Flow Rate And Permeability Determination In Rock Samples From Unconventional Reservoirs – To Support The Geophysical Inversion Model

The purpose of the article is to introduce a deeper insight and understanding of unconventional hydrocarbon reservoir flow mechanisms through tight gas samples originat-ing from a Hungarian formation. The paper describes problems that appear during the meas-urement protocol that was designed to provide strong support for the geophysical inversion model under development within the framework of the PULSE project and the possibilities for preserving the rock material while gaining as much information as possible

POBOLJŠANJE MEHANIČKIH SVOJSTAVA CEMENTNOGA KAMENA U NAFTNIM BUŠOTINAMA UPOTREBOM POLIPROPILENSKIH VLAKANA I ISPITIVANJE NOVE LABORATORIJSKE METODE ZA MJERENJE ČVRSTOĆE VEZANJA CEMENTNOGA KAMENA NA ZAŠTITNE CIJEVI

The main objective of this study is to enhance the poor performance of oil well cement in terms of mechanical properties by using pure polypropylene fibers. Polypropylene fibers were added in increasing concentrations from 0 to 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% by weight of cement (BWOC). Rheological parameters, density, fluid loss, permeability, porosity, compressive strength, tensile strength, and flexural strength were all tested. A new method for measuring the tensile strength of cement samples in the presence of a casing is also evaluated in this research. In addition, the interfacial bonding shear strength, which represents the strength of cement adhesion to the casing, was measured using a new laboratory procedure. The influence of adding polypropylene fibers on rheology, density, and fluid loss can be ignored, according to the results of the experiments. The permeability and porosity of cement samples increased as the proportion of polypropylene fibers increased, according to the findings. Further, an increase in polypropylene fibers concentration up to 0.3% BWOC led to improving the mechanical properties at different curing times. The bonding strength of the casing cement interface improved with increasing polypropylene fibers concentration up to 0.5% BWOC.Glavni je cilj ovoga istraživanja poboljšati učinkovitost cementnoga kamena u naftnim bušotinama u pogledu mehaničkih svojstava korištenjem čistih polipropilenskih vlakana. U istraživanju su polipropilenska vlakna dodavana u koncentracijama od 0 do 0,1 %, 0,3 %, 0,5 %, 0,7 % i 0,9 % masenoga udjela cementa (engl. by weight of cement, BWOC). Ispitana su reološka svojstva, gustoća, gubitak fluida, propusnost, poroznost, tlačna čvrstoća, vlačna čvrstoća i čvrstoća na savijanje. U ovome je istraživanju također ispitivana i nova metoda za mjerenje vlačne čvrstoće uzoraka cementnoga kamena u kombinaciji sa zaštitnim cijevima. Osim toga, novim laboratorijskim postupkom izmjerena je posmična čvrstoća međufaznoga vezanja, koja predstavlja snagu adhezije između cementnoga kamena i zaštitnih cijevi. Na temelju provedenoga istraživanja moguće je zaključiti da je utjecaj polipropilenskih vlakana na reološka svojstva, gustoću i svojstvo gubitak fluida zanemariv. Rezultati upućuju na to da se povećanjem udjela polipropilenskih vlakana povećava propusnost i poroznost uzoraka cementnoga kamena. Nadalje, povećanje koncentracije polipropilenskih vlakana do 0,3 % masenoga udjela cementa dovelo je do poboljšanja mehaničkih svojstava u različitim vremenima očvršćivanja. Čvrstoća vezivanja cementnoga kamena duž zaštitnih cijevi poboljšana je povećanjem koncentracije polipropilenskih vlakana do 0,5 % masenoga udjela cementa