基于CT扫描技术的低渗油藏水敏效应后微观孔隙结构特征

胡心玲; 雷浩

doi:10.19509/j.cnki.dzkq.2022.0092

基于CT扫描技术的低渗油藏水敏效应后微观孔隙结构特征

doi: 10.19509/j.cnki.dzkq.2022.0092

胡心玲,
雷浩^,

中国石油化工股份有限公司江汉油田分公司勘探开发研究院, 武汉 430223

基金项目:

中国石油化工股份有限公司科研项目"新沟嘴组低渗透敏感性储层开发关键技术" P20069-5

详细信息

作者简介:
胡心玲(1975— ), 女, 高级工程师, 主要从事油气田开发与管理工作。E-mail: huxinl.jhyt@sinopec.com

通讯作者:
雷浩(1989— ), 男, 副研究员, 主要从事油气渗流理论与应用和提高采收率研究工作。E-mail: leihaojs89@126.com

中图分类号: P618.13
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- 被引次数: 0
出版历程
- 收稿日期: 2021-08-29

Using CT scanning technology to investigate microscopic pore structure characteristics of low-permeability reservoir rocks after water sensitivity experiments

Hu Xinling,
Lei Hao^,

Research Institute of Petroleum Exploration and Development, SINOPEC Jianghan Oilfield Company, Wuhan 430223, China

摘要

摘要:
为了研究水敏效应对低渗油藏微观孔隙结构特征的影响，将CT在线扫描技术和岩心驱替实验相结合，开展了低渗油藏不同渗透率岩心水敏性评价实验，对水敏过程中孔、喉半径分布特征、配位数、孔隙变化特征、物性参数变化及对储层渗流能力的影响进行了实验研究，并绘制了水敏前后极限注采井距对比图版。结果表明，随着渗透率降低，水敏效应对孔隙、喉道伤害程度越大、平均孔喉配位数减少越多。两者共同作用是造成储层启动压力梯度增加的主要原因；水敏效应对储层喉道伤害程度远大于对孔隙伤害程度；水敏效应造成黏土膨胀、颗粒运移几乎发生在所有孔隙中，但对岩心整体孔隙结构和分布特征影响不大。通过极限注采井距可知，水敏效应造成新沟嘴组低渗油藏极限注采井距减少了153 m，需要通过加密井来调整注采井距，改善注水波及范围。该研究结果对长期注水的水敏性低渗储层开发调整具有现场指导意义。
- CT扫描 /
- 低透油藏 /
- 水敏效应 /
- 微观孔隙结构 /
- 储层伤害
Abstract:
CT scanning and core flooding experiments were combined to investigate the change in microscopic pore structure of low-permeability reservoir rocks due to the water sensitivity effect. Water sensitivity experiments were conducted for low-permeability reservoirs using different permeability core plugs to study the pore throat radius distribution, coordination number, pore structure variation, physical property parameter variation, and effects on the seepage capacity. The comparison plates of the limit injection-production spacing were drawn. The results indicate that the pore throat damage increases while the mean coordination number decreases with the reduction of permeability, which leads to a higher flow resistance and a stronger damage to the microscopic pore structure. These combined effects lead to an increase in the starting pressure gradient. In addition, the damage extent of reservoir throats is much larger than that of pores in the reservoir. Moreover, the swelling of clay minerals and the particle migration mostly present in the pore space due to the water sensitivity effect, which would hardly influence the whole pore structure and distribution feature of the core plug. Furthermore, according to the limit injection-production spacing plates, the limit injection-production spacing of the Xingouzuizu Formation low-permeability reservoir decreases by 153 m, which is caused by the effect of water sensitivity. The injection-production well spacing must be adjusted by the infill well, which can be used to improve the injected water swept volume. This research could provide certain practical guidance for the development adjustment of low-permeability reservoirs featuring the water sensitivity effect under a long period of waterflooding.
- CT scanning /
- low-permeability reservoir /
- water sensitivity effect /
- microscopic pore structure /
- formation damage

HTML全文

图 1 不同渗透率岩心水敏前后孔隙半径分布对比曲线

Figure 1. Frequency distribution of the pore radii of core plugs with different permeabilities before and after water sensitivity tests

下载: 全尺寸图片幻灯片

图 2 不同渗透率岩心水敏前后喉道半径分布对比曲线

Figure 2. Frequency distribution of throat radii of core plugs with different permeability before and after water sensitivity tests

下载: 全尺寸图片幻灯片

图 3 不同渗透率岩心水敏前后配位数分布对比

Figure 3. Coordination number of different permeability core plugs before and after water sensitivity tests

下载: 全尺寸图片幻灯片

图 4 岩心2X-3水敏实验前后二值化后岩心切片图

Figure 4. Core slices after binarization of the 2X-3 core plug before and after water sensitivity tests

下载: 全尺寸图片幻灯片

图 5 岩心2X-1水敏前后三维孔隙网络模型

Figure 5. Three-dimensional pore network model of the 2X-1 core plug before and after water sensitivity tests

下载: 全尺寸图片幻灯片

图 6 水敏前后岩心水相真实启动压力梯度与气测渗透率关系

Figure 6. Relationship between the starting pressure gradient of the liquid phase and gas permeability before and after water sensitivity tests

下载: 全尺寸图片幻灯片

图 7 新沟嘴组低渗储层水敏前后极限注采井距图版

Figure 7. Limit injection-production spacing plate of the Xingouzui Formation low-permeability reservoir before and after water sensitivity tests

下载: 全尺寸图片幻灯片

表 1 实验岩心参数

Table 1. Physical properties of core plugs

岩样	气测渗透率/10^-3 μm²	气测孔隙度/%	长度/cm	直径/cm
2X-1	2.76	9.84	7.06	2.48
2X-2	12.71	15.91	4.13	2.48
2X-3	55.91	17.35	6.97	2.48

下载: 导出CSV

表 2 模拟地层水离子组成数据

Table 2. Ionic composition of the simulated brine

Ca²⁺	Mg²⁺	OH^-	SO₄^2-	CO₃^2-	K⁺+Na⁺	Cl^-
ρ_B/(mg·L^-1)
1 503.0	243.0	25.5	480.3	60.0	47 857.5	29 175.5

下载: 导出CSV

表 3 水敏实验岩心基础物性参数对比

Table 3. Comparison of the physical properties of core plugs before and after water sensitivity tests

岩心编号	气测渗透率/10^-3 μm²	气测孔隙度/%	水敏后渗透率/10^-3 μm²	水敏程度/%	水敏前CT孔隙度/%	水敏后CT孔隙度/%	孔隙度损害率/%
2X-1	2.76	9.84	1.00	63.91	9.82	8.94	8.96
2X-2	12.71	15.91	8.92	29.83	15.80	14.68	7.09
2X-3	55.91	17.35	47.39	15.24	17.45	16.47	5.62

下载: 导出CSV

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