X区块储层敏感性评价试验与成因研究
马杰 李宇 周思宇
摘 ?????要:油田低渗透率储层在进行钻井、固井、增产措施等勘探、开发环节中,储层会与不同类型的入井流体进行接触,当入井液与储层岩石配伍性不好,将会影响储层产量。为了降低开发过程中对X区块储层造成的损害,对其进行了敏感性评价(包括速敏、水敏、应力敏)实验。研究结果表明60-1HF井表现为强速敏、强水敏、中等偏强应力敏;60-2HF井表现为中等偏强速敏、强水敏、强应力敏;60-3HF井表现为中等偏弱速敏、中等偏强水敏、中等偏强应力敏。综合评价该区块为中等速敏、强水敏、强应力敏,该结果对X区块的开发有一定的指导意义。
关 ?键 ?词:储层敏感性;速敏性;水敏性;应力敏感
中图分类号:TE122.2 ??????文献标识码: A ??????文章编号: 1671-0460(2019)02-0364-04
Abstract: In exploration and development links of low-permeability reservoirs such as drilling,cementing and stimulation measures, the oil reservoirs in the oil field will be exposed to different types of well-injected fluids. When the well-in-place fluids are poor compatibility with the reservoir rocks, they will affect the reservoir production. In order to reduce the damage to the X-block reservoir during the development process, sensitivity evaluation (including speed sensitivity, water sensitivity, and stress sensitivity) experiments were performed. The results indicated that the 60-1HF well was characterized by strong velocity sensitivity, strong water sensitivity, and medium-strong stress sensitivity; the 60-2HF well exhibited moderate-strong velocity sensitivity, strong water sensitivity and strong stress sensitivity; the 60-3HF well exhibited moderate-weak velocity sensitivity, moderate-strong water sensitivity and moderate-strong stress sensitivity. Comprehensive evaluation of the block is moderate speed-sensitive, strong water -sensitive, and strong stress-sensitive. This result has certain guiding significance for the development of the X block.
Key words: Reservoir sensitivity; Speed sensitivity; Water sensitivity; Stress sensitivity
储层损害在整个油气勘探开发中都是油藏工程师的首要问题,油田采取的增产措施均可能造成油气储层的伤害,只有通过了解储层敏感性并认识其产生的机理才能根本的解决该问题。地层损害评价以及储层保护的主要内容就是储层敏感性评价与其机理的研究, 并且又是影响低渗储层合理开发的决定性因素[1]。许多学者调研了各种地区以及各种油藏类型的储层,针对低渗储层的敏感性进行了多组岩心流动实验,对其敏感性特征进行了总结与分析[2]。在储层敏感性成因机理研究方面 ,国内外也取得了一定认识[3]。对于敏感性评价国内外已有较为完备的实验方法,我国有SY/T 5336行业标准明确规定实验流程。在储层损害机理研究上,已有X衍射、扫描电镜、CT扫描和恒速压汞等微观实验手段,可以对储层岩石进行全面详细的宏观以及微观研究[4]。
1 ?储层地质作用
储层地质作用之一的压实作用在X区块中由下面几点体现:颗粒间从沉积初始的点接触演变到现有的线接触的接触方式,其中也有少部分凹凸接触;云母在颗粒指尖受到挤压呈现挠曲变形;塑性岩屑挤压变形、刚性颗粒破裂等。研究层段内大量发育的碎屑颗粒广泛形成裂隙,这为不稳定碎屑颗粒后期遭受溶蚀改造提供了更多的渗流通道,使得溶蚀改造能够进行地更加深入[5]。
溶蚀作用主要表現在长石的溶蚀以及岩屑的溶蚀,由于长石的化学不稳定性,使得长石所经历的成岩改造在储层成岩过程中表现地异常突出,主要包括溶蚀作用、碳酸盐交代作用、钠长石化等。在酸性介质条件下,长石部分或全部被溶解,形成粒内溶孔、网状溶孔、溶蚀残骸甚至全部溶蚀形成铸模孔。
2 ?储层敏感性评价试验
2.1 ?试验准备