How do I close log files that are open in OracleServiceORCL after inputting data into Oracle?

I inserted data into a table called

. With this procedure:

CREATE TABLE cell_local_stage1
    (
      construct_id NUMBER(10),
      n_term VARCHAR2 (50),
      enz_name VARCHAR2 (50),
      c_term VARCHAR2 (50),
      cpp VARCHAR2 (50),
      mutations VARCHAR2 (50),
      g_batch VARCHAR2 (50),
      p_batch VARCHAR2 (50),
      c_batch VARCHAR2 (50),
      
      emptycol VARCHAR2(50),
      ind_var_number NUMBER,
      study_id VARCHAR2 (50),
      char_id NUMBER,
      concentration NUMBER (6, 2),
      valid NUMBER (1) DEFAULT 1,
      endpoint1 NUMBER (1),
      method1 VARCHAR2 (50),
      methodv1 VARCHAR2 (50))
      
      
    ORGANIZATION EXTERNAL (
    TYPE ORACLE_LOADER
    DEFAULT DIRECTORY data_to_input
    ACCESS PARAMETERS (
        RECORDS DELIMITED BY NEWLINE 
        SKIP 1
        BADFILE bad_files:'badflie_insert_into_cell_local_stage1_from_cell_local.bad'
        FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
        MISSING FIELD VALUES ARE NULL 
        ) 
    LOCATION ('CELL_LOCAL.CSV')
    ) REJECT LIMIT UNLIMITED;

I got a log file that has this information:

LOG file opened at 08/17/20 22:00:47

Total Number of Files=1

Data File: CELL_LOCAL.CSV

Log File: CELL_LOCAL_STAGE1_4908_22980.log

And when I try to delete that file this messages says that the file is still open: I was able to delete the CSV files, but not the log files. I didn't know I could even open these log files in Oracle. Sorry for such a basic question.