New Techniques for Hydraulic Fracturing in the Hassi Messaoud Field

The Hassi Messaoud oilfield is a thick sandstone reservoir in the north-eastern part of central Algeria. The reservoir was discovered in 1956 and produces from a Cambrian-age sandstone at approximately 3400 meters depth. Hydraulic fracturing has been successfully used to improve oil production since 1990. Pre-treatment injection tests have been conducted on approximately 250 wells and proppant has actually been placed in approximately 200 wells. The 50 wells on which only injection tests were conducted were reviewed. The review showed that there were three main reasons why treatments were aborted after the injection tests: (1) mechanical failure of the well, (2) treating pressure too high, and (3) fracture geometry, as interpreted from temperature logs, created outside target interval. In order to increase the success rate of the treatments two new techniques were recently introduced. ○ Propellant stimulation techniques were used to reduce fracture initiation pressures and to control the fracture initiation point. ○ A dual fracturing technique was introduced to control downward growth of the created fractures. The paper presents three well-documented case histories to illustrate the application of these new techniques. The data presented includes pre- and post-treatment production, peak pressures from the propellant runs, temperature and radioactive tracer logs from after the injection tests, and radioactive tracer logs that show the actual placement of the proppant.