STUDY OF THE EFFECT OF MINERALOGY AND TETURE ON WORMHOLE GEOMETRY ON ACIDIZING OF CARBONATE ROCK WITH DIGITAL VISUAL APPROACH

• Main Author: Sutresno, Wahyu
• Format: Dissertations
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/70029
• Institution: Institut Teknologi Bandung

Stimulation is carried out on oil/gas wells that hae decrease production due to formation damage around the wellbore by improving the permeability of the reservoir rock around the wellbore. One of the stimulation methods is acidizing, which is the process of dissolving rock materials around the hole where the reservoir fluid enters the well by injecting a certain amount of acid into the productive layer. This acidizing is use to eliminate the effect of formation damage around the wellbore, namely the skin by enlarging the rock pores and dissolving the particles that clog the rock pores. Mineralogy elements, mineralogy impurities and rock textures are very likely to affect the results of the acidizing carried out, therefore this study was carried out comprehensively as a proof of the influence of these factors. The method used is to perform petrophysical measurements of rock (permeability and porosity) before and after acid injection in the laboratory on carbonate rock samples from conventional cores where the rock size is + 1 inch x 1,5 inch. Measurements of rock characteristics include XRD (X-Ray Diffraction), SEM (Scanning Electron Microscope) and petrographic analysis of 7 samples. Prior to the injection of 15% acid HCl, the sample was scanned with a Micro CT-Scan to obtain a 3D CT-Scan model from the results, after which the sample was injected with 15% aci HCl. Then the next step is to do a 3D Micro CT-Scan after the acid injection. This research was conducted to determine the effect of mineral impurities (impurities such as quartz, clay minerals, etc) and rock texture on acidification results using high reactive acid. It is possible to affect the value of porosity and permeability after injection. Meanwhile, the results of the 3D CT-Scan produce a geometric wormhole shape after the acid injection and from the results of the acid injection and from the results of the acid injection, the effect of the productivity index (PI) produced on the differences in rock mineralogy. The results of this study indicate that the correlation between the K/K model and the K/K laboratory experiment on carbonate rocks is influenced by the mineralogy of calcite, dolomite, smectite, pyrite, gypsum, anhydrite an quartz. This correlation can be used to predict the K value that occurs if the minerals contained are the same in the carbonate acidification process. As well as the relationship between porosity and permeability functions on rock textures (grainsize, cementation, particles, replacement and rock matrix) which have mineral compositions of calcite, dolomite, smectite, pyrite, gypsum, anhydrite dan quartz in the acidification process of carbonate rocks.