共查询到20条相似文献，搜索用时 437 毫秒
1.
Bruno Goutorbe Francis Lucazeau Alain Bonneville 《Geophysical Journal International》2007,170(2):913-922
Bottom-hole temperatures (BHT) from oil exploration provide useful constraints on the subsurface thermal regime, but they need to be corrected to obtain the equilibrium temperature. In this work, we introduce several BHT correction methods and compare them using a large Australian data set of more than 650 groups of multiple BHT measurements in about 300 oil exploration boreholes. Existing and suggested corrections are classified within a coherent framework, in which methods are divided into: line/cylinder source; instantaneous/continuous heat extraction; one/two component(s). Comparisons with reservoir test temperatures show that most of the corrections lead to reliable estimates of the formation equilibrium temperature within ±10 °C, but too few data exist to perform an intercomparison of the models based on this criterion. As expected, the Horner method diverges from its parent models for small elapsed times (or equivalently large radii). The mathematical expression of line source models suffers from an unphysical delay time that also restrains their domain of applicability. The model that takes into account the difference of thermal properties between circulating mud and surrounding rocks—that is the two-component model—is delicate to use because of its high complexity. For these reasons, our preferred correction methods are the cylindrical source models. We show that mud circulation time below 10 hr has a negligible effect. The cylindrical source models rely on one parameter depending on the thermal diffusivity and the borehole radius, which are poorly constrained, but the induced uncertainty on the extrapolations remains reasonably low. 相似文献
2.
ZK001井钻遇地层为大段泥岩,部分地层为页岩、含盐泥岩、盐膏层。在泥页岩地层进行大口径全面钻进,钻速较快,固控设备能力有限,引起钻屑中粘土颗粒重复性膨胀、软化及裂解分散,最终可能造成粘土侵,对井内安全造成威胁。深部岩膏层易溶于水,从而导致盐层蠕变、井径扩大、井壁失稳等问题。以ZK001井为例,通过优化钻井液体系及现场施工工艺,解决了地层强造浆、盐层失稳等问题。通过岩石力学测试、阳离子交换容量测试、钻井液体系优选及性能测试,确定了上部地层采用聚合物钻井液体系,下部含盐层取芯钻进转换为饱和盐水钻井液体系。通过选用合适的钻井液密度、粘度、切力量、滤失量、含盐量等指标,可以有效控制上部泥岩井壁稳定、含盐层蠕变、井径扩大的问题。钻进过程中钻井液性能稳定且易于维护,从而保证了钻进工作安全、高效、顺利的进行。 相似文献
3.
The inversion of recent borehole temperatures has proved to be a successful tool to determine ancient ground surface temperature histories. To take into account heterogeneity of thermal properties and their non-linear dependence on temperature itself, a versatile 1-D inversion technique based on a finite-difference approach has been developed. Regularization of the generally ill-posed problem is obtained by an appropriate version of Tikhonov regularization of variable order. In this approach, a regularization parameter has to be determined, representing a trade-off between data fit and model smoothness. We propose to select this parameter by generalized cross-validation. The resulting technique is employed in case studies from the Kola ultradeep drilling site, and another borehole from northeastern Poland. Comparing the results from both sites corroborates the hypothesis that subglacial ground surface temperatures as met in Kola often are much higher than the ones in areas exposed to atmospheric conditions (Poland). 相似文献
4.
Elco Luijendijk Marlies ter Voorde Ronald van Balen Hanneke Verweij Erik Simmelink 《Basin Research》2011,23(1):65-82
We performed a detailed analysis of the thermal state of the Cenozoic Roer Valley Graben, the north–western branch of the European Cenozoic Rift System, based on a new set of temperature data. We developed a numerical technique for correcting bottom hole temperatures, including an evaluation of the uncertainty of thermal parameters. Comparison with drill stem test temperatures indicated that the uncertainty in corrected bottom hole temperatures using a two‐component numerical model is approximately ± 4 °C, which is much more accurate than the up to 15 °C errors encountered in often‐used line‐source or Horner correction methods. The subsurface temperatures and the derived regional heat flow estimates of 53 ± 6 to 63 ± 6 mW m?2 show no significant difference between the central rift and the adjacent structural highs. The absence of an elevated heat flow is attributed to the low amount of lithospheric thinning during the Cenozoic rifting phase (β=1.06–1.15). A local thermal anomaly exceeding +10 °C was found in five wells in the north–western part of the rift basin at depths of 1000–1500 m, and is most likely caused by the upward flow of fluids along faults, whereas lower temperatures in the upper 1500 m in the southern part of the rift basin could indicate cooling by topography‐driven groundwater flow. Conflicting ideas exist on the active or passive rifting mechanisms responsible for the formation of the different rift basins of European Cenozoic Rift System. The low spatial variation in heat flow found in this study suggests that the mechanism responsible for forming the Roer Valley Graben is passive rifting. 相似文献
5.
J. Arkani-Hamed 《Geophysical Journal International》1979,56(1):63-80
Summary. Equations governing non-linear and finite-amplitude convection in a heterogeneous planetary interior are developed. Using spherical harmonic expressions of variables, together with Green's function of Laplacian operator in a spherical coordinate, the equations are reduced to one-dimensional integro-differential equations and their numerical solutions are obtained by a finite-difference scheme. The theory is then applied to several lunar models and the following conclusions are obtained.
(1) The mean temperatures and velocities of convecting zones of variable viscosity models are higher than those of constant viscosity ones. This is due to the development of lithospheres with 400–500 km thicknesses in the former models, which reduce heat loss considerably.
(2) Molten regions are continuous shells in variable viscosity models whereas they become discontinuous and localized in a constant viscosity model. The continuous molten shells decrease lateral variations of temperature significantly and tend to stabilize convection.
(3) Lateral variations of viscosity have negligible effects on the thermal evolution of the models considered. 相似文献
(1) The mean temperatures and velocities of convecting zones of variable viscosity models are higher than those of constant viscosity ones. This is due to the development of lithospheres with 400–500 km thicknesses in the former models, which reduce heat loss considerably.
(2) Molten regions are continuous shells in variable viscosity models whereas they become discontinuous and localized in a constant viscosity model. The continuous molten shells decrease lateral variations of temperature significantly and tend to stabilize convection.
(3) Lateral variations of viscosity have negligible effects on the thermal evolution of the models considered. 相似文献
6.
W. F. Waite L. A. Stern S. H. Kirby W. J. Winters D. H. Mason 《Geophysical Journal International》2007,169(2):767-774
Thermal conductivity, thermal diffusivity and specific heat of sI methane hydrate were measured as functions of temperature and pressure using a needle probe technique. The temperature dependence was measured between −20°C and 17°C at 31.5 MPa. The pressure dependence was measured between 31.5 and 102 MPa at 14.4°C. Only weak temperature and pressure dependencies were observed. Methane hydrate thermal conductivity differs from that of water by less than 10 per cent, too little to provide a sensitive measure of hydrate content in water-saturated systems. Thermal diffusivity of methane hydrate is more than twice that of water, however, and its specific heat is about half that of water. Thus, when drilling into or through hydrate-rich sediment, heat from the borehole can raise the formation temperature more than 20 per cent faster than if the formation's pore space contains only water. Thermal properties of methane hydrate should be considered in safety and economic assessments of hydrate-bearing sediment. 相似文献
7.
8.
近50年长江中下游地区夏季气温变化与环流异常 总被引：1，自引：0，他引：1
Using the daily data of temperature from China Meteorological Administration and the NCEP/NCAR reanalysis from 1960 to 2005, we have analyzed the relationships between the summertime high/low temperature events in the middle and lower reaches of the Yangtze River (MLRYR) and the related circulation anomalies in the Eastern Hemisphere. Our results have demonstrated that a significantly increasing trend is observed in daily minimum temperature in the past 50 years. And in some regions in the Northern Hemisphere, the opposite scenarios are observed in circulation anomalies in lower and upper parts of the troposphere in the years when the temperatures are higher than normal, as compared to those in the years when the temperatures are lower than normal in the middle and lower reaches of the Yangtze River (MLRYR). Additionally, the anomalous circulation structure in vertical direction in both the high and lower temperature years are barotropic. It is found that the emergence and maintenance of the aforementioned anomalous circulations are related to three kinds of wave train teleconnection patterns. Further more, influences of the long wave surface radiation on the air temperature are stronger in the nighttime than that in the daytime. While both the maximum and minimum temperatures have negative relationships with the sensible heat flux but positive relationships with the latent heat flux. To some extent, the anomalous dynamic heating (cooling) caused by the vertical thermal advection as well as the diabatic heating (cooling) caused by diabatic processes can explain the formation of the high (low) temperature events in the middle and lower reaches of the Yangtze River (MLRYR) in boreal summer. 相似文献
9.
Using the daily data of temperature from China Meteorological Administration and the NCEP/NCAR reanalysis from 1960 to 2005, we have analyzed the relationships between the summertime high/low temperature events in the middle and lower reaches of the Yangtze River (MLRYR) and the related circulation anomalies in the Eastern Hemisphere. Our results have demonstrated that a significantly increasing trend is observed in daily minimum temperature in the past 50 years. And in some regions in the Northern Hemisphere, the opposite scenarios are observed in circulation anomalies in lower and upper parts of the troposphere in the years when the temperatures are higher than normal, as compared to those in the years when the temperatures are lower than normal in the middle and lower reaches of the Yangtze River (MLRYR). Additionally, the anomalous circulation structure in vertical direction in both the high and lower temperature years are barotropic. It is found that the emergence and maintenance of the aforementioned anomalous circulations are related to three kinds of wave train teleconnection patterns. Further more, influences of the long wave surface radiation on the air temperature are stronger in the nighttime than that in the daytime. While both the maximum and minimum temperatures have negative relationships with the sensible heat flux but positive relationships with the latent heat flux. To some extent, the anomalous dynamic heating (cooling) caused by the vertical thermal advection as well as the diabatic heating (cooling) caused by diabatic processes can explain the formation of the high (low) temperature events in the middle and lower reaches of the Yangtze River (MLRYR) in boreal summer. 相似文献
10.
The potential use of 40 Ar/39 Ar thermochronologic data from K-feldspars in reconstructing basin thermal history has been evaluated using the example of the Warburton/Cooper/Eromanga Basin, Australia's largest onshore oil- and gas-producing basin. Results from 40 Ar/39 Ar step-heating experiments reveal details of the evolution of the basin system, including the following: (1) the operation of high geothermal gradient regimes during the earliest basin evolution, suggesting that basin formation was active rather than passive; (2) slow cooling from a Permo-Triassic temperature peak of at least 250–300°C; (3) a rise in thermal gradients to contemporary bottom hole temperatures in the last 5–10 Myr; and (4) spatially variable recrystallization events between 100 and 50 Ma and at around 20 Ma. Initial microstructural observations serve as a useful predictor of the quality and nature of the obtainable age information. Data from 'pristine' K-feldspars may constrain the peak temperature conditions experienced in the basin, the basin's early thermal history and also any recent changes in thermal gradient. Contrasting data from texturally modified K-feldspars may constrain times of thermal transients and/or fluid flow, with the preferred interpretation that K-feldspars recrystallize in response to such events. The Warburton/Cooper/Eromanga Basin example suggests that the 40 Ar/39 Ar technique may serve as a useful adjunct to apatite and zircon fission track analysis and conventional organic maturation indices in basin thermal history analysis. 相似文献
11.
Summary The thermomechanical differential equations governing deformation in viscous shear zones have been solved for both constant velocity and constant stress boundary conditions. The solutions show that the inertial term in these equations can be neglected everywhere.
The starting condition of the constant velocity model has been shown to be a constant velocity gradient and not a Heaviside function. The temperature anomaly produced by shear heating at the centre of the shear zone is shown to increase gradually and continuously with time, not reaching an asymptotic value. Conclusions for the constant velocity boundary condition are otherwise generally similar to those presented by Yuen et al , and agree with Fleitout & Froidevaux. The temperatures reached by constant velocity shears are sufficient for partial melting.
Constant stress boundary condition shear zone models show an initially broad shear zone with uniform shear velocity gradient. Depending on the level of applied shear stress and ambient temperature, localized intense shear heating may develop followed by thermal runaway. At lower ambient temperatures relatively high stresses are required to produce thermal runaway.
The broadening of the constant velocity shear zone proceeds more rapidly with increased ambient temperature. This can be used to show that shear zones broaden with depth. The merging of parallel shear zone pairs has been investigated and shear zones separated by distances of less than 10km coalesce to form a single shear zone within 3 Myr. Only shear zones separated by 50km or more remain distinct over periods of tens of millions of years. 相似文献
The starting condition of the constant velocity model has been shown to be a constant velocity gradient and not a Heaviside function. The temperature anomaly produced by shear heating at the centre of the shear zone is shown to increase gradually and continuously with time, not reaching an asymptotic value. Conclusions for the constant velocity boundary condition are otherwise generally similar to those presented by Yuen et al , and agree with Fleitout & Froidevaux. The temperatures reached by constant velocity shears are sufficient for partial melting.
Constant stress boundary condition shear zone models show an initially broad shear zone with uniform shear velocity gradient. Depending on the level of applied shear stress and ambient temperature, localized intense shear heating may develop followed by thermal runaway. At lower ambient temperatures relatively high stresses are required to produce thermal runaway.
The broadening of the constant velocity shear zone proceeds more rapidly with increased ambient temperature. This can be used to show that shear zones broaden with depth. The merging of parallel shear zone pairs has been investigated and shear zones separated by distances of less than 10km coalesce to form a single shear zone within 3 Myr. Only shear zones separated by 50km or more remain distinct over periods of tens of millions of years. 相似文献
12.
Summary. The Oblique Seismic Experiment (OSE) has been proposed to increase the usefulness of the IPOD crustal borehole as a means of investigating layer 2 of oceanic crust. Specific objectives are: to determine the lateral extent of the structure intersected by the borehole, to analyse the role of cracks in the velocity structure of layer 2, to look for anisotropy which may be caused by large cracks with a preferred orientation and, finally, to measure attenuation in oceanic crust.
The first successful Oblique Seismic Experiment in oceanic crust was carried out in 1977 March in a hole 400 miles north of Puerto Rico. An adequate study of lateral velocity variations was impossible because the hole was not deep enough, the hole was inadequately logged, and the small scale basement topography was not known. In general both P - and S -wave velocity profiles suggest that the crack density decreases with depth in layer 2. Velocities at the bottom of layer 2 are the same as matrix velocities for basalt, implying that crack density may be negligible at this depth. No convincing evidence for anisotropy in either layer 2 or 3 is found from travel time analysis. The hole was not deep enough to measure attenuation from normal incidence shots and amplitudes were not consistent enough to obtain a measure of attenuation from long range shots. 相似文献
The first successful Oblique Seismic Experiment in oceanic crust was carried out in 1977 March in a hole 400 miles north of Puerto Rico. An adequate study of lateral velocity variations was impossible because the hole was not deep enough, the hole was inadequately logged, and the small scale basement topography was not known. In general both P - and S -wave velocity profiles suggest that the crack density decreases with depth in layer 2. Velocities at the bottom of layer 2 are the same as matrix velocities for basalt, implying that crack density may be negligible at this depth. No convincing evidence for anisotropy in either layer 2 or 3 is found from travel time analysis. The hole was not deep enough to measure attenuation from normal incidence shots and amplitudes were not consistent enough to obtain a measure of attenuation from long range shots. 相似文献
13.
Two injection tests, shallow and deep, followed by repeated temperature logging were performed in the Lake City, California OH-1 corehole, to delineate permeable zones, investigate the permeability of rocks adjacent to the wellbore, and to test the validity of maximum-reading thermometer (MRT) measurements collected during the drilling process that show lower than static temperatures above a depth of 2100 ft and significantly higher than static temperatures below a depth of about 2500 ft. The tests confirmed several permeable zones in OH-1. At about 300 ft, there is a strong zone of lateral flow, and at 947 ft there is a major outflow zone for injected fluid. Two other possible permeable flow zones were detected from the thermal recovery logs: one at about 1500 ft and another at about 2300 ft. The 2300 ft permeable zone seems to be an inflow zone, and the source of a probable downflow responsible for cooling the wellbore below about 2500 ft. The hotter MRT data obtained during drilling may be reconciled with the significantly lower static temperature logs if downflow from about 2300 ft is present. 相似文献
14.
通过野外抽水试验方法,确定了柴达木盆地马海盐湖储卤层渗透系数,并结合地下卤水赋存特征与沉积环境对其渗透性能进行分析。结果表明：本地区石盐层大多不纯,石盐晶体内包裹有泥、砂,且晶体间也有泥、砂充填。在石盐沉积期间,由于受到洪水与间歇性河流影响,导致地质环境演化过程中沉积形成的储卤层渗透性能在各处相差较大,区域地下卤水的连通性相对较弱。根据试验开采区27口开采井钻孔资料和地下卤水监测数据,进行了储卤层差异性分类,将钻孔所揭露储卤层划分为3种类型,不同类型储卤层卤水富集性能具有较大差异,表现为渗透系数和单井涌水量在平面分布上的较大数值差距。通过对钻孔岩心岩性、孔隙特征及补给条件等方面进行分析,得出卤水富集性能强的基本条件：储卤层具备天然良好的颗粒骨架和稳定的卤水补给来源与通道。依据储卤层渗透性能和卤水富集规律,将马海盐湖试验开采区划分出不同地下卤水富集区段。 相似文献
15.
Temperature–depth profiles measured in boreholes contain a record of temperature changes at the Earth's surface. The degree to which these profiles and surface air temperature records track each other is quantitatively assessed for the northern plains of the USA. Surface air temperature records are used as a forcing function to generate synthetic transient temperature profiles which are compared with transient temperatures derived from borehole temperature–depth data. These comparisons indicate that surface air and ground temperatures are correlated. Furthermore, these comparisons yield a long-term mean temperature tied to the meteorological record which provides a context for interpreting contemporary warming trends. Our results indicate that warming recorded in surface air temperature time series represents a positive departure above baseline temperature estimates. 相似文献
16.
Edward Bryant 《The Australian geographer》1987,18(2):101-113
A CO2‐warming atmospheric scenario, whereby increased concentrations of ‘greenhouse’ gases result in higher temperatures that either melt near‐polar ice or cause thermal expansion of ocean waters, thus leading to increased sea‐levels and exacerbated coastal erosion, assumes fundamental but unproven cause‐and‐effect relationships. General circulation models have reinforced claims of an accelerated warming and indirectly given support to the complete scenario, but ignore the point that global climate and not just air temperatures have changed over the past century. Indeed, it is difficult to prove that air temperatures have warmed naturally outside of urban centres over this period. To attribute recent temperature increases to anthropogenic factors and to extrapolate these trends to the future also ignores the historic variability of climate. What is more, an eustatic rise in sea‐level cannot be discerned from the background noise of technically or climatically induced changes. Even if sea‐level was rising, coastal erosion may be accounted for better by a suite of inter‐related climatic factors including changes in rainfall regimes, hemispheric circulation and storminess. 相似文献
17.
Holographic in situ stress measurements 总被引：3，自引：0，他引：3
18.
温州三垟湿地底泥氮、磷含量及其对水质的影响 总被引：12，自引：2，他引：10
为探讨温州三垟湿地底泥中氮、磷营养盐含量及其对水质的影响,测定了三垟湿地水体、底泥中的氮、磷含量。结果表明,三垟湿地底泥中富含氮、磷等营养盐,当氧化还原环境发生变化时,底泥可成为水体的主要污染源;底泥中的全氮、全磷若有1％释放,则会使水体中的总氮增加0．63—3．10mg／L,总磷增加0．94—4．70mg／L;若一次释放,则会使水体中的总氮增加62．50～310．00mg／L,总磷增加94．13～470．00mg/L;因此在当前情况下,即便切断外源污染,三垟湿地水体仍将长期处于富营养化状态。 相似文献
19.
青藏高原西部区域多年冻土分布模拟及其下限估算 总被引：3，自引：0，他引：3
准确评估青藏高原西部多年冻土的空间分布及多年冻土下限深度情况对该区地下水资源利用、生态环境保护有重要意义.本文依托科技基础性工作专项“青藏高原多年冻土本底调查”在该区及周边取得的冻土调查资料,利用遥感数据和扩展地面冻结数模型模拟了该区多年冻土的空间分布,调查区的模拟验证表明该方法有较高的精度.在此基础上,根据有限的地温实测资料建立了地温与位置、高程、坡向和太阳辐射的关系,并根据地温-下限关系估算了该区多年冻土下限深度的分布情况.研究表明,该区有多年冻土约占36.9%,季节冻土占57.5%,多年冻土主要分布在34°N~36.5°N范围的喀喇昆仑、西昆仑一带,季节冻土主要分布在塔里木盆地和34°N以南地区.阿里高原及以南是岛状多年冻土分布区域,其多年冻土分布面积少于此前出版的冻土图所绘制的.青藏高原西部区域的多年冻土下限深度整体表现为由东南-西北逐渐加深. 相似文献
20.
As sediment accumulation indicates basin subsidence, erosion often is understood as tectonic uplift, but the amplitude and timing may be difficult to determine because the sedimentary record is missing. Quantification of erosion therefore requires indirect evidence, for example thermal indicators such as temperature, vitrinite reflectance and fission tracks in apatite. However, as always, the types and quality of data and the choice of models are important to the results. For example, considering only the thermal evolution of the sedimentary section discards the thermal time constant of the lithosphere and essentially ignores the temporal continuity of the thermal structure. Furthermore, the types and density of thermal indicators determine the solution space of deposition and erosion, the quantification of which calls for the use of inverse methods, which can only be successful when all models are mutually consistent. Here, we use integrated basin modelling and Markov Chain Monte Carlo inversion of four deep boreholes to show that the erosional pattern along the Sorgenfrei–Tornquist Zone (STZ) in the eastern North Sea is consistent with a tectonic model of tectonic inversion based on compression and relaxation of an elastic plate. Three wells in close proximity SW of the STZ have different data and exhibit characteristic differences in erosion estimates but are consistent with the formation of a thick chalk sequence, followed by minor Cenozoic erosion during relaxation inversion. The well on the inversion ridge requires ca. 1.7 km Jurassic-Early Cretaceous sedimentation followed by Late Cretaceous–Palaeocene erosion during inversion. No well demands thick Cenozoic sedimentation followed by equivalent significant Neogene exhumation. When data are of high quality and models are consistent, the thermal indicator method yields significant results with important tectonic and geodynamic implications. 相似文献