Waterflooding: Chemistry

It is becoming increasingly recognized that chemistry issues can and have a significant impact on the way a waterflood project progresses. This topic is therefore the first to be covered in a series of books addressing various factors associated with waterflood. These issues might primarily affect the operating costs associated with a project, but they can also impact recovery. For example, in fields where reservoir souring has occurred, there can be constraints related to the hydrogen sulfide content of gas export volumes. In extreme cases, these constraints could require wells producing high volumes to be shut in, and production will, at the best, be deferred but there might also be a negative impact on ultimate recovery. Similar, high hydrogen sulfide producing wells might need to be shut in because of well-integrity concerns associated with the corrosion impacts on well materials. In such cases it is highly likely that stranded oil volumes cannot then be produced because the remaining volumes do not facilitate economic repairs, so this factor suggests a very high likelihood of an overall recovery impact. This is just one possible impact that chemistry can have on waterflood performances for injectivity but also might affect recovery through changes to rock wettability (low-salinity flooding), scaling problems, wax and asphaltene problems, and hydrating formation. Consequently, a range of chemistry-related issues can materially influence waterfloods. These issues will be explored in more detail in this book.