Inspired by the success of North American unconventional resources, many shale oil operators in China adopted the intensive completion and fracturing practice for field development. The intention of the aggressive scheme was to improve individual well productivity as well as the ultimate recovery. Similar to the shale oil counterpart in North America, however, frequent frac hits have been reported in the recent years, and the increase of the engineering parameters has not always increased field productivity. Based on geo-engineering work in Ordos basin, we developed and tested an innovative strategy, pattern fracturing, to solve this issue, and it proved to be an effective and low-cost completion and fracturing optimization method for reservoir management.

Pattern fracturing differs from the previous field practice by dividing pad wells into two groups, each with a distinctive strategy for the job design and execution sequence. One group is defined as energy charger (EC) and the other as reinforced producer (RP). EC wells adapt to the large-volume high-rate fracturing practice to maintain the long-term reservoir pressure. The RP wells adapted to an intensive staging with low-volume low-rate fracturing practice, which aims to create a better near-wellbore flowing environment. EC wells are to be completed earlier than the RP wells, so that the RP well engineering parameters can use the previous monitoring and observation as a reference. Essentially, pattern fracturing is a platform-based reservoir management approach.

Pattern fracturing was evaluated with reservoir simulation for validity and then put into practice in a five-well testing site on platform-A in Ordos basin. The result from the pattern fracturing trial was encouraging. In addition to the lower horsepower consumption, the higher efficiency of job execution, and fewer perceived frac hits from offset wells, the production performance from platform-A showed positive results in both EC and RP wells. This indicates that by assigning the wells into different groups and refining the strategy and design for each of group, there is a good chance of improving the productivity with less cost.

Pattern fracturing is an innovative completion and fracturing optimization approach with reservoir management purposes used in horizontal well groups, particularly fit for the scenario of unconventional resources.

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