Effective porosity

About: Effective porosity is a research topic. Over the lifetime, 1199 publications have been published within this topic receiving 26511 citations.

The tensorial nature of effective porosity and large-scale dispersion coefficients: Application to the Creston study area, Eastern Washington

Abstract: To describe flow in a complex system of fractures requires an understanding of the effects of direction or orientation on several hydrologic characteristics, such as hydraulic conductivity, porosity, and dispersion coefficient. The theory for hydraulic conductivity is well understood; this report deals with the effects of fracture orientation on porosity and dispersion coefficient. The tensorial nature of effective porosity was examined and was found to be a second-rank tensor in fractured rock units. Porosity varies at a fixed point, depending on its orientation. A method to calculate a dispersion coefficient from field tracer tests is described. The components of the dispersion coefficient can be calculated from the concentration profiles observed in downgradient observation wells. The method provides a procedure for studying the dispersion effect in large-scale field testing. The application of this method was successfully demonstrated in a tracer test performed in the research wellfield at the Creston study area, Lincoln County, Washington.

Saturated conductivity and effective porosity of the forest soil

Abstract: Soil samples were taken from different soil depth of different forest soil story in the Natural Reserve of Changbai Mountain, and their saturated conductivity and effective porosity were measured. The variation of saturated conductivity and effective porosity with different soil depth were studied by regressive analysis and a logarithmic model. The results were compared with the exponential model (Beven 1982). The results of comparison showed that the logarithmic model was more accurate and reasonable than the exponential model for forest catchment.

Petrophysical parameters estimation and reservoir characterisation based on well log data in the Joya Mair Oil Field, Minwal X-01 Well, Potwar Sub-Basin and Upper Indus Basin of Pakistan

Abstract: The aim of this study is to assess the reservoir potential of the Eocene age Chorgali and Sakesar formations encountered in Minwal X-01 Well Potwar Sub-Basin.The current study is concerned with the reservoir potential evaluation using petrophysical approach of Minwal X-01 located in Potwar basin. Minwal X-01 is selected for research, where the prevailing assessment involves identifying, marking, analysing and interpreting the reservoir zones from well logs and computational analysis through different formulas. Several well logs were used comprising sonic log, gamma ray log, density log, neutron log, and resistivity logs. The petrophysical parameters such as the shale volume (Vsh), total porosity (PHT), effective porosity (PHE), water saturation (Sw), hydrocarbon saturation (Sh), and pay zone were assessed from wireline logs. The best possible reservoirs in the study area are Chorgali and Sakesar formations in Minwal X-01. These reservoirs have good net pay zones thicknesses (20-52 feet). Based on well log data, these reservoirs are classified as excellent reservoirs owing to their high effective porosity and hydrocarbon saturation.

Research on the Relationship between Effective Porosity and Ratio of Cement to Stone of Non-Sand Concrete Well Pipe

Abstract: Non-sand concrete well pipe is widely used in dewatering construction of deep foundation pit, the running effect of water-filtration well pipe have a close relationship with casting-pipe porosity, material ratio and casting-pipe time. With a long term test, the indicators' critical values of casting-pipe based on maximum porosity is proposed, which is under a condition of ensuring the adequate strength of non-sand pipe and different proportion of limestone cement and stones. The critical values have a great significance to improving non-sand pipe effective porosity, reducing permeation resistance and increasing infiltration capacity, and also can provide a reference for the design and constriction of similar projects.

Multi-disciplinary 3-D reservoir characterization and flow simulation of Aptian/Albian silicate sandstone reservoirs in Bredasdorp Basin, offshore South Africa

Abstract: ENGLISH ABSTRACT: Geological models remain the required input in flow simulators for use by reservoir engineers to simulate performance and optimize oil recovery. The lack of complete subsurface information however, continues to pose a challenge to accurate geological characterisation. A 3-D geologic reservoir model of identified reservoir sand-bodies (WBRED-A, WBRED-B, WBRED-C and WBRED-D) was created to evaluate reservoir fluid-flow performance by way of a systematic workflow that integrates reservoir characterisation, reservoir modelling, upscaling and fluid-flow simulation using a range of data sets. These include: 2-D seismic profiles, well logs, cores, sedimentary logs, and well tests from three exploratory wells. The modelling /approach employed deterministic geological processes in a stochastic framework, hence combining benefits of both deterministic and stochastic modelling methods arranged in nested steps defined primarily by: (1) the creation of a 3-D reservoir model with an anatomy based on concepts of depofacies and their distribution and partitioning, (2) upscaling (i.e. selection of an optimal upscaling method) of the 3-D reservoir model for realistic and representative reservoir anatomy and (3) fluid-flow simulation (i.e. steady state simulation based on assigned two-phase flow parameters of depofacies). The juxtaposing and organisation of observed lithofacies features (sedimentary structures and facies associations) in a down-dip depositional profile allowed for the reconstruction of depositional lithofacies architecture and geometric elements. Six depofacies were recognised (proximal mouth bar, distal mouth bar, delta front, distributary channel, overbank/inter-channel and floodplain/inter-channel deposit), which are broadly grouped into four main lithofacies associations (massive sandstone, interbedded sandstone, claystone, and soft-sediment deformation). Reservoir sandbodies are indicative of a depositional system characterised by a succession of superimposed deltaic cycles which control vertical and horizontal reservoir connectivity. A description of reservoir petrophysics revealed that the WBRED-D presents the lowest average poro-perm results of the four units investigated. Moderate to excellent poro-perm relationship is confirmed within the two main reservoir types-distributary channel-fill and inter-channel reservoirs for WBRED-B, WBRED-C and WBRED-D. Effective porosity values in WBRED [A-D], ranges from 0.14 to 0.35 indicating moderate to very good reservoir quality, while permeability values ranges from 6mD to 602mD and is attributed to well sorted sands. The key control of effective porosity and permeability is the continuity and connectivity of the channel sands and inter-channel deposits. Besides, average water saturation values in the units range from 12% to 69% representative of a reservoir system considered satisfactory for hydrocarbon production. Ten stratigraphic flow units are mapped within WBRED [A-D] and define predictable hydraulic conductivity, storage and porosity of…