Analyses of Formation Damage Caused by Drilling Fluid in Bamboo field (Sudan)

Abstract

Formation Damage is any reduction in near well bore permeability which in this study is a result of any material from drilling and completion operations. In spite of many studies, there have been only a few reported attempts to mathematically model the pertinent processes. This research applying the wojtanowicz et. al. model in Bamboo-Sudan oilfield to study the drilling fluid effects in the Bentiu reservoir formation (Units 1, 2, and 3) and the amount of formation damage for well (X West-4). Laboratory experiments were done to evaluate the mud cake thickness and the filtration. The correlation of experimental work and mathematical model was in great benefit by reducing the percentage of solids. Formation damage mechanisms vary depending on the well operation types, reservoir and fluid conditions. The rock properties were the base for all calculations and assumptions done throughout the data evaluation and the constants determination. The wojtanowicz et al model and drilling fluid new design proposed considered as the optimum to use in bamboo field. Foreign particles invasion damage to formation could be controlled by reducing of Barite solids from (4.76%) to (2.2%). The Pore Blockage by External Particles Diagnostic Chart for Unit-1, 2 and 3 were obtained assuring that the damage could be control and reduced by using the optimum concentration of barite (2.2%). Finally, it is high recommended to continue searching on (apply CaCO3 in this work and study the effects of it, using local products (Arabic Gum, الزيوت النباتية, …, etc.) which have the same specifications with the imported additives).for the benefits of economical hazard reduction. Specially, in this study the reduction was 9.6% barite quantity in cubic meter (overall operation cost).