The application of horizontal wellbore drilling and multistage fracturing technology has been playing a pivotal role in unlocking shale-gas reserves globally. More recently, the same technology has been applied to both new and mature oil fields. A key question for economic optimization of these assets is what fracture spacing to use along a horizontal wellbore. Of equal importance is what spacing to use for multilaterals and the wellbores themselves to achieve optimal drainage of the reservoir. In addition, the design of the fracturing treatments must be optimized. To address these questions, a combination of reservoir and fracturing simulation has been applied. The required input data are provided through a combination of advanced log and core analyses, diagnostic fracture injection testing (DFIT), rate transient analysis (RTA), and characterization of fracture geometry through microseismic monitoring. Fluid rheology is characterized using pressurized rheometers and flow loops. This paper presents results of this work using examples of current Canadian oil and shale-gas reservoirs and a methodology to improve the economic return of different completion and production scenarios.

In recent years, the industry has shifted its focus toward developing unconventional and conventional tight-oil plays, which has led to a steep learning curve in the development and application of new technologies. This paper discusses the progression and findings of operators in a Canadian unconventional oil play, and how current techniques are providing operators with reduced stimulation costs and improved fracture placement, leading to higher initial production rates and cumulative production.With the advancement of horizontal drilling and completion techniques, operators are revisiting oil plays that had previously been developed with vertical wells or unstimulated, horizontal wells. In many cases, these plays were uneconomic to pursue, except during periods of higher oil prices. With recent improvements in horizontal-stimulation techniques, operators are now finding that cost-effective stimulation methods can be applied that improve the economics of both conventional and unconventional plays.In one Canadian light-oil play, coiled-tubing (CT) conveyed, openhole fracturing was used initially as a stimulation technique. Production gains were noted, but the water from an adjacent zone limited the effectiveness of this technique. Operators then proceeded to use openhole packer completions as a means of controlling the fractures. This method provided positive isolation between openhole compartments but limited the number of zones that could be completed as well as the options available for workovers following the fracture treatments. More recently, operators have successfully used monobore drilling and completion techniques with a CT-deployed straddle frac stimulation method, providing both economic and low-operational-risk wells at lower drilling and completing costs.The benefits of the monobore drilling and completion systems are: • Reduced drilling time over other methods • Single-stage cementing options • Single-trip perforating • Full-diameter wellbore simplifies completions.• Flexibility in number of intervals and spacing • Fracture treatments designed are to maximize zonal coverage • Ability to control fracture placement to avoid nearby water zones • Flexibility to alter job design during treatment • Ability to return to the well following the initial treatment for future treatments • Lower water requirements for stimulation • Reduced costs lessen environmental impact with reduced water volume • Reliable, proven, straightforward process