This paper will demonstrate how the acid fracturing stimulation using different technologies in multidisciplinary team integration helped un-locking the production potential and setting up development strategy for Tuba tight carbonate reservoir, with case histories.
Upcoming Reservoirs in North Kuwait (NK) oil fields will play significant role for meeting NK's strategic production target. Recent full field study of Tuba carbonate reservoir makes it the largest Oil in-Place of the Upcoming Reservoirs in NK.
Tuba, though discovered in the 60's, is still relatively under-exploited presently with only 12 active wells with very low total production rate compared to other reservoirs. High reservoir heterogeneity, tightness and poor fluid properties necessitate the move from conventional matrix stimulation to Acid Fracturing technology targeting better Frack conductivity and deep penetration for effective productivity and recovery enhancement. With efforts of multidisciplinary team, Acid Frac fluid, diverter and high leak off control technologies have been designed and executed successfully in 9 wells (7 vertical and 2 multistage horizontal) covering multiple reservoir layers with very positive results that proved the concept and supported more TUBA development.
Many technical and operational challenges were faced and properly handled with lessons learned are to be considered in next designs and executions.
Despite the close results yielded from the multistage acid fracturing in two horizontal wells compared to the results from 7 vertical wells, it is still early to evaluate stimulation potential of horizontal against vertical wells. It needs more production history and more wells to evaluate long term sustainability.
The results of such evaluation will formulate the drilling, completion and stimulation development strategy for the entire TUBA reservoir including early fracturing stimulation to improve initial productivity that will contribute significantly to the NK production target.