Identifier

etd-04092015-162336

Degree

Master of Science in Petroleum Engineering (MSPE)

Department

Petroleum Engineering

Document Type

Thesis

Abstract

Hydraulic fracturing has been serving as the principal reservoir stimulation technique for decades to improve production capacities of low permeability formations. On the other hand, through core and outcrop studies, advanced logging tools, microseismic fracture mapping and well testing analysis, it has been further revealed that many of the shale gas formations are naturally fractured. The presence of natural fractures and their interactions with hydraulic fractures must be taken into consideration while designing fracturing treatment. Although most natural fractures are cemented by precipitations during diagenesis, they may be reactivated during hydraulic fracturing and serve as weak paths for fluid flow and fracture growth. However, current technologies for evaluating naturally fractured reservoirs are incapable of accurately estimating the distribution and properties of natural fractures. Core and outcrop studies involve significant uncertainties in sampling and modeling of microfractures, and prediction of macrofracture properties based on biased observation might lead to erroneous estimation. Existing numerical modeling approach for naturally fractured reservoirs requires accurate details about natural fractures, which is often difficult or expensive to gather during hydraulic fracturing. Moreover, these numerical modeling usually does not incorporate post-treatment measured data, which could not reflect the actual reservoir characteristics. This research proposes a multi-discipline data integration workflow to estimate the characteristics of natural fracture network based on formation evaluations, microseismic data, treatment history and production history. Least-square modeling is first conducted to find natural fracture gridding systems that result in smaller overall squared error between fracture networks and double couple microseismic events. Forward modeling that incorporates Discrete Fracture Network (DFN) is subsequently used to simulate hydraulic fracturing treatments, and the net pressure responses from simulations and field measurements are quantitatively compared to determine the degree of match of natural fracture networks. Reservoir simulation tools are also used thereafter to simulate the production of hydrocarbon from such naturally fractured reservoirs, and the production history from simulations and the actual well will be compared to further evaluate the fitness of natural fracture realizations. This workflow is able to integrate scientific data from multiple aspects of the reservoir development process, and results from this workflow will provide both geologist and reservoir engineers an innovative assessment tool for evaluating and modeling naturally fractured reservoirs.

Date

2015

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Dahi Taleghani, Arash

DOI

10.31390/gradschool_theses.769

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