Dalian July 1st (Wang Lifeng) On July 1st, it was learned from Daqing Oilfield that a new breakthrough has been made in the effective development of thin and uneven oil reservoirs in the Xingba District West Block of Xinnan Oilfield. With the combination of 'comprehensive utilization of well network + precise stratification + precise fracturing' efficiency model, so far, the exploitation degree of this block has increased by 3.3%, the oil production rate has increased from 0.44% to above 0.46%, and the recovery rate has increased by 0.61%.

Technicians at the Xinnan Oilfield of Daqing Oilfield are working on the fracturing site - Photo by Wang Lifeng

The initial layout of the Xingba District West Block was a 300-meter water injection well network. After a long period of development, the problems of low multi-directional connectivity ratio, large injection and production well spacing, poor water injection effect, and high proportion of inefficient wells have become increasingly prominent.

How to establish an effective displacement system? Technicians at Daqing Oilfield combine the comprehensive utilization of well network with the adjustment of injection and production systems, and have started to implement the comprehensive utilization of well network. By opening secondary dense wells in the non-main oil layer of the Puyi group, and forming a well network with the third wells, the original four sets of well networks in the whole area have been merged into three sets, achieving the reduction of injection and production well spacing. The water absorption thickness of the second and third wells before and after perforation has increased significantly, with the proportion of water displacement control increasing by 6.6%, and the development effect is good.

In order to continue maintaining a high oil production rate and ensuring the development level of the block, technicians proposed the precise stratification method in the Xingba District West Block to narrow the differences between layers and increase the exploitation thickness of the oil layer.

As of now, a total of 91 wells have been implemented in the Xingba District West Block for precise stratification and layer combination, increasing the ratio of exploited layers in single wells by 5.17%, the ratio of exploited sandstone by 6.36%, and the effective exploitation ratio by 5.99%.

In order to further explore effective ways to utilize thin and uneven oil layers, improve the degree of reservoir exploitation and single well production, technicians proposed to try using precise fracturing technology at the beginning of this year, to establish effective injection and production in thin and uneven oil layers, thus achieving effective displacement. Technicians implemented more than 20 precise fracturing in the Xingba District West Block, and after fracturing, the connection with adjacent wells was affected to varying degrees, with significant effects, increasing the exploitation thickness of sandstone by 7.47%, and the exploitation thickness of thin and uneven layers by 10.23%.

This combination of 'comprehensive exploitation of well network + precise stratification + precise fracturing' efficiency model will also provide a new approach for the efficient development of thin and uneven oil layers in other blocks of Daqing Oilfield.