Numerical Simulation Study on the Effect of Horizontal Well Reservoir Stimulation for Gas Hydrate Production

A new gas hydrate reservoir stimulation method of in-situ fracturing with transient heating is proposed, in line with analysis of the technological bottlenecks faced by marine gas hydrate production. This method injects the developed chemical reagents into a hydrate reservoir through hydraulic fracturing, releasing heat during the chemical reaction to increase the hydrate decomposition rate. The chemical reaction product furthermore has a honeycomb structure to support fractures and increase reservoir permeability. Based on the geological model of natural gas hydrate in the South China Sea, three development methods are simulated to evaluate hydrate production capacity, consisting of horizontal well, fractured horizontal well and in-situ fracturing with transient heating well. Compared with the horizontal well, the simulation results show that the cumulative gas production of the fractured horizontal well in one year is 7 times that of the horizontal well, while the cumulative gas production of in-situ fracturing with transient heating well is 12 times that of the horizontal well, which significantly improves daily efficiency and cumulative gas production. In addition, the variation patterns of hydrate saturation and temperature-pressure fields with production time for the three exploitation plans are presented, it being found that three sensitive parameters of fracture conductivity, fracture half-length and fracture number are positively correlated with hydrate production enhancement. Through the simulations, basic data and theoretical support for the optimization of gas hydrate reservoir stimulation scheme has been provided.

THEORY AND APPLICATION OF FRACTIONAL STEP CHARACTERISTIC FINITE DIFFERENCE METHOD IN NUMERICAL SIMULATION OF SECOND ORDER ENHANCED OIL PRODUCTION

A kind of second-order implicit fractional step characteristic finite difference method is presented in this paper for the numerically simulation coupled system of enhanced （chemical） oil production in porous media. Some techniques, such as the calculus of variations, energy analysis method, commutativity of the products of difference operators, decomposition of high-order difference operators and the theory of a priori estimates are introduced and an optimal order error estimates in l^2 norm is derived. This method has been applied successfully to the numerical simulation of enhanced oil production in actual oilfields, and the simulation results ate quite interesting and satisfactory.

Theory and application of numerical simulation method of capillary force enhanced oil production

A kind of second-order implicit upwind fractional step finite difference methods are presented for the numerical simulation of coupled systems for enhanced （chemical） oil production with capillary force in the porous media. Some techniques, e.g., the calculus of variations, the energy analysis method, the commutativity of the products of difference operators, the decomposition of high-order difference operators, and the theory of a priori estimate, are introduced. An optimal order error estimate in the l2 norm is derived. The method is successfully used in the numerical simulation of the enhanced oil production in actual oilfields. The simulation results are satisfactory and interesting.

STUDIES ON STEROID PLANT-GROWTH REGULATOR 27.ENHANCED PRODUCT DIASTEREOMERIC EXCESSES IN ASYMMETRIC DIHYDROXYLATION OF THE(22E,24R)-AND THE(22E,24S)-24-ALKYL STEROIDAL UNSATURATED SIOECHAIN BY USING THE SHARPLESS IMPROVED CHIRAL LIGAND

The osmium tetroxide catalyzed asymmetric dihydroxylation of the(22E)- steroidal sidechain is described and an unexpected 8:1 ratio of(22R,23R)and (22S,23S)was obtained from the(22E,24S)-24-ethyl substituted sidechain.

Optimization of gas lift system for well performance improvement in Asmari formation:A techno-economic perspective

Well productivity in the Asmari carbonate formation of southwest Iran has decreased in recent years as a result of production issues.The production rate must be maintained below 1500 STB/day to prevent water coning.In this study,a gas lift well is modeled using data from one of the producing wells of this field.Nodal analysis is performed using lift-gas injection rates and wellhead pressures at different reservoir pressures and water cut conditions to optimize production.Economic aspects are considered to optimize the artificial gas injection rates at different tubing head pressures and water cut conditions.Increasing the lift-gas injection rate from 0.4 MMscf/day to 1 MMscf/day enhances the oil production rate by 37.71%and 43.89%for 10%and 30%water cut conditions,respectively.Gas injection rates of 5.2 MMscf/day and 5.4 MMscf/day are determined to be economically optimal for 30%water cut with tubing head pressures of 260 psig and 270 psig,respectively.

Enhancing production of a 24-membered ring macrolide compound by a marine bacterium using response surface methodology

A 24-membered ring macrolide compound,macrolactin A has potential applications in pharmaceuticals for its anti-infectious and antiviral activity.In this study,macrolactin A was produced by a marine bacterium,which was identified as Bacillus subtilis by 16S ribosomal RNA(rRNA) sequence analysis.Electrospray ionization mass spectrometry(ESI/MS) and nuclear magnetic resonance(NMR) spectroscopy analyses were used to characterize this compound.To improve the production,response surface methodology(RSM) involving Box-Behnken design(BBD) was employed.Faeces bombycis,the main by-product in sericulture,was used as a nitrogen source in fermentation.The interactions between three significant factors,F.bombycis,soluble starch,and(NH4)2SO4 were investigated.A quadratic model was constructed to fit the production and the factors.Optimum medium composition was obtained by analysis of the model.When cultivated in the optimum medium,the production of macrolactin A was increased to 851 mg/L,2.7 times as compared to the original.This study is also useful to find another way in utilizing F.bombycis.

Reduction of OsFLW7 expression enhanced leaf area and grain production in rice

Increasing rice production is important to ensure food security in China[1].Exploring yield potential and identifying genes beneficial to yield are important goals in the modern rice breeding.Generally,controlling leaf morphology,increasing photosynthesis efficiency and modulating the‘‘sink-source"relationship can promote the breeding of high-yield rice as well as other cereal crops[2–4].The morphology of the leaf includes length,width

In-situ grown CuO_(x)nanowire forest on copper foam:A 3D hierarchical and freestanding electrocatalyst with enhanced carbonaceous product selectivity in CO_(2)reduction

Electrocatalytic carbon dioxide(CO_(2))reduction is considered as an economical and environmentally friendly approach to neutralizing and recycling greenhouse gas CO_(2).However,the design of preeminent and robust electrocatalysts for CO_(2)electroreduction is still challenging.Herein,we report the in-situ growth of dense CuO_(x)nanowire forest on 3D porous Cu foam(CuO_(x)-NWF@Cu-F),which can be directly applied as a freestanding and binder-free working electrode for highly effective electrocatalytic CO_(2)reduction.By adjusting the surface morphology and chemical composition of CuO_(x)nanowires via surface reconstruction,large electrochemically active surface area and abundant Cu(+1)sites were generated,leading to remarkable activity for CO_(2)electroreduction.The as-prepared hierarchical conductive electrode exhibited an enhanced Faradaic efficiency of 15.0%for ethanol formation(FE_(C_(2)H_(5)OH))and a total Faradaic efficiency of 69.4%for all carbonaceous compounds(FE_(C-total))at a mild applied potential of–0.45 V vs.RHE in 0.1 M KHCO_(3)electrolyte.It achieved a 4-fold increase in FE_(C-total)than that of Cu nanowire forest supported on 3D porous Cu foam(Cu-NWF@Cu-F)obtained by in-situ reduction of the CuO_(x)-NWF@Cu-F via annealing at H_(2)atmosphere,and thereby effectively suppressed the hydrogen evolution side-reaction.