转向重复压裂暂堵剂性能评价

发布时间：2018-01-26 18:54

  本文关键词： 重复压裂 地应力 暂堵剂 水溶性 暂堵　出处：《长江大学》2017年硕士论文　论文类型：学位论文

【摘要】：油气藏在不断开发过程中,随着开采次数的增多,初次压裂的采油量将不断降低,又恢复到最初的低产低效状态。如果继续采用多次压裂的常规方法,将仍是压开老裂缝,起不到显著的增产效果。而转向压裂技术是目前解决老井低产低效比较行之有效的方法。该技术的重要机理在于压裂前向地层挤入一部分暂堵剂暂堵老裂缝,关井憋压一段时间后开启复杂裂缝网络,或是将暂堵剂注入孔眼或缝口,迫使其产生新裂缝,进而加强新高含油气区的“沟通”,提高气井的改造能力[1]。目前,裂缝转向主要有三种方法:1)地应力反转;2)定向射孔诱导3)暂堵转向压裂工艺。本课题从原地应力场分析出发确定了重复压裂前储层的应力分布,并建立原地应力、初次人工裂缝和孔隙压力对原地应力场影响的计算模型;结合岩石造新缝力学分析及裂缝延伸准则,研究了天然裂缝转向及延伸情况。暂堵剂自身性质的优良,决定着缝内转向压裂工艺的成功与否,由于受地应力场及天然裂缝的影响,暂堵转向剂须具备一些特殊性能。本文测试了几种新型的水溶性暂堵转向试剂,通过对它们的静(溶解性、配伍性、表面活性等)、动(暂堵率、解堵率测定)态室内评价实验研究,以及对影响其暂堵效果的工艺因素试验研究,筛选出SC-JXSG、BJ-APJEL两种满足暂堵压裂施工现场要求的高效暂堵剂。该实验结果表明:(1)静态评价实验中,质量分数为3%的SC-JXSG和BJAPGEL两种暂堵剂在30℃时溶解缓慢,60℃~80℃时数小时能充分溶解;最终不溶物含量都较低,最大值仅为5.19%,(2)动态评价实验中,在60℃条件下,注入1PV质量分数为3%的SC-JXSG和BJ-APGEL两种暂堵剂,暂堵率可高达98%;在80℃条件下,反向注入10PV地层水解堵,但解堵效果不是很好,位于50%~80%之间。对比裂缝暂堵和基质暂堵,SC-JXSG暂堵剂对裂缝的暂堵效果较好,BJAPGEL暂堵剂对基质的暂堵效果较好。
[Abstract]:In the process of oil and gas reservoir development, with the increase of production times, the oil production of initial fracturing will be reduced continuously, and then the initial low production and low efficiency will be restored. If the conventional method of multiple fracturing is adopted, the conventional method of multiple fracturing will continue to be adopted in the process of oil and gas reservoir development. Will still be to open the old crack. The technology of turning to fracturing is an effective method to solve the problem of low productivity and low efficiency in old wells. The important mechanism of this technique is to squeeze a part of temporary plugging agent into the formation before fracturing to temporarily block the old fracture. The complex fracture network is opened after shut-in for a period of time, or the temporary plugging agent is injected into the hole or fracture mouth, forcing it to produce new fractures, thus strengthening the "communication" in the high oil and gas bearing area and improving the ability of gas well transformation. [1. At present, there are three main methods of fracture turning: 1) inversion of in-situ stress; 2) directional perforation induces 3) temporary plugging turns to fracturing technology. Based on in-situ stress field analysis, the stress distribution of reservoir before repeated fracturing is determined and the in-situ stress is established. The primary artificial fracture and pore pressure on the original stress field calculation model; Combined with rock fracture mechanics analysis and fracture extension criterion, the natural fracture turning and extending conditions are studied. The good properties of temporary plugging agent determine the success of in-fracture steering fracturing process. Due to the influence of in-situ stress field and natural cracks, the temporary plugging steering agent must have some special properties. In this paper, several new water-soluble temporary plugging reagents were tested, and their static (solubility, compatibility) were tested. SC-JXSG was screened out by surface activity isochron, dynamic (temporary plugging rate, plugging removal rate measurement) indoor evaluation experiment, as well as the experimental study on the technological factors affecting its temporary plugging effect. BJ-APJEL two kinds of high efficiency temporary plugging agents which meet the requirements of temporary plugging fracturing site. The experimental results show that in the static evaluation experiment. Two temporary plugging agents, SC-JXSG and BJAPGEL, with a mass fraction of 3%, dissolve slowly at 30 鈩，

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