Handling excessive water production is one of the most common challenges in mature oil fields. The world produces almost five barrels of water with each barrel of oil. Cyclic Production Scheme (CPS) was applied as a first field trial in the world in one of mature oil fields in Saudi Aramco to maximize ultimate oil recovery, reduce water production and enhance reservoir pressure.
The results of a conceptual simulation model that was built to assess reservoir performance under the CPS are discussed. Sensitivity cases were carried out to identify the most influential reservoir parameters on CPS. This assessment is to support the understanding and engineering interpretation behind the performance of the CPS.
The CPS is an innovative concept to produce oil from mature fields. The scheme requires alternating shutting and flowing wells with high water cut over a predetermined period of time. CPS is not known globally in the oil industry yet.
Over the last decade, cyclic water injection has received great attention since many laboratory works, simulation studies and field tests have shown that it may lead to additional oil recovery, especially in mature oil fields. Excessive water production is one of the most common problems to be dealt with in mature fields1. The world produces 300-400 million barrels water per day (BWPD) for 75 million barrel of oil2. The world average oil recovery factor is estimated to be 35%. Additional recovery over this average dictates the application of novel technologies, economic viability, and in conjunction with effective reservoir management strategies. An estimated 30 giant fields, mostly categorized as mature fields, constitute half of the world oil reserves.
In this study, a conceptual simulation model is built to better evaluate the effects of the CPS on reservoir performance.
Although the CPS is a new concept as mentioned earlier, the cyclic term appeared in the literature since the late 1960s. All previous cyclic works were devoted mainly for water injection to improve oil recovery and optimize water injection as documented extensively in the literature over the past 40 years.