任丘油田雾迷山组白云岩储集层的渗透性试验研究

运用815.02型电液伺服岩石力学试验系统对任丘油田雾迷山组18块白云岩岩芯的渗透性进行了测试.结果表明,溶蚀孔洞型中-亮晶藻屑白云岩和角砾岩,初始和峰值渗透率均较高(分别为143.10×10-7-206.00×10-7Darcy和386.80×10-7-790.00×10-7Darcy),而且破坏强度较低(35.8MPa-55.3MPa);裂隙型白云岩初始渗透率为1.48×10-7-23.40×10-7Darcy,峰值渗透率32.13×10-7-202.10×10-7Darcy;泥质白云岩和硅质白云岩,岩性致密,初始渗透率几乎为零,峰值渗透率66.00×10-7-152.20×10-7Darcy,而且其破坏强度最高可达107.50MPa.同时运用Amray 1000B型电子扫描显微镜和9310型微孔结构分析仪研究了空隙发育对渗透性的影响.

STUDY ON PERMEABILITY TEST OF DOLOMITE RESERVOIR OF WUMISHAN FORMATION IN RENQIU OILFIELD

Rock permeability problem is of great importance for hydraulic enginerring, petroleum developing and coal mining engineering under a water body. Therefore, many researchers in home and abroad had carried out a number of permeability testing for porous and porous-fractured rocks such as sandstone and granite. Nevertheless, until now any reports concerning test results on the permeability of carbonate rock for the complete stress-strain path have not been seen in the literature because karstification causes its anisotropic inhomogeneity increasing. Using Electro-Hydraulic Servocontrolled Rock Mechanics Testing System produced by MTS Company and the transient method, the author had tested the permeability of 18 dolomite core samples collected from the Wumishan Foramtion in the Renqiu Oilfield.These results showed that their permeability was mainly controlled by feature of karstific void except the stress state.Based on void feature under SEM and permeability curves in the complete strese strain path,the dolomite of Renqiu Oilfield can be divided into four following types:(1)Mdeium sparite algal dolomite with corrosive cavern, initial permeability is from 143.10porous fractured darcy to 206.00×10^-7 darcy, permeability peak is up before the stress peak, and peak stress is from 45.0MPa to 55.3MPa; (2)Siliceous brecia dolomite with corrosive cavern, initial permeability can up to 690.00×10^-7 darcy becaues of development of karst void, post-peak permeability can continously increase and peak stress is 35.8MPa;(3)Fissured and Micro fisssured dolomite, initial permeability varies from 1.48×10^-7 darcy to 23.4×10^-7 darcy because of difference of their connection and fill; and peak stress varies form 40.8MPa to 58.2MPa;(4)Compacted argillaceous and siliceous dolomite, initial permeabity is almost zero, peak stress can up to 107.5Mpa. Permeability curves of dolomite in the complete stress strain path have many types because of impact of inhomogeneity, and can not be obviously divided into elastic, elastic plastic and strain-softening region such as permeability curves of sandstone. Using 9310 Pore Size produced by Micrometrities Company,the author also studied the change of pore and micro-fissure of dolomite samples duriag testing process, the results shown that pore and micro-fissure in sample obviously increase, porosity and pore throat become great.Comparing with the curve of mecury injection before testing, peak of mecury injection in the region that pore diameter is more than 100μm has risen greatly. The above-mentioned testing results can provide a theoretical base for further development of the Renqiu Oilfield.