ABSTRACT

In economic downturns, rigless operations for production optimization, well integrity and reservoir management is the one of the viable solutions when Companies are looking for cost reduction without hampering operations. Zonal Isolation is the solution for reducing unwanted Water & Gas production, as well as for eliminating problems of cross flow. One of the effective technologies for zonal isolation is the organic cross-linked polymer gels.

The reliability, wider temperature range of application, long-term stability and relatively low cost are some of the factors that helped in the spread of the technology in the last two decades. Polymer gels gave solutions to many reservoir, completion & wellbore problems.

Cross flow is a common problem that occurs in multilayer producing wells that takes place in highly depleted mature fields. In one of the cases discussed in this paper, this problem led to the inability to recover the hydrocarbon reserves in one of the layers and hence results in a reduction in hydrocarbon recovery. Long-term selective zonal isolation in a multilayer well is a challenge due to the need of proper placement in the targeted zone. Selective, high strength and permanent zonal isolation using organic cross-linked polymer was the optimum solution to isolate the depleted zone.

In this case, application and techniques of placing a non-damaging temporary gel system to isolate the deeper oil-producing zone and the use of Organically Cross-Linked Polymer (OCP) system to seal permanently the thief zone, was necessary & proved successful. The sealant used employs a porosity filling strategy that seals the permeability by forming a hydrogel.

The key to success with this zonal isolation technology was the clear understanding of the problem, the objectives, and the placement technique in each case. Multi-disciplinary team of various departments and service company professionals was involved to thoroughly study the case, review the design of each proposal and decide on the optimal execution during field operations.

The paper considers treatment techniques, operations and the results obtained from different zonal isolation cases and the approach to solve several well problems using organic cross-linked polymer systems.

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