长宁龙马溪组页岩水基钻井液研究

发布时间：2018-01-14 14:10

  本文关键词：长宁龙马溪组页岩水基钻井液研究　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 页岩气 水基钻井液 封堵性 抑制性 润滑性

【摘要】：油基钻井液在页岩气井钻井中占据着主导地位,但随着人们环保意识的不断提高和为了增加经济效益,页岩水基钻井液逐渐成为人们关注的重点。常规水基钻井液体系对页岩水平井而言,其润滑性和井眼清洁能力较差,在造斜段和长水平段易出现高摩阻和高扭矩的现象,同时水相的侵入还会造成页岩水化和内部结构损伤破坏,引起井壁坍塌。这些问题严重制约了水基钻井液在页岩气开发中的应用。因此,针对页岩气层水基钻井液开展系统研究,对我国页岩气的开发具有重要的意义。 本文以长宁龙马溪组页岩为研究对象,在对其组构特征及已钻井地质、工程资料进行系统研究和梳理分析的基础上,开展了页岩水基钻井液的封堵剂、降滤失剂、抑制剂和润滑剂的评价和优选。通过大量的配伍性实验,初步研制出了可用于该页岩气层水平井钻井的水基钻井液体系,并进行了现场试验应用。取得了以下认识和成果： (1)长宁龙马溪组页岩的矿物组成以石英和黏土矿物为主,其中黏土矿物主要以伊利石为主,并含有少量伊/蒙混层和绿泥石。受压实作用影响,页岩矿物颗粒胶结致密,岩石内部发育有大量微孔隙和微裂缝。因此,“有效封堵”和抑制水化是页岩水基钻井液性能设计与优化中必须解决的关键问题。 (2)通过API和高温高压透失水实验优选出了降滤失效果最好的NR-1作为页岩水基钻井液的封堵剂；采用聚合物降滤失剂PAV-LV和磺化降滤失剂RSTF、SMP-Ⅱ三种处理剂复配得到了页岩水基钻井液的降滤失剂；基于浸泡实验,抑制膨润土造浆率实验和滚动回收率实验,优选出了抑制效果较好的聚合醇(PEG)作为页岩水基钻井液的主要抑制剂；室内配制了润滑性能较好的乳液作为页岩水基钻井液的润滑剂。通过复配实验得出降滤失剂的最优加量为：0.6%PAC-LV+4%SMP-II+5%RSTF,封堵剂、抑制剂和润滑剂的最优加量为：2%NR-1+3%PEG+10%乳液。 (3)所研制的页岩水基钻井液体系的封堵能力和抑制性能都较好,并具有良好的润滑性能,其井壁稳定能力强于长宁地区现使用的聚磺和聚合物钻井液体系,而弱于油基钻井液体系。该体系在长宁区块宁A井和宁B井的造斜段表现出了较好的性能,不仅大幅度减少了钻井液的成本和钻屑处理费用,而且还降低了对环境污染的风险。 (4)该体系在现场试验应用时,只达到井斜角57°。现场试验发现,要使该体系能够在页岩水平井中安全钻进,其封堵能力还需进一步提高,润滑性能还需进一步改善。页岩水基钻井液中还需选用或研制抑制性更强的抑制剂。
[Abstract]:Oil based drilling fluid plays a leading role in shale gas well drilling, but with the continuous improvement of people's awareness of environmental protection and in order to increase economic benefits. Shale water-based drilling fluid has gradually become the focus of attention. Conventional water-based drilling fluid system for shale horizontal wells, its lubricity and wellbore cleaning ability is poor. The phenomena of high friction and high torque are easy to occur in the diagonal and long horizontal sections, and the invasion of water phase will also cause shale hydration and internal structure damage. These problems seriously restrict the application of water-based drilling fluid in shale gas development. It is of great significance to the development of shale gas in China. In this paper, the shale of Changning Longmaxi formation is taken as the research object. Based on the systematic study and analysis of its fabric characteristics, drilling geology and engineering data, the plugging agent of shale water-based drilling fluid is developed. Evaluation and selection of filtrate reducer, inhibitor and lubricant. Based on a large number of compatibility experiments, a water-based drilling fluid system for drilling horizontal well of shale gas reservoir has been preliminarily developed. The field test and application have been carried out, and the following knowledge and results have been obtained: 1) the mineral composition of Changning Longmaxi formation shale is mainly composed of quartz and clay minerals, in which the clay minerals are mainly Illite, and contain a small amount of Iraq / Mongolia layer and chlorite, which are affected by compaction. The shale mineral particles are cemented and dense, and a large number of micro-pores and micro-fractures are developed in the rock. Therefore, "effective plugging" and hydration inhibition are the key problems in the design and optimization of shale water-based drilling fluid performance. (2) through API and high temperature and high pressure water permeation experiments, NR-1, which has the best filtration reduction effect, is selected as the plugging agent for shale water-based drilling fluid. The filtration reducer of shale water-based drilling fluid was obtained by using polymer filtration reducer PAV-LV and sulfonated filter reducer RSTF SMP- 鈪，

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