Easy to read and written straightforward for those who are out of drilling discipline. Liked the language used, even if in some cases it is difficult to understand the terminology or use your imagination. Disliked there is a lot of US oil wells history kind of information which makes u to read more extra stuff. I would recommend this book to those who have already done basic courses in reservoir, drilling and completion and willing to summarise or strengthen their week points.
P.S. I was looking for how to estimate drilling duration per type of rock which book has not answered.