41 m。分析认为滑塌体分布范围广、发育层数多、单层厚度大,具有地震成因的特点,其分布受乐山—龙女寺古隆起东南斜坡控制,是近距离搬运、快速堆积沉积作用的产物,不同井区对同一地震事件的沉积响应不同,单层滑塌体可能是对1次地震事件的响应,也可能是多次地震事件叠加的结果。滑塌体的发现为川南龙马溪组的地层对比提供了新的沉积学信息,同时滑塌体厚度大、裂缝发育程度高、具有良好的储盖条件,可成为下一步页岩气勘探的备用层系。

四川盆地华蓥山断裂带南段地应力方向的差异:来自钻孔成像测井的启示

华蓥山断裂带作为四川盆地内规模最大的断裂带,两侧地质构造存在较大差异,历史上该断裂带上频发5级左右地震,现今仍具一定活动性,扰动着盆地的地应力场。明确华蓥山断裂带的地壳应力状态可以提高对该地区活动变形、构造活动以及地震活动性的认识,并对后续华蓥山断裂带研究提供参考依据。在收集整理华蓥山断裂带南段8处钻孔测井成像(钻孔崩落与钻孔诱发张裂缝)数据基础上,结合中国现代地应力场和四川盆地东南缘的地震震源机制解数据对其地应力特征进行了综合分析。研究结果表明:华蓥山断裂带南段南部地区大多数钻孔的最大水平主应力为北西西—南东东向,与四川盆地区域应力场方向一致,仅1处钻孔的最大水平主应力呈北东东—南西西向;在南段中部地区钻孔的最大水平主应力均为北东东—南西西向,对比四川盆地区域应力场呈逆时针偏转。应力方向发生偏转主要是由华蓥山断裂带基底性质变化、构造应力和区域应力场的综合作用造成的。

真三轴煤层钻孔承载破坏层理效应试验研究

为探究层理对真三轴环境下煤层钻孔动态破坏特征影响,采用煤岩体单面可视真三轴试验仪器开展含层理煤层钻孔承载破坏试验,并结合数字图像相关和声发射分析方法进行研究。研究结果表明:试样破坏经历3个阶段,阶段Ⅰ,分析区域边缘剪切应变集中,孔壁破裂伴随煤颗粒弹射,声发射累计事件数和能量活跃性较低;阶段Ⅱ,孔周剪切应变场呈蝴蝶形状分布特征,孔壁两侧煤碎片弹射、煤块剥落,呈“V”形破坏,声发射累计事件数和能量活跃性较高;阶段Ⅲ,试样层理处剪切应变集中,出现宏观剪切裂纹,呈拱形分布特征,声发射累计事件数和能量活跃性强烈。研究结果对钻孔卸压机制研究具有参考意义。

Fracturing timing of Jurassic reservoirs in the Dibei-Tuziluoke gas field,Kuqa foreland basin:Evidence from petrography,fluid inclusions,and clumped isotopes

Determining the timing of fracturing is crucial for understanding reservoir evolution and hydrocarbon accumulation in foreland basins.Using fracturing data from cores,borehole images,and outcrops,combined with the clumped isotope(D47)and fluid inclusion analyses of carbonate minerals filled in pores and fractures,this study ascertained the fracturing timing of the Jurassic reservoirs in the Dibei-Tuziluoke Gas Field,Kuqa Foreland Basin.Data from outcrops and borehole images show two dominant fracture sets in the study area:W-E and NE-SW striking fractures.Some W-E striking fractures are carbonate-filled,while NE-SW striking fractures lack mineral fillings.Bitumen veins,not easy to be identified in borehole images,are prevalent in cores.The petrographic analysis reveals that these bitumen veins formed before the calcite cementation in pores and display high viscosity and low maturity.Homogenization temperatures(T_(h))from primary fluid inclusion assemblages in two representative calcite vein samples were notably lower than T_(△47) values from corresponding samples.This suggests the △_(47) signature underwent alteration due to partial reordering during burial.Thus,△_(47)-derived temperatures(apparent temperatures)may not faithfully represent the mineral precipitation temperatures.When plotting these apparent temperatures vs.the burial history,only the possible latest ages of fracturing emerged.These ages were further refined by considering petroleum charging,tectonic evolution,and stress orientation.Bitumen-filled fractures likely resulted from the Late Cretaceous uplift,marking the migration of low-maturity hydrocarbons in the study area.Carbonate-filled E-W striking fractures emerged during the late Miocene(~13-6.5 Ma)alongside fold development.NE-striking fractures that crosscut W-E ones possibly formed recently due to stress reorientation.

利用水下电阻率层析成像技术探测坝址岩溶溶洞

内河航运和水电开发工程在推进社会进步中发挥了重要作用,然而部分河底岩溶溶洞广泛发育,严重影响工程选址及建设。提出水下电阻率层析成像探测方案,并将该方法应用于广东东江下矶角航电枢纽工程,共布设6条700 m长横跨江面的测线,单个水底电缆排列包含40个电极,极距5 m,相邻排列重复观测长度为100 m。反演得到的三维电性结构刻画了高阻砾石层、低阻砂岩和高阻灰岩等关键地质单元,结合已有钻孔资料划分出多个隐伏溶洞靶区。水下电阻率层析成像施工难度大,正反演计算复杂,研究成果可为后续电阻率层析成像和水下灾害地质异常体探测提供参考。

旋挖灌注桩水平裂缝成因及检测方法探讨

文章以深圳地区某项目旋挖灌注桩桩身完整检测为例,分析旋挖灌注桩水平裂缝的成因,并通过比较低应变法、高应变法、声波透射法、钻芯法及孔内摄像法,探讨多种检测方法在灌注桩水平裂缝检测方面的优缺点和适用性,以期为类似工程提供参考。

大埋深煤层开采覆岩离层发育层位定位方法研究

离层注浆是减少开采后地面沉降,以及防治离层水害的重要手段,其中,确定注浆层位作为注浆工程的首要难题,影响着地面减沉和水害防治效果,在离层形成过程中,不同的覆岩结构对离层的发育影响至关重要。本文以门克庆煤矿11-3101工作面地质条件为工程研究背景,基于Winkler弹性地基上的薄板理论,推导了岩板竖向挠度计算公式,结合“关键层”理论,建立了覆岩离层发育层位及其空间特征预计模型。同时,利用三维离散元技术研究了工作面覆岩离层的发育规律。通过在11-3101工作面开展离层注浆工程,应用钻孔冲洗液漏失量观测和钻孔彩色电视成像技术对离层发育层位进行现场实测,将模型预计成果和数值模拟结果与实测结果对比,验证了理论预计和模拟模型预测结果的可靠性。同时,通过观测注浆前后地表沉降情况可知,下沉速率减少了58.6%,注浆减沉效果显著。该模型可为后续该地区离层注浆和离层水害防治提供更加精确的层位选择。

基于能量耗散理论的深部巷道围岩松动圈范围分析

以某矿上组煤一采区回风大巷穿层4号煤层为背景,基于能量耗散理论进行巷道围岩松动圈范围研究分析,基于能量平衡方程和围岩松动圈能量分析理论建立拱形巷道能量耗散力学模型,确定巷道围岩松动圈破坏范围与能量耗散量呈正相关关系。基于摩尔-库伦应变软化本构模型,开发了基于FLAC3D软件能量耗散fish程序并进行数值模拟,确定了模型巷道能量耗散范围平均为5.9 m,结合现场钻孔成像试验,确定了大巷围岩松动圈破坏范围分别为5.9 m和6.04 m,证明了能量耗散理论能够较好适用于围岩松动圈范围的分析研究。

月潭水库坝址裂隙结构面调查及分析

文章针对月潭水库坝址裂隙结构面采用了地表地质测绘、钻孔电视录像以及勘探平洞内裂隙调查等方法,对坝基缓倾角裂隙结构面进行了统计分析,为坝基抗滑稳定分析评价提供了地质依据。

井中地震三维高效黏声逆时偏移成像方法及应用

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