Stratigraphic Exploration Research Articles

A data extension framework of seismic-induced gravelly soil liquefaction based on semi-supervised methods

In studies of gravelly soil liquefaction discrimination, the number of training samples significantly affects model performance. However, historical earthquakes provide limited instances of gravelly soil liquefaction, resulting in no guarantee of the generalization performance of existing models. Additionally, valuable data from liquefiable critical layer points and unlabeled points outside the critical layer are often overlooked in stratigraphic exploration, despite their high value. Therefore, in this paper, a data extension method for semi-supervised learning based on the Markov chain Monte Carlo–Bayesian network (MCMC-BN) method is proposed and a semi-MCMC-BN gravelly soil liquefaction discrimination model is constructed. By effectively mining the available site liquefaction information, the proposed method increases the sample size of the gravelly soil liquefaction dataset by approximately 4 times, expanding 120 initial liquefaction samples to 476. The results demonstrate that the extended liquefaction database improves the distribution of liquefaction data for gravelly soils. The semi-supervised learning model outperforms the supervised learning model, highlighting the feasibility of the semi-supervised approach for gravelly soil liquefaction discrimination. In addition, debris flow data for the Wenchuan area, China, are used to validate the effectiveness of the proposed method. Finally, the impacts of the confidence level magnitude, critical soil layer selection, and different machine learning methods on the data extension outcomes are discussed. The expanded database can provide data support to studying gravelly soil liquefaction, and the proposed data expansion framework can be used for related research in other fields.

Static Reservoir Simulations and Seismic Attributes Application to Image the Miocene Deep-Water Reservoirs in Southeast Asia

Globally, deep-water reservoir systems are comprised of a variety of traps. Lateral and downdip trapping features include sand pinch-outs, truncation against salt or shale diapirs, and monoclinal dip or faulting with any combination of trapping designs; the potential for massive hydrocarbon accumulations exists, representing significant exploration prospects across the planet. However, deep-water turbidites and submarine fans are two different types of traps, which are developed along the upslope and the basin floor fans. Among these two traps, the basin floor fans are the most prolific traps as they are not influenced by sea-level rise, which distorts the seismic signals, and hence provides ambiguous seismic signatures to predict them as hydrocarbon-bearing zones for future explorations. Therefore, the deep-water channel-levee sand systems and basin floor fans sandstone define economically viable stratigraphic plays. The subsurface variability is significant, and hence, characterizing the thick (porous) channelized-basin floor fans reservoir is a challenge for the exploitation of hydrocarbons. This study aims to develop seismic-based attributes and wedge modeling tools to accurately resolve and characterize the porous and gas-bearing reservoirs using high-resolution seismic-based profiles, in SW Pakistan. The reflection strength slices better delineate the geomorphology of sand-filled channelized-basin floor fans as compared to the instant frequency magnitudes. This stratigraphic prospect has an area of 1180 km2. The sweetness magnitudes predict the thickness of channelized-basin floor fans as 33 m, faults, and porous lithofacies that complete a vital petroleum system. The wedge modeling also acts as a direct hydrocarbon indicator (DHI) and, hence, should be incorporated into conventional stratigraphic exploration schemes for de-risking stratigraphic prospects. The wedge model resolves a 26-m thick hydrocarbon-bearing channelized-basin floor fans lens with a lateral distribution of ~64 km. Therefore, this wedge model provides ~75% correlation of the thickness of the LSL as measured by sweetness magnitudes. The thickness of shale that serves as the top seal is 930 m, the lateral mud-filled canyons are 1190 m, and the thick bottom seal is ~10 m, which provides evidence for the presence of a vibrant petroleum play. Hence, their reveals bright opportunities to exploit the economically vibrant stratigraphic scheme inside the OIB and other similar global depositional systems.

3-D quantitative seismic imaging of tectonically-influenced Middle-Eocene carbonates stratigraphic traps of SE-Asian basins using spectral decomposition: Implications for hydrocarbon exploration

Carbonates form energetic stratigraphic petroleum systems. The tectonic uplifting and subsidence significantly affect the overall reservoir configurations. During these stratigraphic scenarios, the prediction of accurate thickness for subsidence and uplifting zones becomes challenging. The band-limited seismic data interpretation tools fail to detect the zones of thinning and thickening of sediments along with uplifting and subsidence. The band-limited seismic does not have the tuning frequency, that can be used to predict the accurate vertical thickness of the thin-bedded carbonates. The constant wavelet-based transformation tool (WT) and inverted reservoir simulations have robust implications for the quantification of any depositional system. Especially, when the reservoir is shallow marine, the application of WT has resolved a variety of stratigraphic traps in terms of their seismic and sedimentological aspects. The stratigraphic traps are comprised of thin beds, which are not resolvable on conventional seismic. These traps require a specific tuning frequency, which is the key ingredient for the prediction of oil and gas inside them and can only be obtained by the implementation of the WT tool. Therefore, the WT, static stratigraphic thickening wedge models (SSTWM), and WT–based instantaneous spectral thickness modeling (ISTM) tools are applied on a gas field in Indus Basin, Pakistan. The 43-Hz CWT images the densely fractured and faulted network within the shoal reservoir limestone lenticular lens (SRLL) with an aerial extent of 208 km2 in southwest-northeast orientations. The band-limited attributes revealed poor imaging of sub-surface carbonate systems. The 43-Hz wavelet-based SSTWM predicts a 15-m-thick coarse-grained SRLL along subsidence and a 12-m-thick fine-grained SRLL along uplifting zones. Post-stack processing at 43-Hz CWT tuning frequency predicts the 18 and 10 m thick sediments for SRLL along the subsidence and uplifting zone. The ISTM predicts a thickness of 31 m during subsidence within the SRLL and 14 m for uplifting zones. The 43-Hz tuning frequency-based processing at ISTM predicts enhanced thicknesses of 41 and 18 m for subsiding and uplifting sediments that are trapped inside the shoal limestone petroleum systems. The quantitative visualization of AI with the predicted thicknesses at ISTM has provided robust clues for imaging the internal stratigraphic architecture of the SRLL. The linear regression analysis remained a very successful tool for assessing the quantitative aspects of SRLL with a strong R2 > 0.95, which has implicated the real-time imagining of sea-level fall and rise. Only post-stack seismic data processing at 43-Hz found a very effective exploration tactic in predicting the enhanced thicknesses, and lateral continuity of the reservoir, and improved the S/N by removing the tuning effect of ambiguous lithology/fluids, which have accurately predicted the exact location along the subsidence zones. This workflow can act as an analogue stratigraphic exploration of remaining gas fields within Asian Basins and similar geological settings.

Geoscience Poster G8: Geomechanical rock properties of the Officer Basin

Poster G8 The Officer Basin spanning South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. Despite numerous demonstrated oil and gas shows, the Officer Basin remains a frontier basin for energy exploration with significant uncertainties due to data availability. Under the EFTF Officer–Musgrave Project, Geoscience Australia acquired new geomechanical rock property data from forty core samples in five legacy stratigraphic and petroleum exploration wells that intersected Paleozoic and Neoproterozoic aged intervals. These samples were subjected to unconfined compressive rock strength tests, Brazilian tensile strength tests and laboratory ultrasonic measurements. Petrophysical properties were also characterised via X-ray computerised tomography scanning, grain density and porosity-permeability analysis. Accurate characterisation of static geomechanical rock properties through laboratory testing is essential. In the modern exploration environment, these datasets are a precompetitive resource that can simplify investment decisions in prospective frontier regions such as the Officer Basin. To access the poster click the link on the right. To read the full paper click here

Geomechanical rock properties of the Officer Basin

The Officer Basin spanning South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. Despite numerous demonstrated oil and gas shows, the Officer Basin remains a frontier basin for energy exploration with significant uncertainties due to data availability. Under the EFTF Officer–Musgrave Project, Geoscience Australia acquired new geomechanical rock property data from forty core samples in five legacy stratigraphic and petroleum exploration wells that intersected Paleozoic and Neoproterozoic aged intervals. These samples were subjected to unconfined compressive rock strength tests, Brazilian tensile strength tests and laboratory ultrasonic measurements. Petrophysical properties were also characterised via X-ray computerised tomography scanning, grain density and porosity-permeability analysis. Accurate characterisation of static geomechanical rock properties through laboratory testing is essential. In the modern exploration environment, these datasets are a precompetitive resource that can simplify investment decisions in prospective frontier regions such as the Officer Basin.

ПРОБЛЕМЫ ВОЗРАСТНОЙ И ГЕНЕТИЧЕСКОЙ ДИАГНОСТИКИ ЧЕТВЕРТИЧНЫХ ОТЛОЖЕНИЙ В ДОЛИНЕ СРЕДНЕГО ТЕЧЕНИЯ Р. ЕНИСЕЙ (ЕНИСЕЙ-НИЖНЕАНГАРСКИЙ СТРАТИГРАФИЧЕСКИЙ РАЙОН И РАЙОН МИНУСИНСКИХ КОТЛОВИН)

The article is devoted to the state of stratigraphic exploration maturity of the Eopleistocene – Neo-Рleistocene Quaternary deposits on the boundary of mountain and plain territories in the non-glacial area. The material analysis shows an inadequate rationale of the existing stratigraphic schemes, according to which the ladder of alluvial terraces of these territories was formed sequentially during the Eopleistocene, Neo-Pleistocene and Holocene. The revising of representative sections was carried out, the provision of them with geochronological data, the accuracy of age and genetic diagnostics were evaluated.

Application of Microbial Geochemical Exploration Technology in Identifying Hydrocarbon Potential of Stratigraphic Traps in Junggar Basin, China

Even though three-dimension seismic has been widely applied in the eastern slope of Fukang sag with several fluvial channel sand bodies identified as in Jurassic Toutunhe group, the hydrocarbon charge of these stratigraphic traps is hard to predict and still of great uncertainty. Microbial geochemical exploration technology (MGCE), which detects the microbial and geochemical anomalies in surface soil, was applied to delineate three hydrocarbon play fairways, identify six favorable prospects and to predict the geochemical properties of the reservoirs at depth. The results of MGCE survey agreed well with the drilling results of 10 wells and demonstrated the applicability and effectiveness of MGCE in the exploration of stratigraphic traps in this area. Furthermore, the integration of geology, geophysics, geochemistry and geo-microbiology, so-called 4G exploration, led to the discovery of the Qigu group as a new hydrocarbon-bearing play in late Jurassic formation in this area. MGCE technology and 4G integrated exploration has not only made the breakthrough of Qigu discovery, but also opened a new model for stratigraphic reservoir exploration in the area.

Sequence stratigraphy of a mixed siliciclastic-carbonate setting, Scotian Shelf, Canada

During the Jurassic Period, a large-scale carbonate bank (Abenaki Formation) and a siliciclastic (Sable) delta coexisted in North America. Conventionally, carbonate systems (in situ) are separated from siliciclastic systems (transported) because of their contrasting origin. However, we developed a case study to show that the basic principles of sequence stratigraphy remain applicable. We integrated the results obtained from a regional 2D study and a detailed follow-up study using 3D seismic data of the Scotian Shelf, Canada. The results were integrated with the prepared Wheeler diagrams, and a unified sequence stratigraphic framework was proposed. We determined that two second-order sequences were developed on a larger scale during the Jurassic Period. The first sequence developed during the transition from a ramp to rimmed margin. The second sequence developed during the evolution from a rimmed to ramp margin. These sequences formed a distinct stratigraphic style throughout the Scotian Shelf. The siliciclastic supply varied from the northeast to the southwest depending on the studied site; however, the regions close to the siliciclastic supply contained well-defined clinoform patterns. The topsets of such clinoforms were mostly eroded. Their directions were also found to be different than the carbonate-related clinoform geometries. Most of the carbonates were developed; as such, they kept up and prograded toward a backreef margin during the rimming stages. The second-order sequences were further subdivided into four third-order sequences. These were studied using the 3D seismic data and were found to contain several barrier reefs that could have stratigraphic exploration potential in the Penobscot area.

Integrated outcrop reservoir characterization, modeling, and simulation of the Jackfork Group at the Baumgartner Quarry area, western Arkansas: Implications to Gulf of Mexico deep-water exploration and production

The lower Pennsylvanian Jackfork Group in Arkansas has been the subject of studies, field trips, and publications for many years because of excellent outcrop exposures of different deep-water architectural elements. This latest study is focused on the Baumgartner Quarry located near Kirby, Arkansas, which exposes a series of vertical walls in three dimensions. This quarry has not been as well documented as other popular exposures, although three-dimensional (3-D) quarry faces exist, and the quarry strata comprise part of a complete 600-m (1970-ft)-thick near-continuous Jackfork stratigraphic sequence not unlike younger deep-water stratigraphic exploration targets in the Gulf of Mexico and elsewhere. Subsurface problems including reservoir uncertainties and reservoir performance of lobe versus channel-fill deposits are addressed based on our work in the quarry. A 3-D sequence-stratigraphic model was developed using a correlation of seven measured stratigraphic sections in the quarry. The 180-m (590-ft)-thick quarry strata consist of a lower lowstand systems tract (LST) (lower sandstones) dominated by channel-fill sandstones, overlain by a shaly transgressive systems tract (condensed section), and then by an upper LST (upper sandstones) dominated by sheet or lobe sandstones. This model was translated into an updip against salt field, which is analogous to some deep-water Gulf of Mexico reservoirs. Performance simulation was conducted on the model using a one-injector water well and two vertical producing wells, one of which was connected to the injector via a channel sandstone and the other of which was offset from the channel sandstone. Results yielded 60% more production from the connected injector-producer pair than from the nonconnected pair. Comparison between the lower (channel-prone) sandstones and the upper (sheet-prone) sandstones revealed that the sheet-prone sandstone is more sustainable, whereas the channel-prone sandstone exhibits a larger drop in production rate during a 10-yr production period. These results illustrate the value of 3-D outcrop models for reservoir performance simulation for development planning of deep-water fields with limited data control, such as in the deep-water Gulf of Mexico.

Recent geomorphic changes in the Liaohe Estuary

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes drilling and 30 km shallow stratigraphic exploration from 2002 to 2005. The main tidal depositional body of the modern Liaohe River delta is located in the Shuangtaizihe Estuary. The stratum within the depth of 10 m includes tidal bank facies, tidal channel facies and neritic facies with paleo-delta facies underlying them. The sediments of tidal bank facies are mainly composed of sand and silt with siltation load and suspended load of about 50% respectively in proportion. The sediment of tidal channel facies and neritic facies is composed of clayey silt and silty clay which belongs to suspended load. The study area was a small bay between the old Daliaohe River, the old Dalinghe River and the Raoyanghe River complex delta since the Holocene to 1896. Many tidal banks formed and expanded rapidly after the Shuangtaizihe River was excavated by labor in 1896. The runoff and sediment discharge have decreased since the construction of brake at the Shuangtaizihe River in 1958.The Shuangtaizihe Estuary is in the state of deposition as a whole whose tidal bank is increasing and expanding southward, westward and northward. The maximum expansion speed is 87 to 683 m/a and the mean depositional rate is 0.189 m/a. Erosion occurred in some part of tidal bank with average erosional rate of 0.122 m/a. The tidal channel was filled up with sediment at a migration speed of 48–200 m/a. Geomorphologic changes have happened under the combined influences of runoff, ocean dynamics and human activities. The main source of sediment changes from river sediment to sediment driven by tidal current and longshore current.

Instantaneous spectral attributes to detect channels

Channels filled with porous rock and encased in a nonporous matrix constitute one of the more important stratigraphic exploration plays. Although attributes such as coherence can be used to map channel width, they are relatively insensitive to channel thickness. In contrast, spectral decomposition can be used to map subtle changes in channel thickness. The peak spectral frequency derived by using the short-window, discrete Fourier transform (SWDFT) is an excellent tool for mapping such changes along an interpreted horizon. We show that by use of instantaneous spectral attributes, we can generate equivalent maps for complete seismic volumes. Because we are often interested in mapping high-reflectivity channels encased in a lower-reflectivity matrix, we find that a composite plot of the peak frequency and the above-average peak amplitude accentuates highly tuned channels. Finally, by generating a composite volume using peak frequency, peak amplitude, and coherence, we can establish not only the channel thickness, but also its width. We demonstrate the value of such 3D volumetric estimates through application to (1) a marine survey acquired over Tertiary channels from the Gulf of Mexico and (2) a land data survey acquired over Paleozoic channels from the Central Basin Platform, west Texas, United States. The channels in both marine and land surveys can be highlighted through composite-volume analysis.

ABSTRACT: Stratigraphic Framework and Exploration Potential of Sligo Formation Carbonates (Lower Cretaceous) in South Texas

ABSTRACT: Stratigraphic Framework and Exploration Potential of Sligo Formation Carbonates (Lower Cretaceous) in South Texas

ABSTRACT: Trap and Seal Analysis in Carbonate Stratigraphic Trap Exploration - Lower Miocene, Pearl River Mouth Basin, China

ABSTRACT: Trap and Seal Analysis in Carbonate Stratigraphic Trap Exploration - Lower Miocene, Pearl River Mouth Basin, China

Essential Elements of Significant Stratigraphic Exploration Plays in Ordovician to Lower Permian Carbonates in the Midland Basin : ABSTRACTS

Essential Elements of Significant Stratigraphic Exploration Plays in Ordovician to Lower Permian Carbonates in the Midland Basin : ABSTRACTS

Sequence Stratigraphic Framework And Exploration Potential of Lower Permian (Wolfcampian) Gravity-Flow Deposits, Eastern Midland Basin, Texas: ABSTRACT

Eight major Wolfcampian sequences (W1-W8) have been identified on seismic data and well logs in a 1500 square mile study area along the Eastern Shelf of the Midland Basin. These sequences compose two lower frequency sequences (W1-W5 & W6-W8) which are separated by a major erosional surface associated with a sea-level fall near the time of the early-middle Wolfcampian boundary. Sea-level falls associated with sequences W5 and W6 resulted in significant erosion of platform-margin deposits, incision of a submarine canyon several miles into the Eastern Shelf, and deposition of carbonate gravity flows in the Midland Basin. Gravity flows entered the basin via the submarine canyon and fed basin-floor fan systems which extend up to 25 miles basinward of the toe-of-slope. Within the study area, production from carbonate gravity-flow deposits is mostly from three submarine fan systems within sequences W5 and W6 - the Credo (10 MMBOER) fan (oldest) , the Triple M (5 MMBOER)-Howard Glasscock (7 MMBOER) fan, and the Hutto (5 MMBOER) fan (youngest). The maximum gross thickness of the fans ranges from 100 to 200 feet. Regional isolith and seismic amplitude data were used to high-grade a 70 square mile area in the vicinity of Triple M andmore » Howard Glasscock fields. Model-based velocity inversions, constrained by sonic and density data from 52 wells, were performed utilizing a grid of 2-D seismic data and a 3-D survey. Both Triple M and Howard Glasscock fields are clearly defined by high-velocity anomalies within the productive basin-floor fan interval of sequence W6. An untested high-velocity anomaly with a velocity signature and stratal geometry similar to the two fields, and estimated reserves of 5 MMBOER, is scheduled to be drilled in 1995.« less

A Revised Cenozoic Geochronology: Template for Global Stratigraphic Correlations and Petroleum Exploration in the 1990s: ABSTRACT

A Revised Cenozoic Geochronology: Template for Global Stratigraphic Correlations and Petroleum Exploration in the 1990s: ABSTRACT

Seismic Modeling for Gas Field Development in Offshore Niger Delta: A Case History: ABSTRACT

In practice, seismic data has been used to map the geometry of events in the subsurface, mainly from reflection continuity and the character of reflection packages. Seismic modeling techniques are attempts to mathematically and geometrically represent the geology of the subsurface and to depict the interaction of the geology with a propagating seismic wave front. In the Niger delta, recent development in stratigraphic exploration has induced the examination of more subtle features of reflection, mainly polarity, amplitude, and waveform, to define the limits of seismic resolution and hence predict the geometry of the subsurface fluid and solid interfaces. The field being appraised for development in this study is located approximately 35 km offshore southeast of the Niger delta in a water depth ranging from 20 to 25 m, and the project involves a modeling evaluation of five sand units encountered at different levels in the subsurface. The sands being modeled occur within the Agbada Formation (Miocene age), an alternation sequence of transitional sands and shales characterized by high-amplitude, anomalous seismic events over the Nkop field. Structurally, the field is characterized by seaward facing, contemporaneous growth faults consisting mainly of a rollover anticline located in a regional fault couple, bounded to more » the north and south by a growth fault. « less

Predictive Seismic Modeling Case History from the Niger Delta

Seismic modeling techniques provide the mechanics for simulating the geology of the subsurface by depicting the impact of a propagating seismic wavefront on subsurface structures. In practice, seismic data have been used to map the geometry of events in the subsurface, mainly from reflection continuity and the character of reflection packages. In the Niger delta, recent developments in stratigraphic exploration has induced the examination of more subtle features of reflection, mainly polarity, amplitude, and waveform to define the limits of seismic resolution and hence predict the geometry of subsurface fluid and solid interfaces. The case history discussed here involved interpretative study for defining the fluid contents of prospective oil and gas leads as indicated by anomalous seismic events on a Niger delta field located in a water depth of 25 m. An appropriate source signal (5-35 Hertz minimum phase) is selected, and the wavelet is convolved with a practical geologic model to obtain a synthetic seismogram. By an interactive process involving slight modifications in the geologic model, a synthetic seismogram is ultimately derived that matches a field signal, thus providing a more accurate prediction of the geological formation under study. The technique was effect (as confirmed by later drilling) inmore » appraising the fluid contents of the targeted pay zones encountered at gas/water, oil/water, and gas/oil/water contacts in the O field, located in the eastern offshore area of the Niger delta. The method further demonstrated that structural and stratigraphic modeling are effective tools for testing the mapability of a geologic concept and are able to evaluate the significance of reflectivity changes or anomalies on uncalibrated seismic data.« less

Integrated Geologic and Geophysical Mapping: An Example from the Muddy Sandstone Wind River Basin, Wyoming: ABSTRACT

Muddy Sandstone stratigraphic traps have been the primary stratigraphic exploration target in the Wind River basin (WRB) for BP Exploration and many in industry since the discovery of the Grieve field (30 MMBO, 60 bcf of gas) in 1954. Since 1984 in the eastern WRB, 18 wildcats have been drilled resulting in three new field discoveries which total approximately 23 MMBOE. BP Exploration staff has successfully predicted the reservoir outcome of over 95% of the wildcats by incorporating log facies and facies models with seismic amplitude mapping of the Muddy reflector. The Early Cretaceous Muddy Sandstone unconformably overlies the earlier Cretaceous marine Thermopolis Shale and is conformably overlain by the marine Mowry Shale. An incised valley system was cut into the Thermopolis Shale during a eustatic sea level drop. During the ensuing sea level rise in the southeast portion of the WRB, the Recluse sandstone is the primary Muddy reservoir unit. Secondary Muddy sandstone deposition of marine shoreline sandstones occurred during fluctuations of the primary eustatic sea level cycle. Therefore, in certain areas of the WRB , the Recluse member sandstones can be overlain and/or underlain by marine sandstones. In areas where the older and younger marine sandstones are absent,more » seismic amplitude mapping, incorporating well control, provides a method of mapping the extent of the valley fill sediments. The Muddy valley-fill sediments are generally less than 30 m thick and are encased in slower velocity shales. When valley-fill sediments are present, the Muddy reflector is high amplitude in contrast to low amplitudes when the valley-fill is absent. Estimates of valley fill lithology are provided through synthetic modeling of well logs representing different lithofacies. The resulting wavelet characterization, which includes wavelet shape and peak-to-trough time separation, improves predictability of sandstone distribution.« less

Environmental Impact Assessment for Commercial Real Estate Transfers

Environmental site assessments in conjunction with the sale or purchase of commercial real estate is a rapidly expanding area of applied environmental geology and has produced much business activity for environmental consultants. The Superfund Amendments and Reauthorization Act of 1986 (SARA) and similar state legislation have focused the attention of financial institutions, insurance firms, attorneys, and developers on avoiding purchase of environmentally-impacted property. Under this legislation, purchasers of impacted property may be held liable for remediation and any health hazard associated with the site. Evaluation of soil, air, ground- and surface-water conditions, and quality for both industrialized and vacant land are required for the assessment. Assessments of industrial property may also require an audit of current operating, maintenance, and hazardous materials handling procedures. Interviews and site reconnaissance generally indicate the need for statistically-based soil and ground-water sampling to follow-up preliminary work. Proper design of the sampling program requires prior geophysical and stratigraphic exploration. Additional public concern for maintaining the quality of soil and groundwater resources is likely to increase in the future; successful litigation for obtaining financing for remediation, particularly with the passage of SARA and similar state superlien and commercial property transaction laws, will pressure buyers of commercial property to have thorough assessments performed that include well-designed soil and ground-water studies.