Fanhua Zeng

A semi-analytical model for hydraulically fractured horizontal wells with stress-sensitive conductivities

In the literature, fracture conductivities are usually assumed as being constant in the hydraulic fracture modeling. But in some cases the fracture conductivity that is a function of stress/pressure can change significantly during depletion. Experimental results prove that hydraulic fracture conductivities can be reduced to as low as a few percent of original values when confining stress increases. To study such stress-dependent effect, this paper develops a semi-analytical model and facilitates the transient pressure analysis of fractured horizontal wells with stress-sensitive hydraulic fracture conductivities. Consideration of the stress-dependent conductivities leads to a strongly nonlinear mathematical model. In order to solve this problem, hydraulic fractures are discretized into several slab source segments. The fluid flow and pressure drop along and inside each fracture segment are calculated in turn at each time step. Then, the hydraulic fracture conductivities are updated based on the latest pressure drop distribution. During each time step, an iteration process is applied to accelerate the convergence of conductivities. The effect of stress-sensitive conductivities on transient pressure behavior was studied, and type curves were documented. As the fracture conductivity decreases, the pressure and corresponding pressure derivative curves rise quickly, and when the conductivity declines to a minimum, the increasing pressure drop slows down. As a result, a hump appears in the pressure derivative curves. The hump’s appearance and shape are determined by hydraulic fracture stress-sensitive and reservoir properties. One field example of a fractured well was analyzed by the type-curve matching method, and stress-sensitive properties were estimated. At last, the production predictions with and without stress-sensitive fractures were compared.

Estimation of Shale Intrinsic Permeability with Process-Based Pore Network Modeling Approach

A multi-scale pore network model is developed for shale with the process-based method (PBM). The pore network comprises three types of sub-networks: the

A semi-analytical model for multi-stage fractured horizontal wells

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Gas well production analysis with non-Darcy flow and real-gas PVT behavior

μm-scale sub-network, the nm-scale pore sub-network in organic matter (OM) particles and the nm-scale pore sub-network in clay aggregates. Process-based simulations mimic shale-forming geological processes and generate a

Enhancing Oil Rate in Solvent Vapour Extraction Processes Through Tee-Well Pattern

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Using transient temperature analysis to evaluate steam circulation in SAGD start-up processes

μm-scale sub-network which connects interparticle pores, OM particles and clay aggregates. The nm-scale pore sub-networks in OM and clay are extracted from monodisperse sphere packing. Nm-scale throats in OM and clay are simplified to be cylindrical and cuboid-shaped, respectively. The nm-scale pore sub-networks are inserted into selected OM particles and clay aggregates in the