A Transient-Pressure-Based Numerical Approach for Interlayer Identification in Sand Reservoirs

Almost all sandstone reservoirs contain interlayers. The identification and characterization of these interlayers iscritical for minimizing the uncertainty associated with oilfield development and improving oil and gas recovery.Identifying interlayers outside wells using identification methods based on logging data and machine learning isdifficult and seismic-based identification techniques are expensive. Herein, a numerical model based on seepageand well-testing theories is introduced to identify interlayers using transient pressure data. The proposed modelrelies on the open-source MATLAB Reservoir Simulation Toolbox. The effects of the interlayer thickness, position,and width on the pressure response are thoroughly investigated. A procedure for inverting interlayer parametersin the reservoir using the bottom-hole pressure is also proposed. This method uses only transient pressuredata during well testing and can effectively identify the interlayer distribution near the wellbore at an extremelylow cost. The reliability of the model is verified using effective oilfield examples.

Effect of fracture fluid flowback on shale microfractures using CT scanning

The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.

Effects of mineralogical composition on uniaxial compressive strengths of sedimentary rocks

Figuring out rock strength plays essential roles in the sub ground mining activities,such as oil and gas well drilling and hydraulic fracturing,coal mining,tunneling,and other civil engineering scenarios.To help understand the effects of the mineralogical composition on evaluating the rock strength,this research tries to establish indirect prediction models of rock strength by specific input mineral contents for common sedimentary rocks.Using rock samples collected from the outcrops in the Sichuan Basin,uniaxial compression tests have been conducted to sandstone,carbonate,and shale cores.Combining with statistical analysis,the experimental data prove it true that the mineralogical composition can be utilized to predict the rock strength under specific conditions but the effects of mineralogical composition on the rock strength highly depend on the rock lithologies.According to the statistical analysis results,the predicted values of rock strengths by the mineral contents can get high accuracies in sandstone and carbonate rocks while no evidences can be found in shale rocks.The best indicator for predicting rock strength should be the quartz content for the sandstone rocks and the dolomite content for the carbonate rocks.Especially,to improve the evaluation accuracy,the rock strengths of sandstones can be obtained by substituting the mineral contents of quartz and clays,and those of carbonates can be calculated by the mineral contents of dolomite and calcite.Noticeably,the research data point out a significant contrast of quartz content in evaluating the rock strength of the sandstone rocks and the carbonate rocks.Increasing quartz content helps increase the sandstone strength but decrease the carbonate strength.As for shale rocks,no relationship exists between the rock strength and the mineralogical composition(e.g.,the clay fractions).To provide more evidences,detailed discussion also provides the readers more glances into the framework of the rock matrix,which can be further studied in the future.These findings can help understand the effects of mineralogical composition on the rock strengths,explain the contrasts in the rock strength of the responses to the same mineral content(e.g.,the quartz content),and provide another indirect method for evaluating the rock strength of common sedimentary rocks.

Evaluation of Cobalt Application Combined with Gypsum and Compost as a Regulator of Cabbage Plant Tolerance to Soil Salinity

In response to the global food crisis and the imperative to address soil degradation, the international agricultural policy is actively working to alleviate the adverse impacts of soil salinity. As part of this initiative, a field trial spanning two consecutive seasons (2019/20-2020/21) was conducted under saline conditions. The primary objective was to evaluate the influence of various compost sources, including vermicompost at a rate of 0.5 ton·fed-1 and plant residues compost at a rate of 5.0 ton·fed-1, as main plots. Subplots were established by applying agricultural gypsum, both in the presence and absence of gypsum requirements. Additionally, sub-subplots were created by externally applying cobalt at a rate of 10.0 mg·L-1, with one sub-subplot receiving foliar cobalt application and the other not. The trial sought to assess the growth performance, chemical composition, enzymatic antioxidants, yield, and quality of cabbage plants (Brassica oleracea var. capitata L.) cultivated in saline soil. According to the findings, cabbage plants exhibited the most favorable response in terms of plant height, chlorophyll content, carotene levels, leaf area, nitrogen (N), phosphorus (P), potassium (K), head yield, vitamin C, and total dissolved solids (TDS) when treated with vermicompost, followed by plant compost. Conversely, plants grown without compost exhibited the least improvement in performance. Cabbage treated with agricultural gypsum requirements showed better performance than those without gypsum amendment. Moreover, plants subjected to cobalt spray demonstrated the highest growth, yield, and quality parameters compared to those without cobalt foliar application. In contrast, the control group (plants without the studied treatments) displayed the highest levels of enzymatic antioxidants, specifically catalase and peroxidase. This indicates that soil salinity stress led to an increase in catalase and peroxidase production in cabbage plants as a defense against the harmful impact of reactive oxygen species (ROS) resulting from soil salinity stress. The applied treatments (compost, gypsum, and cobalt) led to a reduction in the cabbage plant’s inherent production of catalase and peroxidase. Generally, the combined treatment of vermicompost × gypsum requirements × cobalt proved effective in mitigating the detrimental effects of soil salinity on cabbage plants. These findings hold significance for farmers and policymakers aiming to enhance agricultural productivity in regions affected by soil salinity. Additionally, further research can explore the long-term effects of these treatments on soil health and crop sustainability.

Contamination and Ecological Risk Assessment of Heavy Metal in the Sediment of Turag River, Bangladesh: An Index Analysis Approach

Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The present study investigated the extent of pollution of sediments of this river and analyzed the regional variability for the concentrations of Cr, Pb, Zn, Cu and Cd—all of concern because of their potential toxicity, using atomic absorption spectrophotometer. As per US EPA sediment quality guideline, metal concentrations ranged between Cd: 0.00 - 0.80, Cr: 32.00 - 75.50, Cu: 46.30 - 60.00, Pb: 28.30 - 36.40, and Zn: 94.60 - 190.10 mg/kg in the Turag river sediments. Cr, Cu, Zn belongs to moderately to highly polluted, Pb and Cd belongs to not polluted for Turag river. The heavy metals contamination in the sediments were also evaluated by applying Index of geo-accumulation (Igeo), contamination factor (Cf), pollution load index (PLI) etc. Toxicity characteristics leaching procedure (TCLP) test (US EPA 1311) for sediment samples have been performed also for metals (Pb, Cd, Cr, Cu and Zn) to determine the readily toxicity level of heavy metals. Sieve analysis of sediment performed in this study to determine the physical characteristic of sediment samples. The metal concentrations are well below the regulated level as per US EPA. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate.

南海海域平台方位和布置的研究

平台的方位和布置需要考虑多种因素,如作业安全需要(靠船作业、直升机起降等)、海上施工安全需要、平台设计的安全规定、及季风、台风、海浪、海流等环境因素。如果布置不好,将给生产带来不利,影响生产的效率,甚至引起事故发生(比如船舶碰撞平台、飞机起降失败等)。陆丰13-2油田开发调整项目是依托在生产的LF13-2井口平台新建一座8腿的钻采综合平台,新旧平台之间用栈桥进行连接。起初ODP方案中新旧平台成夹角布置,不利于生产期间船舶靠泊作业。经过深圳分公司与研究总院多次探讨,提出了多个平台布置方案。最终双方确定了一个较满意的平台布置方案,并报有限公司批准。该平台方位和布置的探讨为今后的平台方位和布置设计积累了经验。在项目开发的初期,确定好平台的方位和布置具有深远的意义。

Contribution of safe motherhood solidarity groups in using and accessing maternity services during a period of armed conflict

This report presents the results of a study on Reproductive Health done in North Kivu in September 2009. It was conducted by HEAL Africa, in partnership with the Provisional Division of Health, and financed by the University of Ottawa, Canada/CRDI with technical assistance from Western Cape University of South Africa. The study was conducted in the health zones of Birambizo and Kayna within the framework of the central office. The focus of the report is on one aspect of Reproductive Health—Low Risk Maternity. This study was conducted in rural areas given that Reproductive Health indicators are much weaker when compared with urban areas, according to EDS RDC, 2007 [1]. This study emphasizes the following points: General characteristics of the participants in the study, and the utilization and accessibility of maternity services in rural areas in conflict situations. The formula SPSS 12.0.1 was used to facilitate data analysis in the study. This study comes at a point in time when its relevance to HEAL Africa’s work will assist HEAL and its partners in determining the focus of interventions done in health zones in order to improve maternal and neonatal health. HEAL Africa firstly stepped into a Safe Motherhood pilot project in June 2006 for 9 months in the Masisi zone, then in 2007 in the Birambizo and Kayna health zones. In November 2007, HEAL expanded into Walikale and in October 2008, into Kirotshe, Binza, and Lubero. The intervention kit consists of reinforcing the capacity of existing health facilities, training traditional midwives who serve as a link between the community and the health structures, the provision of sanitary equipment, medical essentials and community mobilization was done through local leaders about health and reproduction, and organizing women of reproductive age in solidarity groups (SG) to generate maternity insurance. The community approach “Solidarity Groups for Maternity Insurance” constitutes the spine of HEAL Africa within the support it provides in Reproductive Health. The principal idea is to educate and train communities on how to use the MMR services that are available in their community, and to remove financial barriers to accessing health services. The 4 pillars that comprise the Safe Motherhood program are: family planning, prenatal care, safe assisted delivery and essential obstetric care. These four strategic measures are integral in assuring primary health care and equality for women. This study evaluates this approach, keeping in mind local strategies and their effects on improving the utilization and accessibility of reproductive health services.

Studies on Biomass Yield, Morphological Characteristics and Nutritive Quality of Napier Cultivars under Two Different Geo-Topographic Conditions of Bangladesh

The aim of the present study was to evaluate the performance of Napier cultivars in terms of forage yield, plant morphology and nutrient contents under two different agro-ecology and geo-topographic conditions. Three Napier cultivars being conserved by Bangladesh Livestock Research Institute (BLRI), namely-BLRI-Napier 1, (BN-1), BLRI-Napier 3 (BN-3) and Merkeron (BN-5) were selected to cultivate in severe drought prone areas (called Barind) and non-drought area at Savar (Modhupur terrace). Stem cuttings were planted in rows apart from 70 cm and 35cm spacing between plants. Data of 6 consecutive harvests from a period of approximately one year were collected and analyzed statistically by “R” software. The results showed that cultivar and location had a significant (P < 0.001) effect on biomass yield, plant height and leaf-stem ratio (LSR), while number of tillers were significantly varied with locations. BN-3 yielded the highest biomass (33.32 t/ha/harvest) at non-drought location (42.98 t/ha/harvest). The highest plant height was obtained in BN-1 (171.2 cm) at non-drought location (174.6 cm). Number of tillers per hill ranged from 25.4 to 26.3 among cultivars (P > 0.05) and the highest tillers were found at non-drought location (28.1 no). The best LSR was estimated from BN-5 (0.86) at drought location (0.95). The proximate analysis showed that CP, ADF and NDF in whole plant were varied significantly (P < 0.001), being the highest contents in BN-1 (10.69%, 46.20% and 54.58%, respectively). On the other hand, DM and ash contents did not differ significantly (P > 0.05) among cultivars which ranged from 15.80% to 17.13% and 13.10% to 14.58%, respectively. The highest CP content in whole plant was obtained at non-drought location (11.89%), while the lowest ash (10.57%) and NDF (52.71%) contents were obtained at the same location. The highest CP contents in leaf were found at non-drought (15.03%) and the lowest ash (9.86%) at the same location. The highest CP contents (5.90%) in stem were found at non-drought location, while the lowest ash (11.28%) and NDF (54.59%) contents were obtained at the same location. Finally, the experiment reveals the superiority in biomass yield and nutritional quality (in terms of CP content) with the ranking orders of BN-3 > BN-1 > BN-5 and BN-1 > BN-3 > BN-5. Therefore, it may be concluded that BN-1, BN-3, and BN-5 cultivars were well adapted in both drought and non-drought conditions, although performance showed better in later conditions. However, in terms of forage yield and overall nutrient composition, the performance of BN-3 was the best irrespective of locations.

Comparative Study on Biomass Yield,Morphology,Silage Quality of Hybrid Napier and Pakchong and Their Utilization in Bull Calves

This work was conducted to compare the potentiality between BLRI Napier-3(BN-3)and Pakchong(PK)fodders.In a completely randomized design(CRD)layout,10 plots(5 m′5 m each)were prepared and stem cuttings were transplanted.Fodder plants were harvested at 70,80 and 90 days after plantation(DAP)followed by making silage.Ten Red Chittagong Cattle(RCC)growing bull calves were selected and equally divided into two treatment groups fed only silages for nutrient utilization and growth evaluation.The highest biomass yield(69.3 ton/ha)and plant height(104.6 cm)were observed in PK at 90 DAP.The highest leaf weight(498.6 g/plant)and leaf to stem ratio(LSR)(1.53)were observed in BN-3 at 70 DAP,which was decreased gradually in progressing maturity.Conversely,stem weight was increased with progressing maturity.Dry matter(DM)(24.71%),total ash(8.35%)and acid detergent fiber(ADF)(61.89%)in PK silage were significantly higher.On the other hand,crude protein(CP)(9.86%),organic matter(OM)(91.65%)and neutral detergent fiber(NDF)(88.06%)in PK silage did not differ with BN-3 silage.Dry matter intake(DMI)and crude protein intake(CPI)from PK silage(2.25 kg/day/animal and 0.22 kg/day/animal)were significantly higher.Digestibility of DM(55.07%),CP(62.35%),OM(57.85%),total ash(30.89%),ADF(73.02%)and NDF(78.19%)for PK silage were significantly higher.N-intake(35.57 g/d)from PK silage was significantly higher,although,N-retention did not differ significantly.There were no significant differences in weight gain of calves fed PK(117 g/d)and BN-3(68 g/d).It can be concluded that PK silage is comparatively better than BN-3 in respect to biomass yield,digestibility and nutrient utilization in growing bull calves.

Evaluation Method for Tunneling Stability of TBM Cutterhead

In the process of tunneling of tunnel boring machine (TBM), different geological conditions often correspond to different working conditions, and the randomness of geological conditions also causes the order of occurrence of each working condition to be different. Under the conversion of different working conditions, this makes the vibration of different types of cutterheads different. How to choose the appropriate type of cutterhead according to different geological conditions is very important for saving engineering cost and increasing cutterhead life. In view of the above situation, this paper proposes a stability evaluation method during the TBM tunneling process to select the appropriate cutterhead type. Firstly, the corresponding relationship between geology and working conditions is established according to different geological conditions, and the input loads corresponding to geological conditions are obtained. Then, it is substituted into the dynamic model of the cutterhead system, the vibration response boundaries of each degree of freedom are obtained by solving. And the average value of the maximum boundary amplitude of each degree of freedom is taken to represent the extreme vibration of the cutterhead under the corresponding working conditions. Finally, by comparing the fluctuation of the ultimate vibration amplitude of each type of cutterhead in the process of working condition conversion, the results are as follows: when the transition between homogeneous strata and composite strata is normal and there is no large turning and deviation correction, the vibration response of the two-part cutterhead is the smallest, and the two-part cutterhead is the best choice. Otherwise, the five-part cutterhead is the best choice, while the stability of the integrated cutterhead is the worst.