The new generation of Power Water Injectors (PWI) wells with longer open-hole (OH) horizontal section has been grown significantly in Saudi Arabia especially in the new development fields. One of these new complex fields have been developed with over 120 PWI wells with OH sections in the range of 2,000-10,000 feet. While the long OH horizontal wells have several advantages, they also have a challenge for the rig-less intervention. This paper summarizes the development and enhancement of techniques implemented during the acid stimulation treatment of extended-reach wells using CT without mechanical assistant tools like vibration or CT tractors.

During the initial CT interventions in this field, several challenges were encountered, e.g., stuck CT due to pressure differentials and slack-off weight due to sudden dogleg or azimuth changes. Previous simulations and studies resulted to a combination of techniques to the CT intervention procedure to extend the CT reach and minimize the operational problems and costs. Remarkable improvements were achieved by performing additional simulation runs, correlating the CT weight loss vs. the horizontal sections geometry and analyzing all available operational data.

By incorporating enhanced intervention procedures based on the lessons learned from the previous jobs, a new reach records were achieved successfully on the wells with over 7,000 ft. As a result, additional cost savings were realized since most of the extended reach wells were stimulated without using CT tractor. One of these wells reached a total measured depth of 5 km and horizontal OH length of 3 km, which is the longest record in the region.

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