val customSchema = StructType(Array(
    StructField("numicu", StringType, true),
    StructField("fecha_solicitud", TimestampType, true),
    StructField("codtecnica", StringType, true),
    StructField("tecnica", StringType, true),
    StructField("finexploracion", TimestampType, true),
    StructField("ultimavalidacioninforme", TimestampType, true),
    StructField("validador", StringType, true)))

val df_explo = spark.read
        .format("csv")
        .option("header", "true")
        .option("delimiter", "\t")
        .option("timestampFormat", "yyyy/MM/dd HH:mm:ss") 
        .schema(customSchema)
        .load(filename)