A carbonate formation in northwestern Kazakhstan is a challenging environment for acid stimulation because of its thick intervals, heterogeneity, and natural fractures. From production log interpretation, it was observed that the layers were not being depleted uniformly because of the difference in flow properties, resulting in an uneven distribution of flow from perforations. The challenge was to achieve a more uniform flow profile.

The paper will show the effect a self-diverting acidizing system has brought to field productivity when benchmarked to historical treatment methodologies. A net gain of 1900 cubic meters per day (m[3]/d) was realized as a result of the treatment campaign on 17 wells. The benefits to reservoir management from treating the heterogeneous long intervals and achieving uniform flow profiles will be discussed in detail through a comprehensive review of pre- and post-treatment production profile logs.

The new treatment methodology employed has been used in freshly drilled wells. The paper will discuss the effect on productivity as well as how the methodology has been incorporated into subsequent field development planning.

Keywords:
matrix, reservoir pressure, nadezhdin spe 92831, drillstem/well testing, fluid dynamics, well logging, evaluation, drillstem testing, kozhasai field, productivity impact
Subjects:
Well & Reservoir Surveillance and Monitoring, Reservoir Fluid Dynamics, Formation Evaluation & Management, Perforating, Acidizing, Production logging, Flow in porous media, Open hole/cased hole log analysis, Drillstem/well testing, Completion Installation and Operations
Copyright 2005, Society of Petroleum Engineers
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