Improving Cement Sheet Contraction and Strength Retrogression of Oil Well Using Local Materials (Silica Flour, Egg Shell, Periwinkel Shell, Palm Kernel Fibre Aggregate and Saw Dust). BJMAS [Internet]. 2025 Nov. 11 [cited 2025 Nov. 11];6(6):1-17. Available from: https://bjmas.org/index.php/bjmas/article/view/1414