Muhammad Hasbul Irfaan Bin Hasbullah creator author. text my 2025 2025 monographic eng xi, 31 pages : illustrations ; This study explains how to create a phosphorus-modified lignosulfonate from sawdust and use it to water-based drilling fluid to enhance performance and thermal stability. To enhance its useful qualities, lignin was chemically altered by sulfonation and phosphorus inclusion after being extracted using the more environmentally friendly organosolv technique. Under HPHT conditions, the produced modified lignosulfonate was assessed for mud cake features, fluid loss, and rheological parameters. Better thermal stability, fluid loss management, and mud cake integrity were demonstrated by the results, which also highlighted the potential of phosphorus-modified lignosulfonate as an effective, practical, and sustainable addition for use in HPHT drilling operations. specialized Muhammad Hasbul Irfaan Bin Hasbullah Faculty of Chemical and Process Engineering Technology Final Year Report (Bachelor of Technology Mechanical Engineering (Petroleum) with Hons ) -- Universiti Malaysia Pahang Al-Sultan Abdullah - 2025 Include bibliographical reference Faculty of Chemical and Process Engineering Technology Dissertations Universities and colleges Dissertations Theses Dissertations THE0010920 (Local) https://umpir.ump.edu.my/id/eprint/48082 https://umpir.ump.edu.my/id/eprint/48082 UMPSA 260806 20260806180144.0 eng