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五七地区沉积了大量的膏盐岩层。在剖面中,含盐段由泥岩和盐岩组成一百多个韵律层,砂岩夹于含盐段之中。盐岩层单层厚度最大可达几十米,总厚度可达千米以上。在钻井过程中,盐岩层被钻井泥浆溶解,使钻井泥浆盐化。这种盐水泥浆的矿化度一般都在10万毫克/公斤以上,最高达30万毫克/公斤。在井下温度条件下,泥浆电阻率很低,一般只有0.02～0.05欧姆米。采用普通电法测井困难很大,因为低电阻率泥浆的导电能力很强,在井内形成强分流,从而使普通电法中短电极测井方法无法应用。另外,
A large number of gypsum-salt rocks have been deposited in the 57 area. In the profile, the salt section consists of more than one hundred rhythm layers of mudstone and salt rock sandwiched between salt sections. Salt rock monolayer thickness up to tens of meters, the total thickness of up to kilometers. During drilling, the salt rock is dissolved by the drilling mud and the drilling mud is salinized. The salinity of this brine slurry is generally above 100,000 mg / kg, up to 300,000 mg / kg. Under downhole temperature conditions, mud resistivity is very low, typically only 0.02 to 0.05 ohm-meter. Ordinary electrical logging is very difficult because of the high electrical conductivity of low resistivity mud and strong shunting in the well, making it impractical to use the short electrode logging method in common electrical methods. In addition,