孔隙流体核磁共振弛豫特征及油水层识别方法

Relaxation features of pore fluid and water/oil bed recognition with NMR technology

为了得到丰富的孔隙流体信息,要对含油岩心的原始新鲜样、盐水饱和样及氯化锰浸泡样进行分析。这3次分析的谱图有的谱峰位置一致,解释较容易;有的则发生错位,峰形变化也较大,解释比较困难。为了搞清这种变化的原因,对地面原油和孔隙流体在不同原油性质、不同润湿性、不同样品存放时间等条件下的弛豫特征分别进行了实验研究。结果表明,孔隙流体的弛豫特征受油质、润湿性及样品存放时间的影响,润湿性影响油峰和水峰的幅宽和面积,油质和样品存放时间影响谱峰的位置和幅度,在此基础上提出了不同孔隙结构的油水层判识方法,提高了油水层的判识准确率。

In recent years, Magnetic Resonance-Mud Logging (MR-ML) technology has been widely developed and applied. In order to get abundant information about subsurface geology, one rock sample with oil is often analyzed three times, that is, fresh sample, the same sample saturated with brine, the same sample soaked with manganese chloride solution. It's easy to interpret when the peak locations of these three spectra are matched, but sometimes the peaks of these three spectra may be mismatched and therefore difficult to be interpreted. In order to make this reason clear, bulk oil and pore fluid with different oil property, different pore structure, different wettability and different storage time are tested and studied. The result shows that the relax features of pore fluid are affected by oil property, wettability and storage time; wettability affects relative width and area of water peak and oil peak; oil property and storage time affect the position and amplitude of peaks. This research result makes clear the relax feature of pore fluid, and the reason of peak mismatch, and peak shape variation, so it contributes to the improvement of oil and water bed evaluation level.