Water dump flood is a non-conventional and cheaper alternative as compared to surface water injection commonly used to support reservoir pressure. The major costs associated with surface injection includes water treatment as well as sourcing of the water. The dump flood technique helps eliminate these costs thereby improving project and field economics. A dump flood technique eliminates the requirement of drilling an additional water producer well. In order for the dump flood technique to be successful, adequate production from the source and good injection rates into the target interval are key requirements. If either one of them are not met there is likely to be detrimental effects on the objective of the dumpflood. This paper details the risks and challenges identified for the subject well and the methods & technologies implemented to ensure the success of the project.
As part of the water injection strategy in the subject field, water dump flood was deployed. These wells source water from a prolific aquifer and with the aid of artificial lift, and the water was then injected into the upper reservoir to improve sweep efficiency and pressure maintenance. Dump flood technology uses two perforation intervals : one source interval and another as an injection interval. For the subject well, water productivity was established from the source formation. Upon initial tests, the target injection zone showed poor injectivity both pre- and post- matrix stimulation. Hence a new strategy of implementing hydraulic fracturing to improve the injectivity in conjunction with the dump flooding technique in the subject well was attempted for the first time in Kuwait. Special consideration had to be taken while optimizing hydraulic fracturing design taking into account pump discharge pressure and formation closure pressure. This paper also covers the special design considerations taken into account when selecting and designing the artificial lift equipment for a fractured and dump flooded well.
Successful execution of hydraulic fracturing was critical in order to achieve the required injectivity in the target formation. During the execution of hydraulic fracturing, it was observed that once the near well bore damage was by-passed, the fluid leak-off increased significantly due to high formation permeability. This paper will detail the various decisions taken during operational execution to ensure success of the treatment. Post fracturing results that contributed to the success of the first hydraulically fractured dump flood well in the country will be discussed. This success ensured that the well could be completed with the designed completion and artificial lift strategy resulting in minimal workover requirement.
The lessons learnt from this first hydraulic fractured dump flood well will be applied across the field. The technique will help to optimize recovery and project economics through efficient injection. This technique unlocks a new method which will play a significant role in maximizing oil recovery in Kuwait.