Lithological Information Research Articles

Construction and application of the 3D geo-hazard monitoring and early warning platform

Abstract As geo-hazard monitoring data increases in category and size, conventional geo-hazard information management systems, without a unified integration framework and visualized data display, are unable to satisfy the urgent needs of geo-hazard information management. Representational State Transfer (REST), a resource-centered service architecture, abstracts data and services into resources for unified Uniform Resource Identifier access, enabling it to take full advantage of HTTP with great flexibility and scalability. Based on the REST service architecture, this paper constructs a 3D geo-hazard monitoring and early warning platform with sound service compatibility and scalability by integrating geographical information, real-time monitoring data, and early warning models into the 3D Digital Earth framework. The platform displays topography, stratum lithology, and relevant information, as well as real-time monitoring data in a 3D visual, and provides early warning services for geo-hazards through access to real-time early warning models. As a result, it is capable of providing comprehensive information management, monitoring, and early warning of multiple geo-hazards, aiding decision-making in disaster prevention and mitigation, and enhancing the information level of geo-hazard prevention and mitigation work.

Rapid Mapping of Hydrological Systems in Tanzania Using a Towed Transient Electromagnetic System.

Limited knowledge of local groundwater systems often results in the failure of boreholes to yield water of the required quantity and quality. This is particularly problematic in the developing world, where financial resources are often limited, and failed wells represent a significant financial burden. To enhance understanding of local hydrological systems, noninvasive geophysical methods can aid the understanding of hydrogeological structures and identification of groundwater sources needed to optimize siting of wells. Here, we highlight the utility of a relatively new towed-transient electromagnetic system, called tTEM. This system is a rapidly deployable mobile geophysical method well-suited to cost-efficient characterization of local-to-regional groundwater systems. Results from tTEM surveys conducted in two refugee camps and several host communities in western Tanzania demonstrate the capability of the method to characterize shallow aquifer systems with high lateral and vertical resolution, with data collection typically exceeding 15 to 20 line-kilometers (km) per day. This work focuses on tTEM's ability to provide semiquantitative insights into regional hydrogeological settings when supporting data required for more rigorous interpretation/modeling is lacking. The system provided useful data within communities with low density of electrification and near buildings with metal roofs and walls. tTEM-derived resistivity profiles were correlated with limited local borehole lithologic information to develop conceptual models of the local groundwater systems. These models were used to successfully guide the siting of a production well and to identify future drilling targets in the refugee camps and surrounding communities.

STOCHASTIC POROSITY MODELING IN VOLCANIC RESERVOIR JATIBARANG FORMATION

Jatibarang Formation known as interesting volcanic reservoir in North West Java Basin. The reservoir was characterized by altered and naturally fractured that has significantly producing light oil. The volcanic Jatibarang reservoir consist of 3 volcanic cycles that are cycle 1, cycle 2 and cycle 3 with 16 faults configuration. Total and Fracture porosity modeling was conducted to determine secondary porosity distribution using stochastic method. Lithofacies and property lateral variation were generated to visualize geological model. Total porosity was estimated using formation evaluation. Natural subsurface fracture has been identified by bore hole image (formation micro imager) and geophysical log from several wells in the Jatibarang Field. It has provided both lithology and property reservoir information. Lithofacies tuff and non tuff model has been used as a constrait to distribute pore pressure and bulk modulus. Then, porosity model was distribution using the collocated-co kriging method. The purpose of this study was to determine the distribution of total and fracture porosity of the Jatibarang volcanic reservoir.

Key Technologies for Deep Horizontal Well Drilling of Shale Gas in Luzhou of Sichuan Basin

The drilling of deep shale gas horizontal wells in Luzhou block of Sichuan Basin has been chanllenged by long drilling cycle, low rate of penetration (ROP), high drilling tool vibration, poor drillability of special lithological formations, horizontal wellbore instability, high formation temperature, and high friction torque and sticking risk etc.. To solve these problems and to ensure operation safety and increase cost-efficiency, technological research was carried out on casing program design of horizontal wells, wellbore trajectory control and optimization of horizontal sections. As a result, the optimal parameters of the radical drilling method were recommended, and shock absorption, speed-up, and high efficient rock breaking technologies for special lithological formations were preferentially adopted. In addition, drilling fluid system and performance parameters were recommended based on pilot tests of ground cooling equipment. In this way, key drilling technologies with high operation safety and efficiency were formed for the deep shale gas horizontal wells in Luzhou block. Through the application of the key technologies in four wells in Luzhou block, the experimental results show that the drilling cycle was redcued by 14.5% and no downhole failure was reported for average well depth of 5,601.00 m and the horizontal section length of 1,884.00 m. So these technologies can meet the requirement of safe and efficient drilling as well as wide application scope in Luzhou.

The method for prediction of formation pore pressure based on mechanical specific energy theory

With traditional prediction methods, the accuracy for prediction of formation pressure is low in formations with complex lithology, such as saline aquifers, fractured formations and carbonate rocks. Therefore, in Qinghai Oilfield, in order to ensure the drilling safety, studies have been conducted in order to find the method for predicting the pore pressure of E32 formation, in which the lithology is complex. Mechanical specific energy is the total energy required for breaking and removing rock per unit volume. With the increase of depth, the confining pressure of rock and vertical effective stress increase. Therefore, more energy is required to break and remove rock per unit volume. However, in abnormal high-pressure formation, pore fluid bears some overburden pressure, and the rock effective stress is reduced, leading to less requirement for mechanical specific energy. Therefore, it is feasible to evaluate the formation pressure qualitatively based on the mechanical specific energy theory. In this study, according to the actual drilling conditions, a model for prediction of formation pressure has been constructed and optimized on the basis of mechanical specific energy theory. With this model, the prediction accuracy on formation pressure has been improved obviously. This model has been used in prediction of formation pressure of the E32 formation in several wells in Qinghai Oilfield, which are carbonate rocks with fractures developed. The application results show that this formation pressure prediction model based on the mechanical specific energy works well in prediction of formation pore pressure, with an error less than 12%, which meets the engineering requirements. It provides a new method for predicting the pore pressure in complex lithologic formations such as carbonate rocks.

Mineralisation potential assessment using analytical hierarchy process (AHP) modeling technique: A case study of Ilesha schist belt, southwestern Nigeria

A mineralisation potential assessment in part of Ilesha Schist belt of southwestern Nigeria was carried out using multi criteria decision analysis (MCDA) in the context of analytical hierarchy process (AHP). Three parameters sourced from aeromagnetic, electrical resistivity and geological data were identified to favour gold mineralisation in the study area. These parameters include lineament density (Ld), lithology (Lt), and electrically derived coefficient of anisotropy (An). The application of data enhancement techniques such as total horizontal derivative, 3-D Euler deconvolution and source edge detection were employed in the production of lineament map of the study area. Two hundred and sixty-five (265) vertical electrical sounding (VES) points were investigated using Schlumberger configuration. Coefficient of anisotropy derived from the Dar-Zarouk parameters was obtained from the synthesized VES data. The lithologic information was obtained from the existing geological map of the area. The orientations of lineaments displayed on the aeromagnetic results suggest predominantly NE-SW trending structures, which are characteristic of the Pan African orogenic events in the area. However, few of the E-W trending lineaments are imprints of secondary structural alteration. Furthermore, the Euler deconvolution solutions revealed that the area is characterised by geological contacts with estimated depth of 94–600 m. The coefficient of anisotropy results obtained from the geo-electric parameters vary from 1.00–2.87. AHP weighting and ranking technique was used to develop a reliable mineralisation potential model (MPM). In line with the recommended lower limit of 10 %, the consistency ratio of the developed model is 9.61 %. The produced MPM was classified into low, moderate and high mineralisation potential zones. Preliminary validation of the MPM using the existing pits in the area showed 79 % success rate. The validation of the model using the existing geochemical information from the previous studies indicated 85 % agreement with the conceptual model; thus, confirming the reliability of the produced MPM. The developed model is therefore believed to serve as a future reference in the resource management of the study area.

Middle Devonian brachiopods of the Reggane area (Algerian Sahara): palaeontology, stratigraphy and environments

ABSTRACT The Middle Devonian of the Djebel Aberraz (Reggane basin, Algerian Sahara) shows clays/limestone alternances subdivided in two lithological formations: ‘Adrar Morrat Clays’ and the ‘Azzel Matti Limestones’. The alternances yielded a benthic fauna composed of brachiopods associated to bryozoans, trilobites, crinoids and rare nectonic cephalopods. The taxonomic ranges of the brachiopods shows 14 species grouped into 13 genera, briefly described with their stratigraphic ranges. Most of the species are well known in the palaeobiogeographical Gondwana’s realm. The sedimentary environment showed small variations between the offshore and offshore-transition during the Eifelian, marked by the presence of the Glyptogypa multiplicata ecozone associated to Leptaena sp. cf. dicax, Schizophoria (Schizophoria) cf. schnuri bicissa, Aulacella prisca, Atrypa (Planatrypa) squamifera, Productella sp. cf navicella, Kransia (Fatimaerhynchia) goldfussii, Kransia (Fatimaerhynchia) signata, Athyris curvata and Cyrtina intermedia. The Givetian strata evolved in an offshore environment with the Lebanzuelle? issoumourensis issoumourensis ecozone associated with Pseudocamarophoria undulataeformis, Cyrtina intermedia, Beckmannia beckmanni and Dicamara prunulum. The transgressive Middle Devonian strata of Djebel Aberraz constitute deepening-up sequence where the brachiopod stocks followed the bathymetric stress by less diversity and moderate richness.

Lithology Identification, Shale Volume Estimation and Formation Wate Saturation of Fenchuganj Gas Field Using Wireline Log Data

This study has been undertaken with a view to interpreting and analyzing different types of logs, detecting hydrocarbon-bearing sand zone, identifying the lithology, estimating shale volume, and determining water saturation of the formation of the Fenchuganj gas field. Fenchuganj gas field is in the southern part of Bangladesh in the Sylhet division. It lies in the Surma basin and characterized as a water drive gas field. Gamma Ray (GR) log and Spontaneous Potential (SP) log analysis help to interpret the formation lithology. After interpreting lithology, the gamma-ray log and SP log were analyzed further, and the hydrocarbon-bearing zone was detected. From the analysis of different logs, for well 4, so many gas-bearing sand zones have been detected. The gas-bearing zones are found between (1585-1595) m, (1600-1610) m, (2409-2420) m, (2265-2270) m, (2295-2303) m, (2435-2450) m, (2465-2480) m, (3150-3155) m, (2955- 2960) m. These are the gas-bearing zones of fenchugonj well-4 determined from the composite log of this field. Water-bearing sand zones are between (1708-1714) m and the fully compacted shale zone is between (1920-1930) m. From the analysis of different logs, for well 5, so many gas-bearing sand zones have been detected. The gas-bearing zones are found between (2365-2385.5) m, (1820-1830) m, (1782-1803) m, (305-308) m, (336.5-338.5) m, (607.5-609.5) m. These are the gas-bearing zone of fenchugonj well-5 determined from the composite log of the field. Shale volume has been estimated from the gamma-ray log and from resistivity logs by the true resistivity method. In well 4, the calculated value of shale volume by Gamma Ray method and true Resistivity methods were respectively 15% and 6%, in well 5 these values were 7.25% and 7.64%. Formation water resistivity was determined from the formula and taken as 0. 1ohm-m and mud filtrate resistivity 0.76 ohm-m. for well-4 and for well-5 it was taken as 0.7 ohm-m (from the provided composite log of well 4 and 5). Formation true resistivity Rt was estimated directly from the ILD log and true resistivity log. The average value of Rt for well-5 was 33.75 ohm-m and for well-4 the value is 34.09 ohm-m. From the RFOC log, flushed zone resistivity Rxo was calculated directly. Water saturation has been determined by three different techniques named Archie, Indonesia, and Simandoux method. For well 5, the value of average water saturation found from Archie, Indonesia, and Simandoux model was 8.5%,22%, and 24.84%, and for well-4. The value of average water saturation was found as 7.3%,18%, 20.51%respectively.

Study of Intelligent Identification Method for Drilling Condition and Lithology in Underground Coal Mine Based on Deep Learning

It is important to accurately master the downhole drilling parameter information and drilling formation lithology for the sake of efficient and reasonable gas extraction, hole arrangement and construction safety. According to different detection information, an identification & interpretation model for drilling engineering parameters and a lithology identification & interpretation model in while-drilling azimuthal Gamma logging were established. Next, the drilling conditions were judged and the lithology was discriminated. However, this method relied heavily upon the professional quality and working experience of workers. By numerically simulating the influence laws of azimuthal Gamma logging on the amplitude values of detection data under different borehole sizes, a more suitable method was chosen and applied to the automatic lithology explanation and identification during the logging. An object identification method combining deep convolutional neural network (CNN) and multi-weight multi-task learning mechanism was established, followed by the residual network design, in an effort to elevate the network training rate.

The Sedimentary Geochemistry and Paleoenvironments Project.

The Sedimentary Geochemistry and Paleoenvironments Project.

Research of tight gas reservoir simulation technology

The stimulation of tight gas reservoir in Linxing block of Shanxi Province has always been a difficult problem. This paper describes and analyzes the formation lithology, physical properties and sensitivity of the reservoir. And introduces the pulse power technology and controllable shock wave technology, and focuses on the research and analysis of the latter. The results of field test show that: In the application of plug removal and permeability enhancement of low permeability tight gas oil and gas wells in medium and shallow wells (well depth less than 3000m), the controllable shock wave technology has achieved good results in increasing production and injection. Field application shows that the technology is basically mature and can be further promoted. Compared with traditional technologies such as acidizing and plugging removal, controllable shock wave technology has the advantages of layered implementation, strong pertinence, simple operation, wide adaptability and better effect.

CONDITIONS FOR THE IMPLEMENTATION OF THE PALEONTOLOGICAL DIRECTION OF GEOTURISM WITHIN THE NATURE NATURAL PARK "PODOLSKY TOVTRY"

The publication highlights the regional conditions for the development of geotouristic forms of using paleontological objects, the territory of the NPP "Podolski Tovtry" The need to introduce and develop specialized tourism products based on the paleontological resource base and regional conditions within the Podolskie Tovtry NPP is a reaction to the concentration of tourist groups within the natural park, as well as a noticeable decrease in interest in traditional sites.
 Paleontological Geotourism is a specialized area of activity that requires special training. Its forms of implementation are combined with traditional tourism products, the compactness and complexity of the placement of lithological formations makes it possible to implement sharply contrasting thematic approaches (sandy Neogene beach, Silurian coral reef, mammoth tundra), and locations within mined out pits or specially equipped nature conservation objects - ecological - educational influence combined with economic and social effect.
 The main conditions for the development of the direction on the territory of the natural park are the set of features of the lithological base and natural geomorphological, as well as economic objects that reveal paleontological locations. The analysis of the conditions of the transport and technical infrastructure, interaction with traditional forms of nature management, as well as tourist sites, which have long been included in the regional recreational complex, has been carried out.
 To experimentally confirm the regional efficiency of the paleogeotourism direction, the authors of the study selected three model sites that meet these criteria, carried out in cooperation with representatives of NPP "Podilski Tovtry" and the City Council of Kamianets-Podilskyi their primary infrastructure equipment, and equipped and the museum exposition was tested and the possibilities of conducting paleontological master classes were studied. Geotourism products have been developed and partially implemented in cooperation with interested tour operators.
 These aspects of the development of the paleontological direction of geotourism from the standpoint of regional conditions are a means of substantiating the regional strategy for the development of environmentally friendly forms of nature management within the NPP "Podilski Tovtry". They are aimed primarily at demonstrating the effectiveness of the research area and its compatibility with the already established traditional economic forms, which will solve the problems of access and use of paleontological objects and promote the participation of local communities and regional businesses in its implementation. Partial practical testing of the second results of regional conditions presented in the publication can become the basis of scientific discussion on the effectiveness of selected geotourism forms, their compliance with the conditions and accordingly adjust further scientific and applied research in this direction.
 Key words: geotourism, paleotours, Podilski Tovtry

Application of modified managed aquifer recharge model for groundwater management in drought-prone water-stressed Barind Tract, Bangladesh

The core challenge of Barind Tract (BT), located in the northwest region of Bangladesh, is to make water available for agricultural, drinking, domestic, and other uses and ultimately for the survival of flora and fauna. Over extraction of groundwater for irrigation, less rainfall, fewer sources of surface water, high temperature, and thick top clay that limits the natural recharge are the major causes of continuous depletion of groundwater level (GWL) in the BT, which demands managed aquifer recharge (MAR) technique as the modified form matching with the lithology as well as the aquifer condition of the area. So, the study aimed to design, construct a recharge well (RW) and a water filtration unit as a specific MAR method to evaluate their performance for groundwater recharging through rooftop rainwater harvesting in the Barind Multipurpose Development Authority (BMDA) Mohanpur office campus, Rajshahi under the BT region. In this view, necessary data and information like rainfall, GWL, lithology, and other information related to the study were collected from the BMDA Mohanpur office and field investigation. Lithological samples of the Mohanpur office campus were collected through drilling arrangement, and grain sizes of the aquifer samples were analyzed in the laboratory, then designed the RW and installed at the BMDA Mohanpur office campus accordingly. A water filtration unit was designed considering the average maximum daily rainfall. Rooftop rain waters were collected from the office building and a training shed near the uPVC pipeline, filtered through the sand-gravel filtration media of the filtration unit, and finally recharged to the groundwater through RW. GWL fluctuation of the observation well (OW) installed near the RW was monitored using Auto Water Level Recorder (AWLR). Performances were evaluated based on groundwater recharge, GWL fluctuation with the rainfall, and quality of water. The study found that groundwater recharging occurred significantly, groundwater level rose when rainwater was infiltrated into the groundwater, and water quality parameters remained within the acceptable limit for drinking use according to standards like Bangladesh Drinking Water Standard (2005) and WHO (2008).

Delineation of Lithological Formation in Bukit Merah, Semanggol, Perak Using Groundwater Modelling Software

The knowledge of lithological formation is important to determine the potential aquifer for water resources management. This study aims to delineate the lithological formation of Bukit Merah, Semanggol using geological data. The preparation of lithological formation in the study was based on several factors such as electrical resistivity survey data, available well lithologies, geological map, and geological-related studies in the study area. The Electrical Resistivity Tomography (ERT) profile produced from the resistivity survey was interpreted based on previous studies to determine the subsurface materials on the location. The estimation of soil lithology for the remaining wells was done to generate the overall subsoil pattern in the study area. A total of 15 types of soil were classified to represent the actual lithology in the study area. The simplification of the actual lithology was carried out based on rocks and soils group. The elevation of the ground surface and each soil layer were imported into Visual MODFLOW software, then the interpolation of elevation points was done. Two interpolators; Kriging and Natural Neighbouring were used to generate ground surface and model layers similar to the topography in the study area. As a result, it has been identified that the study areas consist of 4 main layers of lithological formation which are unconsolidated deposit, sedimentary, metamorphic, and granite. The upper layer is dominated by unconsolidated with a maximum thickness of about 150 m in the coastal area. Hence, it is concluded that the unconsolidated deposit layer in Bukit Merah is highly potential with groundwater resources in the alluvium aquifer at the upper layer which has the potential to be developed for purpose of irrigation in a paddy field in the Kerian area.

Data-driven prediction for carbonate lithologies based on new ensemble learning of logging sequences

Lithology prediction, especially for carbonate and volcanic reservoirs, is universally viewed as a crucial job in early petroleum exploration because the predicted lithology information is significant to some basic geological work such as stratigraphic correlation or sedimentation modeling. Although being capable to provide effective results in many practices, the typical methods normally cannot reach the goals when dealing with the complex lithology prediction. In order to solve such problem perfectly, a new hybrid neural network, a transformation of probabilistic neural network (PNN) by integrating CRBM (continuous restricted Boltzmann machine) and (PSO) particle swarm optimization, is proposed in this article. The raw data with high correlation can be filtered by CRBM, and then changes to be a new data set with low correlation. The utilization of PSO is to optimize the window length of probability density distribution for each kind of pattern. Then, with the help of CRBM and PSO, PNN becomes potential to make accurate judgments for test points. The data used for validation is collected from 8 cored wells of A oilfield. In two designed experiments, the proposed method gives higher prediction accuracies compared with other validated models, all of which are over 90%. Test results convincingly prove that the new hybrid network is capable to provide an effective solution for the complex lithology prediction, and the predicted results are reliable enough to serve as the reference data for further geological studies.

Predictive lithological mapping based on geostatistical joint modeling of lithology and geochemical element concentrations

The spatial analysis and interpretation of lithological and geochemical sampling information are central in mineral prospecting and initial geological-mining exploration to delineate exploration targets and locate economic mineralization. This work compares two geostatistical approaches for the spatial prediction of lithological classes through a case study in mineral prospection, considering lithological and geochemical information at a set of surface samples. Both approaches calculate the probabilities of occurrence of the lithological classes at unsampled locations and select the most probable class as the predicted lithology. A split-sample technique is used to assess their performance, with the predictions being made at a testing data subset on the basis of the information of a training subset. The first approach relies on a cokriging of the lithological class indicators and yields an accuracy score (percentage of matches between true and predicted lithological classes) of 90.5%, while the second approach, consisting of a plurigaussian modeling of the classes, increases this score to 92.6%. Unlike the former approach, it also provides consistent outcomes of both the lithological classes and the geochemical covariates, which is valuable for mineral prospectivity mapping.

Computation of cementation factor and saturation exponent for selected oil fields in southern Iraq

This study aims to calculate cementation factor and water saturation exponent for fourdifferent lithological formations from different oil fields in south of Iraq and compare theresults with typical values of these reservoir parameters. The formations that being selectedfor this study are: Yamama Formation in West Quran (WQ-60 well), Zubair Formation insouth Rumaila (Ru-64 well), Nahr Umr Formation in Luhais oil field (Lu-5 well), andMishrif Formation in Tuba oil field (Tu-4 well). The cementation factor for clasticformations (Zubair and Nuhr Umr) was calculated via Wyllie (1949) and He (2005)empirical equations. It is found that the value of this parameter is estimated to be 1.1 and1.90 m for the Zubair formation using Wyllie equation and is equal to 2.4 and 1.6 m forNahr Umr Formation according to the He equation. For the carbonate formations (Yamamaand Mishrif), the cementation factor was estimated using Borai (1987) and Focke andMunn (1987) equations. This parameter was equal to 1.3 for both formations according toFocke and Munn (1978) and estimated to be 1.95 and 1.98 for Yamama and Mishrifformations according to equation developed by the Borai. The calculated saturationexponent was 2.5, 2, 2.21 and 0.5 in Zubair, Nahr Umr, Mishrif, and Yamama formations,respectively. The new calculated values were then applied in the Archi equation to estimatewater saturation. The obtained results were compared with that calculated in laboratory(from core). Results showed that Wyille equation is better than the He equation. The finalresult confirmed that Wyllie equation is more accurate than He equation for calculatingcementation factor in sandstone, while Borai equation was more accurate than Focke andMunn equations for the cementation factor in limestone rocks.

Research on Red-Bed Soft Rock Engineering Properties and Foundation Appraisement of Construction Engineering in Guangzhou

Based on the methods of geological drilling, literature research, induction and statistics, the site investigation of an old industrial park reconstruction project in Haizhu District of Guangzhou city was completed. The landform, formation lithology, structure and hydrogeological characteristics were systematically identified. Combined with indoor test and in-situ test, the variation rules of physical and mechanical parameters of argillaceous siltstone with different weathering degrees in the site were analyzed, and the evaluation results were given. The engineering suitability and the foundation stability are evaluated. The results showed that the weathering of soft rock makes the statistical standard values of compression coefficient, compression modulus, direct fast shear cohesion and internal friction angle of rock and soil decrease. Under the saturated state, the average value of strongly weathered argillaceous siltstone is 1.51 MPa, and that of moderately weathered argillaceous siltstone is 6.2 MPa. The strength of soft rock is low after softening with water, and the differential weathering of rock mass is strong. There are great differences in rock strength, local differences between fully and strongly weathered rock surfaces, and great changes in thickness. The weathering is extremely heterogeneous, in which the influence of structure, lithology, fissures and groundwater played a key role. The foundation is generally in a stable state, and the site is suitable for the construction of the project. The research results can provide reference for similar geotechnical engineering investigation and design.

Electron spin resonance (ESR) in petrophysical characterization of pure carbonatic rocks and containing oil

Petrophysical evaluation from laboratory and well logging data, such as gamma ray, Nuclear Magnetic Resonance (NMR) and resistivity has been used to identify and evaluate oil zones in reservoirs. Gamma ray log is able to predict lithologies along the well, and X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) techniques also provide important lithological laboratory information. The NMR log directly estimates the porosity of the rock. Resistivity log identifies the water region, but cannot provide information about oil saturation. However, the application of unconventional techniques, such as Electron Spin Resonance (ESR), can be of great relevance in the well logging, adding information about lithologies, oil quality and saturation. The ESR technique, which can directly estimate the oil saturation inside the rock, can also provide important information about the origin and formation of rocks. This technique could be an advance for the oil industry, helping to understand the geothermal processes suffered by the rocks and identifying important regions of the reservoir. Thus, in this work, we studied carbonate rock (limestone and dolomite) samples with and without oil, by ESR technique. Firstly, the effectiveness of ESR in the differentiation of carbonates (calcitic and dolomitic) without oil was tested, through the analysis of manganese ion impurity, which promotes the replacement of calcium and magnesium ions in calcites and dolomites. The samples had a typical manganese ESR signature. The hyperfine parameter, A, was homogeneous for both limestone and dolomites. The zero-field split parameter, D, showed variability, as reported in the literature. The studies were carried out at X-band frequency. The analysis by XRF and XRD provided information on the chemical and mineralogical composition of the carbonates, which were added to the ESR data for application in a correlation matrix, by which it was identified that the components CaO and MgO were directly related to the intensity of the ESR signal and the concentration of CaO was inversely related to the concentration of Al2O3 and SiO2. In one limestone rock sample was incorporated oil, with 25° API and moderate biodegradation level, to identify by ESR, the oil presence inside this rock. The technique was able to identify the oil and its saturation in the rock through the detection of free radical signal, g = 1.9951. The innovative application of the ESR technique to identify oil in varying saturation, in carbonate rock samples from the Illinois Basin (USA), was successful. These results demonstrated that this technique in addition to being accurate, non-destructive and relatively low cost, could be used in mud logging operations providing results for lithological characterization, oil identification and its saturation inside the reservoirs.

Typical Zone Division of Karst Kevelopment in China

Determining the typical area of karst development in China would provide positive reference for theoretical research of engineering geology in karst areas in China. By quantitative or semi-quantitative analyzing on the distribution characteristics, climatic conditions and formation lithology of carbonate rocks in China, regional difference characteristics of karst development in carbonate rock regions in China is evaluated, and finnally the representative karst zone in China is reasonably and theoretically delineated and demonstrated. Results show that: the pure Carbonate rocks in southwest of China in tropical and subtropical climate zone which are very favorable for karst development, distributes continuously and massively, and therefore can be considered as the most typical karst area,. this is also a very explanation that karst morphology develops completely. Especially, karst in the zone including Guangxi Zhuang Autonomous Region, southeast and north-east of Guizhou province, and southeastern of Chongqing Municipality, is the most representative karst region in southwest of china because of its the purest carbonate rocks.