Abstract. Downhole monitoring using streaming potential measurement has been developing in order to respond to actual reservoir condition. Most studies have emphasized on monitoring water flooding at various reservoir condition and improving the approaches of measurement. Enhanced Oil Recovery (EOR) could significantly improve oil recovery and the efficiency of the process should be well-monitored. Alkaline-surfactant-polymer (ASP) flooding is the most promising chemical EOR method due to its synergy of alkaline, surfactant and polymer, which could enhance the extraction of residual oil. However, limited studies have been focused on the application of streaming potential in EOR processes, particularly ASP. Thus, this paper aims to review the streaming potential measurement in downhole monitoring with an insight for EOR application and propose the potential measurement in monitoring ASP flooding. It is important for a preliminary study to investigate the synergy in ASP and the effects on oil recovery. The behaviour of streaming potential should be investigated when the environment of porous media changes with respect to ASP flooding. Numerical model can be generated from the experimental data to forecast the measured streaming potential signal during production associated with ASP flooding. Based on the streaming potential behaviour on foam assisted water alternate gas (FAWAG) and water alternate gas (WAG) processes, it is expected that the streaming potential could change significantly when ASP flooding alters the environment and surface properties of porous media. The findings could provide new prospect and knowledge in the relationship between streaming potential and ASP mechanisms, which could be a potential approach in monitoring the efficiency of the process.

TThe filter cake removal is of primary concern in a horizontal oil producer. It has been highlighted in many publications that the cleanup process in long horizontal and multilateral wells is a challenging task. Many chemical solutions have been used to remove the polymeric and bridging agents in oil producers. Due to their nonspecific characteristics, the chemical solutions have their limitations and in some cases have affected the well productivity. Thus an enzyme treatment using Pullulanase had been applied to degrade the mud filter cake of drill-in fluids, which comprised starch and xanthan gum. In this research work, static fluid loss and soaking tests were performed at temperatures ranging from 75°F to 250°F. The experimental results revealed that the efficiency of the cleaning solution comprising Pullulanase in degrading starch and xanthan gum was influenced by solution temperature and its concentration. For 6% concentration of Pullulanase, the highest degrading efficiencies experienced were 63%, 74%, 87%, 66% and 59% at temperatures of 75°F, 100°F, 150°F, 200°F, and 250°F respectively. In terms of concentration, it was found that 6% of Pullulanase gave the optimum efficiency as compared to 7% and 8% concentrations at temperature of 150°F. The experimental results also proved that enzyme stabilizer and viscoelastic surfactant could prevent the deactivation of enzyme activity at temperatures above 150 °F. Penyingkiran kek turas menjadi perhatian utama dalam pengeluar mendatar minyak. Permasalahan ini telah diketengahkan dalam banyak penerbitan yang menyatakan bahawa proses pembersihan telaga mendatar yang panjang dan telaga berbilang sisi ialah suatu tugas yang mencabar. Pelbagai larutan kimia telah digunakan untuk menyingkir agen polimer dan agen penitian dalam pengeluar minyak. Berikutan ciri-cirinya yang tak khusus, larutan kimia mempunyai penggunaan yang terbatas dan dalam kes tertentu telah menjejaskan kebolehpengeluaran telaga. Sehubungan itu, rawatan enzim yang menggunakan Pullulanase telah diaplikasi untuk menurunkan kek turas bendalir gerudi yang mengandungi kanji dan gam xantan. Dalam penyelidikan ini, ujian kehilangan bendalir statik dan ujian rendaman telah dilaksanakan pada suhu yang berjulat dari 75°F hingga ke 250°F. Hasil kajian membuktikan bahawa kecekapan larutan pembersih yang mengandungi Pullulanase dalam menurunkan kanji dan gam xantan adalah dipengaruhi oleh suhu larutan dan kepekatannya. Untuk kepekatan 6% Pullulanase, kecekapan penurunan tertinggi yang dialami ialah 63%, 74%, 87%, 66%, dan 59% masing-masing pada suhu 75°F, 100°F, 150°F, 200°F, dan 250°F. Dari segi kepekatan, Pullulanase dengan kepekatan 6% telah memberikan kecekapan optimum yang lebih baik berbanding kepekatan 7% and 8% pada suhu 150 °F. Hasil kajian turut membuktikan bahawa penstabil enzim dan surfaktan likat-anjal berupaya mencegah daripada berlakunya penyahaktifan aktiviti enzim pada suhu yang melebihi 150°F.