利用侵入因子与视自然电位差交会识别低孔低渗储层流体性质

Identification of Fluid Property in Low-porosity and Low-permeability Reservoir by Intersection of Invasion Factor and Apparent Self-potential Difference

以齐家北油田古708区块为例,针对该区块低孔低渗储层物性差、非均质性强,测井响应受岩性等因素影响,无法准确识别储层流体性质的实际情况,提出了利用侵入因子与视自然电位差交会图识别地层流体的方法。统计结果显示,对于物性较好的储层,侵入因子大于0.18即可将水层识别出来,对于物性较差的储层,侵入因子为0.45,视自然电位差(ASP)为22,可以将差油层和干层区分开发。利用该方法对控制井古64-79井F19号小层和探井古704井F17号小层进行解释,其结论与试油资料相一致。为了验证该方法的适用性,通过对古708区块37个有试油资料的层段进行测试,显示有33个层段符合,符合率达到89.2%,该方法对低孔低渗复杂储层流体识别有一定的指导意义。由于低孔、低渗储层的特殊性,其相应的测井流体识别方法也应随油田开发程度的深入而不断改进和提高。

In Gu708 block of Qijiabei oilfield,log response can＇t identify the actual fluid property accurately influenced by lithology and other factors in low-porosity and low-permeability reservoirs with bad physical properties and strong heterogeneity.The method of identifying formation fluid is proposed through the cross plot of invasion factor and apparent self-potential difference.The results show that water-bearing formation may be identified when the invasion factor is more than 0.18 for the reservoirs with good physieal proper- ties ; and bad oil-bearing and apparent self-potential formation and dry formations may be identified when the invasion factor is 0.45 difference is 22 for the reservoirs with bad physical properties.This method is ap- plied to subzone interpretation in No.F19 of control well Gu64-79 and No.F17 of exploration well Gu704, and the result is similar with the well test data.In order to verify the feasibility of the method,37 intervals with oil test data in block Gu708 were tested with the results of 89.2%（33 intervals） of the coincidence rate.It has certain significance on guiding the fluid identification .in low-porosity and low-permeability complex reservoirs.The method should be improved along with the deepening of oilfield development for the peculiarity of the reservoirs.