古龙南地区葡萄花油层低阻成因实验研究

Experimental Study on the Genesis of Low Resistivity Oil Reservoirs in Putaohua Formation of Southern Golong Area

针对古龙南地区葡萄花油层存在低阻油层和高阻水层致使该区油水层识别难度较大的问题,选取典型的低阻油层和常规油层岩心样品,对岩样进行物性分析、粒度分析以及压汞、核磁共振、X-衍射等实验。采用对比方法,找出古龙南地区葡萄花油层低阻油层和常规油层在岩性、物性、孔隙结构、黏土矿物以及地层水矿化度等特征上差别。从而得出引起古龙南地区葡萄花油层低电阻率的因素主要有三种:①岩性细,含泥重;②黏土附加导电性强;③微孔隙发育、束缚水饱和度高。为古龙南地区葡萄花低阻油层的识别与解释提供了理论基础。

Since low resistivity oil reservoirs and high resistivity water reservoirs are present in Putaohua formation of southern Golong area,oil-water formation recognition is difficult.To solve the problem,the genesis of low resistivity oil reservoirs is made clear first.Therefore,typical low resistivity oil reservoir and conventional oil reservoir core samples are taken,and Petrophysical analysis,Particle size analysis,Mercury-injection,NMR and X-diffraction experiments are done for them.The difference in lithology,petrophysics,pore structure,clay minerals,formation water salinity etc.between low resistivity oil reservoirs and conventional oil reservoirs is found out by comparison.It pointed out low resistivity of oil zones in Putaohua formation of southern Golong area is mainly caused by there factors： fine-grained lithology,high shale content;high clay-excess conductivity;more microscopic cappillary pore,high irreducible water saturation.The result will provide theoretical basis for identification and interpretation of low resistivity oil reservoirs in Putaohua formation of southern Golong area.