Statistical analysis of petrophysical parameters of Middle Miocene rocks from the Polish Carpathian Foredeep

Abstract

Mid dle Mio cene -Sarmatian thin-bed ded sand stone and shales of south ern Po land have been a sub ject of sta tis ti cal stud ies to dif fer en ti ate be tween good and poor res er voir rocks and to show gas-sat u rated lay ers in com par i son to wa ter-sat u rated strata. Sta tis ti cal stud ies in clud ing fractal anal y sis were per formed on well log ging data from the Sêdziszów 34 bore hole drilled in a belt of hy dro car bon de pos its that con tinue be low the north ern edge of the Carpathian-Stebnik overthrust. Lithological vari abil ity and po ros ity dif fer en ti a tion and changes in wa ter satu ra tion were traced on the ba sis of the re sults of well log ging in ter pre ta tion. Ba sic sta tis tics and his to grams of petrophysical pa ram e ters have been ana lysed. A gen er al ized sec ond or der fractal cor re la tion di men sion was cal cu lated for all pa ram e ters and ana lysed as for a time se ries. Fractal di men sions did not cor re lated with the pa ram e ters, but good pos i tive cor re la tions be tween them and the pa ram e ters were ob served and showed that the curves ana lysed had the same type of com plex ity. High cor re la tion co ef fi cients showed pairs of fractal di men sions for those pa ram e ters which had sim i lar vari abil ity and the same curve rough ness. The fractal cor re la tion di men sion de scribed the type of complex ity of the pa ram e ter (curve rough ness) and in di cated, for ex am ple, how shaliness in flu enced the res er voir prop er ties of the lo cal Mid dle Mio cene. There fore, the re sults were also use ful in prac tice, which gave ex tra in for ma tion on thin-bed ded res er voir rocks.

Reservoir properties and facies characterization from core data and well logging: autochthonous Miocene sediments in the Carpathian Foredeep case study

“…FZI was determined according to equation (1) following the Amaefule et al (1993) and Ha Quang & Jarzyna (2013) considerations and on the basis of the theoretical Kozeny-Carman formula (Kozeny 1927, Carman 1937. Bała et al 2012) ExplanationsF tot -total porosity, F ef -effective porosity, K -absolute permeability, Kp nmr tot -NMR total porosity, Kp nmr ef -NMR effective f porosity, d b -bulk density, GR -gamma ray log, GRC -borehole corrected gamma ray log, PHI -total porosity from the comprehensive interpretation, RHOB -bulk density from gamma-gamma log.…”