泥饼性能对冲洗效率的影响研究

发布时间：2019-01-21 16:25

【摘要】：随着对油气资源需求的不断增长和勘探程度的增大,低渗油气藏是目前和未来油气勘探开发的主要对象。水平井钻井技术与储层整体改造技术是低渗透油气藏开发的主要技术手段之一,如果水平井钻井过程中形成的泥饼未被冲洗干净,会加重水泥环与地层易剥离,引起油气窜流,从而影响固井质量。因此在提高低渗油气藏固井质量技术中,提高泥饼的冲洗效率显得越发重要。本文主要研究泥饼性能对冲洗效率的影响,旨在提出一种通过定量调整钻井液添加剂改变泥饼性能从而提高固井质量的方法。本文重点是针对现有高温高压下泥饼形成与冲洗装置的不足进行改进,以及提出泥饼性能调整方法,并改进冲洗施工工艺提高泥饼冲洗效率。具体开展的主要研究工作和取得的主要成果如下：(1)在调研国内外泥饼形成装置和泥饼冲洗装置的基础上,基于固井环空壁面与评价装置内筒壁面处剪切速率相等的原理并结合钻井液和冲洗液的流变模式,改进现有的高温高压动态泥饼形成及冲洗装置,使装置模拟的钻井液和冲洗液流动与实际井下钻井液和冲洗液环空返速的大小一一对应,可以定量模拟泥饼的形成与冲洗。(2)利用泥饼的剪切受力模型,分析影响泥饼冲洗效率的主要泥饼性能参数。通过室内试验评价不同性能泥饼的冲洗效率,并用灰色关联度理论分析得出泥饼的强度对冲洗效率影响最大,其次是压缩性,再次是泥饼厚度,最后是泥饼的渗透率。(3)通过分析钻井液添加剂对泥饼性能的影响,不同的钻井液体系,需要调整不同的添加剂及其加量,以改善泥饼的性能,提高冲洗效率。如1#钻井液同时加入1%的CMC和0.7%的有机分散剂能降低泥饼强度,有效改善泥饼冲洗效率,冲洗效率能达到75%以上。而2#钻井液降失水剂CMC加量为1%-1.5%时,稀释剂加量为0.7%,氯化钾加量为0.3%时能降低泥饼强度,使冲洗效率提高15%。(4)通过调整钻井液添加剂改善泥饼性能、优化钻井液环空返速、优选冲洗液体系和冲洗液用量等施工工艺可以提高低渗油气藏水平井泥饼冲洗效率。
[Abstract]:With the increasing demand for oil and gas resources and the increase of exploration degree, low permeability reservoirs are the main targets of oil and gas exploration and development at present and in the future. Horizontal well drilling technology and reservoir integral reconstruction technology are one of the main technical means for developing low permeability oil and gas reservoirs. If mud cake formed during horizontal well drilling is not washed out, cement ring and formation will be easily stripped off, causing oil and gas channeling. Thus the cementing quality is affected. Therefore, it is more and more important to improve the washing efficiency of mud cake in improving cementing quality of low permeability reservoirs. In this paper, the effect of mud cake properties on washing efficiency is studied, and a method to improve cementing quality by quantitatively adjusting drilling fluid additives to change mud cake performance is proposed. The emphasis of this paper is to improve the existing mud cake forming and washing equipment under high temperature and high pressure, to put forward the method of mud cake performance adjustment, and to improve the washing construction technology to improve the washing efficiency of mud cake. The main research work and main achievements are as follows: (1) based on the investigation of mud cake forming device and mud cake washing device at home and abroad, Based on the principle of equal shear rate between the wall of cementing annulus and the inner wall of the evaluation device, and combining with the rheological model of drilling fluid and flushing fluid, the existing high-temperature and high-pressure dynamic mud cake forming and washing device are improved. By making the flow of drilling fluid and flushing fluid simulated by the device correspond to the actual downhole drilling fluid and flushing fluid return velocity, the formation and flushing of mud cake can be quantitatively simulated. (2) the shearing force model of mud cake is used. The main performance parameters of mud cake which affect the washing efficiency of mud cake are analyzed. The washing efficiency of mud cake with different properties was evaluated through laboratory tests. The results of grey correlation degree theory showed that the strength of mud cake had the greatest influence on the washing efficiency, followed by compressibility, and then the thickness of mud cake. Finally, the permeability of mud cake. (3) by analyzing the influence of drilling fluid additives on mud cake performance, different drilling fluid systems need to adjust different additives and their amount to improve the performance of mud cake and improve the washing efficiency. For example, the mud cake strength can be reduced by adding 1% CMC and 0.7% organic dispersant at the same time, and the washing efficiency of mud cake can be improved effectively, and the washing efficiency can reach more than 75%. The mud cake strength can be reduced when the ratio of CMC, diluent and potassium chloride is 0. 7 and 0.3, respectively, when the CMC of drilling fluid is between 1% and 1.5%, the quantity of diluent is 0.7, and that of potassium chloride is 0.3. (4) by adjusting drilling fluid additive to improve mud cake performance, optimizing drilling fluid annulus return velocity, optimizing washing fluid system and washing fluid dosage, etc., the mud cake washing efficiency of horizontal well in low permeability reservoir can be improved.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE256

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