基于三维地质建模技术的溶土洞注浆量测算应用探讨

传统测算方法无法满足大面积住宅类项目溶土洞注浆量计算的需求,基于此问题,本文提出了三维地质建模测算溶土洞注浆量的技术,以地质勘探钻孔数据为三维地质模型的生成基础。结合粤海·云港城项目11#地块工程的工程背景,通过三维地质建模软件生成高精度的数字模型,理论上可以得到溶土洞的空间体积,再结合溶土洞岩层特质(岩性地质、岩隙率)分析,进而完成溶土洞注浆量的测算,为行业内溶土洞注浆量的测算打开了一个新的视角,可为类似项目溶土洞注浆量测算提供借鉴。

Experimental study of motion characteristics of rock slopes with weak intercalation under seismic excitation

In order to investigate the effect of a weak intercalation on slope stability, a large-scale shaking table model test was conducted to study the dynamic response of rock slope models with weak intercalation.The dynamic response of the prototype slopes were studied in laboratory with the consideration of law of similitude. The initiation failure was observed in the rock slope model with a counter-tilt thin-weak intercalation firstly, not in the slope model with a horizontal thin-weak intercalation. Furthermore, it was interesting that the fracture site is shifted from crest top to the slope surface near the weak intercalation, which is different with the location of failure position in a normal layered slope. We also discussed the effect of the dip angle and the thickness of weak intercalation on the failure mechanism and instability mode of the layered rock slope. From the experimental result, it was noted that the stability of the slope with a counter-tilt weak intercalation could be worse than that of the other slopes under seismic excitation. The findings showed the difference of failure in slopes with a horizontal and counter weak intercalation, and implicated the further evaluation of failure of layered slopes caused by seismic loads.

Acoustic-electrical properties and rock physics models for shale-oil formations:prediction of reservoir properties of interbedded sandstone and shale layers

In recent years,the Yanchang shale-oil formations of the Ordos Basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water discriminations,have been the key targets of unconventional oil/gas resource exploration and development in the relevant areas.The joint acoustic-electrical(AE)properties can be used to interpret reservoir lithology,mineralogy,pore structure,and fluid saturation.To conduct tests of thin section analysis,X-ray diff raction,and ultrasonic and electrical experiments at diff erent pressures and saturation degrees,cores from the shale-oil formations in the Q area of the basin are collected.The variations in AE properties with respect to clay content,porosity,pressure(microfracture),and saturation are analyzed.The experimental results indicate that the rock physics behaviors of sandstones with diff erent clay contents vary significantly.The AE properties of clean sandstones are basically dependent on the microfractures(pressure),while for muddy sandstones,the clay content is an important factor affecting the responses.The target reservoir consists of interbedded sandstone and shale layers.The AE equivalent medium equations and the Gurevich theory are applied to establish the joint models for the diff erent lithologies and simulate the variations in AE properties with respect to fluid type,pore structure,and mineral components.The three-dimensional joint templates of clean and muddy sandstones,as well as shale,are developed based on the elastic and electrical attributes and then calibrated using the experimental and well-log data.The reservoir properties are estimated with the templates and validated by the log data.The results indicate that the joint templates based on lithology characteristics can eff ectively characterize the properties of interbedded sandstone and shale layers.Furthermore,the combined application of AE data provides more beneficial information for the assessment of rock properties,leading to precise estimates that conform with the actual formation conditions.

The significance and variation characteristics of interlay water in smectite of hydrocarbon source rocks

To investigate variation characteristics of interlayer water bound up with organic matter in smectite, organo-clay complexes extracted from grinded source rock samples were determined using thermo-XRD, DTA and PY-GC. The dool diffraction peak of organo-clay complexes is postponed from 250 to 550℃ before reaching 1.00 nm and accompanied by exothermal peaks on DTA and organic matter with abundant C20-C30carbon detected by PY-GC, which is different from single smectite and indicates the existence of organic matter in the interlayer of smectite. Water desorption characteristics of organo-clay complexes are in consistent with smectite at 100 and 600℃, but different from smectite at 550℃ with an additional dehydration peak and a remaining d001 diffraction peak, suggesting the vcater removed at 550℃ is interlayer adsorption water rather than constituent water of clay minerals. Comparing the dehydration order and water loss, we conclude that part of interlayer water of smectite may act as the ＂bridge＂ that binds organic matter and smectite, which results in water-expelled lag beyond 250℃ and may provide a good medium for hydrocarbon migration and oil pool formation.