Extremely low inter-particle or inter-crystalline permeability (i.e., 50 nanodarcies or less) is a common if not defining characteristic of many unconventional reservoirs. In the above scenario, natural fracture networks can be essential in providing surface area and pathways for reservoir fluid flow to the created hydraulic fractures extending from the wellbore. Thus the reservoir area and volume drained by a given wellbore, and the ultimate hydrocarbon production, is often a strong function of the quality of interaction of natural fractures and hydraulic fractures. In favorable cases, the interaction process can re-open mostly healed or cemented natural fracture sets, significantly enhancing system permeability adjacent to the primary hydraulic fractures. In unfavorable cases, fracturing fluid flow into multiple natural fractures can result in excessive treatment pressures, near-wellbore proppant bridging and premature treatment termination.
This presentation will cover a range of issues, and mitigating and balancing strategies as necessary, in executing hydraulic fracturing treatments in naturally fractured unconventional reservoirs.