Admrgpch utility is provided to merge mutliple application patches into single patch. This can help in saving time and effort for executing many patches again and again.
There are some restrictions with AD Merge, it can't be used to merge patches of different releases, platforms or parallel modes.
Syntax Walkthorugh
admrgpch  <source_directory> <destination_directory>

       admrgpch  <-s <source_directory>|-preinstall> -d <destination_directory>
                           [-master <master upgrade driver. Valid only
                                     with -preinstall or -driveronly options>]
                           [-verbose <level>] [-merge_name <pattern>]
                           [-manifest <filename>] [-logfile <filename>]
                           [-driveronly] [-admode]


 -help                                 Print help message.

 -verbose <level>              Can be one of: { 0(SILENT),
                                          1(QUIET), 2(VERBOSE) or 3(LOUD) }
                                          Default - 1(QUIET).

 -merge_name <pattern>  The name of the merged patch (up to 24 chars).
                                          Default - "merged".

 -s <source_directory>       Path of source directory where all patches to be
                                            merged have been unzipped.

 -d <destination_directory>  Path of destination directory where the merged
                                              patch will be created.

 -preinstall                        <APPL_TOP>/admin/<TWO_TASK>/preinstall is the
                                          source directory, like -s option

 -driveronly                         Merge only patch driver files. But files will not
                                            be copied.

 -master <upgrade driver>    Master upgrade driver to be merged with preinstall
                                              upgrade fix drivers

 -admode                              Only AD patches will be merged.
                                             By default non-AD mode

 -manifest <filename>        Full pathname of a file containing the list of
                                            patch zip files to be merged.
 -logfile <filename>           Admrgpch log file name.

Steps for patch merging.

1. Download all the patched which need to be merged.
2. Make a source directory .
    mkdir source_test
3. Unzip all the patches and copy them in source directory.
   -bash-3.2$ ls
    16759426  17385991

4. Make a target directory
    mkdir target_test

5. Now run the below command to merge the patches.

 admrgpch -s source_test -d target_test -merge_name test_patch

Executing the merge of the patch drivers
 -- Processing patch: source_test/16759426
 -- Processing file: source_test/16759426/u16759426.drv
 -- Done processing file: source_test/16759426/u16759426.drv
 -- Done processing patch: source_test/16759426

 -- Processing patch: source_test/17385991
 -- Processing file: source_test/17385991/u17385991.drv
 -- Done processing file: source_test/17385991/u17385991.drv
 -- Done processing patch: source_test/17385991

Copying files...

Character-set converting files...
  2 unified drivers merged.
Patch merge completed successfully
Please check the log file at ./admrgpch.log.
6. Now do to target directory
    cd target_test
    we can see that the merge patch is created with merged driver file.
$ cd target_test
$ ls
16759426_README.html  17385991_README.html  ad             b17385991.ldt  f17385991.ldt  metadata_files
16759426_README.txt   17385991_README.txt   b16759426.ldt  f16759426.ldt  fnd    u_test_patch.drv

Now use normal adpatch from target_test directory for  application of patches and pass u_test_patch.drv when prompted for driver file.