This paper describes successful experiences employed during polymer flooding at Daqing that will be of considerable value to future chemical floods, both in China and elsewhere. Based on laboratory findings, new thoughts have been developed that expand conventional ideas concerning favorable conditions for mobility improvement by polymer flooding. Particular advances integrate reservoir engineering approaches and technology which is elementary for successful application of polymer flooding. These include: (1) Considering permeability differential among the oil zones and interwell continuity, optimizing the oil strata combination and well pattern design. (2) The injection procedures and injection formula are the key points when designing a polymer flood project. These points include: profile modification is needed before polymer injection and zone isolation is of value during polymer injection, higher molecular weight of the polymer used in the injected slugs, large polymer bank size, higher polymer concentrations and injection rate based on the well spacing and injection pressure.(3) Characterizing the entire polymer flooding process in five stages, with its dynamic behavior distinguished by the water cut changes. Additional techniques involved with reservoir engineering should also be considered, such as dynamic monitoring using well logging, well testing, and tracers. Effective techniques are also needed for surface mixing, injection facilities, oil production, and produced water treatment.Continuous innovation and effective response to new challenges must be a priority during polymer flooding. New directions and opportunities at Daqing will (1) explore the feasibility of polymer flood application in poorer ("third-class") strata, (2) to identify new polymers to suit portions of the reservoir with higher temperatures and higher water salinities, and (3) continually see improvements in our approach to polymer flooding.

No abstract

No abstract

We examined how various soil characteristics are associated with Scirpus mariqueter growth and spatial heterogeneity in Shanghai Nanhui Dongtan wetlands and addressed a major knowledge gap regarding the effects of reclamation on microbial communities in the soil. Biolog was used to examine soil carbon resources, diversity, abundance, and community structure of S. mariqueter soil microbes after a 72-h culture. Tidal elevation influenced soil microbes, which used carbon resources at higher rates, exhibited more community diversity and had greater species richness in areas with dense S. mariqueter cover than in bare tidal flats (P < 0.05). Microbial functional diversity also differed significantly across the study region in a manner that reflected S. mariqueter spatial heterogeneity (P < 0.05). In terms of soil characteristics, microbial community diversity was positively correlated with soil salinity, organic carbon, and total phosphorus (P < 0.05), whereas negatively correlated with soil particle size (P < 0.05). The results of this study provide insight into plant-soil interactions of disturbed S. mariqueter wetland ecosystems through clarifying factors that influence soil microbes.

No abstract