Most multilayer sandstone reservoirs in the Bohai Sea have already entered the middle or high water cut production stage with large amounts of remaining oil being scattered distributed. Therefore, there is an urgent need to find a suitable countermeasure to reduce water cut and increase oil recovery. In this study, taking the narrow-channel reservoirs in the M oilfield as an example, we qualitatively described the sand body scale and the contact relationships between different sand bodies, in addition to carefully analyzing the material base and remaining oil distribution characteristics. Accordingly, we proposed a countermeasure based on the injection-production structural adjustment to reduce water cut and increase oil recovery from high water cut, narrow-channel reservoirs. Herein, three optimization strategies were developed based on the proposed development mode: a seepage field optimization strategy was developed based on the quantified injection-production index; a well pattern optimization strategy for narrow-channel reservoirs was developed to overcome the production energy refueling problem; an injection-production measure optimization strategy was developed to tap the different types of remaining oil. Additionally, the well pattern optimization and injection-production optimization strategies were integrated to optimize and adjust the seepage field system. The findings reported herein this paper help understand the development of similar offshore oilfields with a high water cut.

Due to the large amount of complex organics and its low biodegradability, the degradation of printing and dyeing wastewater attracts lots of attention. In this paper, the actual printing and dyeing wastewater was treated by electrochemical method, and the effects of pH, electrolyte concentration, anode electrode, two-dimensional electrolysis, three-dimensional electrolysis, combined processes were discussed. In the combined process case, the electrochemical process as a pretreatment or advanced treatment was explored.. The research showed that the optimal pH value was 3 by two-dimensional electrolysis, while the value was 9by three-dimensional electrolysis. The COD removal rate is 85.4% (three-dimensional) and46.6% (twodimensional). The order of treatment effects of different electrode is as following: SS/PbO 2 >Ti/PbO 2 >Ti/RuO 2 -La 2 O 3 > without electrode plates. The degradation effects of electrolysis, iron-carbon, and Fenton individually are not as good as the combination process, and the electrochemical process is more suitable on the front of iron-carbon process or Fenton process. 1

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The nonuniform distribution of proppant in hydraulic fractures is an essential factor determining the accuracy of well performance evaluation in shale gas reservoirs. In particular, unpropped and propped parts hold distinct closure behavior. To study the impacts of distinct closure behavior between unpropped and propped parts in fracture on gas production, we combine the proppant transport simulation and the 3D hydromechanical coupling simulation. This study quantitatively indicates the significant effects of nonuniform proppant distribution and fracture closure on well performance in shale gas reservoirs. By comparing the well performances with three kinds of typical proppant distribution at the same injection volume, the distribution accumulating near the wellbore is recommended as it can reduce the impact of unpropped fracture and exploit more gas. In addition, the cases with higher natural fracture permeability are found to have less difference in the well performance with different proppant coverages. Therefore, the impacts of nonuniform proppant distribution and fracture closure on well performance in shale gas reservoirs should be investigated comprehensively.