Search

The steam assisted gravity drainage (SAGD) process requires high energy input to maintain the continuous expansion of the steam chamber for achieving high oil recovery. In the late stage of SAGD operation where the oil rate is low and the heat loss is high from a mature steam chamber, maintaining steam chamber pressure with a lower steam injection is the key to maintaining the economic oil-to-steam ratio (OSR). Both laboratory studies and field tests have demonstrated the effectiveness of adding a non-condensable gas (NCG) to the SAGD steam chamber for improving the overall thermal efficiency. In this study, a multi-well reservoir model was built based on the detailed geological description from an operating SAGD project area, which contains thick pay and top water. Grounded with the history matching of more than 20 years of production using CSS (cyclic steam stimulation) and SAGD as follow-up process, the model was applied to optimize the operating strategies for the late stage of SAGD production. The results from this study demonstrated that the co-injection of steam with CO2 or the injection of CO2 only has potential to improve the OSR and reduce emissions by more than 50% through the improvement in steam-saving and the storage of CO2. The results from reservoir modeling indicate that, with the current volume of a steam chamber and an operating pressure of 4.0 MPa, about 55 sm3 of CO2 could be sequestrated and utilized for producing 1.0 m3 of oil from this reservoir through the replacement of a steam injection with CO2 in the late stage of SAGD operation. [ABSTRACT FROM AUTHOR]

The molecular mechanisms underlying photoperiod or temperature control of flowering time have been recently elucidated, but how plants regulate flowering time in response to other external factors, such as water availability, remains poorly understood. Using a large-scale Hybrid Transcription Factor approach, we identified a bZIP transcriptional factor, O. sativa ABA responsive element binding factor 1 (OsABF1), which acts as a suppressor of floral transition in a photoperiod-independent manner. Simultaneous knockdown of both OsABF1 and its closest homologous gene, OsbZIP40, in rice (Oryza sativa) by RNA interference results in a significantly earlier flowering phenotype. Molecular and genetic analyses demonstrate that a drought regime enhances expression of the OsABF1 gene, which indirectly suppresses expression of the Early heading date 1 (Ehd1) gene that encodes a key activator of rice flowering. Furthermore, we identified a drought-inducible gene named OsWRKY104 that is under the direct regulation of OsABF1 Overexpression of OsWRKY104 can suppress Ehd1 expression and confers a later flowering phenotype in rice. Together, these findings reveal a novel pathway by which rice modulates heading date in response to the change of ambient water availability.

Taking 1604 working face of Guhanshan Mine as the research background, by means of a high-precision micro-seismic monitoring system and numerical simulation, the dynamic failure characteristics of the surrounding rock and the danger of water inrush from the floor during the mining of the working face are studied. The results show that the asymmetrical energy release phenomenon occurs along the empty side and along the solid coal side of the bottom floor rock mass along the two sides of the working face. Among them, the bottom floor rock mass along the solid coal side has the largest damage scale with a depth of about 30 m. At a position of 12 m under the floor and 8 m in the inner staggered transportation lane, the energy density value of the surrounding rock is between 5-50 J/m2. Combined with the monitoring results of the surrounding rock deformation of the roadway, it is considered that the bottom pumping lane is located at this position and the mining disturbance is lower; the pumping roadway is located directly below the transport roadway or outside the transport roadway. The energy density of the surrounding rock release is greater than 100 J/m2, and the degree of disturbance is high. The numerical simulation results show that the bottom slot is located in the pressure relief area of the floor when the staggered groove is 8 m, which is located directly below the groove and is in the stress concentration area when the staggered groove is outside.

With the notable achievements attained through the implementation of steam-assisted gravity drainage (SAGD), the vertical–horizontal steam drive (VHSD) emerges as a pivotal technological advancement aimed at significantly enhancing the efficiency of thin reservoir heavy oil recovery subsequent to steam cyclic stimulation. The inclusion of nitrogen assistance has proven effective in enhancing the efficacy of gravity drainage techniques in reservoir development. However, it is noteworthy that this method has only led to improvements in approximately 50% of the well groups within the observed field. The comprehensive evaluation index of VHSD was proposed, and as the objective function, it was determined that the greatest contribution to the VHSD technique lies in oil saturation, accounting for 40% of the overall evaluations. This differs from conventional SAGD operations, where reservoir thickness serves as the primary determinant. Building upon an enhanced physical simulation similarity criterion, two comparative injection scheme experiments were conducted to explore the impact of nitrogen injection on the performance of VHSD and the characteristics of the steam chamber. Nitrogen is distributed in the vicinity of the steam chamber, leading to the formation of a dual mechanism characterized by 'top heat insulation and lateral traction' on the steam chamber. The lateral traction accounts for approximately 25% of the team chamber volume. Additionally, the inducement of nitrogen causes a downward displacement of crude oil, resulting in its accumulation within the high-temperature region of the steam chamber. This, in turn, enhances the contact area between the high-temperature steam and the crude oil, ultimately leading to improvement in production efficiency. Further validation of the impact of nitrogen on steam lateral traction and interlayer steam drainage within the reservoir was confirmed using Xinjiang oilfield testing. The well temperature increased from 75 °C to 130 °C. [ABSTRACT FROM AUTHOR]

Taking No.12051 fully-mechanized coal face of Zhaogu No.1 Coal Mine as research object, thin bedrock deformation and strata behavior in coal seam mining under ultra-thick unconsolidated strata were studied by use of UDEC numerical simulation software. The results show that the first weighting interval and periodical weighting interval of the coal face is 55 m and 15 m respectively. Caving zone and fractured zone appear in overlying strata after mining. The height of caving zone and fractured zone is 12.4 m and 36.7 m respectively. Ratio of caving zone height to mining height is 3.54 and ratio of fractured zone height to mining height is 10.48. Affected zone range of front abutment pressure, peak of front abutment pressure and plastic zone range increase with increase of coal face advancing distance. The front abutment pressure is stable after the first weighting at basic roof, which manifests in the maximum stress concentration factor and plastic zone range basically remain unchanged. The research results can provide basis for surrounding rock stability control of fully-mechanized coal face under the similar geological condition.

The CO2 miscible flooding in Baikouquan tight formation was thoroughly investigated under reservoir condition of 37 MPa and 89 °C. The low-field nuclear magnetic resonance (NMR) system was used to measure the real time oil saturation under high-temperature and high-pressure environment. The results show that the recovery factors of large, medium and small pores are 66.18%, 45.71%, and 12.71%, respectively. A complementary investigation of CO2–brine–rock interaction was performed, which indicate that the small pore throats blockage during the displacement process is the main reason for low recovery in small pores. [ABSTRACT FROM AUTHOR]

Byline: Qingjin Peng, Chunsheng Yu One of the limitations of current Mass Customisation (MC) practice is the inefficient system interaction between product developers and production data. Production data are normally separated from product model during the product review and evaluation during product development. Product Data Management (PDM) systems have been used to integrate product data in the product development, but the user-friendless interface and weak interactive ability of PDM systems have been the obstacle of PDM. This paper introduces a visualised manufacturing information system to integrate product models and production data. Virtual Reality (VR) technology is proposed as a visualised tool for the production data retrieval integrated to the process of product model review and evaluation in the product development. A manufacturing system can be reviewed and configured rapidly according to the need of individual customised products using the developed system. The proposed approach has been used to incorporate flexibility into the industrial MC practice.