Exploratory Holes Research Articles

Study of Water Leakage of a Residential Building (Al-Mansheya Plaza, Khartoum - Sudan)

Water leakage affects concrete and steel buildings in general, the structure members begin collapse in the long time, and thus the building is demolished due to the effect of water leakage. This paper aimed to study of water leakage inside the basement of a seven-storey residential tower in Al-Mansheya – Khartoum state, in order to identify and solve the causes of water leakage. In this study, a borehole 10 meters deep was drilled to identify the level of groundwater, as well as a number of exploratory holes were drilled to track the impact of the leaked water, and the external drainage system units of the building were also investigated. The water leakage causes have been identified and developed a concise action plan to solve this problem as well as a number of necessary recommendations to carry out the necessary maintenance of the building.

A unified model to evaluate shaliness in compacted and soft formations using downhole GR log

Abstract: The conventional GR (gamma ray) index model is widely used to calculate shale volume in a drilling hole. It is just based on the raw downhole GR log. However, it is found that formation porosity and density have effect on the measurement of GR log. This effect is not obvious in compacted formations, but is nonnegligible in soft formations. In this work, a new model based on the concept of matrix GR which is immune to the effect of porosity and density is proposed. We apply the new model and GR index model to two distinct wells, one is ODP Site 1173, representing soft formations, and another is a hydrocarbon exploratory borehole, representing compacted formations. The results of the new model are in better consistent with shale volumes from X-ray diffraction analysis in Site 1173 and well-log inversion in the exploratory hole. At last, we give an explanation to a long-term problem in GR index model that GR index is generally larger than the actual shale volume.

Well site extraction from Landsat-5 TM imagery using an object- and pixel-based image analysis method

Well sites, including both well pads and exploratory core holes, are small polygonal landscape disturbance features approximately one half to one hectare (0.5–1 ha) in area, resulting from oil and gas exploration activities. Automatic extraction and monitoring of such small features using remote-sensing technology at regional scales has always been desirable for wildlife habitat monitoring and environmental planning and modelling. Due to the vast disturbances of well sites in a province like Alberta, Canada, high-resolution imagery is not practical for well site extraction. For operational purposes, mid-resolution and cost-effective satellite imagery such as Landsat is the choice. However, automatic well site extraction using mid-resolution satellite imagery is a challenging task. Wells are typically less than three pixels in width and length in a Landsat multispectral image. Furthermore, the spectral contrast between the well site pixels and the surrounding areas is low due to vegetation regrowth and the spectral complexity of the surrounding environment. This article presents a novel methodology for automatic extraction of well sites from Landsat-5 TM imagery. The method combines both pixel- and object-based image analyses and contains three major steps: geometric enhancement, segmentation, and well site extraction. The method was applied to Landsat-5 TM images acquired over Fort McMurray, Alberta, Canada. For accuracy assessment, four regions of interest were selected and the results of the proposed automatic method were evaluated against visual inspection of the Landsat-8 pan-sharpened image. The method results in a total average correctness, completeness, and quality measures of about 80, 96, and 77%, respectively over the four sites. In addition, the method is very fast as an entire Landsat scene is processed in less than 10 minutes. The method is an operational approach for automatic detection of well sites over the entire province and can dramatically reduce the labour cost of manual digitization for monitoring and updating well site maps.

The Stardalur magnetic anomaly, SW-Iceland: a review of research in 1968--2012

Prominent geophysical anomalies of several km extent were noted in the vicinity of the farm Stardalur in southwestern Iceland in a gravity survey published in 1954, as well as in a 1968 total-field aeromagnetic survey published in 1970, and a seismic refraction study of the crust published in 1971. Further low-altitude and ground magnetic surveys were conducted around Stardalur in 1969–1973, and an exploratory hole was drilled to 200 m depth in 1969–1970 at the site of a very distinct peak in the ground anomaly. Various studies were carried out on a core (to 143 m depth) and on cuttings recovered by the drilling. From 41 m depth down, this material consisted of altered olivine tholeiite lava flows, with a mean remanent magnetization intensity of the order of 15 times the average for Icelandic Tertiary lavas. Modelling of the anomaly peak, which was found to reach at least 27μT above the main geomagnetic field intensity of 52μT, indicated that the lava flows formed a body of dimensions about 200 by 600 m striking NE to NNE, inside a caldera structure. This structure probably dates from a normal-polarity subchron around 2 m.y. ago during the Matuyama geomagnetic chron. Further studies on samples from the Stardalur drill core revealed the presence of quite pure and slightly cation-deficient magnetite, whose percentage in the lavas is more than twice the average for Tertiary basalts in Iceland. The magnetite has largely been formed by exsolution from titanomagnetite, but it is also present in small grains which have separated from olivine. A very minor proportion of the magnetite may be of single-domain size, and it appears not to be a decisive factor in the bulk magnetic properties of the lavas. For instance, the natural remanence is much less resistant to alternating-field demagnetization than could be expected for single-domain grains. It is not certain whether it is a primary thermal remanence or of secondary origin, although the former seems more plausible. In agreement with the conclusions of previous researchers, it appears likely that the strong magnetization is due to a chance combination of circumstances (such as high magnetite content, high oxidation state, and strong ambient field) rather than to some unique phenomenon. In this paper, a new ground magnetic survey at Stardalur is presented, along with a simple model of the source of the main anomaly peak. The geological reasons for the creation of that source remain unknown, but comparisons are made with a magnetic anomaly at Hvanneyri in western Iceland which has similarities with the Stardalur anomaly.

Optimal Density Determination of Bouguer Anomaly Using Fractal Analysis (Case of Study: Charak Area, Iran)

In exploration geophysics the main and initial aim is to determine density of under-research goals which have certain density difference with the host rock. Therefore, we state a method in this paper to determine the density of bouguer plate, the so-called variogram method based on fractal geometry. This method is based on minimizing surface roughness of bouguer anomaly. The fractal dimension of surface has been used as surface roughness of bouguer anomaly. Using this method, the optimal density of Charak area insouth of Hormozgan province can be determined which is 2/7 g/cm^3for the under-research area. This determined density has been used to correct and investigate its results about the isostasy of the studied area and results well-coincided with the geology of the area and dug exploratory holes in the text area.

Optimal Density Determination of Bouguer Anomaly Using Fractal Analysis (Case of study: Charak area, IRAN)

In exploration geophysics the main and initial aim is to determine density of under-research goals which have certain density difference with the host rock. Therefore, we state a method in this paper to determine the density of bouguer plate, the so-called variogram method based on fractal geometry. This method is based on minimizing surface roughness of bouguer anomaly. The fractal dimension of surface has been used as surface roughness of bouguer anomaly. Using this method, the optimal density of Charak area insouth of Hormozgan province can be determined which is 2/7 g/c ଷ for the under-research area. This determined density has been used to correct and investigate its results about the isostasy of the studied area and results well-coincided with the geology of the area and dug exploratory holes in the text area.

Motivational disturbances and effects of L-dopa administration in neurofibromatosis-1 model mice.

Children with neurofibromatosis type 1 (NF1) frequently have cognitive and behavioral deficits. Some of these deficits have been successfully modeled in Nf1 genetically-engineered mice that develop optic gliomas (Nf1 OPG mice). In the current study, we show that abnormal motivational influences affect the behavior of Nf1 OPG mice, particularly with regard to their response to novel environmental stimuli. For example, Nf1 OPG mice made fewer spontaneous alternations in a Y-maze and fewer arm entries relative to WT controls. However, analysis of normalized alternation data demonstrated that these differences were not due to a spatial working memory deficit. Other reported behavioral results (e.g., open-field test, below) suggest that differential responses to novelty and/or other motivational influences may be more important determinants of these kinds of behavior than simple differences in locomotor activity/spontaneous movements. Importantly, normal long-term depression was observed in hippocampal slices from Nf1 OPG mice. Results from elevated plus maze testing showed that differences in exploratory activity between Nf1 OPG and WT control mice may be dependent on the environmental context (e.g., threatening or non-threatening) under which exploration is being measured. Nf1 OPG mice also exhibited decreased exploratory hole poking in a novel holeboard and showed abnormal olfactory preferences, although L-dopa (50 mg/kg) administration resolved the abnormal olfactory preference behaviors. Nf1 OPG mice displayed an attenuated response to a novel open field in terms of decreased ambulatory activity and rearing but only during the first 10 min of the session. Importantly, Nf1 OPG mice demonstrated investigative rearing deficits with regard to a novel hanging object suspended on one side of the field which were not rescued by L-dopa administration. Collectively, our results provide new data important for evaluating therapeutic treatments aimed at ameliorating NF1-associated cognitive/behavioral deficits.

Multivariate statistical analysis and 3D-coupled Markov chain modeling approach for the prediction of subsurface heterogeneity of contaminated soil management in abandoned Guryong Mine Tailings, Korea

Various geological materials on the ground surface can be natural or artificial sources of pollutions. The spatial distribution of tailings is required to investigate the geological material pollutions. The objectives of this study were to determine the main factors influencing tailing zonations using a factor analysis, to determine the zonation of tailings with a cluster analysis, and to simulate zonations with three-dimensional coupled Markov chain (3D-CMC) modeling. The database was composed of 12 excavated exploratory holes in the Guryong mine tailings, for which there were analytical data covering the physical, chemical, and mineralogical aspects. The principal component analysis indicated that the tailing composition was mainly affected by three factors out of 21 variables: pH, cation exchange capacity, and mineral composition. Based on these main factors, the tailings were classified into five groups using a cluster analysis. Group I was approximately 50 cm deep from surface and had secondary gypsum (CaSO4·2H2O) and jarosite (KFe3(SO4)2(OH)6). Group II had low pH values caused by strong pyrite oxidation and the greatest amounts of the secondary minerals. In group III and IV, the quantity of the secondary minerals decreased. Group V was characterized by primary calcite (CaCO3) composition. These results were applied to the CMC modeling, and the quantitative 3D distribution of tailing was verified. For the cost-saving prediction of subsurface heterogeneity, 3D-CMC modeling was executed using the selected eight holes data among twelve holes. The unknown four holes, GS3, GS6, GS8 and GS11, are identified as 89.7, 88.6, 80.7 and 81.1 %, respectively. They are recognized as 85.0 % of the total zonation. The zonation method of tailings executed in this study can be utilized in predicting the 3D distribution of the pollution factor. This may be a useful and economical method to identify the environmentally hazardous materials in underground systems.

Proposed algorithm for optimization of directional additional exploratory drill holes and computer coding

Block model estimated based on the drill hole information gathered during exploration stage is not appropriate for short- and medium-term mine planning. Additional information prior to mining is required for various purposes, that the source of this information is drill holes. In most situations, reducing the overall uncertainty on the estimation is the major objective of additional drilling and collecting samples from them. The topic of selecting the optimum location for additional exploratory drill holes has been of interest to mining engineers and geostatisticians in the second half of last century, but all of them are not able to optimize directional drill holes because they are based on the 2D space and do not consider the 3D extension of drill holes and block model. This study introduces a methodology to optimize the dip and location of additional exploratory drill holes based on the defined objective function with considering 3D extension of ore body and drill holes. Direct search simulated annealing used that is efficient and robust method for solving the nonlinear unconstrained global optimization problems. This method is very useful in the case that drilling the drill holes with different dips has been obligated due to topography condition and ore body situation. A case study in gold resource illustrates the method.

The Study on Chemical Weapons Abandoned by Japanese in China: Aim to Ascertain the Burial Sites and Pollution Disposal

Lots of chemical weapons abandoned by Japanese in China during World War II lead to serious harm to human health as well as inducing abrupt casualty accidents. It is put forward that some geophysical methods such as low-altitude thermal infrared remote sensing, 3D high density electrical method and 3D geological radar combined with small-diameter exploratory hole method can be used for detailed detection, to ascertain the burial sites, spatial distribution and pollution degree of approximate confirmed weapons in this paper. Then, on the basis of this, take safety assessment and make programs to manage and prevent collision pertinently in order to establish technique method system of pollution investigation and disposal which is suitable for various conditions and different pollution degree.

Estimate of stress state in rock masses adjacent to open pit walls

It is proposed to study the action exerted by the tectonic stresses on stability of open pit walls by using the method of core disking in exploratory holes and the tectono-physical method based on the analysis of tectonic structure of a rock mass.

Optimal Density Determination of Bouguer Anomaly Using Fractal Analysis (Case of study: Charak area,IRAN)

In exploration geophysics the main and initial aim is to determine density of under-research goals which have certain density difference with the host rock. Therefore, we state a method in this paper to determine the density of bouguer plate, the so-called variogram method based on fractal geometry. This method is based on minimizing surface roughness of bouguer anomaly. The fractal dimension of surface has been used as surface roughness of bouguer anomaly. Using this method, the optimal density of Charak area insouth of Hormozgan province can be determined which is 2/7 g/cfor the under-research area. This determined density has been used to correct and investigate its results about the isostasy of the studied area and results well-coincided with the geology of the area and dug exploratory holes in the text area

Structure and stress state of Hawaiian island basalts penetrated by the Hawaii Scientific Drilling Project deep core hole

As part of the Hawaii Scientific Drilling Project (HSDP), an exploratory hole was drilled in 1993 to a depth of 1056 meters below sea level (mbsl) and a deeper hole was drilled to 3098 mbsl in 1999. A set of geophysical well logs was obtained in the deeper hole that provides fundamental information regarding the structure and the state of stress that exist within a volcanic shield. The acoustic televiewer generates digital, magnetically oriented images of the borehole wall, and inspection of this log yields a continuous record of fracture orientation with depth and also with age to 540 ka. The data depict a clockwise rotation in fracture strike through the surficial Mauna Loa basalts that settles to a constant heading in the underlying Mauna Kea rocks. This behavior reflects the depositional slope directions of lavas and the locations of volcanic sources relative to the drill site. The deviation log delineates the trajectory of the well bore in three‐dimensional space. This path closely follows changes in fracture orientation with depth as the drill bit is generally prodded perpendicular to fracture strike during the drilling process. Stress‐induced breakouts observed in the televiewer log identify the orientations of the maximum and minimum horizontal principal stresses to be north‐south and east‐west, respectively. This stress state is attributed to the combination of a sharp break in onshore‐offshore slope that reduces stress east‐west and the emergence of Kilauea that increases stress north‐south. Breakouts are extensive and appear over approximately 30% of the open hole.

Applied geophysics and the environment in Texas

In Texas applied geophysics for environmental assessments and remediation is boring … literally and figuratively! The state-of-the-art and conventional environmental-engineering approaches require the drilling of tens to hundreds of shallow core holes to characterize the geology at sites such as hazardous waste landfills and underground disposal wells. The use of nonintrusive geophysical methods is a luxury, not a requirement. A proposed “geoscience approach” would require fewer borings and be more cost-effective for the overall project. This approach requires the application of nonintrusive geophysical methods in an appropriate manner prior to drilling exploratory or delineation holes for assessments or characterization.

The Petrophysical Characteristics of Jurassic Reservoirs of the Coastal Mississippi Counties and Adjacent State Waters

The purpose of this study is the determination of petrophysical characteristics observable for Jurassic reservoirs in the study area; these characteristics are important for hydrocarbon production from those reservoirs. The study area consists of the three Mississippi coastal counties, Hancock, Harrison, and Jackson, and Mississippi's state waters offshore. The section of importance to this study is the Upper Jurassic, which is made up of, from oldest to youngest, the Norphlet Formation, Smackover Formation, Haynesville Formation (including a Frisco City-equivalent granite wash and the Buckner Anhydrite), and Cotton Valley Group. Within the study area only one Upper Jurassic gas field has been discovered. The Catahoula Creek field is located onshore in Hancock County in the western portion of the study area and is productive of gas from Cotton Valley sands below 19,000 ft. Well log and core data from dry exploratory holes in the study area were used to supplement the limited reservoir data at Catahoula Creek. Nine wildcat wells have penetrated the Jurassic in the study area, so the Jurassic wildcat drilling density is approximately one wildcat well per 290 mi2. Because of this lack of data in the study area, published information on the following Upper Jurassic fields in southwestern Alabama, both onshore and offshore, is included: Chunchula field (Smackover), Hatter's Pond field (Smackover), Hatter's Pond field (Norphlet), and Lower Mobile Bay Mary Ann field (Norphlet). Structurally, the three coastal counties and offshore state waters of Mississippi occupy the southern flank of the Wiggins Arch, an area of positive Paleozoic basement features, and the related Hancock Ridge. The Jurassic strati graphic section in the study area consists of more than 5,000 ft of clastics, evaporites, and carbonates at depths below 17,000 ft to 24,000 ft.

Hotspot origin of the Mississippi embayment and its possible impact on contemporary seismicity

Previous authors have related the Late Cretaceous/early Tertiary subsidence of the Mississippi embayment to the opening of the Gulf of Mexico, but the Gulf opened earlier in Triassic/Jurassic time. We offer an alternative hypothesis that development of the embayment was coeval with the passage of the Mississippi Valley graben system over the Bermuda hotspot about 90 Ma. Several lines of evidence of significant uplift of the embayment axis accompanying mid-Cretaceous magmatism and prior to Late Cretaceous subsidence support this proposal. First, reactivation of the Pascola arch in the northern embayment is recorded by flanking deposits of basal Upper Cretaceous gravel. Second, beneath a regional mid-Cretaceous unconformity, subcrops of Jurassic and Early Cretaceous strata define a pronounced southwest-plunging arch in the southern embayment. This arch is collinear with an arch revealed in Paleozoic rocks after restoration to mid-Cretaceous structural geometries. Third, a deep weathering profile on mid-Cretaceous alkalic plutons along the western embayment margin is nonconformably overlain by Paleocene sediments, and rapid mid-Cretaceous cooling of these intrusions has been interpreted from apatite fission tracks. Moreover, exploratory holes along the embayment axis encountered similar weathered alkalic intrusions nonconformably overlain by basal Upper Cretaceous strata. Fourth, there was an anomalous influx of clastic sediment into the northern Gulf of Mexico during mid-Cretaceous time, and subsequent clastic facies patterns suggest the Mississippi River drainage began to enter the Gulf in the Late Cretaceous. Passage of the Mississippi Valley graben over the Bermuda hotspot during elevated hotspot activity of Cretaceous time may have significantly weakened the previously rifted lithosphere. Rifted continental margin at Charleston, South Carolina, also passed over this hotspot in latest Cretaceous time. Similarly, the St. Lawrence rift system passed over the Great Meteor hotspot during the Cretaceous. It is important to note that these rift systems are the principal loci of strong seismicity in eastern North America, and thus weakening by increased Cretaceous hotspot activity may be an important common factor for these seismic rift zones.

Geophysical study of the Taharoa ironsand deposit, west coast, North Island, New Zealand

Abstract The Taharoa prospect is one of the many beach and dune deposits of titanomagnetite sands ("ironsands") along the west coast of the North Island of New Zealand. Various geophysical methods were used to determine which of these is suitable for delineating titanomagnetite concentration patterns in the deposit, which covers an area of c. 15 km2, and whether a reliable estimate of the total mass of titanomagnetite ore could be obtained. Seismic refraction studies provided a detailed structural model of the deposit. Interpretation of these data, controlled in part by a few deep exploratory holes, defined an upper horizon of unconsolidated, titanomagnetite‐rich sands (Nukumiti and Paparoa Sands Members) reaching a maximum thickness of 60 m. It is underlain by a weakly cemented, saturated sand layer (Te Akeake Sands Member) up to 100 m thick, with an average titanomagnetite concentration of about 18%. The two horizons are separated by a 42 ka old layer of tephras and paleosols up to 15 m thick. The compressional‐wave seismic velocity of the upper, dry, enriched sands is very low, and increases linearly with depth from about 0.24 km/s to a maximum of 0.65 km/s, with a rate of increase between 18 and 32/s. The velocity of the lower horizon is almost constant at 1.7 ± 0.1 km/s. Mesozoic greywacke basement with a velocity of 4.1 ± 0.7 km/s underlies the deposit. The concentration of titanomagnetite within the seismic model was determined by detailed interpretation of airborne magnetic surveys flown at altitudes of 185 m and 370 m above sea level. Residual anomalies were obtained after reducing the magnetic effect of the entire deposit, assuming a homogeneous induced magnetisation of 6.7 A/m (equivalent to that of sand with 18% by weight of titanomagnetite). The residuals were interpreted in terms of an array of vertical prisms representing the enriched Nukumiti and Paparoa sands. Magnetic susceptibilities of up to 0.75 were interpreted, corresponding to a titanomagnetite concentration of 54% by weight. Although titanomagnetite concentrations in the sands can produce a gravitational effect of up to 10 um/s2, residual gravity anomalies could not be used to assess concentration patterns independently because the anomalies are disturbed by larger effects associated with the irregular greywacke basement. However, gravity interpretation models were used to define the depth to basement rocks in areas not covered by the seismic surveys. Tests showed that titanomagnetite sands at Taharoa are nonconductive; electrical resistivity, IP, and EM methods could not be used to define ore concentrations. The total mass of titanomagnetite in the Taharoa deposit was obtained by combining the magnetic and seismic models. The Nukumiti and Paparoa Sands Members contain a total of 205 ± 30 million tonnes of titanomagnetite ore within sands with an average concentration of 38% (by weight). An additional 360 ± 75 million tonnes of titanomagnetite are contained in the Te Akeake Sands Member, but at a lower concentration of about 18% by weight.

Preliminary Feasibility Study of the Coal-Bed Methane Resource in Pennsylvania

Coal-bed methane gas content data were obtained from exploratory drill holes, premining degasification drill holes, and methane recovery test projects from the Main Bituminous and Northern Anthracite fields of Pennsylvania. Exploratory coal cores tested ranged from the Pennsylvanian-Permian Dunkard Group to the Pennsylvanian Allegheny Group. Total gas contents were determined for each coal sample by using the UD Bureau of Mines direct method of testing. Graphical analyses of depth and thickness vs. total gas content revealed a direct correlation between depth and gas content. However, further study is needed to determine if significant gas contents are a functions of thickness. Gas values were approximately 1,000 Btu/scf, comparable to that of natural gas. Extremely low heating values, however, accompanied shallow, above-drainage coal beds (less than 500 ft) proximal to mining operations. Geologic factors that determine the feasibility of coal-bed methane development are (1) coal rank, (2) depth of overburden, (3) coal-bed thickness, (4) favorable structure and fracture permeability, (5) permeability of adjacent strata (6) water content, and (7) pressure/stress relationships. The developer must also evaluate economic, political, and legal issues when planning a project in the Northern Appalachian coal basin. Most of the available coal information in Pennsylvania is base onmore » the minable coals. A more definitive estimate of the basin's deepest coal resources and gas contents are critical to the development of coal-bed methane as a resource.« less

Intraoperative ultrasound imaging of the entire brain through unilateral exploratory burr holes after severe head injury: technical note

A portable ultrasound unit with a 3.5-MHz probe allows accurate imaging of both cerebral hemispheres and partial imaging of the posterior fossa through unilateral exploratory burr holes or a craniotomy. In patients with clinical signs of transtentorial herniation after severe head injury, this unilateral technique can detect extraaxial and intraparenchymal mass lesions more accurately than is possible with bilateral exploratory burr holes.

Oil and Gas Developments in Upper Gulf Coast of Texas in 1989

Onshore drilling in the upper Gulf Coast of Texas during 1989 totaled 638 wells, a 21.6% decrease from 1988's total of 814 wells. Exploratory drilling remained at the same level, but development drilling declined 30.2% from 1988. Thirty-four new-field discoveries resulted from drilling 141 new-field wildcat wells in 1989, a 23.6% success rate. Fifty-three other wildcat discoveries resulted from drilling new-pool, deeper pool, or extension wells with a 60.2% success rate. The Eocene trend was once again the most active exploratory trend onshore with 40.6% of the onshore drilling; the Oligocene and Cretaceous trends had 25.3% and 3.1% of the onshore exploration activity, respectively. Offshore exploratory drilling in 1989 totaled 74 wells, a 32.1% decrease from 1988. Development drilling offshore nearly tripled with 174 development wells drilled in 1989 compared to 64 wells drilled in 1988. The exploratory success rate offshore was 31.1%. Exploration activity resulted in 20 new-field discoveries and 3 new-pool, deeper pool, or extension discoveries. Forty exploratory dry holes were drilled offshore in 1989. Offshore, the Miocene trend was most actively explored with 8.1% of the exploratory drilling in 1989 (66 wells were listed as undesignated).