Research And Application Of Borehole-surface Electrical Resistivity Method Of Monitoring Hydraulic Fracturing In The Oilfield

It’s important to monitor hydraulic fracture accurately, which can help to predict fracturingresults and provide the basis for the parameters of fracturing design. Besides, it can infer thedistribution of remaining oil. The hole-surface electrical resistivity method is a good andextensive use method recently.Hole-surface electrical resistivity method is a primary method in the solid polymetallicminerals exploration and it’s a coalition of electrical logging and surface DC electrical method.The basis principle is that we can put power supply in hole, measuring the variation of potentialor potential gradient on the surface caused by variation of stratum resistivity by during powertransmission and supply, which can understand the feature of resistivity on the ground. It is amethod of low cost, easy operator, easy implementation, easy source of field and it can notdisturb performance of hydraulic fracturing and affect productivity. So I studied hole-surfaceelectrical resistivity method, and it is applied to hydraulic fracturing in the oil field.At first,3-D hole-surface electrical resistivity method forward calculation is a necessarycondition of realizing hole-surface resistivity method applied on monitoring hydraulic fracturing.I conducted forward calculation study according to the potential formula caused by line currentsof arbitrary shape and finite difference method. I build various earth-electricity models,comparing the measured results and investigation depth on condition that we use potentialmethod and potential gradient method. I analysis the measured results influence of oil reservoirresistivity, leakage current on the surface and complex terrain. Secondly, noise elimination is animportant step of experimental data disposal outdoors. I analysis the collection data, whichinclude gyroscope interference, power interference and random interference. I adopt least-squarepolynomial fitting method, butterworth low-pass filter and numerical average algorithmrespectively, as a results, the SNR is improved. Besides, I raised that using BP neural networkadjusts field distortion response caused by complex terrain. At last, I introduced coded signal tofracturing monitor of hole-surface electrical resistivity method. The coded signal is used to bepower supply and adopting correlation method remove interference, which improved SNR andincreased detection depth. The paper introduced how to produce coded signal, correlationproperties and principle of the correlation detection. I analysis the reason of correlation method dispose interference and its parameters selection method.We have developed hole-surface electrical resistivity imaging equipment in support of Jilinprovince technology and evolving program called the develop of hole-surface networkingelectrical resistivity imaging equipment. We did lots of experiments outdoors in Daqing, Jilin,Liaohe and so on, getting good measured results. The paper gave an example of Daqingchaoyanggou fractured well, introduced the general situation of equipment.