含瓦斯煤体渗吸水变形特征实验研究

为了研究含瓦斯煤体渗吸水变形特征,利用自主设计搭建的承压瓦斯自然吸水实验系统,开展煤体在0.5、1.0、1.5、2.0 MPa瓦斯吸附平衡压力下的自然渗吸水实验。实验结果表明:气体吸附阶段,瓦斯压力越大,煤体横、纵变形量越大,纵向变形量约为横向变形量的2倍;自然渗吸阶段,煤体横、纵变形量均大于同一瓦斯压力下单纯气体吸附过程,实验系统环境压力值小幅升高,压力上升最大值为0.013 MPa,表明水渗吸同时存在瓦斯解吸过程;卸压泄水阶段,不同瓦斯压力下煤体的含水率分别为0.98%、1.05%、1.51%、2.24%,体应变和初始瓦斯压力二次相关,煤体体应变残余变形值较大,表明水渗吸作用后含瓦斯煤体变形的不可逆性和破坏性。

低渗透凝析气藏反凝析水锁伤害解除方法现状

低渗透凝析气藏的反凝析污染、水锁伤害对气井生产、气藏采收率等产生严重影响,因此研究解除凝析气藏近井地层反凝析、反渗吸地层伤害,提高气井产能的技术方法,具有重要的实际意义。调研了国内外文献,详细阐述了反凝析和水锁效应机理,提出了各种解除此两种伤害的方法,并提出在注气吞吐之前先注入一个有限尺寸的甲醇溶液前置段塞来解除反凝析油和水锁产生的地层堵塞,以改善注气吞吐,提高凝析气井产能的效果,该方法在现场得到了成功应用。

组合段塞工艺解除凝析气井水锁伤害实验评价

在凝析气井生产过程中,井底长期积液极易导致近井地带发生反渗吸水锁效应,形成水锁伤害,降低储层渗流能力,增大生产压差,严重影响气井产能的释放.以Y凝析气井为例,采用考虑反渗吸水锁的气井产能方程,分析反渗吸水锁效应对气井产能的影响,并采用“甲醇+酸+解水锁剂+氮气吞吐”组合段塞工艺方式,开展Y井长岩心解除水锁效果实验评价.实验结果表明,气井无阻流量随着反渗吸水锁侵入深度的增大而急剧降低,“甲醇+酸+解水锁剂+氮气吞吐”组合段塞解除水锁效果很好,渗透率恢复倍数达到6.2.

The Unsaturated Hydraulic Parameters for Aeolian Sand

The water characteristic curve for aeolian sand in two processes of wetting and drying was obtained by the negative water column technique.The values of fitting parameters were calculated according to Van Genuchten formula and the parameters that characterized the prosperities of aeolian sand such as the unsaturated infiltration coefficient and specific water capacity were obtained.The results showed that the water characteristic curve for aeolian sand in wetting process had greater hysteresis quality than ...

凝析气藏伤害机理及长岩心实验研究

低渗凝析气藏的储层伤害机理和实验研究是气藏开发的重点和难点。基于反凝析和反渗吸水锁伤害机理,通过毛管模型推导低渗凝析气藏水锁伤害锁解除理论模型。通过建立真实气田的长岩心实验,定量模拟了反凝析和反渗吸水锁伤害,反凝析伤害和反渗吸水锁伤害大幅度降低储层渗透率。最后基于机理和长岩心实验研究成果,对南海西部低渗凝析气田的地质油藏方案进行了优化,降低了开发风险,为低渗凝析气田开发提供重要指导。

Effect of Irrigation Water Quality on Soil Hydraulic Conductivity

The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the higher the electric conductivity (EC) of irrigation water,the higher the soil HC became.The soil HC doubled when EC increased from 0.1 to 6.0ds m^-1.High sodium-adsorption ratio(SAR) of irrigation water would have an unfavorable effect on soil HC.Soil HC decreased with the increasing of SAR,especially in the case of higher soil suction.An interaction existed between the effects of EC and SAR of irrigation water on soil HC.The HC of unsaturated soil dependent upon the macropores in surface soil decreased by one order of magnitude with 1 KPa increase of soil suction.In the study on the effect of very low soluble salt concentration (EC=0.1 ds m^-1 of irrigation water on soil HC,soil HC was found to be lowered by 30% as a consequence of blocking up of some continuous pores by the dispersed and migrated clay particles.Nonlinear successive regression analysis and significance test show that the effects of EC and SAR of irrigation water on soil HC reached the extremely significant level.

Fibrous TiO_2 prepared by chemical vapor deposition using activated carbon fibers as template via adsorption,hydrolysis and calcinations

TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by N2 to an APCVD （chemical vapor deposition under atmospheric pressure） reactor at ≤200 ℃. Activated carbon fibers （ACFs） were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron micros- copy （SEM）, transmission electron microscopy （TEM）, Brunauer, Emmett and Teller （BET） and X-ray diffraction （XRD） analysis The pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m^2/g and 148 m^2/g for samples deposited at 100 ℃ and 200℃ （using ACFI700 as template）, respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds.

裂缝气藏水侵机理及对开发影响实验研究

针对裂缝—孔隙型气藏水侵规律及影响气藏采出程度机理的认识难题,采用物理模拟实验技术,开展了贯通水平裂缝条件下的水侵规律实验、储层基质渗吸水实验以及储层基质渗吸水后对储层供气机理的影响实验,明确了储层基质水侵与裂缝水侵的区别,认识了裂缝—孔隙型边底水气藏水侵规律及其对气藏产能以及采收率的影响机理,即裂缝水侵过程中边底水会沿裂缝快速突进、同时储层基质会渗吸水、基质渗吸水后减少气相渗流通道,从而增加储层基质气相渗流阻力,降低气藏稳产能力和最终采出程度,该项机理认识揭示了裂缝气藏水侵后导致气井产量、最终采出程度大幅度下降的主要原因。在上述机理认识基础上,进一步研究了贯通裂缝水侵前沿推进速度与储层物性、水体大小的关系,分类测试了不同渗透率储层基质渗吸水的能力,模拟评价了不同渗吸水方式和渗吸水量对气藏储层稳产能力和最终采出程度的影响,研究成果可以为我国塔里木盆地迪那气田、克深气田以及四川盆地磨溪龙王庙气藏科学开发提供技术支持。

Percutaneous aspiration and drainage with adjuvant medical therapy for treatment of hepatic hydatid cysts

AIM:To determine the efficacy and success of percutaneous aspiration irrigation and reaspiration(PAIR) in the management of hepatic hydatidosis.METHODS:Twenty-six patients with 32 hepatic hydatid cysts had PAIR.Twenty-two patients received at least 2 wk of drug therapy before the procedure was carried out to reduce the risk of recurrence from spillage during the procedure.The procedure was performed under local anesthesia with a 19-gauge 20 cm long needle,the cyst was punctured,cystic content(approximately 30 mL) was aspirated by a 12-14 F pigtail catheter and aspirated fluids were sent for analysis.Once the cyst was almost empty,two-thirds of the net amount of material aspirated was replaced by hypertonic saline and left in the cavity for about 30 min,with the catheter left in place for reaspiration of most of the fluid.When the amount of fluid drained was less than 10 mL per 24 h,the drainage catheter was removed.RESULTS:All 32 cysts showed evidence of immediate collapse after completion of the procedure,and before discharge from hospital,ultrasound examination showed fluid reaccumulation in all cysts.Serial follow-up showed a progressive decrease in the size and change in the appearance of cysts.To confirm the sterility of these cystic cavities,seven cysts were reaspirated on average 3 mo after the procedure.Investigations revealed no viable scolices.CONCLUSION:PAIR using hypertonic saline is very effective and safe with proper precautions.

Stability Analysing of Unsaturated Soil Slope

The stability of unsaturated soil slope has been the hot point recently. Especially, the seeping rainfall makes losing stability of unsaturated soil slope, and causes enormous loss to the producation and safety of other people. The seeping rainfall makes volumetric water content of unsaturated soil slope changing, and the volumetric water content has directly relationship with matric suction. And matric suction also has directly relationship with the stability of unsaturated soil slope. So the change of matric suction influence the stability changing, that is, safety coefficient has decided relationship with volumetric water content. The profile of dangerous volumetric water content curves of unsaturated soil slope has been obtained. If a volumetric water content curve of some unsaturated soil slope belongs to one of these dongerous curves, the unsaturated soil slope could be in danger. So this is called DVWCCP(dangerous volumetric water content curves profile). By monitoring the volumetric water content curves can obtain the stability information of some soil slope to serve producing and safety.

Research on Permeability of Multiphase Medium of Middle to High-Rank Coals

The permeability of coal of middle to high ranks were tested using He,CH 4 and H 2O in single phase medium and using CH 4 and H 2O in double phase medium. The relation between adsorption and permeability of those media was discussed, and the seepage flow characteristics of methane-water medium in coals were analyzed. The result shows that the coalbed methane resource of high-rank coal reservoirs in China is still recoverable.

Influence of Water Vapor on Silica Membrane： Adsorption Properties and Percolation Effect

The influence of water vapor on silica membrane with pore size of ,-4A has been investigated in terms of adsorption properties and percolation effect at 50 and 90 ℃. Two methods are employed： spectroscopic ellipsometry for water vapor adsorption and gas permeation of binary mixture of helium and H2O The adsorption behaviors on the silica membrane comply with the first-order Langmuir isotherm. The investigation demonstrates that helium flux through the silica membrane decreases dramatically in presence of H20 molecules. The transport of gas molecules through such small pores is believed not to be continuous any more, whereas it is reasonably assumed that the gas molecules hop from one occupied site to another unoccupied one under the potential gradient. When the coverage of H20 molecules on the silica surface increases, the dramatic decrease of helium flux could be related to percolation effect, where the adsorbed H20 molecules on the silica surface block the hopping of helium molecules.