Effect of Multi-phase Flow on Recovery of Fracture Fluid and Gas in Marcellus Shale Reservoirs

Open Access
Author:
Abah, Alphonsus Igoche
Graduate Program:
Petroleum and Natural Gas Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
August 23, 2013
Committee Members:
  • Yilin Wang, Thesis Advisor
Keywords:
  • Hydraulic
  • fracture
  • fracturing
  • marcellus
  • proppant
  • multi-phase flow
  • shut-in
  • capillary pressure
Abstract:
ABSTRACT Hydraulic fracture treatment of shale gas wells does not always yield the expected folds of increase in gas production. Low production rates could be attributed to a number of factors like proppant crushing, proppant diagenesis, clay swelling and rock-fluid interactions based on previous work (Osholake, Wang, Ertekin, 2011; Yue, 2012). In this research work, we evaluated the effect of multi-phase flow, capillary pressure, length of shut-in time and proppant crushing on performances of hydraulically fractured Marcellus Shale wells. To accomplish this, a 2-dimensional, 2-phase water-gas model was developed using a commercial software. Three hydraulic fracture (HF1, HF2, HF3) with different network sizes were used to simulate the effect of the above factors on long-term gas production and fracture fluid recovery from hydraulically fractured Marcellus wells. Two types of proppants were used to evaluate the effect of conductivity on the impact of the factors being studied. With high conductivity 20/40 ceramics proppant in the hydraulic fractures, long term gas production was not affected by any of the factors studied. With 20/40 ceramics fracture fluid recovery on the other hand was affected by all the factors studied. Shut-in time had the greatest effect on fracture fluid recovery. Less than 1% of the fracture fluid used for treating the well was recovered after 1-year shut-in. With the less conductive 100 mesh sand, long term gas production and fracture fluid recovery were affected by some of the factors studied. Multi-phase flow and proppant crushing were found to decrease cumulative gas production. Effect of proppant crushing on gas production was greater compared to multi-phase flow. In twenty years of production, multi-phase flow decreased gas production by 1.8%, 2.2% and 3.9% in HF1, HF2 and HF3 respectively while proppant crushing decreased gas production by 3.5%, 3.9% and 5.8% in HF1, HF2 and HF3 respectively. Capillary pressure had little or no effect on long-term gas production, but was observed to delay gas peak during initial production. Long term gas production was unaffected by shut-in time. Fracture fluid recovery was decreased by high capillary pressure, increased shut-in time and proppant crushing. After one year of shut-in, less than 1 % of fracture fluid was recovered. The new understanding helps engineers design better treatment and flowback operation in Marcellus.