Date of Award

January 2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Petroleum Engineering

First Advisor

Hadi H. Jabbari

Abstract

The hydrocarbon production improvement in unconventional reservoir development hasbeen driven by the application of modern horizontal drilling and multi-stage hydraulic fracturing (MSHF) techniques, which makes it possible to access low porosity (<10%) and low permeability (<0.1 mD) formations. Large stimulated reservoir volumes (SRVs) have been created through breakthroughs in hydraulic fracturing technology; however, fracture treatment is not necessarily effective. Operators have started utilizing tighter spaced clusters, longer stage lengths, and greater proppant volumes to design hydraulic fracture stimulation. However, the ultimate oil recovery reported by several studies is less than 8% due to a rapid decline in unconventional well performance and by approximately 75% within the first two years of well production as a result of several reasons. This research presents an integrated approach of unconventional reservoir applications to increase well/reservoir contact area (i.e., large stimulated reservoir volumes “SRVs”) and efficiently produce more trapped oil in the pore matrix from liquid-rich shale reservoirs. In order to achieve research goals, this dissertation is divided into three phases. In the first phase, we present a combination of the Diagnostic Fracture Injection Test (DFIT) and post-treatment pressure falloff analysis, which can help to design intelligent production and improve well performance. Our field study from the STACK Play, Anadarko Basin, Oklahoma, explains the objective optimization workflow of diagnostic tools. The falloff pressure analysis provides vital information, assisting operators in fully understanding models for fracture network characterization. In the second phase, this research aims to study the capability of high-viscosity friction reducers (HVFRs) by examining the produced water from the Bakken Formation through an integral approach. Surfactant application as an additive to the HVFRs is investigated in high TDS (total dissolved solids) conditions. The results show that using a surfactant mixed with the fracturing fluids can improve proppant transport, fracture conductivity profile, and thus higher effective fracture half-length compared to current practice. It is found that such a fracturing fluid mixed with surfactant can increase Estimated Ultimate Recovery (EUR) by as high as 15% compared with linear gel and HVFRs with produced water (HVFR-PR) due to larger propped SRVs. In the final phase, the experimental work is presented to evaluate the feasibility of the Enhanced Oil Recovery (EOR) method using the CO2 huff-n-puff (HNP) protocol in the Middle Bakken Formation, the Mountrail County, Williston Basin, ND. The objective is to evaluate the incremental oil recovery from CO2-EOR under several operational and well/reservoir conditions scenarios. The parameters considered in the sensitivity study include temperatures, pressure, soak time, and a number of injection cycles to obtain optimum conditions under which the incremental oil recovery from the MB Formation is increased. The wettability alteration (i.e., contact angle) is also studied using rock-chip samples before and after the HNP experiment at the Bakken reservoir conditions (present, for example, P & T in psi/F). As overall outcomes from this research, the CO2-HNP process has a good potential in the lab and could be succeeded economically in field applications that might reduce the need for refracturing stimulation or infill drilling.

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