B737 flight crew reported they taxied on to a runway instead of the assigned taxiway.

Attributes
ACN	1694442
Time
Date	201910
Local Time Of Day	1801-2400
Place
Locale Reference	MSY.Airport
State Reference	LA
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 356 Flight Crew Type 6000
Person 2
Function	First Officer Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Last 90 Days 47 Flight Crew Type 1931
Events
Anomaly	Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Ground Incursion Runway Ground Incursion Taxiway

Narrative:

After landing tower instructed us to turn right and taxi to gate. As I slowed the aircraft and turned to the right on what I thought was a taxiway; I actually turned onto a runway and then left on a taxiway and the first officer called ground to continue to taxi to the gate. We had briefed to turn on two other taxiways depending on the landing to go to our gate. We slowed quicker than expected. As I looked at the chart on the efb; I thought the taxiway we were turning on was X. After clearing I realized it was an X for a closed portion. We continued to the gate and had to hold out. I discussed with the first officer what had happened. It is a hot spot and I should have realized. I was a little distracted from the strong crosswind landing and calling for the flaps and stowing the speed brake as we exited the runway. Neither tower nor ground said anything about the mistake. Maybe have tower say turn on a specific taxiway not just 'turn right'. Don't mark a closed portion with an X that can be read as a letter not an X for closure. Better briefing from me.

Original NASA ASRS Text

Title: B737 flight crew reported they taxied on to a runway instead of the assigned taxiway.

Narrative: After landing Tower instructed us to turn right and taxi to gate. As I slowed the aircraft and turned to the right on what I thought was a taxiway; I actually turned onto a runway and then left on a taxiway and the First Officer called Ground to continue to taxi to the gate. We had briefed to turn on two other taxiways depending on the landing to go to our gate. We slowed quicker than expected. As I looked at the chart on the EFB; I thought the taxiway we were turning on was X. After clearing I realized it was an X for a closed portion. We continued to the gate and had to hold out. I discussed with the First Officer what had happened. It is a hot spot and I should have realized. I was a little distracted from the strong crosswind landing and calling for the flaps and stowing the speed brake as we exited the runway. Neither Tower nor Ground said anything about the mistake. Maybe have Tower say turn on a specific taxiway not just 'turn right'. Don't mark a closed portion with an X that can be read as a letter not an X for closure. Better briefing from me.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.