Effective porosity

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

Reliability of velocity-deviation logs for shale content evaluation in clastic reservoirs: a case study, Egypt

Abstract: The shale content is important in reservoir quality evaluation. There are good relations between effective porosity, permeability, and shale content in clastic rocks. One of the main objectives of the velocity-deviation log is that it could indicate permeability qualitatively. The velocity-deviation logs could be calculated from density and neutron porosity logs in carbonate rocks. The velocity deviation calculated from the density log is more reliable than that from neutron log in various clastic rocks to assess its validity in shale volume estimation. This study is carried out in clastic reservoirs drilled by four wells from different hydrocarbon fields in various. Three wells act as train wells and the fourth one is used as a test well. The regression analysis method is used to show the effectiveness of the relationships between the different velocity deviations using density and neutron logs. The relations of the three train wells clarify that there are excellent reliable relations in case of the density log and poor in case of the neutron log. This may be attributed to the effects of hydrogen in shale lattice leading to erroneously overestimated neutron porosity. The correlation coefficients between the compiled three studied train wells and velocity deviation from density porosity log are high and good with very dependable relations. Shale content can be predicted from density velocity-deviation log by using these excellent relationships. The deduced equation is used to predict shale content in the fourth testing well with excellent reliability. The shale content is estimated by the random vector functional link (RVFL) network method to evaluate the predicted results. The matching between the three curves of Vsh, Vsh (VDd), and Vsh (RVFL) is very good with standard errors of Vsh (VDd) and Vsh (RVFL) are 0.13 and 0.17, respectively, which clarify that the two methods are close to each other.

Prediction of vertical permeability and reservoir anisotropy using coring data

Abstract: Most reservoirs have different degrees of permeability anisotropy. Optimization of recovery is crucially dependent on the reservoir quality and anisotropy. The ratio of vertical and horizontal permeability is important when reservoir anisotropy (Kv/Kh) and heterogeneity cannot be neglected. Therefore, an accurate knowledge of vertical and lateral permeability distribution is essential for better reservoir characterization. This work uses routine core data for analysis to develop new correlations and characterization of a sandstone reservoir under development. The two main goals of this study are to use core data to (1) develop correlations capable of predicting vertical permeability from horizontal permeability or mean hydraulic radius and (2) develop another correlation capable of predicting the permeability anisotropy ratio (Kv/Kh) using effective porosity data. To accomplish the objectives of this project, various petrophysical properties were experimentally measured for 112 core samples extracted from an actual sandstone reservoir. The measurements included vertical permeability, horizontal permeability, effective porosity and saturations of oil and water. Applications of the developed results of this study help enhancing the prediction of vertical permeability, improving reservoir characterization and providing better simulation studies.

Determining of formation water saturation to estimate remining hydrocarbon saturation in the x layer y field

Abstract: Efforts are made to find the remaining hydrocarbons in the reservoir, requiring several methods to calculate the parameters of reservoir rock characteristics. For this reason, logging and core data are required. The purpose of this research is to estimate the Remaining Hydrocarbon Saturation that can be obtained from log data and core data. With several methods used, can determine petrophysical parameters such as rock resistivity, shale volume, effective porosity, formation water resistivity, mudfiltrate resistivity and rock resistivity in the flushed zone (Rxo) and rock resistivity in the Uninvaded Zone which will then be used to calculate the Water Saturation value Formation (Sw) and Mudfiltrat Saturation. (Sxo) In this study four exploratory wells were analyzed. Shale volume is calculated using data from Gamma Ray Log while effective Porosity is corrected for shale volume. Rw value obtained from the Pickett Plot Method is 0.5 μm. The average water saturation by Simandoux Method were 33.6%, 43.4%, 67.0% and 39.7% respectively in GW-1, GW-2, GW-3 and GW-4 wells. While the average water saturation value by the Indonesian Method were 43.9%, 48.8%, 72.3% and 44% respectively in GW-1, GW-2, GW-3 and GW-4 wells. From comparison with Sw Core, the Simandoux Method looks more appropriate. Average mudfiltrate (Sxo) saturation by Simandoux Method were 65.5%, 68.2%, 77.0% and 64.6% respectively in GW-1, GW-2, GW-3 and GW wells -4. Remaining Hydrocarbon Saturation (Shr) was obtained by 34.5%, 31.8, 23%, 35.4% of the results of parameters measured in the flushed zone namely Rxo, Rmf and Sxo data. For the price of Moving Hydrocarbons Saturation or production (Shm) is 31.9%, 24.8%, 10%, 24.9% in wells GW-1, GW-2, GW-3 and GW-4.

다공벽의 기체역학에 관한 연구

Abstract: Perforated wall has long been employed to control a variety of flow phenomena. It has been, in general, characterized by a porosity of the perforated wall. However, this porosity value does not take account of the number and detailed shape of porous holes, but is defined by only the ratio of the perforated area to total wall surface area. In order to quantify the porous wall effects on the flow control performance, an effective porosity should be known with the detailed flow properties inside the porous holes. In the present study, a theoretical analysis using a small disturbance method is performed to investigate detailed flow information through porous hole and a computational work is also carried out using the two-dimensional, compressible Navier-Stokes equations. Both the results are compared with existing experimental data. The gasdynamical porosity is defined to elucidate the effect of perforated wall.