Abstract
In Kuwait, drilling and deployment plans focus mainly on drilling vertical wells through a wide range of reservoirs consisting of high- and low-permeability sandstones and carbonates, with varying crude types from medium-heavy to condensate. Since 1935, Kuwait has produced mainly from the types of reservoirs that keep its daily production as high as possible to accommodate the country's economic needs. With the aging of these mature reservoirs, reservoir pressure reduction and water production become a major challenge, in addition to the limited access to drilling resources. Accordingly, exploring different reservoirs and unlocking the potential of the existing low- to mid-permeability reservoirs through advanced fracturing technologies are considered the alternative plan to compensate for production decreases and to improve oil production. However, implementing such technologies requires a customized design and candidate selection process.
The plan involved a multidisciplinary well candidate screening and selection criteria for different reservoirs and fields. The criteria include different parameters such as bubblepoint pressure, minimum formation thickness, and rock mineralogy, in addition to the study of the previously applied production enhancement technologies. About 50 wells have been selected from different reservoirs and fields across Kuwait for the initial pilot plan to evaluate the potential of a wide range of reservoirs. Then, a customized fracturing technology design followed that included operational planning, execution, and evaluation.
Approximately 20 fracturing treatments were executed successfully, and the post-job evaluation showed two- to four fold gains in production. This changed the development strategy and allowed for further development plans for these reservoirs. These newer plans included the application of technologies such as channel fracturing for proppant fracturing and fiber-laden self-diverting acid system for acid treatments.
The well candidate selection criteria and customized design of channel fracturing technology for the sandstone reservoirs and fiber-laden self-diverting acid system technology for fractured carbonate reservoirs resulted in a total additional gain of approximately 15,000 B/D. The detailed engineering design from candidate selection to treatment and the application of optimized hydraulic fracturing technologies enabled production enhancement and additional recoverable reserves from the most challenging low-permeability and low-API gravity candidates for the first time in Kuwait where conventional stimulation techniques were not providing the expected results.
