geochemical variations among eastern saudi arabian paleozoic condensates related to different source kitchen areas abstract large reserves of gas and condensate are found in paleozoic reservoirs khuff unayzah and jauf in the ghawar area of eastern saudi arabia the source rock for these hydrocarbons is the basal organic rich hot shale of the qusaiba member of the silurian qalibah formation this is the same prolific source rock that generated the sweet light crude oil and condensate found in the unayzah reservoirs in central saudi arabia thermal maturity modeling of the source rock identifies two kitchen areas to the east and west of the ghawar structure the west kitchen was well into the oil window by 210 ma while the east kitchen was just entering the oil window large areas of both kitchens were in the wet gas window by 125 ma and by 90 ma most of the area north of ghawar was generating dry gas in eastern saudi arabia paleozoic oil and condensate are found in early formed structures carboniferous and early triassic growth whereas late cretaceous and tertiary structures contain only dry gas the geochemistry of the oils and condensates indicates two groups each generated from a different hydrocarbon kitchen suggesting that the two kitchens differ slightly in organic facies within each group variations among hydrocarbons are related to the thermal maturity of the source rock during generation within the khuff reservoir gas souring is caused by thermochemical sulfate reduction

fracture apertures from electrical borehole scans three dimensional finite element modeling was performed to investigate the response to fractures of the formation microscanner mark of schlumberger which records high resolution electrical scans of the borehole wall it is found that the equation w carmbrx0l describes over two orders of magnitude of resistivity contrasts between borehole mud and the formation the relationship between fracture width w in mm formation sensitivity rx0 mud resistivity rm and the additional current flow a caused by the presence of the fracture a is the additional current which can be injected into the formation divided by the voltage integrated along a line perpendicular across the fracture trace coefficient c and exponent b are obtained numerically from forward modeling tool standoffs of up to 2 5 mm and fracture dips in the range from 0 to 40 were found to have an insignificant effect on the above relation a three step approach to detect trace and quantify fractures is used potential fractures in formation

active deformation within the zagros mountains deduced from gps measurements we present and interpret the results of global positioning system gps measurements at 35 stations in and beside the zagros mountain belt sw iran for three campaigns ending march 1998 december 1999 and june 2001 preliminary motion estimates show clearly the change in character along the strike of the belt stations to the se move at 13 22 3 mm a 1 towards n 7 5 e with respect to eurasia most of the shortening indicated by the gps velocities seems to occur in the se zagros along two major seismic zones and along the zagros front to the nw stations move oblique to the trend of the belt towards n 12 8 w at 14 19 3 mm a 1 most of the shortening in the nw zagros seems to occur along the mountain front fault with its major earthquakes as well as along the zagros front the change in direction and magnitude of the velocity vectors across the north south trending kazerun and karebas faults involves extension of up to 4 mm a 1 along the strike of the zagros belt

multi scale imaging and simulation of structure flow and reactive transport for co2 storage and eor in carbonate reservoirs as we continue to use fossil fuels for our energy supply the concentration of co2 in the earth s atmosphere is likely to continue to increase it has been shown that this is correlated with an increase in the temperature of the atmosphere and potential associated climate change to mitigate this problem carbon capture and storage ccs has been mooted over the past decade in this chapter we will focus on co2 storage in downhole rock formations rock formations suitable for storage include saline aquifers and depleted oil and gas reservoirs also coal bed methane cbm reservoirs may be suitable for storage but we will not consider these in the current chapter in the case of saline aquifers we consider only the storage of co2 in the case of depleted oil gas reservoirs the storage of co2 can be combined with enhanced oil recovery eor this may lead to a more favorable economic scenario and has recently been coined as ccus carbon capture and utilized storage in particular we will focus in this chapter on carbonate reservoirs sandstone reservoirs have been relatively well studied however much less is known about the storage properties of carbonate rocks which have very different petrophysical and flow properties moreover carbonate rocks constitute a significant fraction of existing depleted hydrocarbon reservoirs our aim is to study the pore scale properties of carbonates and upscale these to the core and field scales first carbonates have a very different structure from sandstones associated with their composition and diagenesis carbonates usually have a much broader pore size distribution psd than sandstones with extensive microporosity cantrell and hagerty 1999 in addition carbonates are often naturally fractured ameen et al 2010 this leads to a broad range of heterogeneity as a function of length scale in comparison

precision analysis of first break times in grid models rectangular grid velocity models and their derivatives are widely used in geophysical inversion techniques specifically seismic tomographic reconstruction techniques whether they be based on raypath methods bregman et al 1989 moser 1991 schneider et al 1992 cao and greenhalgh 1993 zhou 1993 or full wave equation methods vidale 1990 qin and schuster 1993 cao and greenhalgh 1994 for calculating synthetic arrival times involve propagation through a grid model likewise migration of seismic reflection data using asymptotic ray theory or finite difference pseudospectral methods stolt and benson 1986 zhe and greenhalgh 1997 involve assigning traveltimes to upward and downward propagating waves at every grid point in the model the traveltimes in both cases depend on the grid specification however the precision level of such numerical models and their dependence on the model parameters is often unknown in this paper we describe a two dimensional velocity model and derive an err

a scale independent approach to fracture intensity and average spacing measurement fracture intensity the number of fractures per unit length along a sample line is an important attribute of fracture systems that can be problematic to establish in the subsurface lack of adequate constraints on fracture intensity may limit the economic exploitation of fractured reservoirs because intensity describes the abundance of fractures potentially available for fluid flow and the probability of encountering fractures in a borehole traditional methods of fracture intensity measurement are inadequate because they ignore the wide spectrum of fracture sizes found in many fracture systems and the consequent scale dependence of fracture intensity an alternative approach makes use of fracture size distributions which allow more meaningful comparisons between different locations and allow microfractures in subsurface samples to be used for fracture intensity measurement comparisons are more meaningful because sampling artifacts can be recognized and avoided and because common thresholds of fracture size can be enforced for counting in different locations additionally quantification of the fracture size distribution provides a mechanism for evaluation of uncertainties estimates of fracture intensity using this approach for two carbonate beds in the sierra madre oriental mexico illustrate how size cognizant measurements cast new light on widely accepted interpretation of geologic controls of fracture intensity

dual porosity fractured miocene syn rift dolomite reservoir in the issaran field gulf of suez egypt a case history of the zonal isolation of highly fractured water carrier bed

modern sedimentation in the japan trench implications of the mineralogy and chemistry of clays sampled from sediment traps abstract to determine the mineralogical and chemical characteristics of clay minerals the composition of the clay sized fraction and the sedimentological processes which affect these clay particles two sediment traps were moored at depths of 8700 and 4000 m at the triple junction of the japan trench six types of clay minerals and nine types of non clay minerals were identified by transmission electron microscopy smectite and illite were the most important clay minerals whereas quartz and plagioclase were the major non clay minerals chemical analyses of the clay minerals showed that the smectite was an fe al beidellite illite a di octahedral type rich in potassium and chlorite an fe mg type two major mechanisms govern the transportation of the lithogenic mineral particles in the japan trench 1 transportation by the turbidity currents in the neighbouring trough and canyon and 2 wind borne transport of loess from mainland china the settling time of clay sized minerals to the bottom of the japan trench was roughly estimated to be 1 year

the paleozoic petroleum geology of central arabia exploratory drilling in central saudi arabia has established significant paleozoic petroleum potential in this region in recent discoveries the permian interval of the unayzah formation has been identified as the primary oil and gas reservoir the unayzah formation consists of alluvial and fluvial to shallow marine siliciclastic sandstones and siltstones that were deposited on a major pre unayzah unconformity saudi arabian paleozoic oil is a high gravity 43 53 degrees api crude with low sulfur content usually less than 0 07 that is classified as arabian super light oil gas with condensate has also been discovered in the unayzah formation the identified paleozoic traps are moderate relief fault generated structures with generally 30 100 m of closure unayzah structural traps developed primarily during the triassic to early jurassic however an earlier phase of significant pre unayzah structural development is also indicated between the devonian and late carboniferous and is related to a hercynian structural event post triassic structure in central arabia is mainly regional and results principally from late cretaceous to tertiary development of the central arabian arch the established source rock is the basal qusaiba shale a widespread organic rich shale that was deposited following regional deglaciation in the early silurian migration occurred regionally updip through unayzah formation reservoirs from the underlying qusaiba shale subcrop and or vertically along fault bounded zones on the flanks of structures from the underlying qusaiba shale interbedded upper permian shales and evaporites provide a top seal for the unayzah and form the basal sequence of the overlying transgressive khuff carbonate pre qusaiba reservoir targets include the cambrian ordovician saq sandstone the ordovician qasim formation and upper ordovician to lower silurian periglacial clastics of the zarqa and sarah formations high gravity low sulfur oil has also been discovered in this pre qusaiba clastic section the reservoirs of the pre qusaiba structures are fault bounded and sources laterally by the down faulted qusaiba shale

diverse fracture properties and their impact on performance in conventional and tight gas reservoirs saudi arabia the unayzah south haradh case study the upper permian carboniferous unayzah formation in south haradh saudi arabia includes two major mechanical and petrophysical layers that are separated by shale rich zones open tectonic fracture clusters are rare and not essential for fluid flow in the unayzah a zone which has high porosity and permeability however such fracture clusters are essential to and impact the production performance in the unayzah b c tight gas reservoir the occurrence of the tectonic fractures in the unayzah formation is linked to the rock mechanical properties which vary with porosity shale volume cement type and texture the b c unit is more fractured than the a unit but its layers vary in the degree of fracturing the variation in fracture development within the b c unit results in differences in fracture enhanced permeability based on production profiles where flow is restricted to preferentially fractured mechanical layers that lack effective vertical fluid communication with other layers we identify two tectonic fracture systems an older subordinate fully mineralized system and a younger primary mostly open system early extensional fractures including joints and faults developed parallel to the basement faults during the opening of the neotethys these are fully mineralized and have little or no function as fluid conduits the younger system includes open fracture clusters that are predominantly parallel or nearly parallel to the regional east northeast west southwest maximum horizontal stress of the zagros that has been active since the late cretaceous and is independent of local structures therefore these fractures are controlled by remote stresses instead of the basement rooted forced folds and faults in this article we demonstrate that in the unayzah b c natural fractures are essential to permeability and in some areas to porosity and thence to reservoir performance the results of this study are being implemented in well placement and completion design to optimize the intersection of open fracture clusters with positive preliminary results

the function of fractures and in situ stresses in the khuff reservoir performance onshore fields saudi arabia the highly variable performance of the permian triassic khuff reservoir in onshore saudi arabia has been attributed to the presence of natural fractures similar preproduction pressure profile and hydrocarbons in the different reservoir units in some fields have been attributed to vertical communication through large faults to validate these assumptions we studied the static and dynamic data from the khuff reservoir in 19 major structural traps we identified two distinctive fracture domains based on fracture orientation and density fracture evolution is mainly controlled by the extensional and consequent compressional plate tectonics instead of local structures in situ stresses are dominated by the zagros plate tectonics and affect fracture aperture differently in the two fracture domains the fracture impact on the khuff reservoir performance is mostly subtle because of the nature and distribution of the fractures high fracture enhanced productivity occurs locally in some of the producing wells and it results from high density fracture clusters including mesoscopic faults with channel type apertures the following findings challenge the perceived major functions of fractures in the khuff reservoir performance in onshore fields 1 individual fractures are dominantly tensile and small mesoscopic and microscopic 2 individual faults are small and not readily resolvable at seismic scale 3 the depth and carbonate nature of the khuff reservoir make the fractures highly susceptible to fast healing unless preserved within the hydrocarbon column 4 initial vertical pressure gradient changes with production indicate a lack of present day communication across the anhydrite sealing layers between the different khuff reservoir units 5 horizontal well direction does not generally have an impact on productivity and 6 sustained and heavy losses of circulation are rarely encountered in the khuff reservoir wells mohammed s ameen received his ph d and diploma of imperial college in structural geology and geomechanics from imperial college london 1988 he has more than 20 years of academic and industrial experience and has patented a new method for the characterization of microfractured reservoirs he has published 25 articles on fractures and folds and has edited three special publications for the geological society london he conducted the first classic work on the fractures and folds across the taurus zagros range iraq covering 30 major fold traps the work is published in the aapg bulletin the geological magazine and the journal of petroleum geology he joined the reservoir characterization department at saudi aramco in 1998 since 2004 he has been leading the structural geology and rock mechanics group in the geological technical services division saudi aramco he is an active member of the aapg society of petroleum engineers european association of geoscientists and engineers and the geological society london ismail m buhidma is a petroleum engineering consultant in the gas reservoir management division of saudi aramco with 32 years of diverse industrial experience for the last 12 years he has been actively involved in aramco s nonassociated gas development program his areas of interest include reservoir management well performance analysis well test analysis phase behavior geomechanics reservoir simulation reservoir characterization and well stimulation prior to joining aramco ismail worked for exxon in libya schlumberger and atlantic richfield in the usa and qatar petroleum in qatar ismail holds b s and m s degrees in petroleum engineering from the university of tulsa he is a member of society of petroleum engineers spe and has published numerous spe appears zillur rahim is a petroleum engineering consultant with saudi aramco working in gas field development he received his b s degree from algerian petroleum institute and m s degree and ph d from texas a m university college station all in petroleum engineering he has 25 years of industry experience has published more than 50 technical papers and has taught numerous industry courses previously he worked with holditch and associates petroleum consultants and with schlumberger reservoir technology group his area of expertise includes reservoir engineering hydraulic and acid fracturing and reservoir management

a review on the applications of image logs in structural analysis and sedimentary characterization abstract image logs provide important information on lithology sedimentary textures paleoflow directions fractures and in situ stress analysis lacking of criteria used for establishing the image log facies limits the applications of image logs in sedimentary reservoir interpretation this paper provides a thoroughgoing review focusing on the recent applications of borehole image logs for sedimentological and structural description and interpretation and aims to establish image log facies which can provide guidelines in sedimentary reservoir interpretation this paper firstly summarizes the principles and basic characteristics of various imaging logging tools and then briefly introduces the pre processing workflow of the image log data then the generated images are used for depth and orientation shifts of cores by calibrating individual sedimentary and structural features descriptive and concise image log facies are established based on combinations of image textures including dip type dip pattern and color scheme and the characteristics as well as physical criteria for each individual image facies are summarized the established image log facies are then interpreted in terms of structural and sedimentological features such as lithology sedimentary structures vugs fractures and faults the image log facies and its stacking patterns are then used to interpret the lithofacies associations by calibrating with cores and conventional logs natural fractures and induced fractures are recognized by image logs and the principles of breakouts and drilling induced fractures for in situ stress analysis are reviewed then the applications of image logs in investigation of fracture attitudes and states as well as in computation of fracture parameters are summarized the procedures to evaluate fracture effectiveness through image logs are discussed at last the application of image logs for structural dip analysis is reviewed and image logs are used for recognizing faults fracture sets and attitudes of stratum through the dip patterns the basic procedures for paleocurrent reconstruction which includes dip picking of cross beddings structural dip determination and structural dip removal are reviewed then the paleocurrent directions of the lower cretaceous bashijiqike formation in the kuqa depression were reconstructed which could help further understanding of the depositional systems this review will help extend the utility of image logs in interpreting small to large scale sedimentary and structural features and bridges the gaps between well log analysis and sedimentary and structural interpretation

possible forced folding in the taurus zagros belt of northern iraq the folds in the taurus zagros belt of northern iraq have generally been considered to be decollement buckle folds this implies the presence of a decollement horizon at or near the base of the sedimentary cover the infra cambrian hormuz salt and a passive role of the precambrian basement in the tectonic evolution of the folded belt structural stratigraphic geophysical and remote sensing evidence suggests that forced folding due to faulting in the basement has played a significant role in the development of many of the folds in this region this is clear from the substantial evidence of basement faulting the lack of any convincing evidence for the presence of an extensive and regional decollement horizon i e the hormuz salt between the basement and the cover rocks and the geometries of the folds and related mesostructures the study shows that in the taurus foothills zone the folds are short oval in plan shape and arranged in an en echelon pattern along two sets of dislocation zones in the basement however the folds in the zagros foothills zone are longer linear and arcuate in plan shape many of the studied folds show similar features to those observed in the rocky mountains u s a

comparison of carbonate reservoir fractures from core and modern electrical borehole images abstract several methods exist for collecting data about opening mode fractures hereinafter fractures in subsurface reservoir rocks the datasets with the exception of core data are indirect and subject to limited resolutions this paper includes new results on the detection of fractures in carbonate reservoirs by modern electrical borehole imagers barren fractures and calcite filled fractures calcite veins were described and compared from whole core and borehole images these datasets were obtained from directional drilling into the arab petroleum reservoirs in a low relief dome structure in eastern arabia the comparison of fracture abundance resulted in a significant mismatch because many reservoir fractures in the core could not be detected from corresponding borehole images most calcite veins were undetected because of their small widths below 2 mm exceptions include a few calcite veins of 0 5 mm that were detected because of the strong contrast between resistive veins and conductive host rock beds the barren fractures that are aligned sub parallel to the maximum horizontal principal stress shmax were detected more abundantly than other non aligned barren fractures the present day shmax is roughly trending between 60 and 100 azimuth in eastern arabia the aligned fractures have larger apertures in the borehole images than the non aligned fractures the apertures diminish in size as the fractures gradually deviate in orientation from the shmax most of the non aligned barren fractures were undetected except the fractures with rough and mismatching walls this indicates that the walls of the non aligned fractures are mechanically closed by the normal shmax and that the remaining apertures were dependent on the availability of roughness mismatches between the closed fracture walls electrical borehole images are biased in measuring fracture abundance but indispensable to detect and measure the orientations and apertures of fractures especially the large i e more conductive fractures in reservoir rocks

active tectonics of the alpine himalayan belt between western turkey and pakistan summary over 80 new fault plane solutions combined with satellite imagery as well as both modern and historical observations of earthquake faulting are used to investigate the active tectonics of the middle east between western turkey and pakistan the deformation of the western part of this region is dominated by the movement of continental material laterally away from the lake van region in eastern turkey this movement helps to avoid crustal thickening in the van region and allows some of the shortening between arabia and eurasia to be taken up by the thrusting of continental material over oceanic type basement in the southern caspian mediterranean makran and black sea thus central turkey bounded by the north and east anatolian strike slip faults is moving west from the van region and overrides the eastern mediterranean at two intermediate depth seismic zones one extending between antalya bay and southern cyprus and the other further west in the hellenic trench the motion of northern iran eastwards from the van region is achieved mainly by a conjugate system of strike slip faults and leads to the low angle thrusting of iran over the southern caspian sea the seismicity of the caucasus shows predominantly shortening perpendicular to the regional strike but there is also some minor elongation along the strike of the belt as the causcasus overrides the caspian and black seas the deformation of the eastern part of this region is dominated by the shortening of iran against the stable borders of turkmenistan and afghanistan the north east direction of compression seen in zagros is also seen in north east iran and the kopet dag where the shortening is taken up by a combination of strike slip and thrust faulting large structural as well as palaeomagnetic rotations are likely to have occurred in ne iran as a result of this style of deformation north south strike slip faults in southern iran allow some movement of material away from the collision zone in ne iran towards the makran subduction zone where genuinely intermediate depth seismicity is seen within this broad deforming belt large areas such as central turkey nw iran azerbaijan central iran and the southern caspian appear to be almost aseismic and therefore to behave as relatively rigid blocks surrounded by active belts 200 300 km wide the motion of these blocks can usefully be described by poles of rotation the poles presented in this paper predict motions consistent with those observed and also predict the opening of the gulf of iskenderun ne of cyprus the change within the zagros mountains from strike slip faulting in the nw to intense thrusting in the se and the relatively feeble seismicity in se iran baluchistan this description also explains why the north south structures along the iran afghanistan border do not cut the east west ranges of the makran within the active belts surrounding the relatively aseismic blocks a continuum approach is needed for a description of the deformation even though motions at the surface may be concentrated on faults the evolution of fault systems within the active zones is controlled by geometric constraints such as the requirement that simultaneously active faults do not in general intersect many of the active processes discussed in this paper particularly large scale rotations and lateral movement along the regional strike are likely to have caused substantial complexities in older mountain belts and should be accounted for in any reconstructions of them

a new technology for the characterization of microfractured reservoirs test case unayzah reservoir wudayhi field saudi arabia this article presents a test case of a new technology using artificially enhanced anisotropy of magnetic susceptibility referred to here as eams for the characterization of microfractured reservoirs these are reservoirs in which microfractures are essential to porosity and or permeability a conventional geological characterization is costly time consuming and difficult to quantify in terms of assessing fracture impact on porosity and permeability therefore an efficient and effective method is required to characterize these microfractures and to determine their contribution to porosity and permeability the eams technology which we developed and tested allows rapid analysis that bridges reservoir geology and engineering using petrography the margin of error to detect microfractures that impact porosity and or permeability is 43 however it requires three times the sampling rate of the new eams technology the lower part of the unayzah reservoir unayzah b c in the wudayhi field saudi arabia where fractures were studied and microfractures are known to impact reservoir performance is used to develop and verify the eams technology the results show that eams derived microfracture fabric strikes east northeast west southwest consistent with that obtained by geological means the effective porosity profile obtained from eams tests is similar to that of the conventionally acquired porosity open microfractures in tested samples increase mean values of reservoir effective porosity by 36 50 in unayzah b c the occurrence of connected microfractures is estimated to cause an increase in average permeability of 75 in unayzah b c this is in agreement with the fact that wells in microfractured unayzah b c have 4 5 14 times the productivity of wells as nonfractured sections of this reservoir a maximum permeability trend of northeast southwest permeability anisotropy is detected the implementation of the eams technology in other fields with microfractured reservoirs will directly impact operational and simulation effort

fracture detection in oil based drilling mud using a combination of borehole image and sonic logs abstract the deeply buried 5 5 7 1 km lower cretaceous bashijiqike sandstones are important fractured reservoirs in the kuqa depression in these high temperature high pressure drilling environments oil based muds are used to limit drilling risks and improve efficiency making facture detection using resistivity based image logs difficult the maximum horizontal stress sh max trends close to north south 0 10 based on orientations of the drilling induced fractures and borehole breakouts core descriptions thin sections and image logs used to describe the fractures in the bashijiqike sandstone reservoirs show that opening mode natural fractures are common and the fractures range from fully open to sealed by calcite and clay minerals the open fractures are dominantly steeply dipping or vertical and primarily strike north south locally horizontal fractures or fractures with low angle dip are detected we compare fracture visibility on image logs acquired in the same ks 2 2 12 key well in oil based mud and water based mud fmi hd logs successfully detect large 0 1 mm aperture vertical fractures in oil based mud better than obmi image logs and the two imaging tools have a similar ability in detecting the high dip angle fractures since the ubi tool is not affected by oil based muds most of the fractures can be picked out on ubi images minor negative deviations of bulk density could be observed in fractured zones and the presence of fractures obviously causes an increase in sonic transit time full waveforms from dsi tools combined with electrical image logs detect fractured zones both the velocity and amplitude of the sonic waves are sensitive to fractures and the fractured zones could be identified according to the attenuation of stoneley waves the combination of cores image logs and full wave sonic logs offers comprehensive detection of fractures in oil based mud environments

fracture density in the deep subsurface techniques with application to point arguello oil field because monterey formation reservoirs rely on fractures joints for permeability quantitative information on fracture spacing is important to exploration strategies and for understanding reservoir behavior density of joints in cores of four wells from the point arguello reservoir has been determined with a new probability based method and these subsurface joint densities are compared with joint densities measured at nearby outcrops my measure of joint density is the fracture spacing index which is the slope of the trend of layer thickness to joint spacing a single set of extension joints that strike parallel to bedding dip predominates at outcrops likewise the cores contain a single set of extension joints perpendicular to the anticline axis and parallel to present day maximum horizontal compressive stress in core and at outcrop the only lithologic control on joint density is between nonjointed mudstone and harder more brittle jointed rocks within each well the fracture spacing index is the same for all hard rocks though it varies between wells in the reservoir joint density relates to structural position the most densely jointed strata fracture spacing index 0 45 are from the hinge of a minor anticline where its plunge steepens a less steeply plunging anticlinal nose has lower joint density fracture spacing index 0 30 the lowest joint density fracture spacing index 0 095 and 0 12 is in cores from gently dipping areas at outcrops in various structural settings the fracture spacing index is the same approximately 1 29 in chert dolostone and porcelanite and siliceous shale these rocks may be saturated with joints so that differences in brittle strain due to local structural variations have been overwhelmed as joints continued to form during unroofing of these strata chert looks more fractured than other lithologies because of thin bedding fracture spacing index is used to compute such parameters as fracture porosity and volume of fractures that directly contact the well bore these parameters may be important when trying to model the behavior of a petroleum reservoir or when trying to assess the feasibility of strongly deviating wells to improve the performance of a fracture reservoir

utilization of observations of well bore failure to constrain the orientation and magnitude of crustal stresses application to continental deep sea drilling project and ocean drilling program boreholes