As nouns the difference between study and investigation is that study is (label) a state of mental perplexity or worried thought while investigation is the act of investigating; the process of inquiring into or following up; research; study; inquiry, especially patient or thorough inquiry or examination; as, the investigations of the philosopher and the mathematician; the investigations of the judge, the moralist.
As a verb study is (usually|academic) to revise materials already learned in order to make sure one does not forget them, usually in preparation for an examination.
First thank you for this question, and also, may thanks for all authors for their explanations;
From point view of science and engineering the word "Investigation" it is used when the research included or specified in "Experimental Work" and not a theoretical work. Ont he other hand, the word "Study" it is global word and used to express all types of research work.