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Rugang Y.,Great Wall Drilling Company | Chunyao P.,Great Wall Drilling Company | Zhenhua Z.,Great Wall Drilling Company | Dongxu J.,China Central Depository & Clearing Co., Ltd.
SOCAR Proceedings | Year: 2017

The objective of this work is to provide a new insight into the spatial distribution of physical, chemical structure of the filter cake layer. The spatial distribution was characterized by various analytical techniques, including high-temperature high-pressure (HTHP) fluid loss test, scanning electron microscopy (SEM), energy dispersive spectrum (EDs), particle size distribution (PSD), fluorescence test, pore size, porosity, density, water and polymer content measurement etc.. Specific cake resistance and the permeability of the filter cake were measured. The results obtained show that the spatial distribution of filter cake layer structure changes from the top layer to bottom layer. A large amount of deformable colloid particles in the filter cake layer is beneficial to the reducing of the cake permeability. The polymer and water content of the cake layer decreased from the top cake layer to the bottom cake layer. Through the SEM images, cake layer was found to have a loose outer surface when compared with the bottom cake layer. © 2017 "OilGasScientificResearchProject" Institute. All rights reserved.


Xu C.,Southwest Petroleum University | Kang Y.,Southwest Petroleum University | Chen F.,China Central Depository & Clearing Co., Ltd. | You Z.,University of Adelaide
Journal of Petroleum Science and Engineering | Year: 2017

Developed fractures are beneficial for the efficient development of tight reservoir. They also lead to drill-in fluid loss and induce severe formation damage. Fracture plugging with loss control material (LCM) is the most common way to control drill-in fluid loss in fractured formation. Fracture plugging effect largely depends on the strength of fracture plugging zone, because in most cases plugging failure is caused by the strength failure of plugging zone. However, the effects of LCM mechanical and geometric parameters on plugging zone strength are still unclear. Moreover, traditional LCM selection is mainly performed by trial-and-error method, due to the lack of mathematical models. This paper develops an analytical model for plugging zone strength accounting for the frictional failure and shear failure of fracture plugging zone. Effects of LCM mechanical and geometric properties on plugging zone strength are analyzed. The proposed model is validated by laboratory data. Application procedure of the proposed model to drill-in fluid loss control is developed and successfully applied to the field case study in Sichuan basin, China. The modelling results show that particle-particle friction angle, particle-fiber friction angle, fiber tensile strength, D90 degradation rate, and friction angle between plugging zone and fracture surface are main mechanical parameters affecting the plugging zone strength. Particle size distribution, aspect ratio and initial angle of fiber, and plugging zone porosity are main geometric parameters during loss control. Single LCM parameters are applied to the selection of LCM type. Plugging zone parameters are used for the determination of optimal LCM concentration. Reasonable combination of rigid granule, fiber and elastic particle can create a synergy effect to optimize the plugging zone strength and loss control effect. © 2016 Elsevier B.V.


Xu C.,Southwest Petroleum University | Kang Y.,Southwest Petroleum University | Chen F.,China Central Depository & Clearing Co., Ltd. | You Z.,University of Adelaide
Journal of Natural Gas Science and Engineering | Year: 2016

Well-developed natural fractures are beneficial for the economic and efficient development of tight reservoirs. However, they also lead to drill-in fluid loss and induced severe formation damage. Fracture plugging with loss control material (LCM) is the most common way to control lost circulation. Fracture plugging effect largely depends on the fracture propagation pressure, because plugging failure is mainly caused by fracture propagation in fractured formation. Nevertheless, the effects of the plugging parameters on the fracture propagation pressure are still unclear. The current paper develops a mathematical model for fracture propagation pressure accounting for fracture plugging. Key indexes are proposed for fracture plugging optimization based on parameter analysis. Laboratory experiments are conducted to select reasonable LCM type and concentration. The application procedure of the proposed model to drill-in fluid loss control is presented and successfully applied to field case study. The modelling results show that the plugging zone length, width and permeability are the major plugging parameters that affect the fracture propagation pressure. The larger the plugging zone width and the smaller the plugging zone length and permeability, the higher the fracture propagation pressure. Maximum plugging pressure, total loss volume before sealing and D90 degradation rate are proposed as the three indexes for LCM selection. Experimental results show that the combination of rigid granule, fiber and elastic particle can create a synergistic effect to optimize the fracture plugging effect. For the 500 μm width fracture, the optimal concentrations for rigid granule, fiber and elastic particle are 5.0%, 1.5% and 2.5%, respectively. © 2016 Elsevier B.V.


Hu Z.,China Central Depository & Clearing Co., Ltd. | Wang Q.,China Central Depository & Clearing Co., Ltd. | Chen T.,China Central Depository & Clearing Co., Ltd.
Drilling Fluid and Completion Fluid | Year: 2017

Waste drilling fluids in Changqing gas field are treated with gel-breaking and solid-liquid separation technologies to conform to the environment protection requirements. In gel-breaking the drilling fluids, a new gel-breaking agent, CQPJ-1, was developed to replace the single-purpose, slow and low-efficiency conventional gel-breaking agents. CQPJ-1 is able to reduce the quantity of electric charge of clay colloids and suspended particles, thereby decreasing the coagulation stability of the suspension system. By oxygenolysis, CQPJ-1 decomposes polymer materials, producing primary radicals and initiating a chain oxidation reaction, thereby dramatically reducing the molecular weight of polymer. CQXN-1, a cationic polymeric flocculant with moderate molecular weight, was selected to flocculate destabilized clay particles through its cationic group and long molecular chain, making the flocs much easier to mechanically dewater than flocs flocculated with inorganic flocculants. Laboratory evaluation has been conducted on the performance of gel-breaking agents, including H2O2, potassium permanganate, sodium phosphite and CQPJ-1, and the performance of flocculants such as poly aluminum chloride, poly ferric chloride, aluminum sulfate and CQXN-1. It was found that, using existing solids-control equipment, a waste drilling fluid with pH adjusted between 6.0-6.5, after treatment with 2%CQPJ-1 for 3 hours and then adding 0.15%CQXN-1, can be solid-liquid separated at 2, 200 r/min. The separation efficiency and results have achieved the expected goal. Contamination index of the liquid phase from the treated waste drilling fluid was greatly reduced, and drilling fluids prepared with the liquid obtained had properties conforming to the requirements of drilling operation. © 2017, The Editorial Board of Drilling Fluid & Completion Fluid. All right reserved.


Swinburn B.,University of Auckland | Swinburn B.,Deakin University | Sacks G.,Deakin University | Vandevijvere S.,University of Auckland | And 19 more authors.
Obesity Reviews | Year: 2013

Summary: Non-communicable diseases (NCDs) dominate disease burdens globally and poor nutrition increasingly contributes to this global burden. Comprehensive monitoring of food environments, and evaluation of the impact of public and private sector policies on food environments is needed to strengthen accountability systems to reduce NCDs. The International Network for Food and Obesity/NCDs Research, Monitoring and Action Support (INFORMAS) is a global network of public-interest organizations and researchers that aims to monitor, benchmark and support public and private sector actions to create healthy food environments and reduce obesity, NCDs and their related inequalities. The INFORMAS framework includes two 'process' modules, that monitor the policies and actions of the public and private sectors, seven 'impact' modules that monitor the key characteristics of food environments and three 'outcome' modules that monitor dietary quality, risk factors and NCD morbidity and mortality. Monitoring frameworks and indicators have been developed for 10 modules to provide consistency, but allowing for stepwise approaches ('minimal', 'expanded', 'optimal') to data collection and analysis. INFORMAS data will enable benchmarking of food environments between countries, and monitoring of progress over time within countries. Through monitoring and benchmarking, INFORMAS will strengthen the accountability systems needed to help reduce the burden of obesity, NCDs and their related inequalities. © 2013 The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of the International Association for the Study of Obesity.


Xu Z.,Shanghai JiaoTong University | Wang M.,China Central Depository & Clearing Co., Ltd. | Zhao C.,Shanghai JiaoTong University
ICOPE 2015 - International Conference on Power Engineering | Year: 2015

Pool boiling heat transfer performances of metal foams with gradient pore densities have been experimentally investigated in saturated deionized water at atmospheric pressure. Foam materials are copper and nickel, foam porosity is fixed as 0.98, and foam thickness are from 4 mm to 14 mm. The experimental results show that, compared to uniform metal foams, metal foams with gradient pore densities significantly enhance pool boiling heat transfer, but the enhancement degree is affected by foam thickness and material; pool boiling heat transfer performance of metal foam with gradient pore densities decreases with increasing SDS concentration, and adding the surfactant SDS into water makes the CHF reach earlier. Adding Al2O3 nanoparticles severely weakens the pool boiling heat transfer of copper foam with gradient pore densities. © 2015 The Japan Society of Mechanical Engineers.


Aaron G.J.,Global Alliance for Improved Nutrition GAIN | Dror D.K.,U.S. Department of Agriculture | Yang Z.,China Central Depository & Clearing Co., Ltd.
Nutrients | Year: 2015

Multiple-micronutrient (MMN) fortification of beverages may be an effective option to deliver micronutrients to vulnerable populations. The aim of the present systematic review and meta-analysis is to evaluate the nutritional impacts of MMN fortified beverages in the context of low-middle income countries. A systematic search of published literature yielded 1022 citations, of which 10 randomized controlled trials (nine in school-aged children and one in pregnant women) met inclusion criteria. Results of school-aged children were included in the meta-analysis. Compared to iso-caloric controls, children who received MMN fortified beverages for 8 weeks to 6 months showed significant improvements in hemoglobin (+2.76 g/L, 95% CI [1.19, 4.33], p = 0.004; 8 studies) and serum ferritin (+15.42 pmol/L, [5.73, 25.12], p = 0.007; 8 studies); and reduced risk of anemia (RR 0.58 [0.29, 0.88], p = 0.005; 6 studies), iron deficiency (RR 0.34 [0.21, 0.55], p = 0.002; 7 studies), and iron deficiency anemia (RR 0.17 [0.06, 0.53], p = 0.02; 3 studies). MMN fortified beverage interventions could have major programmatic implications for reducing the burden of anemia and iron deficiency in school-aged children in low-middle income countries. Additional research is needed to investigate effects on other biochemical outcomes and population subgroups. © 2015 by the authors; licensee MDPI, Basel, Switzerland.


Luo M.,China University of Petroleum - East China | Jia Z.,China University of Petroleum - East China | Sun H.,China University of Petroleum - East China | Liao L.,China Central Depository & Clearing Co., Ltd. | Wen Q.,China University of Petroleum - East China
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2012

The rheological behavior and microstructure of anionic fatty acid methyl ester sulfonate sodium (MES) surfactant micelle solution with pyroelectric nanoparticle were investigated by dynamic light scattering (DLS), freeze-fracture transmission electron microscopy (FF-TEM) and rheological measurement. The formation of wormlike micelle due to salt addition was observed and the nanoparticle can accelerate the micelle growth and entanglement with each other. The effect of concentration of surfactant, added salt and pyroelectric barium titanate (BaTiO 3) nanoparticle were investigated, respectively. The viscosity of MES micelle solution increases with the temperature rise within a certain range because of the pyroelectric effect of nanoparticles. At low temperature (∼25°C), the sample with 0.6wt.% nanoparticle behaves like an elastic gel with an infinite relaxation time and viscosity. The change of microstructure and rheological properties for MES viscoelastic micelle solutions may be attributed to the electrostatic interaction and pseudo-crosslinking between micelles and nanoparticles. MES viscoelastic micelle solution can retain high viscosity at elevated temperature due to nanoparticle addition and has very attractive for reservoir stimulation and enhanced-oil-recovery in higher temperature reservoirs. © 2011 Elsevier B.V.


LIN Y.,Southwest Petroleum University | DENG K.,Southwest Petroleum University | SUN Y.,Southwest Petroleum University | ZENG D.,China Central Depository & Clearing Co., Ltd. | XIA T.,China National Petroleum Corporation
Petroleum Exploration and Development | Year: 2016

The unified algorithm of through-wall yield collapse pressure for casing with due consideration of strength differential (SD), yield-to-tensile strength ratio, material hardening and intermediate principal stress, which is suitable to calculate collapse strength of all casing has been obtained based on unified strength theory, and four classical through-wall yield collapse formulas of casing have been presented based on the L. Von Mises, TRESCA, GM and twin yield strength criterion. The calculated value is maximum based on the twin yield strength criterion, which can be used as upper limit of through-wall yield collapse pressure, and the calculated value is minimum based on the TRESCA strength criterion, which can be used as lower limit of through-wall yield collapse pressure in the design process. Numerical and experimental comparisons show that the equation proposed by this paper is much closer to the collapse testing values than that of other equations. © 2016 Research Institute of Petroleum Exploration & Development, PetroChina


Wensheng W.,China University of Petroleum - Beijing | Wei N.,China University of Petroleum - Beijing | Li L.,China Central Depository & Clearing Co., Ltd.
Geophysics | Year: 2013

Because of the effects of background and measurement environment and multiplet effects of different elements, high-precision analysis of mixed capture γ-ray energy spectra of complicated formations remains challenging for geochemical elemental logging. The direct demodulation (DD) method makes full use of the measured data information, enabling physical constraints to be rationally applied to the spectral analysis process, and can yield high-precision elemental content from poor-statistics, low signal-to-noise ratio, and disturbed data. We construct mixed formations of different sandstones and limestones, mixed formations of sandstone and anhydrite, and more complicated mixed formations of multiple lithologies and employ Monte Carlo numerical simulations to obtain the neutron-capture γ-ray energy spectra of these mixed formations. We then employ the DD method and the weighted-least-squares (WLS) method to analyze quantitatively such mixed spectra, respectively, and compare the results with the actual contents of formation elements. The results indicate that the DD method offers higher precision spectral analysis compared with the results of the WLS method. The results for the capture γ-ray energy spectra of the formation for two actual wells also indicate that the DD method can be useful for spectral analysis in actual application. © 2014 Society of Exploration Geophysicists.

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