Technical advances
in hydraulic fracturing and horizontal drilling
technologies enable shale to be commercially exploited. Due to the
technical and economic limitations of well testing in shale gas plays,
rate transient analysis has become a more attractive option. After
hydraulic fracturing, flow mechanisms in multiple scaled pores of
shale become extraordinarily complicated: adsorption in nanopores,
diffusion in micropores, and non-Darcy flow in macropores. Moreover,
shale gas reservoirs are stress-sensitive because of ultralow permeability
and diffusivity in a matrix. Furthermore, the porosity and permeability
of natural fractures are stress-dependent as well. Accounting for
all of these complex flow mechanisms, especially the aforementioned
stress-sensitive parameters, a semianalytical production solution
of a multiple fractured horizontal well (MFHW) can rapidly predict
the entire production behavior. Scholars have done much work on the
complex flow mechanisms of shale. Most models regarded permeability
as a stress-sensitive parameter while diffusivity and porosity were
considered to be a constant. However, diffusivity and porosity were
proved to be stress-sensitive as experimental science developed. In
this study, we present a novel semianalytical model for rate transient
analysis of MFHW, which simultaneously incorporates multiple stress-sensitive
parameters into flow mechanisms. Substituting stress-dependent parameters
(diffusivity, porosity, and permeability) into governing equations
resulted in strong nonlinearities, which was solved by employing the
perturbation method. Production behaviors with only stress-sensitive
permeability were compared with multiple stress-dependent parameters.
The new model with multiple stress-sensitive parameters declined slower
than the permeability-sensitive model, and the new model matched better
with the field data. In addition, the effects of major stress-sensitive
parameters on production decline curves were analyzed by the proposed
model. The sensitivity analysis indicated that different parameters
had their own degree of sensitivity intensity and influence on the
production period. Finally, 1001 wells from the Marcellus shale play
were divided into three well groups. Estimated inversion values of
reservoir parameters from the three well groups and relevant single
wells were consistent with the field data. The inverted values of
single wells fluctuate within the inversion values of well groups,
which indicates that the production behavior of well groups could
be a guide for rate transient analysis of a single well in shale gas
reservoirs.