Over the past year and a half, the price of oil has plummeted from over $100 US per bbl in early 2014 to less than $47 US per bbl in the mid of 2017. In an attempt to sustain production without incurring significant additional expenditures, some operators may choose to implement enhanced oil recovery projects (such as waterflooding) while also utilizing existing infrastructure in the field. This paper focuses on one method of doing this by converting watered out or poor-performing horizontal production wells into horizontal water injection wells. The goal of this study was to create a screening criteria list which will enable assessment of a field to see if it could benefit from horizontal injection by way of converted horizontal production wells.
The study began with a literature search to determine if a similar study had been conducted previously. When the study was found to be unique, the literature search then focused on understanding the background of horizontal water injection, along with case studies to see which conditions led to success or poor performance of horizontal water injection schemes. The applications, optimization techniques, evaluation methods and challenges involved in conversion of horizontal production wells to injectors and the horizontal injection process itself have been summarized and compiled into a screening criteria chart which can be broadly applied to any field to see if it is suitable for the proposed application. The screening process works by assigning zero, one, or two points to the response to a number of criteria regarding the reservoir, fluids, wells, and other information. A higher point value indicates a higher likelihood of a positive outcome if a horizontal production well is converted to a water injector.