Common problems in drilling of oil and gas wells in Cuba and their solutions

Due to the complicated formation, most wells in Cuba are extended reach ones, which results in difficult oil and gas development and drilling. Affected by the geological conditions, the development of extended reach wells in Cuba has unique features in borehole stabilization, hole cleaning, drill string force, and treatment of drilling fluids. Taking the successful drilling of GUA-101 well as an example, the problems in development are analyzed one by one, and corresponding solutions are developed. The well has many fault fissures and severe leakage, the borehole is easily to collapse, cuttings fall down to the bottom and block up the hole, resulting in severe sticking. Great friction of drilling string and barite deposit also hinder the drilling. All these problems are solved by timely checking and adjusting drilling fluid properties, using short trip, controlling the speed, enlarging water hole of drill bits, further increasing drilling fluid displacement, and using rotary borehole drilling tools. This lays solid basis for the development of similar wells in the future.