Successful Leak Repair and Restoration of Oil Production a West Kuwait Case Study

Abstract

Two West Kuwait oil wells were completed with initial flowrates of 3,000 and 5,000 stb/d with zero and 25% water cut, respectively. However, water cut increased quickly to 100% for both wells. Therefore, a production logging program was developed to find the source of water flow. Once the source was found a well workover plan was developed. Well intervention was done along with Production Logging to detect the water source and to verify well integrity. Due to the change in well production from oil to water, the operator requested aid in identifying the cause of the production change. The first step in the process was a production logging run, both flowing and shut-in to prove well flow parameters and to identify the source of the water. This involved logging both the completion of interest, with the ability to log other sections of the upper completion if the water source was not initially found. Once the water sources were located a well remediation plan was developed to re-establish both wells production baseline. This paper presents the results from two wells, which initially had the same issue: water production from the upper completion. However, the actual results highlight the capability of production logging to identify the root causes of production drop-off. In the first well, the PLT run discovered no water production from the lower zone, but dump flooding from an upper zone that shut off oil production. The upper zone water production was from a corroded completion, repaired with a perf and squeeze shutting off the water flow. The second well could only be logged during shut-in, where the sensor responses were consistent with water ingress, however, the flowing pass had no sensor responses. This was caused by the jetting of the water inflow from casing damage in the formation above the production zone, making sensors' responses invalid. The shut-in pass clearly showed the location of water ingress, from a casing failure in the completion above the production zone resulting in dump flooding and shutting off oil production. The remediation in this instance was a mechanical repair followed by a cement squeeze to isolate the water zone. Production testing and follow-up PLT runs confirmed the elimination of water production and 100% oil production. This case study shows the power of PLT programs to find water ingress points, even when the inflow is not in the completion zone of interest. This allows the operator to plan remediation programs that results in a return to normal or near normal production levels.