南图尔盖盆地K油田M-Ⅱ储层特征及油水层识别

The Characteristics of M-Ⅱ Reservoir and Recognition of Oil and Water Layer in K Oilfield of South Turgay Basin

针对哈萨克斯坦南图尔盖盆地K油田M-Ⅱ储层油水层难以区分的特点,通过对K油田地质、粘土矿物、试油等资料的分析,利用自然电位幅度差与声波时差交会图版和变m值来计算识别其油水层。M-Ⅱ储层属于三角洲平原的分支河道沉积,砂质岩性较细,自下而上泥质含量增大;粘土矿物主要是吸附性强的伊/蒙混层、伊利石;储层岩石具有强亲水性,导致储层束缚水含量较高,降低了油层的电阻率,造成油层和水层的电阻率差异不明显。储层的自然电位的相对幅度差随着含水饱和度的增大而增大,自然电位测井技术是识别储层含油性的有效方法。岩电试验表明,研究区泥质砂岩储层的孔隙度指数m值随孔隙结构的复杂程度而变化。结合试油成果资料,利用自然电位幅度差与声波时差交会图版来识别可能的油水层,采用变m值计算泥质砂岩储层的含油饱和度,提高了泥质砂岩储层的油层的识别能力。

In consideration of the characteristics of difficulties to distinguish oil and water layer in M-II reservoir of K Oilfield of South Turgay Basin in Kazakhstan,and the response feature in logging curves,by using the information such as geological,clay mineral analysis and testing data,the oil and water layer could be recognized with the cross plot of sonic and the separation of spontaneous potential and the application of varied m value.The M-II reservoir of K Oilfield of South Turgay Basin in Kazakhstan belonged to branch channel deposition of delta plain with fine sandstone of more argillaceous content from the bottom to top.The reservoir was content of clay mineral with adsorptive mixed layer of illite and montomorillonite and illite.The reservoir rock had strongly water affinity,it caused the high content bound water in reservoir and lower resistivity of oil formation.It was difficult to distinguish resistivity of oil layer from water layer.The relative amplitude of SP curve increased with the water saturation.The SP logging technique is the effective way of identifying the oil-beating ability.On basis of the experiment,the m value of pore exponent of shaly sand changes with the complication of pore configuration.The application of varied m value to calculate the oil saturation of shaly sand can enhance the recognition capability of oil formation on basis of the recognized oil and water with the cross plot of sonic and the separation of spontaneous potential combined with test data.