Experimental Evaluation of Locally Synthesized Biodiesel Drilling Fluid

Abstract

Diesel oil has been the preferred base fluid for the formulation of oil-based drilling mud. Diesel oil has negative effects on the environment and there is a growing need for more environmentally sustainable alternatives that can be technically compared to diesel base oil. In recent times, the use of vegetable oils as drilling fluid base oil has been of interest. In this study, 1378 kg/m3 of palm kernel oil-based mud (PKOBM) and palm kernel oil biodiesel based mud (BDBM) were experimentally formulated. BDBM was synthesized by the transesterification of vegetable (palm kernel) oil. The performance of PKOBM and BDBM was then evaluated against conventional diesel oil-based mud (DOBM). The evaluation performed was based on the rheological, filtration and wall building properties, emulsion and thermal stabilities, and acute toxicity of the formulated drilling fluid systems. The results obtained from the study reveal that the mud systems (PKOBM and BDBM) show a typical Herschel-Bulkley (modified power-law) drilling mud rheological pattern at temperatures of 49°C, 66°C and 80°C. BDBM showed comparable rheological properties with better hole cleaning capacity as indicated by a lower flow index. For the filtrate loss test, BDBM exhibited a slightly lower filtrate loss compared to DOBM, whereas PKOBM had a higher fluid loss of 4.4 ml. For the filter cake and thermal stability test, there were no significant changes between DOBM and BDBM, whereas PKOBM had the least desirable performance. BDBM exhibited the most stable emulsion of 1274 volts breaking voltage and PKOBM, the least with 739 volts compared to 1169 volts breaking voltage of DOBM. This study concludes that BDBM could be used as an environmentally sustainable substitute for diesel oil-based mud (DOBM).

Sažetak: Kao bazni fluid za pripremu isplake na bazi ulja najčešće se upotrebljava dizelsko ulje. Dizelsko ulje ima negativan utjecaj na okoliš i sve je veća potreba za ekološki održivijim alternativama koje se s tehničkoga aspekta mogu usporediti s dizelskim baznim uljem. U novije se vrijeme istražuje mogućnost upotrebe biljnih ulja kao baznoga ulja u isplakama. U ovome istraživanju eksperimentalno su pripremljene isplaka (gustoće 1378 kg/m3) na bazi palmina ulja (ulje iz palminih koštica) (PKOBM) i isplaka na bazi biodizela dobivenoga iz palmina ulja (BDBM). BDBM je dobiven transesterifikacijom biljnoga (palmina) ulja. Zatim je napravljena usporedba karakteristika PKOBM-a i BDBM-a i konvencionalne isplake na bazi dizelskoga ulja (DOBM). Isplake su uspoređene na temelju reoloških i filtracijskih svojstava, sposobnosti stvaranja isplačnoga obloga, stabilnosti emulzije, toplinske stabilnosti te akutne toksičnosti. Rezultati dobiveni istraživanjem upućuju na to da isplake PKOBM i BDBM pokazuju tipično Herschel-Bulkley (modificirani eksponencijalni (power-law) model) reološko ponašanje pri temperaturama od 49 °C, 66 °C i 80 °C. BDBM je pokazao usporediva reološka svojstva uz bolji kapacitet iznošenja krhotina nego što bi na to upućivao niži indeks protoka. U testu gubitka filtrata isplake BDBM je pokazao nešto manji gubitak filtrata u odnosu na DOBM, dok je PKOBM imao veći gubitak filtrata, koji je iznosio 4,4 ml. Ispitivanja isplačne obloge (filter cake) i termičke stabilnosti nisu pokazala znatnije razlike između DOBM-a i BDBMa, dok je PKOBM imao najmanje poželjne performanse. U usporedbi stabilnosti emulzija BDBM je pokazao najstabilniju emulziju (destabilizacija emulzije pri naponu od 1274 V), a PKOBM najmanje stabilnu emulziju (destabilizacija pri 739 V), dok u slučaju DOBM-a do destabilizacije emulzije dolazi pri naponu od 1169 V. Temeljem provedenih istraživanja zaključeno je da bi se BDBM mogao koristiti kao ekološki održiva zamjena za isplaku na bazi dizelskoga ulja (DOBM).