冻结孔泥浆置换浆液材料优化及浆液流动混合规律

发布时间：2019-03-04 14:33

【摘要】：近年来,全深冻结凿井技术逐渐在富水岩层井筒建设中得到推广应用,冻结孔的泥浆置换充填工艺得到了发展,然而,现场施工中依然会出现冻结管无法顺利下沉的情况。因此,本文采用室内试验、数值模拟及物理模型试验的方法,开展了冻结孔泥浆置换浆液材料优化及浆液流动混合规律的研究。首先,通过室内试验,在原配方的缓凝水泥浆中掺加超细水泥及外加剂的优化,开展缓凝水泥浆性能优化研究,确定了掺加超细水泥的缓凝水泥浆配方。结果表明:水泥浆中掺加超细水泥对浆液的初始流动性影响不大,但减小了水泥浆的初凝时间。从初始粘度、结石率、初凝时间、析水速率方面比较,水泥浆中超细水泥混掺量宜为20%~40%。在水泥浆中加入缓凝剂与分散剂,超细水泥混掺比例40%的悬浮稳定性比混掺比例30%和35%好。加入相同比例的悬浮剂后,混掺比例为40%的水泥浆悬浮稳定性明显高于混掺比例为30%、35%的水泥浆,且缓凝水泥浆的初始流动性良好。新、原配方的缓凝水泥浆分别与泥浆按照不同体积比混合后,混合浆液的表观粘度值随着缓凝水泥浆的比例增加,先缓慢增加然后快速减小;新配方与泥浆不同比例混合后的表观粘度整体都比原配方略大。混合浆液的初凝时间随着缓凝水泥浆的比例增加,呈先减小后增大的趋势。针对优化后的缓凝水泥浆,获得其表观粘度和动切力等流变参数。其次,通过室内试验,开展隔离液的研究,获得了适用于冻结孔泥浆置换充填的隔离液材料及其配方。试验结果表明:黄原胶掺量达到重晶石粉质量的0.45%时,隔离液的悬浮性能和流动性能优异。掺加2%的磺化褐煤树脂,滤失量为55ml,明显小于木质素磺酸钠和烷基萘磺酸钠。确定隔离液密度为1.30 g/cm3的配方组成为:1.77的水+1的重晶石粉+0.45%黄原胶+2%的磺化褐煤树脂。隔离液与泥浆和缓凝水泥浆的相容性良好,且隔离液的不同密度的悬浮稳定性、滤失性能及流变性能良好,能够满足施工需要。针对上述隔离液,获得了稠度系数和流性指数等流变参数。然后,通过数值模拟,研究了泥浆置换过程的浆液流动混合规律,获得了不同条件下混合段高度的变化规律。结果表明:体积分数为5%~95%的环空混合段高度h随着压浆流量的增加呈先增加后减小;随着壁面粗糙度的增加呈先减小后增大;随着钻杆内径与孔径之比的增加呈先增大后减小,然后再增大;随着浆液塑性粘度和动切力的逐渐增加呈先减小后增大再减小;随着钻杆偏心度的增加呈先减小后增大,且h2不断增大。同时研究了在各种因素最不利条件下所需隔离液的最小体积量。通过正交试验的极差和方差分析,影响h2的因素主次顺序和显著性顺序相同,依次为:钻杆偏心度压浆流量钻杆内径与孔径之比浆液流变参数壁面粗糙度;各因素对宽间隙处混合段高度h(5%~95%)的影响显著性依次为压浆流量因素钻杆偏心度因素壁面粗糙度因素浆液流变参数因素钻杆内径与孔径之比因素。最后,通过物理模拟试验,开展泥浆置换过程的浆液流动混合规律研究。结果表明:物理试验得出的混合段高度h随着流量的增加,h逐渐增大,但增加趋势减缓。对应模型的数值模拟结果表明,随着流量的增加,混合段高度h呈先增大后减小的趋势,但减小趋势很小;物理试验的混合段高度h的结果都比数值模拟的结果偏大,并分析了可能存在的影响因素。
[Abstract]:In recent years, the deep freezing and sinking technology has been widely used in the well-bore construction of the water-rich rock formation, and the mud replacement and filling process of the freezing hole has been developed. However, the construction of the site still has the condition that the freezing pipe cannot sink smoothly. In this paper, the method of indoor test, numerical simulation and physical model test is used to study the optimization of slurry material and the mixing law of slurry flow. First, through the indoor test, the optimization of the super-fine cement and the admixture in the slow-setting cement paste of the original formulation is carried out, and the performance optimization of the retarding cement slurry is carried out, and the formula of the slow-setting cement slurry with the super-fine cement is determined. The results show that the initial fluidity of the slurry is not affected by the addition of the super-fine cement in the cement paste, but the initial setting time of the cement paste is reduced. Compared with the initial viscosity, the stone rate, the initial setting time and the water extraction rate, the mixed content of the super-fine cement in the cement paste is 20-40%. Adding retarder and dispersant in the cement slurry, and the suspension stability of the super-fine cement mixing proportion of 40% is 30% and 35% better than the mixing ratio. After the same proportion of suspending agent is added, the suspension stability of the cement paste with the proportion of 40% is obviously higher than that of the cement paste with the mixing ratio of 30% and 35%, and the initial fluidity of the slow-setting cement slurry is good. And the apparent viscosity value of the mixed slurry is gradually increased and then rapidly reduced with the increase of the proportion of the slow-setting cement slurry after the slow-setting cement slurry of the original formula is mixed with the slurry according to the different volume ratio, and the overall apparent viscosity of the new formula and the slurry is larger than that of the original formulation. The initial setting time of the mixed slurry is increased with the increase of the proportion of the slow-setting cement slurry. The rheological parameters such as apparent viscosity and dynamic cutting force are obtained for the optimized slow-setting cement slurry. Secondly, through the indoor test, the isolation liquid is studied, and the spacer material and its formula are obtained. The results of the test show that when the content of the xanthan gum reaches 0.45% of the mass of the barite powder, the suspension property and the fluidity of the spacer liquid are excellent. By adding 2% of the sulfonated lignite resin, the filtration loss was 55 ml, which was obviously lower than that of the sodium lignosulfonate and the sodium alkylsulfonate. The formulation consisting of 1.77 of water + 1 barite powder + 0.45% xanthan gum + 2% sulfonated lignite resin was determined to have a density of 1.30 g/ cm3. The isolation liquid has good compatibility with the slurry and the slow-setting cement slurry, and the suspension stability, the filter loss performance and the rheological property of the different density of the spacer liquid are good, and the construction requirement can be met. The rheological parameters such as the consistency coefficient and the fluidity index are obtained for the above-mentioned spacer liquid. Then, through the numerical simulation, the mixing law of the slurry flow in the slurry displacement process is studied, and the variation law of the height of the mixing section under different conditions is obtained. The results show that the volume fraction is 5% ~ 95%, the height h of the annular mixing section increases with the increase of the grouting flow, and then increases with the increase of the surface roughness. With the gradual increase of the plastic viscosity and the dynamic cutting force of the slurry, the increase in the increase of the increase in the increase of the eccentricity of the drill pipe and the increase of h2. At the same time, the minimum volume of the required spacer is studied under the most adverse conditions of various factors. Through the range of the orthogonal test and the variance of variance, the main and secondary order and the significance order of the influence of h2 are the same, in order that the ratio of the inner diameter and the bore diameter of the drilling rod with the eccentric degree of the drill rod is the surface roughness of the rheological parameter of the slurry; The influence of each factor on the height h (5% ~ 95%) of the mixing section at the wide gap is the factor of the factor of the ratio of the inner diameter and the diameter of the pipe to the surface roughness factor of the eccentric degree of the drilling rod of the grouting flow. Finally, through the physical simulation test, the slurry flow mixing law of the mud displacement process is studied. The results show that the height h of the mixing section obtained by the physical experiment is gradually increased with the increase of the flow rate, but the trend is decreased. The numerical simulation results of the corresponding model show that with the increase of the flow, the height h of the mixing section is the tendency to decrease after the first increase, but the trend is small; the result of the height h of the mixing section of the physical test is larger than that of the numerical simulation, and the possible influence factors are also analyzed.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD265.3

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