<informationTable xmlns="http://www.sec.gov/edgar/document/thirteenf/informationtable" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <infoTable>
       <nameOfIssuer>AT&amp;T INC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>00206R102</cusip>
       <value>528</value>
       <shrsOrPrnAmt>
           <sshPrnamt>12230</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>12230</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ALLSTATE CORP</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>020002101</cusip>
       <value>273</value>
       <shrsOrPrnAmt>
           <sshPrnamt>3897</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>3897</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>CIGNA CORP</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>125509109</cusip>
       <value>815</value>
       <shrsOrPrnAmt>
           <sshPrnamt>6366</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>6366</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>CHEVRON</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>166764100</cusip>
       <value>322</value>
       <shrsOrPrnAmt>
           <sshPrnamt>3072</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>3072</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>CISCO SYSTEMS INC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>17275R102</cusip>
       <value>287</value>
       <shrsOrPrnAmt>
           <sshPrnamt>10010</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>10010</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>CONCHO RESOURCES</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>20605P101</cusip>
       <value>361</value>
       <shrsOrPrnAmt>
           <sshPrnamt>3024</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>3024</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>CONTINENTAL RESOURCES</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>212015101</cusip>
       <value>389</value>
       <shrsOrPrnAmt>
           <sshPrnamt>8600</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>8600</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>DIAMONDBACK ENERGY INC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>25278X109</cusip>
       <value>312</value>
       <shrsOrPrnAmt>
           <sshPrnamt>3419</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>3419</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>EOG RESOURCES INC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>26875P101</cusip>
       <value>337</value>
       <shrsOrPrnAmt>
           <sshPrnamt>4040</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>4040</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>EMERSON ELECTRIC CO</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>291011104</cusip>
       <value>231</value>
       <shrsOrPrnAmt>
           <sshPrnamt>4424</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>4244</Sole>
           <Shared>180</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>EXXON MOBIL CORP</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>30231G102</cusip>
       <value>863</value>
       <shrsOrPrnAmt>
           <sshPrnamt>9207</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>9207</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>GENERAL ELECTRIC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>369604103</cusip>
       <value>601</value>
       <shrsOrPrnAmt>
           <sshPrnamt>19101</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>19101</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>GENESIS ENERGY</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>371927104</cusip>
       <value>11511</value>
       <shrsOrPrnAmt>
           <sshPrnamt>300000</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>300000</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ISHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>464287226</cusip>
       <value>3562</value>
       <shrsOrPrnAmt>
           <sshPrnamt>31628</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>31628</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ISHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>464287226</cusip>
       <value>99</value>
       <shrsOrPrnAmt>
           <sshPrnamt>877</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>OTR</investmentDiscretion>
       <votingAuthority>
           <Sole>877</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ISHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>464287465</cusip>
       <value>3938</value>
       <shrsOrPrnAmt>
           <sshPrnamt>70543</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>70543</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ISHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>464287465</cusip>
       <value>294</value>
       <shrsOrPrnAmt>
           <sshPrnamt>5272</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>OTR</investmentDiscretion>
       <votingAuthority>
           <Sole>5272</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ISHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>464287630</cusip>
       <value>3087</value>
       <shrsOrPrnAmt>
           <sshPrnamt>31732</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>31732</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>ISHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>464287630</cusip>
       <value>275</value>
       <shrsOrPrnAmt>
           <sshPrnamt>2823</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>OTR</investmentDiscretion>
       <votingAuthority>
           <Sole>2823</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>KIMBERLY CLARK CORP</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>494368103</cusip>
       <value>583</value>
       <shrsOrPrnAmt>
           <sshPrnamt>4244</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>4244</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>OCCIDENTAL PETROLEUM</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>674599105</cusip>
       <value>383</value>
       <shrsOrPrnAmt>
           <sshPrnamt>5070</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>5070</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>PIONEER NATURAL RESOURCES</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>723787107</cusip>
       <value>346</value>
       <shrsOrPrnAmt>
           <sshPrnamt>2290</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>2290</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>POWERSHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>73935X583</cusip>
       <value>5575</value>
       <shrsOrPrnAmt>
           <sshPrnamt>61584</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>61584</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>POWERSHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>73935X583</cusip>
       <value>618</value>
       <shrsOrPrnAmt>
           <sshPrnamt>6822</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>OTR</investmentDiscretion>
       <votingAuthority>
           <Sole>6822</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>POWERSHARES</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>73936Q769</cusip>
       <value>334</value>
       <shrsOrPrnAmt>
           <sshPrnamt>14550</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>14550</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>RSP PERMIAN INC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>74978Q105</cusip>
       <value>304</value>
       <shrsOrPrnAmt>
           <sshPrnamt>8700</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>8700</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>SPDR</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>78462F103</cusip>
       <value>512</value>
       <shrsOrPrnAmt>
           <sshPrnamt>2443</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>2443</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>SABRA</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>78573L106</cusip>
       <value>365</value>
       <shrsOrPrnAmt>
           <sshPrnamt>17694</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>17694</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>TEXAS CAPITAL BANCSHARES</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>88224Q107</cusip>
       <value>935</value>
       <shrsOrPrnAmt>
           <sshPrnamt>20000</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>20000</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>VANGUARD ADMIRAL FUNDS INC</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>921932885</cusip>
       <value>4449</value>
       <shrsOrPrnAmt>
           <sshPrnamt>44350</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>44350</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>VANGUARD ADMIRAL FUNDS INC</nameOfIssuer>
       <titleOfClass>ETF / CLOSED EN</titleOfClass>
       <cusip>921932885</cusip>
       <value>381</value>
       <shrsOrPrnAmt>
           <sshPrnamt>3801</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>OTR</investmentDiscretion>
       <votingAuthority>
           <Sole>3801</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>WAL-MART STORES INC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>931142103</cusip>
       <value>254</value>
       <shrsOrPrnAmt>
           <sshPrnamt>3473</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>3473</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>WELLS FARGO &amp; CO</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>949746101</cusip>
       <value>372</value>
       <shrsOrPrnAmt>
           <sshPrnamt>7870</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>7870</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
   <infoTable>
       <nameOfIssuer>EATON CORP PLC</nameOfIssuer>
       <titleOfClass>COMMON STOCK</titleOfClass>
       <cusip>G29183103</cusip>
       <value>634</value>
       <shrsOrPrnAmt>
           <sshPrnamt>10609</sshPrnamt>
           <sshPrnamtType>SH</sshPrnamtType>
       </shrsOrPrnAmt>
       <investmentDiscretion>SOLE</investmentDiscretion>
       <votingAuthority>
           <Sole>10609</Sole>
           <Shared>0</Shared>
           <None>0</None>
       </votingAuthority>
   </infoTable>
</informationTable>
