Meanwhile,the models of the correlation between the porosity,density and interval transit time have been set up,and according to the models of the correlation,the porosity values of the pore developed dolomite may be determined.

From this study, it is found that the porosity values from the 5 approaches is in a sequence from high to low like this: absolute porosity from physical test>opening porosity from helium instrument > the porosity from SEM >effective porosity from mercury injection>the porosity from thin section.

In C/O logging, CI and CIM2 curves represent the porosity values. Porosities of reservoirs in middle or later oilfield developments can be computed accurately after the C/O logging curves are calibrated by the core data. This method solved the problems arising from the time deference while computing porosity with the open-hole logging information and has acquired a better field application.

The two methods give similar porosity values between 0.3% and 10%.

The porosity values estimated by the NDT methods have been confirmed by destructive testing, which included metallography and vacuum volumetric measurement using nitrogen absorption.

Minimum porosity values of 2.1%, 3.7%, and 5.3%, respectively, were obtained for the JP-5000, the DJ-2700, and the Axial III guns.

The numerical results indicate that as the reactant porosity values are decreased, the combustion velocity first increases because of an increase in the thermal conductivity.

In static compression, for comparable compositions and moisture content the same porosity values are attained for mixtures with a clay addition at pressures 3-4-fold lower than those required for mixtures without clay.

Porosity is one of the important parameters for evaluating hydro- carbon reservoir,it can be determined by making core analysis,logg- ing,mathematical model,etc.However,these discrete porosity values can not delineate the local variation of reservoir porosity.Practice proves the feasibility of calculating the porosity of fluid-filled sand- stone by Wyllie formula.On the basis of seismic interval velocities, the porosities along seismic lines can be determined using Wyllie for- mula integrated...

Porosity is one of the important parameters for evaluating hydro- carbon reservoir,it can be determined by making core analysis,logg- ing,mathematical model,etc.However,these discrete porosity values can not delineate the local variation of reservoir porosity.Practice proves the feasibility of calculating the porosity of fluid-filled sand- stone by Wyllie formula.On the basis of seismic interval velocities, the porosities along seismic lines can be determined using Wyllie for- mula integrated with a modification formula which copes with poro- sity deviation due to mud-filled pores;thus areal porosity variation can be mapped.The examples in the paper demonstrate the effective- ness of the method described in this paper.

In accordance with the geological properties of the Carboniferous reservoir in East Sichuan,it can be divided into three parts as the limestone,pore developed dolomite and pore undeveloped dolomite according to its reservoir properties.Through exploration,it is proved that the fracture developed dolomite with high porosity may be mainly taken as the reservoir,therefore,to recognize the fracture developed intervals with high porosity becomes an important aspect of reservoir evaluation.Owing to the fact that...

In accordance with the geological properties of the Carboniferous reservoir in East Sichuan,it can be divided into three parts as the limestone,pore developed dolomite and pore undeveloped dolomite according to its reservoir properties.Through exploration,it is proved that the fracture developed dolomite with high porosity may be mainly taken as the reservoir,therefore,to recognize the fracture developed intervals with high porosity becomes an important aspect of reservoir evaluation.Owing to the fact that the vertical variations in lithological and petrophysical properties may be relatively accurately reflected by log data,the log eigen values of six conventional logging suites for various lithological properties or the same lithology with various petrophysical properties of the Carboniferous in East Sichuan are obtained by use of the geological and log data comprehensively,and through the inversion of the log eigen values obtained,it is proved that they are authentic.In the light of the log eigen values,the pore developed dolomite,pore undeveloped dolomite and limestone in the Carboniferous reservoir can be divided and the fluid bearing situation in the pores of rocks can also be judged.Meanwhile,the models of the correlation between the porosity,density and interval transit time have been set up,and according to the models of the correlation,the porosity values of the pore developed dolomite may be determined.When the log eigen values mentioned above are used for seismic data processing,the lithological and petrophysical variations in the Carboniferous may be forecasted,then the lithological trap can be fixed.

By using the observed data of porosity, P- and S-wave velocity from 46 wells in an area, we estab-lish a linear formula on the relation between porosity and P- and S-wave velocity. Thus, the porosities can be predicted by use of P- and S-wave velocities rather than any other parameters, and the precision is obviously higher than the prediction precision of Wyllie formula. But the porosities predicted by the lin-ear formla have the averaging phenomenon. The observed data from 46 wells have been used for the neural...

By using the observed data of porosity, P- and S-wave velocity from 46 wells in an area, we estab-lish a linear formula on the relation between porosity and P- and S-wave velocity. Thus, the porosities can be predicted by use of P- and S-wave velocities rather than any other parameters, and the precision is obviously higher than the prediction precision of Wyllie formula. But the porosities predicted by the lin-ear formla have the averaging phenomenon. The observed data from 46 wells have been used for the neural network to leam. Then the neural network is used to perform function approximation. So the nonlinear formula on the relation between porosity and P- and S-wave velocity in the area has been built.The nonlinear formula is clearly more approximate to the observed data. Therefore the precision is im-proved, and the arveraging phenomenon of the predicted porosity values is eliminated.