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1.
How to Choose Priors for Bayesian Estimation of the Discovery Process Model   总被引：1，自引：0，他引：1  
The Bayesian version of the discovery process model provides an effective way to estimate the parameters of the superpopulation, the efficiency of the exploration effort, the number of pools and the undiscovered potential in a play. The posterior estimates are greatly influenced by the prior distribution of these parameters. Some empirical and statistical relationships for these parameters can be obtained from Monte Carlo simulations of the discovery model. For example, there is a linear relationship between the expectation of a pool size in logarithms and the order of its discovery, the slope of which is related to the discoverability factor. Some simple estimates for these unknown play parameters can be derived based upon these empirical and statistical conclusions and may serve as priors for the Bayesian approach. The priors and posteriors from this empirical Bayesian approach are compared with the estimates from Lee and Wang's modified maximum likelihood approach using the same data.  相似文献   

2.
Estimates of the number of undiscovered deposits on a statewide basis offer a different perspective on the nation's undiscovered resources of gold, silver, copper, lead, and zinc. Mean estimates of the number of undiscovered deposits statewide were extracted from the estimates of undiscovered deposits nationwide. More than 50 undiscovered deposits are estimated to occur in Alaska, Arizona, Nevada, and Wisconsin. Estimating the number of undiscovered deposits statewide serves as a measure of a state's total remaining mineral resources in known conventional deposit types.  相似文献   

3.
The daily water balance for the drainage basin of Koryto Glacier, Kamchatka Peninsula, Russia, was calculated during the period from August to September 2000. The result shows that 14×106 m3 of meltwater and 2×106 m3 of rainwater entered the basin, while 26×106 m3 of water drained from the basin through proglacial streams. Thus, about ?9×106 m3 of water storage reduction occurred in the basin. Vertical displacements of the glacier surface showed that the volume change due to contraction of subglacial cavities was nearly 20% of the total storage change. The remaining fraction of water storage during the period is thought to be stored in englacial and supraglacial locations. The estimate of water balance components in the early ablation season in 2000 indicates that meltwater was already stored within the glacier before the spring, even during the previous year, and that the stored water drained through the ablation season.  相似文献   

4.
The use of untreated surface water for domestic purposes has resulted in the infection of some people by guinea worm and other water borne diseases in the Northern Region of Ghana. The aim of this study is to assess the current groundwater quantity and quality conditions in the 7,820 km2 Daka catchment and project the water demand in 2025. Results of groundwater analyses generally show good water quality for domestic use. Borehole analyses indicate that the catchment’s groundwater system can be characterized by a regolith aquifer underlain by a deeper fractured rock aquifer in some areas. The current per capita water demand is estimated at 40 l/day although 60 l/day is the desired amount, indicating that with the current population of 363,350, the projected water demand for the communities is 21,800 m3/day. With a projected population of 555,500 in 2025, an expected 33,300 m3/day of water is required. The estimated optimum potential groundwater available for use in the catchment is 154 × 106 m3/year (4.24 × 105 m3/day). However, the current total groundwater abstraction is only 8,876 m3/day or 2% of the optimum. In comparison, the projected total current and 2025 water demands are only 5 and 8%, respectively, of the optimum potential groundwater available for use in the catchment. In addition, only 1,780 m3/day (0.65 × 106 m3/year) or 0.06% of the average annual flow of 1,016 × 106 m3/year of the Daka River is treated for domestic use. These figures reveal that a significantly very large water resource potential exists for both surface and groundwater development in the Daka catchment. It is suggested that their development should proceed conjunctively.  相似文献   

5.
Song  Yanchen  Wang  Enze  Peng  Yuting  Xing  Haoting  Wu  Kunyu  Zheng  Yongxian  Zhang  Jing  Zhang  Na 《Natural Resources Research》2021,30(6):4355-4377

The Paleogene upper Xiaganchaigou Formation (E32) is the most important source rock and reservoir in the Qaidam Basin. However, there are few studies on the processes of hydrocarbon accumulation in this formation; therefore, its hydrocarbon resource potential has not been estimated reasonably. This paper evaluates the hydrocarbon generation properties in light of an improved hydrocarbon generation and expulsion potential model. According to the geochemical characteristics of source rocks and the petrological features of reservoirs, the potentials of different resource types, including conventional oil, tight oil and shale oil, are quantified by combining the buoyancy-driven hydrocarbon accumulation depth (BHAD) and the lower limit for movable resource abundance. The results show that the source rocks are characterized by a large thickness (more than 1000 m), moderate organic matter content, high marginal maturity and a high conversion rate (50% hydrocarbons have been discharged before Ro?=?1%), which provide sufficient oil sources for reservoir formation. Moreover, the reservoirs in the Qaidam Basin consist mainly of low-porosity and low-permeability tight carbonates (porosity of 4.7% and permeability less than 1 mD). The maximum hydrocarbon generation, expulsion, retention and movable retention intensities at present are 350?×?104 t/km2, 250?×?104 t/km2, 130?×?104 t/km2 and 125?×?104 t/km2, respectively. The thresholds of hydrocarbon generation, expulsion and BHAD were 0.46% Ro, 0.67% Ro and 0.7% Ro, respectively. Moreover, the dynamic evolution process of hydrocarbon accumulation was divided into three evolution stages, namely, (a) initial hydrocarbon accumulation, (b) conventional hydrocarbon reservoir and shale oil accumulation and (c) unconventional tight oil accumulation. The conventional oil, tight oil and movable shale oil resource potentials were 10.44?×?108 t, 51.9?×?108 t and 390?×?108 t, respectively. This study demonstrates the good resource prospects of E32 in the Qaidam Basin. A comprehensive workflow for unconventional petroleum resource potential evaluation is provided, and it has certain reference significance for other petroliferous basins, especially those in the early unconventional hydrocarbon exploration stage.

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6.
In this paper, we analyzed the spatial patterns of cultivated land change between 1982 and 2011 using global vector-based land use/land cover data. (1) Our analysis showed that the total global cultivated land area increased by 528.768×104 km2 with a rate of 7.920×104 km2/a, although this increasing trend was not significant. The global cultivated land increased fastest in the 1980s. Since the 1980s, the cultivated land area in North America, South America and Oceania increased by 170.854×104 km2, 107.890×104 km2, and 186.492×104 km2, respectively. In contrast, that in Asia, Europe and Africa decreased by 23.769×104 km2, 4.035×104 km2 and 86.76×104 km2, respectively. Furthermore, the cultivated land area in North America, South America and Oceania exhibited significant increasing trends of 7.236× 104 km2/a, 2.780×104 km2/a and 3.758×104 km2/a, respectively. On the other hand, that of Asia, Europe and Africa exhibited decreasing trend rates of–5.641×104 km2/a,–0.831×104 km2/a and–0.595×104 km2/a, respectively. Moreover, the decreasing trend in Asia was significant. (2) Since the 1980s, the increase in global cultivated lands was mainly due to converted grasslands and woodlands, which accounted for 53.536% and 26.148% of the total increase, respectively. The increase was found in southern and central Africa, eastern and northern Australia, southeastern South America, central US and Alaska, central Canada, western Russia, northern Finland and northern Mongolia. Among them, Botswana in southern Africa experienced an 80%–90% increase, making it the country with the highest increase worldwide. (3) Since the 1980s, the total area of cultivated lands converted to other types of land was 1071.946×104 km2. The reduction was mainly converted to grasslands and woodlands, which accounted for 57.482% and 36.000%, respectively. The reduction occurred mainly in southern Sudan in central Africa, southern and central US, southern Russia, and southern European countries including Bulgaria, Romania, Serbia and Hungary. The greatest reduction occurred in southern Africa with a 60% reduction. (4) The cultivated lands in all the continents analyzed exhibited a trend of expansion to high latitudes. Additionally, most countries displayed an expansion of newly increased cultivated lands and the reduction of the original cultivated lands.  相似文献   

7.
An unconventional, continuous petroleum system consists of an accumulation of hydrocarbons that is found in low-matrix-permeability rocks and contain large amounts of hydrocarbons. Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation (T3x5) are currently regarded as the most prolific emerging unconventional gas plays in China. The conventional and systematical evaluation of T3x5 source rocks was carried out for the first time in the western Sichuan basin (WSD). Hydrocarbon generation and expulsion characteristics (including intensity, efficiency, and amount) of T3x5 source rocks were investigated. Results show that T3x5 source rocks are thick (generally >200 m), have high total organic content (TOC, ranging from 2.5 to 4.5 wt%), and dominated by III-type kerogen. These favorable characteristics result in a great hydrocarbon generating potential under the high thermal evolution history (R o > 1.2%) of the area. An improved hydrocarbon generation potential methodology was applied to well data from the area to unravel the hydrocarbon generation and expulsion characteristics of T3x5 source rocks in the WSD. Results indicate that the source rocks reached hydrocarbon expulsion threshold at 1.06% R o and the comprehensive hydrocarbon expulsion efficiency was about 60%. The amount of generation and expulsion from T3x5 source rocks was 3.14 × 1010 and 1.86 × 1010 t, respectively, with a residual amount of 1.28 × 1010 t within the source rocks. Continuous-type tight-sand gas was predicted to develop in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration (i.e., the hydrocarbon generation and expulsion center was located in Chengdu Sag), the Jurassic sandstone reservoirs were tight, and the gas expelled from the T3x5 source rocks migrated for very short distances vertically and horizontally. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3 × 108 t. The T3x5 gas shale has good accumulation potential compared with several active US shale-gas plays. Volumetrically, the geological resource of shale gas is up to 1.05 × 1010 t. Small differences between the amounts calculated by volumetric method compared with that by hydrocarbon generation potential methodology may be due to other gas accumulations present within interbedded sands associated with the gas shales.  相似文献   

8.
Li  Nan  Cao  Rui  Ye  HuiShou  Li  Qiang  Wang  Yitian  Lv  Xiping  Guo  Na  Su  Yuanxiang  Hao  Jianrui  Yin  Shitao  Chu  Wenkai 《Natural Resources Research》2022,31(4):2129-2161

The mineral system modeling approach for prospectivity mapping is an efficient and economic method to assess undiscovered mineral potential quantitatively. It is a procedure of modeling, acquiring, and coupling the proxies of footprints of mineral systems at multiple scales (e.g., regional, district, and deposit scales). In this approach, the critical issue from multiple scales is that the data collected are asymmetrical from the superficial to the deep or from mine to its brown fields, so that it is hard to employ and integrate them. To complete this study, firstly, multi-tactic 3D geological modeling methods, including the explicit, the implicit, and inversion, were used to build geological models in the condition of asymmetrical datasets at the deposit and district scales. Secondly, indicators acquired in drill-intensive fields among multisource datasets composed of geology, geochemistry, geophysics and alteration data were transferred to studies in deep and brown fields. Finally, deep (~?1,100 m) and circumjacent potentials of mine were targeted in the Haoyaoerhudong gold deposit situated in the Urad Middle Banner area, Inner Mongolia, which is one of the largest black-rock-series-type gold mines in China. This proposed procedure is more visual, clear, intuitive, and transferable to drive mineral system approach to exploration discovery than previous GIS-based studies.

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9.
There exists great potential of rural land consolidation in China due to the aggravated hollowed villages against the background of rapid rural-urban transformation. The paper aims to investigate the potential of rural land consolidation within four urbanization scenarios: Complete urbanization, Semi-urbanization, Urbanization in batches and prospective urbanization in 2020. Research findings show that, (1) the potentials of rural land consolidation in complete and semi-urbanization are 809.89×104 hm2 and 699.19×104 hm2 respectively while rural consolidation rates are 50.70% and 43.77%. As for the urbanization in batches and urbanization in 2020, the potentials are 757.89×104 hm2 and 992.16×104 hm2. (2) Beside Tibet and Ningxia, rural consolidation rates in most provinces are between 40% and 60%, and the land increase rates are between 3% and 12%. Significant correlation between potential of rural land consolidation and the degree of hollowed villages is also found. (3) Evident differences of potential of rural land consolidation exist across provinces. Rural consolidation rates in the East and Central provinces are higher than that in the West provinces. Villages in the developed areas have higher consolidation rates than those in the less developed areas, and villages in the plain areas tend to have higher consolidation rates than those in the mountainous areas.  相似文献   

10.
Mesozoic sediments are source rocks for nearly half the world’s hydrocarbon reserves. Hence, there is great interest in the oil industry to know the trap and sub-trappean sediment thickness and their extent in the trap covered regions of Jamnagar study area. The microbial prospecting method is applied in the Jamnagar sub-basin, Gujarat for evaluating the prospects for hydrocarbon exploration by investigating the anomalous abundance of n-pentane- and n-hexane-oxidizing bacteria of this area. A total of 150 near-surface soil samples were collected in Jamnagar sub-basin, Gujarat for the evaluation of hydrocarbon resource potential of the basin. In this study, bacterial counts for n-pentane-utilizing bacteria range between 1.09 × 102 and 9.89 × 105 cfu/g and n-hexane-utilizing bacteria range between 1.09 × 102 and 9.29 × 105 cfu/g. The adsorbed hydrocarbon gases consisting of ethane plus hydrocarbons (ΣC2+) of 1–977 ppb and n-pentane (nC5) of 1–23 ppb. The integrated geomicrobial and adsorbed soil gas studies showed the anomalous hydrocarbon zones nearby Khandera, Haripur, and Laloi areas which could probably aid to assess the true potential of the basin. Integrated geophysical studies have shown that Jamnagar sub-basin of Saurashtra has significant sediment thickness below the Deccan Traps and can be considered for future hydrocarbon exploration.  相似文献   

11.
The modified Arps-Roberts Discovery Process Modeling System [ARDS (Ver. 4.01)] has recently been upgraded [ARDS (Ver. 5.0)] and applied to a wide variety of field discovery and wildcat drilling data with differing characteristics. ARDS is designed to forecast the number and sizes of undiscovered fields in an exploration play or basin by using historical drilling and discovery data. Fields used as input may be grown or ungrown. Two models for field growth—one offshore and the other onshore—have been implemented (Schuenemeyer and Drew, 1996). Uncertainty attributable to field growth is estimated via simulation. This upgrade of ARDS has been designed to handle situations when the data cannot be partitioned into homogeneous regions, but where estimation of the number of remaining oil and gas fields is still meaningful. In this upgrade of ARDS, many restrictions, which include those on the number of fields and wildcat wells required to forecast the size distribution of the oil and gas fields that remain to be discovered in an exploration play, a basin, or other target area, have been removed. In addition, flexibility has been gained by reforming the criteria for convergence of the model. In all, 32 basins and subbasins in South America were examined, 18 of which had sufficient data to be amenable to forecasting the field-size distribution of undiscovered oil and gas resources directly by using the Petroconsultants Inc. (1993) field discovery and wildcat drilling data. Overall, ARDS (Ver. 5.0) performed well in estimating the field-size distribution of undiscovered oil and gas resources in the 18 basins and subbasins. The aggregate volume of undiscovered petroleum resources was characterized by using histograms of the distribution of resources and the following five statistics: the mean, the 80% trimmed mean, and the 10,50 (median), and 90 quantiles. More than 38 billion barrels of oil equivalent (BOE) in fields that contain more than one million BOE individually were forecast as remaining to be discovered. The largest basin, the Campos (Brazil), is forecast to contain nearly 10 billion BOE undiscovered resources. The East Venezuela Basin (excluding the Furrial Trend) is forecast to contain about 8 billion BOE; the Austral-Magallanes Basin (Argentina and Chile), about 7 billion BOE; and the Napo (Colombia and Ecuador) and the Neuquen (Argentina) Basins, between 3 billion and 4 billion BOE. A subset of these basins that illustrate the increased flexibility of ARDS are discussed.  相似文献   

12.
We initially estimated the cropland area at county level using local historical documents for the Songnen Plain (SNP) in the 1910s and 1930s. We then allocated this cropland area to grid cells with a size of 1 km × 1 km, using a range of cultivation possibilities from high to low; this was based on topography and minimum distances to rivers, settlements, and traffic lines. Cropland areas for the 1950s were obtained from the Land Use Map of Northeast China, and map vectorization was performed with ArcGIS technology. Cropland areas for the 1970s, 1980s, 1990s, 2000s, and 2010s were retrieved from Landsat images. We found that the cropland areas were 4.92 × 104 km2 and 7.60 × 104 km2, accounting for 22.8% and 35.2% of the total area of the SNP in the 1910s and 1930s, respectively, which increased to 13.14 × 104 km2, accounting for 60.9% in the 2010s. The cropland increased at a rate of 1.18 × 104 km2 per decade from the 1910s to 1970s while it was merely 0.285 × 104 km2 per decade from the 1970s to 2010s. From the 1910s to 1930s, new cultivation mainly occurred in the central SNP while, from the 1930s to 1970s, it was mainly over the western and northern parts. This spatially explicit reconstruction could be offered as primary data for studying the effects of changes in human-induced land cover based on climate change over the last century.  相似文献   

13.
The U.S. Geological Survey recently assessed undiscovered conventional gas and oil resources in eight regions of the world outside the U.S. The resources assessed were those estimated to have the potential to be added to reserves within the next thirty years. This study is a worldwide analysis of the estimated volumes and distribution of deep (>4.5 km or about 15,000 ft), undiscovered conventional natural gas resources based on this assessment. Two hundred forty-six assessment units in 128 priority geologic provinces, 96 countries, and two jointly held areas were assessed using a probabilistic Total Petroleum System approach. Priority geologic provinces were selected from a ranking of 937 provinces worldwide. The U.S. Geological Survey World Petroleum Assessment Team did not assess undiscovered petroleum resources in the U.S. For this report, mean estimated volumes of deep conventional undiscovered gas resources in the U.S. are taken from estimates of 101 deep plays (out of a total of 550 conventional plays in the U.S.) from the U.S. Geological Survey's 1995 National Assessment of Oil and Gas Resources. A probabilistic method was designed to subdivide gas resources into depth slices using a median-based triangular probability distribution as a model for drilling depth to estimate the percentages of estimated gas resources below various depths. For both the World Petroleum Assessment 2000 and the 1995 National Assessment of Oil and Gas Resources, minimum, median, and maximum depths were assigned to each assessment unit and play; these depths were used in our analysis. Two-hundred seventy-four deep assessment units and plays in 124 petroleum provinces were identified for the U.S. and the world. These assessment units and plays contain a mean undiscovered conventional gas resource of 844 trillion cubic ft (Tcf) occuring at depths below 4.5 km. The deep undiscovered conventional gas resource (844 Tcf) is about 17% of the total world gas resource (4,928 Tcf) based on the provinces assessed and includes a mean estimate of 259 Tcf of U.S. gas from the U.S. 1995 National Assessment. Of the eight regions, the Former Soviet Union (Region 1) contains the largest estimated volume of undiscovered deep gas with a mean resource of343 Tcf.  相似文献   

14.
Based upon the Bayesian framework for analyzing the discovery sequence in a play, a Markov chain Monte Carlo sampler—the Metropolis–Hastings algorithm, is employed to sample model parameters and pool sizes from their joint posterior distribution. The proposed sampling scheme ensures that the parameter space of changing dimension can be traversed in spite of the unknown number of pools. The equal sample weights make it easy to obtain the confidence intervals and assess the statistical error in the estimates, so that the statistical behaviors of the discovery process modeling can be well understood. Two application examples of the Halten play in Norwegian Sea and the Bashaw reef play in the Western Canada Basin show that, the computational advantage of this method to the simple Monte Carlo integration is considerable. In order to increase the convergence speed of the sample chains to the posterior distributions, several parallel simulations with different starting values are recommended.  相似文献   

15.
With rapid economic development in China, crops have undergone remarkable changes in both their type and spatial pattern. Timely and accurate information of crop type distribution will help government and agricultural producers quickly understand regional agricultural production conditions to better facilitate appropriate adjustments in planting patterns and policies. Another benefit of acquiring such knowledge of crops is that it should enhance regional agricultural competitiveness, optimize resource allocations, and further guarantee national food security. Towards this end, and using the Zhangye City in the Heihe River Basin as a study area, the present research elaborated upon a methodology to classify crop type distribution based on multi-temporal Thematic Mapper and Enhanced Thematic Mapper Plus (TM/ETM+) images. Using this methodology we achieved the spatial distributions of crop types in Zhangye City in 2007 and 2012, and analyzed changes in their distributions over this period. In addition, some landscape indices were calculated to clarify the landscape pattern of crops. The crop conversion potentials in 2017 were modeled using four conversion sub-models of the Multi-Layer Perceptron (MLP) neural network. Generally, the overall accuracy of crop classification in Zhangye was high, at 89.38%. From 2007 to 2012, the cultivated land area in Zhangye increased from 463.81 × 103 ha to 493.89 × 103 ha. The sowing area of corn and oilseed rape increased by 39.21 × 103 ha and 5.99 × 103 ha, respectively, while for wheat and barley the sowing area decreased by 3.61 × 103 ha and 9.14 × 103 ha, respectively. Considering other crop types as a group, their sowing area decreased by only 2.37 × 103 ha. The increase in corn sowing area mainly came from the conversion of other crops to corn, which accounted for 43.09% of its total sowing area in 2012. Furthermore, corn and oilseed rape showed a tendency of intensive sowing, whereas for wheat and barley the tendency was towards scattered sowing. For the future, corn has high conversion potential in Linze and Gaotai counties of Zhangye, while wheat, barley and oilseed rape have high conversion potentials in Minle and Shandan counties.  相似文献   

16.
Terminus geometry, ice margins, and surface elevations on Rabots glaciär were measured using differential GPS during summer 2011 and compared with those similarly measured in 2003. Glacier length over the eight years decreased by ～105 m corresponding to 13 m a?1, a rate consistent with ice recession over the last several decades. Measured changes in surface elevations show that between 2003 and 2011 the glacier's volume decreased by ～27.6 ± 2.6 × 106 m3, or 3.5 ± 0.3 × 106 m3 a?1. This compares favorably with an estimate of ?28.1 ± 2.6 × 106 m3 based on a mass‐balance approach. The rate of volume loss appears, however, to have significantly increased after 2003, being substantially greater than rates determined for the intervals 1959–80, 1980–89, and 1989–2003. This increase corresponds to a sustained interval of more negative summer balances. Previous work suggests that as of 2003 Rabots glaciär had not yet completed its response to a ～1°C warming that occurred c. 1900, and thus the current marked increase rate of ice loss might reflect the effect of recent, or accelerated regional warming that occurred during the last decade superimposed on its continued response to that earlier warming.  相似文献   

17.
Estimates of the number of undiscovered deposits offer a unique perspective on the nation's undiscovered mineral resources. As part of the 1998 assessment of undiscovered deposits of gold, silver, copper, lead, and zinc, estimates of the number of deposits were made for 305 of the 447 permissive tracts delineated in 19 assessment regions of the country. By aggregating number of undiscovered deposits by deposit type and by assessment region, a picture of the nation's undiscovered resources has emerged. For the nation as a whole, the mean estimate for the number of undiscovered deposits is 950. There is a 90% chance there are at least 747 undiscovered deposits and a 10% chance there are as many as 1,160 undiscovered deposits. For Alaska, the mean estimate for the number of undiscovered deposits is 281. There is a 90% chance there are at least 168 undiscovered deposits and a 10% chance there are as many as 402 undiscovered deposits. Assuming that the majority of deposits used to create the grade and tonnage models that formed the basis for estimating the number of undiscovered deposits are significant deposits, there remain about as many undiscovered deposits as have already been discovered. Consideration of the number of undiscovered deposits as part of national assessments carried out on a recurring basis serves as a leading indicator of the nation's total mineral resources.  相似文献   

18.
祁连山区季节性积雪资源的气候分析*   总被引：14，自引：0，他引：14  
陈乾  陈添宇 《地理研究》1991,10(1):24-38
本文采用1986年10月至1988年9月NOAA—9、10两颗卫星的AVHRR资料标准化后反演的积雪参量,对照祈连山区26个气象站1951—1988年逐日雪深、雪密度和积雪日数的资科,修正卫星反演的平均值。得到高分辨率多年平均雪深和雪盖频率的空间分布。从而估算出各流域平均雪储量,并与降雪量和春季融雪径流作对此分析。  相似文献   

19.
生态服务价值与方法研究   总被引：6，自引：0，他引：6  
1Ecosystemservicesandtheirvalueoftheworld1.1EcosystemservicesHuman societies derive many essential goods from natural ecosystems, including seafood, game animals, fodder, fuelwood, timber, and pharmaceutical products (Constanza, 1997). These goods represent important and familiar parts of the economy. What has been less appreciated until recently is that natural ecosystems also perform fundamental life-support services without which human civilizations would cease to thrive. These include the…  相似文献   

20.
Discovery process modeling has gained wide acceptance in the Chinese exploration community. In recent years, a variety of discovery process models have been applied to the prediction of undiscovered petroleum resources at the play level in sedimentary basins in China. However, challenging problems have been encountered, particularly when one method alone has been applied to small plays in nonmarine sedimentary basins or in plays with an unusual order of discovery wells. This paper presents results gotten by using the lognormal discovery process model of the Geological Survey of Canada and the geoanchored method for three petroleum plays in basins with different geologic settings. Although the predicted shapes of the parentsize distributions which use these two models, were not always similar, the expected values of the total resources and the number of fields (pools) to be discovered are comparable. The combined use of two discovery process models in the same play compensates for the weaknesses in one method compared with the other and vice versa. Thus, more reliable estimates are the result.  相似文献   

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