Large-scale physical simulation of injection and production of hot dry rock in Gonghe Basin,Qinghai Province,China

Based on the independently developed true triaxial multi-physical field large-scale physical simulation system of in-situ injection and production,we conducted physical simulation of long-term multi-well injection and production in the hot dry rocks of the Gonghe Basin,Qinghai Province,NW China.Through multi-well connectivity experiments,the spatial distribution characteristics of the natural fracture system in the rock samples and the connectivity between fracture and wellbore were clarified.The injection and production wells were selected to conduct the experiments,namely one injection well and two production wells,one injection well and one production well.The variation of several physical parameters in the production well was analyzed,such as flow rate,temperature,heat recovery rate and fluid recovery.The results show that under the combination of thermal shock and injection pressure,the fracture conductivity was enhanced,and the production temperature showed a downward trend.The larger the flow rate,the faster the decrease.When the local closed area of the fracture was gradually activated,new heat transfer areas were generated,resulting in a lower rate of increase or decrease in the mining temperature.The heat recovery rate was mainly controlled by the extraction flow rate and the temperature difference between injection and production fluid.As the conductivity of the leak-off channel increased,the fluid recovery of the production well rapidly decreased.The influence mechanisms of dominant channels and fluid leak-off on thermal recovery performance are different.The former limits the heat exchange area,while the latter affects the flow rate of the produced fluid.Both of them are important factors affecting the long-term and efficient development of hot dry rock.

Stress sensitivity of formation during multi-cycle gas injection and production in an underground gas storage rebuilt from gas reservoirs

Permeability sensitivity to stress experiments were conducted on standard core samples taken from Wen 23 Gas Storage at multi-cycle injection and production conditions of the gas storage to study the change pattern of stress sensitivity of permeability.A method for calculating permeability under overburden pressure in the multi-cycle injection and production process was proposed,and the effect of stress sensitivity of reservoir permeability on gas well injectivity and productivity in UGS was analyzed.Retention rate of permeability decreased sharply first and then slowly with the increase of the UGS cycles.The stress sensitivity index of permeability decreased with the increase of cycle number of net stress variations in the increase process of net stress.The stress sensitivity index of permeability hardly changed with the increase of cycle number of net stress variations in the decrease process of net stress.With the increase of cycle number of net stress variation,the stress sensitivity index of permeability in the increase process of net stress approached that in the decrease process of net stress.The lower the reservoir permeability,the greater the irreversible permeability loss rate,the stronger the cyclic stress sensitivity,and the higher the stress sensitivity index of the reservoir,the stronger the reservoir stress sensitivity.The gas zones with permeability lower than 0.3’10-3 mm2 are not suitable as gas storage regions.Stress sensitivity of reservoir permeability has strong impact on gas well injectivity and productivity and mainly in the first few cycles.

Numerical simulation of operation performance on production and injection of a double well geothermal system in Kailu Basin, Inner Mongolia

Inner Mongolia is abundant in geothermal resources,but the development and utilization of medium-depth geothermal resources for clean heating in winter is still in the preliminary stage compared with the neighboring provinces.In this paper,a recently developed geothermal heating system using the Mesozoic sandstone reservoirs in Baokang of Kailu Basin,Eastern Inner Mongolia was investigated,a threedimensional geological model of a pair of production and injection well was established,and numerical simulations on the long term operation performance were conducted and verified by pumping test and water level recovery test data.The effects of flow rates,the direction of wells,injection temperature and ratios on the flow field and water level in the thermal reservoir were analyzed.The results show that considering a 30-year operation period and a production rate from 90 m^(3)/h to 110 m^(3)/h,the optimum well spacing can be increased from 225 m to 245 m,with an average value of 235 m.With the decrease of the injection temperature,the cold front of the injection water has an increasing influence on the temperature in the production well.A complete injection or the principle of production according to injection is recommended in order to maintain the long-term operation stability.In addition,the location of the injection well should be arranged in the downstream of the natural flow field.The present results can provide a useful guide for the optimum design and performance prediction of geothermal wells,thus maintaining the production and injection balance and promoting the sustainable development and utilization of medium-depth and deep geothermal resources.

Lag times in toe-to-heel air injection(THAI)operations explain underlying heavy oil production mechanisms

From a time value of revenue point of view,it is preferred that the time between reservoir stimulation and oil production response is small.Heavy oil combustion processes have a lag time between air injection and liquid production,but the common practice in production data analysis uses simultaneous injection and production data when seeking a relationship between them.In this research,the time scales of production for the Kerrobert toe-to-heel air injection(THAI)heavy oil project in Saskatchewan,Canada,is analyzed by using cross correlation analysis,i.e.time delay analysis between air injection and oil production.The results reveal two time scales with respect to production response with two distinctive recovery mechanisms:(1)a short time scale response(nearly instantaneous)where oil production peaks right after air injection(directly after opening production well)reflecting cold heavy oil production mechanisms,and(2)a longer time scale(of order of 100-300 days)response where peak production occurs associated with the collective phenomena of air injection,heat generating reactions,heat transfer,and finally,heated mobilized heavy oil drainage to the production well.This understanding of the two time scales and associated production mechanisms provides a basis for improving the performance of THAI.

An analysis method of injection and production dynamic transient flow in a gas field storage facility

A dynamic transient flow analysis method considering complex factors such as the cyclic injection and production history in a gas field storage facility was established in view of the limitations of the existing methods for transient flow analysis and the characteristics of the injection-production operation of strongly heterogeneous gas reservoirs, and the corresponding theoretical charts were drawn. In addition, an injection-production dynamic transient flow analysis model named "three points and two stages" suitable for an underground gas storage(UGS) well with alternate working conditions was proposed. The "three points" refer to three time points during cyclic injection and production, namely, the starting point of gas injection for UGS construction, the beginning and ending points of the injection-production analysis stage;and the "two stages" refer to historical flow stage and injection-production analysis stage. The study shows that the dimensionless pseudo-pressure and dimensionless pseudo-pressure integral curves of UGS well flex downward in the early stage of the injection and production process, and the dimensionless pseudo-pressure integral derivative curve is convex during the gas production period and concave during the gas injection period, and the curves under different flow histories have atypical features. The new method present in this paper can analyze transient flow of UGS accurately. The application of this method to typical wells in Hutubi gas storage shows that the new method can fit the pressure history accurately, and obtain reliable parameters and results.

Injection-production parameters optimization research SAGD production stage

Steam assisted gravity drainage （SAGD） technology has been industrialized popularization and application in our country, according to the characteristics of Xing group I SAGD experimental zone in liaohe oilfield, SAGD production stage injection-production parameters such as the operating pressure, Sub - Cool control, steam injection rate, steam dryness, production factor are studied and selected.

Study on Injection-Production System Adjustment of Fault Block Reservoir Based on Equilibrium Displacement

This paper proposed a method of injection-production system adjustment to solve the problem that the water flooding effect was restricted because of the horizontal and vertical contradictions during the development process of fault block reservoirs. Considering the heterogeneity of reservoir, the Buckley-Leverett water flooding theory was applied to establish the relationship between the recovery and cumulative water injection. In order to achieve the goal of vertically balanced recovery of each section, the calculation method of vertical sectional injection allocation was proposed. The planar triangular seepage unit was assumed and sweep coefficients of different oil-water distribution patterns were characterized using multi-flow tube method. In order to balance and maximize the plane sweep coefficient, the calculation method of plane production system optimization was obtained. Then the injection-production system stereoscopic adjustment method based on equilibrium displacement was proposed with vertical sectional injection allocation and plane production system optimization. This method was applied to injection and production adjustment of BZ oilfield in southern Bohai. The effect of water control and oil increase was obvious. This method can greatly improve the effect of water flooding of offshore fault block reservoirs with the adjustment of injection-production system.

Calculation of Beam Intensity Distribution for the Neutral Beam Injection in EAST

Theoretical beam intensity distribution is derived for the neutral-beam-injection ion source with a multi-slot extraction in EAST. The beam intensity profile, both along and perpendicular to the injecting direction and the beam power deposition to the inner elements in the neutral beam injector （NBI） are evaluated. The results indicate that the transverse beam intensity is much higher than the longitudinal one. This study could provide information for the design of vacuum system, structure of inner elements and cooling system of the neutral beam injector in EAST.

Effect of Interaction Intensity on Alignment and EFL Learners’ Oral Production in the ReadingSpeaking Integrated Continuation Task

This study aims to uncover the relationship between interaction and alignment in a readingspeaking integrated continuation task, especially focusing on whether an increase in interaction intensity can lead to stronger alignment and further generate positive effects on L2 learning. To this end, 31 participants were asked to perform reading-speaking integrated continuation tasks under three different conditions featuring low, medium and high interaction intensity respectively. The results showed that 1) alignment existed in the reading-speaking integrated continuation task;2)increasing interaction intensity generated stronger alignment at both linguistic and situational levels;3) growing interaction intensity contributed to more coherent and accurate L2 oral production. These findings not only proved the workings of mind-body-world alignment, but also testified that increasing interaction intensity could bring about a stronger alignment effect(Wang,2010), which then contributed to better L2 oral performance. These findings confirm again the role of interaction in L2 learning and suggest that alignment could possibly be a mediating factor that links interaction and L2 development. Pedagogical implications for teaching and learning L2 speaking are discussed.

Effects of harvest intensity on the marketable organ yield,growth and reproduction of non-timber forest products(NTFPs):implication for conservation and sustainable utilization of NTFPs

Background:Non-timber forest products(NTFPs)are an important part of forest biodiversity,and the subsistence and trade of local people,especially in less developed countries.Because of the high ecological and economic value,NTFPs have faced the problem of over-exploitation,and the key to solve this problem is to determine the feasible way of sustainable utilization of NTFPs.Harvest intensity is one of the most important and easily controlled utilization factors,which can greatly influence the plant individual survival,growth and reproductive performances,and even the population structure and dynamics.Therefore,we chose two common and important NTFPs species with different marketable parts(i.e.,Acanthopanax senticosus with tender leaves and Aralia elata with tender buds)as our study objects.Aiming to determine the optimum harvest intensity for sustainably utilizing both NTFPs species,five levels of harvest intensity treatments(i.e.,control,light,medium,high and severe)were designed to assess the effects of harvest intensity on their marketable organ yield,plant growth and reproductive performances.Results:The biomass growth rates of marketable organ and plant growth of A.senticosus under light harvest intensity treatment were significantly higher than those under other harvest intensities.The plant height growth and 1000-seed weight of A.elata under severe harvest intensity treatment were significantly lower than those under control treatment.Conclusions:The light harvest intensity with 25% leaf removal and the high harvest intensity with all terminal buds harvested are the optimum harvest intensity to maintain the sustainable utilization of A.senticosus and A.elata,respectively.These findings could provide managers with basic but practical guidance for making decisions about the sustainable harvest management plan for the cultivated NTFPs species,and further provide a theoretical basis for managers to establish the harvest regulations for wild NTFPs species.Consequently,the local residents or communities can improve their income while ensure the sustainable development of wild NTFPs.

Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions,China

Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studied. Fixed observation results from 1993to 2002 showed that pools covering about 15% of total area could store up 10% of surfacerunoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio ofinterception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in thecatchment area system, and benefited the aquatic culture and helped to resist seasonaldrought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 tkm-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddyfield increased steadily (>10%); water storage enhanced by more than 20% in sloping landand dryland in drought season; crop production increased by more than 20%; and productionof trees, fruits, tea and fish as well as land productivity increased yearly.

Semi-Quantitative Histological Analysis of the Effect of Intense Pulsed Light (IPL) and Carbon Dioxide (CO₂) Intradermic Injection on Fibroblast and Collagen Proliferation in the Skin of Wistar Rats

Background: In recent years, so-called “non-ablative rejuvenation” has been carried out with the use of lasers or intense pulsed light (IPL) to stimulate collagen production by dermal fibroblasts. Intradermal infusion of CO2 stimulates fibroblasts and the synthesis of collagen and elastin, contributing to the retraction of the skin and tissue rejuvenation. Objectives: To evaluate the effects of IPL and the intradermal infusion of CO2 on fibroblast proliferation and collagen in the skin of female rats. Methods: Sixteen adult female Wistar rats were divided into two groups of eight animals. Group 1 underwent IPL and group 2 underwent intradermal CO2 infusion. There was a total of 8 weeks of treatment. We conducted a punch in each animal before any procedure (T0), another punch in the middle of treatment at 4 weeks post-procedure (T1) and a punch at the end of treatment at 8 weeks post-procedure (T2). The cells involved in inflammation, fibrosis and vascularization of the injured tissue by histopathology were analyzed. Results: There was statistically significant fibroblast proliferation and collagen proliferation noted when analyzing all 16 animals together and also when considering the two study groups separately. In both groups, the greatest proliferation of fibroblasts coincided with periods of increased collagen production. Conclusion: Both IPL and intradermal CO2 infusion stimulated fibroblast and collagen proliferation in the skin of the rats studied.

Changes and Effecting Factors of Grain Production in China

Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper aims to examine the spatial and temporal change characteristics of total grain production and its affecting factors. The results show that： 1） During 1980 to 2007, total grain production increased from 3.20 ~ 108 t to 5.02 x 108 t in China, with annual increasing rate of 1.68%. From the regional disparities, most of the regions present increasing trend of total grain production except for several regions with higher level of economic development; 2） Grain sown area decreased from 1.17 × 108 ha in 1980 to 1.06 x 108 ha in 2007, which has negative effect on total grain production; 3） The increase of grain yield per unit area caused by land use intensity changes contributed to the increase of total grain yield greatly. However, as the land use intensity showed that farmers pay more attention to labor-saving input but not yield-increasing input, the less enthusiasm of farmers in grain production may become an important constraint on fu- ture grain production increase in China; 4） Based on the results, this paper proposed different land management poli- cies in different regions, for example, the government should protect cultivated land, promote large scale production. As to the less developed regions, the government should pay more attention to agricultural subsidies to promote farm- ers＇ enthusiasm in grain production.

Progress and prospects of oil and gas production engineering technology in China

This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.

The Effects of Shade Tree Types on Light Variation and Robusta Coffee Production in Vietnam

Vietnam is well-known as the second largest global coffee producer and the largest worldwide exporter of Robusta coffee. However, the Robusta coffee sector in Vietnam is facing many problems, including low quality, high external inputs and water shortages as a result of shade tree eradication. A six-month research project was conducted that focused on effects of shaded tree types on variation of light intensity and aspects of Robusta production. Three shade tree species at different planting densities and shade provision were investigated, including 46 trees of Durian ha–1 (14% shade), 35 trees of Sennaha–1 (17% shade), and 60 trees of Leucaena ha–1 (34% shade), and unshaded site (Open) was used as a control. The study found that light intensity declined 50% with Durian, 58% with Senna and 60% with Leucaena compared with the Open site (2096 μmol?m–2?s–1). Within the coffee canopy, a significant decline in light intensity was observed from the top of the canopy to the bottom. The percentage of light at the middle (90 cm above ground) and bottom (30cm) levels of the coffee canopy was declined by 81% and 88% respectively for the Open site, and 86% and 92% for the Leucaena site. There were no differences in the number of flowers branch–1 tree–1 and fruit set between shaded and unshaded coffee sites. However, a significant difference in first fruit drop was observed.

Kansei Engineering Applied to the Form Design of Injection Molding Machines

This study investigated the relationship between a subject’s evaluation of injection molding machines (IMMs) and formal design features using Kansei engineering. This investigation used 12 word pairs to evaluate the IMM configurations and employed the semantic differential method to explore the perception of 60 interviewees of 12 examples. The relationship between product feature design and corresponding words was derived by multiple regression analysis. Factor analysis reveals that the 12 examples can be categorized as two styles—advanced style and succinct style. For the advanced style, an IMM should use a rectangular form for the clamping-unit cover and a full-cover for the injection-unit. For the succinct style, the IMM configuration should use a beveled form for the safety cover and a vertical rectangular form for the clamping-unit cover. Quantitative data and suggested guidelines for the relationship between design features and interviewee evaluations are useful to product designers when formulating design strategies.

H_2 PRODUCTION BY ANABAENA VARIABILIS MUTANT IN COMPUTER CONTROLLED TWO-STAGE AIR-LIFT TUBULAR PHOTOBIOREACTOR

A 4.34 liter two stage air lift photobioreactor incorporating Anabaena variabilis ATCC29413 mutant PK84 was used to study H 2 production. Results showed that H 2 production increased with increasing light intensity from 47 μE/(m 2·s) up to 190 μE/(m 2·s), but that further increase of light intensity decreased the H 2 production because of the inhibition due to the high pO 2. The data also indicated that longer argon gas charge resulted in more H 2 produced due to the increase of nitrogenase activities and heterocyst frequency, and that more than 1.3 L net H 2 was produced from this computer controlled photobioreactor.

Research on the Equivalence Between Double Differential- mode Current Injection and Radiation Test Method

There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cable simultaneously, a double differential-mode current in- jection test method (DDMCI) is proposed. The method adopted the equivalence source wave theorem and Baum-Liu-Tesche(BLT) equation as its theory foundation. The equivalent corresponding relation between injection voltage and radiation electric field intensity is derived, and the phase relation between the two injection voltage sources is confirmed. The results indicate that the amplitude and phase of the equivalent injection voltage source is closely related to the S parameter of directional coupling device, the transmission line length, and the source vector in BLT equation, but has nothing to do with the reflection coefficient between the two equipment pieces. Therefore, by choosing the right amplitude and phase of the double injection voltage sources, the DDMCI test is equivalent to the radiation test for two interconnected equipment of a system.

Simulation of pore space production law and capacity expansion mechanism of underground gas storage

One-dimensional gas injection storage building and one-cycle injection-production modeling experiment,and two-dimensional flat core storage building and multi-cycle injection-production modeling experiment were carried out using one-dimensional long core and large two-dimensional flat physical models to find out the effects of reservoir physical properties and injection-production balance time on reservoir pore utilization efficiency,effective reservoir capacity formation and capacity-reaching cycle.The results show that reservoir physical properties and formation water saturation are the main factors affecting the construction and operation of gas-reservoir type underground gas storage.During the construction and operation of gas-reservoir type gas storage,the reservoir space can be divided into three types of working zones:high efficiency,low efficiency and ineffective ones.The higher the reservoir permeability,the higher the pore utilization efficiency is,the smaller the ineffective working zone is,or there is no ineffective working zone;the smaller the loss of injected gas is,and the higher the utilization rate of pores is.The better the reservoir physical properties,the larger the reservoir space and the larger the final gas storage capacity is.The higher the water saturation of the reservoir,the more the gas loss during gas storage capacity building and operation is.Optimizing injection-production regime to discharge water and reduce water saturation is an effective way to reduce gas loss in gas storage.In the process of multiple cycles of injection and production,there is a reasonable injection-production balance time,further extending the injection-production balance period after reaching the reasonable time has little contribution to the expansion of gas storage capacity.

Stable Production Technology for Horizontal Well Development in Shallow Water Delta Oilfield of Bohai Bay, China

BZ Oilfield is a medium-sized oilfield with shallow delta facies deposits in Bohai Bay of China,compared with fluvial and delta facies oilfields,there is no mature experience for reference of reservoir configuration,well pattern arrangement and development model in offshore oilfields in China.In view of the difficulty in describing the reservoir configuration of shallow water delta,the single distributary sand dam in shallow water delta is characterized by well-seismic combination and multi-attribute constraints.The mathematical mechanism model of pinch-out position of sand body is established,fine characterization of BZ shallow water delta reservoir is put forward.The horizontal well pattern arrangement type for shallow water delta reservoir is proposed and the method of well pattern optimization based on vertical displacement theory is put forward.A method of inversion of reservoir connectivity using production dynamic data by numerical well testing is proposed and a new method for optimizing water injection rate in water injection wells is proposed aiming at the difficulty of recognizing injection-production connectivity of shallow water delta reservoirs.The fine configuration of BZ shallow water delta reservoir based on distributary sand dam is proposed,which guides the recognition of remaining oil distribution law.By deploying adjustment wells,the water flooding coincidence degree of actual drilling is 86% compared with that of pre-drilling prediction,which indicates that the research results of reservoir configuration can effectively guide the understanding of oilfield geology.Through the theoretical well arrangement type of vertical displacement of single sand body in horizontal wells of shallow water delta reservoir,a high water flooding recovery rate of 35% is achieved in primary well pattern.The connectivity coefficients of injection-production boundary of shallow water delta reservoir configuration are calculated,and the water injection distribution coefficients are obtained by normalizing the directional coefficients.This paper presents a configuration method based on multi-attribute fusion under the constraints of sedimentary process.In this paper,a shallow water delta reservoir configuration method based on multi-attribute fusion constrained by sedimentary process is proposed,and the injection-production connectivity coefficient and injection well distribution coefficient of the configuration boundary are calculated.