Effective porosity

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

Petrophysical characterizations of Mishrif Formation in Selected Wells of Tuba Oil Field, Southern Iraq

Abstract: The current study includes building (CPI) & Petrophysical Evaluation of the Mishrif Formation (Cenomanian-Early Turonian) in Tuba oilfield, southern Iraq by using Interactive Petrophysics Program v3.5 (IP) to evaluate different logs parameters that control the reservoir quality of Mishrif Formation such as shale volume, effective porosity, and water saturation. Mishrif Formation is subdivided into several units, which are characterized by different reservoir properties. These units are Top of Mishrif, MA, CR2, MB1, and MB2.The results of computer processed interpretation (CPI) show that the major reservoir unit are (MB1 and MB2), which are characterized by high effective porosity and oil saturation. In addition, these units consist of vuggy rudist-bearing facies. The units TM,MA have lower reservoir quality due to low values of effective porosity and high water saturation .The low effective porosity in these units is related to the dominance of lime-mud rich facies that are recognized in deep marine and lagoon facies associations. The unit CR2 represents a cap unit, which extends in all studied wells.

Reserve estimation method for fracture-cavity bottom water reservoir

Abstract: The invention relates to a geologic survey method and aims to provide a reserve estimation method for a fracture-cavity bottom water reservoir, and the method is wide in application range and relatively small in estimation error. The method comprises the following steps of S01: calculating the total volume Vt of a reservoir geologic body; S02: finishing division of a type-I fracture-cavity reservoir, a type-II fracture-cavity reservoir and effective porosity of each fracture cavity, establishing a relationship with a fracture-cavity attribute of an earthquake in combination with well-to-seismic calibration, and determining upper and lower limits of the fracture-cavity reservoir; S03: performing hollowing description on different levels of fracture-cavity reservoirs to obtain the volume VI of the level-I fracture-cavity reservoir and the volume VII of the level-II fracture-cavity reservoir; S04: calculating the volume of a type-III fracture-cavity reservoir; S05: obtaining effective porosity values of the different levels of the fracture-cavity reservoirs; S06: calculating geologic reserves of the different levels of the fracture-cavity reservoirs; and S07: calculating the total reserve of the reservoir geologic body.

Effective porosity and density of carbonate rocks (Maynardville Limestone and Copper Ridge Dolomite) within Bear Creek Valley on the Oak Ridge Reservation based on modern petrophysical techniques

Abstract: The purpose of this study is to provide quantitative data on effective porosity of carbonate rock from the Maynardville Limestone and Copper Ridge Dolomite within Bear Creek Valley based on modern petrophysical techniques. The data will be useful for groundwater-flow and contaminant-flow modeling in the vicinity of the Y-12 Plant on the Oak Ridge Reservation (ORR). Furthermore, the data provides needed information on the amount of interconnected pore space potentially available for operation of matrix diffusion as a transport process within the fractured carbonate rock. A second aspect of this study is to compare effective porosity data based on modern petrophysical techniques to effective porosity data determined earlier by Goldstrand et al. (1995) with a different technique. An added bonus of the study is quantitative data on the bulk density and grain density of dolostone and limestone of the Maynardville Limestone and Copper Ridge Dolomite which might find use for geophysical modeling on the ORR.

An application of the archie's law to the hydrogeological investigation of an alluvial coastal plain

Abstract: SUMMARY A calibration of the so called Archie's law, based on hydrogeological and geophysical data, is presented. This petrophysical law, originally employed by petroleum geologists as an aid to interpret geophysical well logs, if suitably calibrated with direct measurements of the involved parameters, may represent an useful tool for the hydrogeological prospecting in areas with a quifers encroached by salt water. Particularly, the vanishing of surface conductance effect in the electrical flow inside the porous medium, permits to express total porosity only in terms of formation factor without regards to textural composition of finer matrix. As an example of this approach, the hydro-geophysical investigation of lower Cornia plain (Western Tuscany) is presented; data coming from 50 Vertical Electric Soundings, the majority of which calibrated with stratigraphical records, from direct testing of groundwater salinity in wells and from granulometric analysis of acquifer, were used. According the colected data, Archie's law is validated in the tested area; average value obtained of apparent formation factor for the acquifer of Cornia plain is 5,4; the intrinsic formation factor, depending only on total porosity, is 12. The value of total porosity obtained is 25%; on the basis of this datum and the granulometric composition of acquifer, it is estimated a value of 15% for the effective porosity.

Genetic Classification of Porosity Formation and Destruction in Carbonate Rocks: ABSTRACT

Abstract: For a proper evaluation of the reservoir potentialities of carbonate rocks the exact causes of porosity formation and destruction need to be known. Such a genetic approach to a classification has to be practical enough to be applicable at the well site, yet sophisticated enough to allow meaningful interpretations. All old attempts at classification of porosity have been either descriptive or insufficiently accurate. For example, the term "leaching" is meaningless, unless it is specified if it pertains to subaerial leaching, or leaching accompanying recrystallization, or leaching resulting from dolomitization. An attempt is made herein to propose a genetic classification which has been tested in its applicability, both at the well site and in the laboratory. There are basically 2 types of porosity--primary and secondary. Primary porosity developments were formed at time of deposition prior to diagenetic alterations of the sediment. Secondary porosity formations are introduced after deposition by early or late or even post-diagenetic activity. Primary porosity may be subdivided into intergrain and intragrain porosity. Secondary porosity formation may represent the following types: (1) subaerial leaching of the grains (moldic porosity) or the carbonate mud matrix; (2) recrystallization porosity, based primarily on (a) leaching accompanying the recrystallization process, (b) rearrangement of the crystal fabric (interstitial porosity), and (c) preservation of primary porosity by fast diagenetic hardening; (3) dolomitization porosity, based primarily on (a) leaching resulting from the dolomitization process, (b) volume reduction caused by a slight density difference between calcite and dolomite, (c) preservation of the primary porosity by fast diagenetic hardening, and (d) interstitial porosity created by dolomitization and subsequent recrystallization; (4) fracture porosity, either by itself or furthe enlarged by subsequent leaching. Partial or complete porosity destructions in carbonates result primarily from (a) fibrous calcite wall linings, (b) sparry calcite precipitation, (c) sparry dolomite precipitation, (d) anhydrite and gypsum infills, (e) infilling by other evaporites, (f) infill by clay, silt, or sand, (g) infill by carbonate mud, (h) infill by isolated dolomite rhombohedra, and (i) collapse of the former depositional fabric. End_of_Article - Last_Page 154------------