缔合聚合物泡沫压裂液体系研究

发布时间：2018-05-03 08:23

本文选题：泡沫压裂液 + 缔合聚合物　；参考：《西南石油大学》2015年博士论文

【摘要】：泡沫压裂液以良好的抗剪切性能、较强的携砂能力、低滤失、低伤害以及快速返排等特点被认为是功能最全面的储层改造流体。但传统的泡沫压裂液体系依然是建立在以交联技术为特点的水基胍胶压裂液基础之上,交联技术存在的弊端在泡沫压裂液上依然存在。现有交联技术通过改变pH值来改变交联时间和抗温能力,pH值的增加将会对碱敏性储层造成伤害,对于本身呈酸性的二氧化碳泡沫压裂液体系,不得不寻求新的稠化剂和交联剂,使得问题越来越复杂。交联技术还会带来更多的水不溶物,影响增产效果。同时还存在施工摩阻难以减小、抗剪切性能难以提高、抗温能力难以进一步突破等一系列问题。近年来随着以黏弹性表面活性剂压裂液为代表的一系列新型非交联压裂液的出现,非交联技术已经逐渐成为压裂液技术发展的一个重要方向。本文围绕传统胍胶泡沫压裂液存在的问题和压裂液技术发展的方向展开研究,通过理论研究、室内试验和现场应用取得了以下主要成果和认识：(1)运用超分子化学与超分子结构溶液理论与实践,采用微观和宏观研究相结合的方法和技术手段,通过对一系列不同疏水基含量、不同水解度的缔合聚合物的研究,建立了缔合聚合物分子结构与聚合物溶液黏弹性之间,溶液黏弹性和泡沫稳定性之间的相互作用关系。确定了适用于泡沫压裂液使用的缔合聚合物的最佳分子结构。(2)使用环境扫描电镜、荧光探针法、电导率等方法证实了缔合聚合物溶液的空间网络结构、聚合物溶液在气液界面的富集等作用对泡沫的稳定性具有非常积极的作用。(3)通过对聚合物溶液的流变性研究发现,由于缔合聚合物特殊的分子结构,使其聚合物溶液具有剪切增稠和剪切稀释两种特殊的剪切诱导流变行为。当剪切速率较小时,随着剪切速率的增加,聚合物溶液黏度急剧上升。当剪切速率超过一定值后,随着剪切速率的增加,溶液黏度又急剧下降。这种特殊的流变行为既有利于泡沫的生成,又有利于泡沫的稳定。缔合聚合物溶液的缔合网络结构使其不需要交联就具有了形成泡沫压裂液所需的流变特性。(4)通过对泡沫压裂液的流变性研究发现,泡沫柏拉图通道结构的儿何拓扑变化赋予了泡沫新的黏弹特性。缔合聚合物溶液形成泡沫后,泡沫的储能模量增加了3倍,远大于基液或气体的单一相的弹性,弹性的大大增强也就意味更强的携砂能力。(5)通过对单剂的筛选和泡沫压裂液综合性能的室内评价,形成了缔合聚合物泡沫压裂液体系。该体系具有增黏性能好、携砂能力强、对岩心基质渗透率伤害低的特点。在基于实验和理论研究结果的基础上,突破传统对水基压裂液交联技术的认识,采用分子间缔合技术手段来获得了具有我们所需要功能的非交联缔合结构泡沫压裂液体系。(6)研制了流动回路摩阻测试装置,通过该装置的评价表明,缔合聚合物泡沫压裂液体系还具有摩阻低,抗剪切性能良好的特点。与化学交联相比,缔合作用表现出了特有的降阻优势,为解决泡沫压裂液摩阻难以降低的重大技术难题提供了一种有效的方法。室内试验证实了缔合聚合物泡沫压裂液的设想是完全正确和可行的。(7)利用该泡沫压裂液体系,成功进行了两井次的试验性施工。这是缔合聚合物泡沫压裂液体系在国内页岩气开发上的首次应用。现场施工表明缔合聚合物泡沫压裂液性能优良,完全能够满足该类地层的压裂要求,该体系对页岩地层伤害小,措施见效快,施工结束后总计排液80m3后即产气,3mm油嘴放喷点火,压力在11MPa以上,无阻流量达到10×104m3/d,增产效果明显。本文通过理论、室内研究和现场应用证明了缔合聚合物泡沫压裂液体系原理正确性和技术的可行性,为丰富我国泡沫压裂液种类、拓宽缔合聚合物的应用范围、提高低渗透油气田的高效开发水平提供了必要的理论基础和实验依据。
[Abstract]:The foam fracturing fluid is considered to be the most fully functional reservoir reconstruction fluid with the characteristics of good shear resistance, strong sand carrying capacity, low filtration loss, low damage and rapid return, but the traditional foam fracturing fluid system is still based on the water-based guanidine glue fracturing fluid based on crosslinking technology and the disadvantages of cross linking technology. The existing crosslinking technology changes the crosslinking time and the temperature resistance by changing the pH value. The increase of pH value will cause damage to the alkali sensitive reservoir. For the acidic carbon dioxide foam fracturing fluid system, it has to seek new thickener and crosslinking agent, making the problem more and more complicated. Cross linking technology It also brings more water insoluble substances, which also affects the effect of increasing production. At the same time, there are a series of problems such as difficult to reduce construction friction, difficult to improve shear property, and difficult to break through the temperature resistance. In recent years, a series of new type of non crosslinking fracturing fluid, represented by viscoelastic surfactant fracturing fluid, has been developed, and the non crosslinking technology has already been developed. It has gradually become an important direction of the development of fracturing fluid technology. This paper focuses on the existing problems of the traditional guanidine gum foam fracturing fluid and the direction of the development of fracturing fluid technology. Through theoretical research, the following main achievements and understanding are obtained in the laboratory and field application: (1) using the theory of supramolecular and supramolecular structure solution The interaction between the molecular structure of the associating polymer and the viscoelasticity of the polymer solution, the viscoelasticity of the solution and the stability of the foam are established through the combination of microcosmic and macro research methods and technical means. The best molecular structure for the association polymer used in foam fracturing fluid. (2) the spatial network structure of the associating polymer solution was confirmed by the environmental scanning electron microscope, the fluorescence probe method, the conductivity and so on. The enrichment of the polymer solution in the gas-liquid interface has a very positive effect on the stability of the foam. (3) through the polymer The study of the rheological properties of the solution shows that the polymer solution has two special shear induced rheological behaviors due to the special molecular structure of the associative polymer, which makes the polymer solution with shear thickening and shear diluting. When the shear rate is small, the viscosity of the polymer solution increases with the increase of shear rate. The viscosity of the solution decreases sharply. This special rheological behavior is beneficial to the formation of foam and the stability of the foam. The association network structure of the associative polymer solution has the rheological properties needed to form foam fracturing fluid without cross linking. (4) through the study of the rheological properties of foam fracturing fluid The topology changes of the foam Platon channel structure give the new viscoelastic properties of the foam. After the formation of a polymer solution foam, the storage modulus of the foam has increased by 3 times, far greater than the elasticity of the single phase of the base liquid or gas, and the great enhancement of elasticity means stronger sand carrying capacity. (5) through the screening of single agent and foam fracturing The laboratory evaluation of comprehensive properties of liquid formed an association polymer foam fracturing fluid system. This system has the characteristics of good viscosity enhancement, strong sand carrying capacity and low permeability damage to core matrix. Based on the experimental and theoretical research results, it breaks through the traditional understanding of the crosslinking technology of water based fracturing fluid and uses the intermolecular association technical hand. The non crosslinked associative foam fracturing fluid system with the function we need is obtained. (6) a flow circuit friction test device has been developed. Through the evaluation of the device, the association polymer foam fracturing fluid has a low friction resistance and good shear resistance. Compared with chemical crosslinking, the association effect shows the special effect. In order to provide an effective method to solve the major technical problems that are difficult to reduce the frictional resistance of the foam fracturing fluid, the laboratory tests have confirmed that the idea of the association polymer foam fracturing fluid is completely correct and feasible. (7) the experimental construction of two wells has been successfully carried out by using the foam fracturing fluid system. This is an association polymer. The foam fracturing fluid system is used for the first time in the development of shale gas in China. The field construction shows that the association polymer foam fracturing fluid has excellent performance and can fully meet the fracturing requirements of this kind of formation. The system has little damage to the shale formation, and the measures are effective quickly. After the completion of the total arrangement of 80m3, the gas producing, the 3mm oil nozzle is fired and the pressure is in 11M. Above Pa, the unhindered flow rate is 10 * 104m3/d, and the effect of increasing production is obvious. Through the theory, indoor research and field application prove that the principle of the association polymer foam fracturing fluid system is correct and the technology is feasible, in order to enrich the type of foam fracturing fluid in our country, broaden the application range of the association polymer and improve the efficient development of the low permeability oil and gas field. The level provides the necessary theoretical basis and experimental basis.

【学位授予单位】：西南石油大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TE357

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