Use of Oriented Perforation and New Gun System Optimizes Fracturing of High Permeability, Unconsolidated Formations

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWhen designing fracture treatments for high permeability formations, fracture conductivity is a primary factor in attaining maximization of completion economics. Optimum fracture design would dictate the knowledge of fracture orientation and the utilization of oriented perforation to optimally place the fracture. While in many unconsolidated formations, the contrast between horizontal stress is small or even insignificant; taking advantage of this situation often improves the efficiency and placement of a fracture.It is generally believed that existing spiral patterns used in more conventional slurry pack completions give better radial flow performance because of the uniform perforation distribution around the wellbore. However, when a hydraulic fracture is created, the majority of flow into the wellbore is delivered through the perforations that are communicated to the fracture. This is especially true when many of the unconsolidated formations suffer a high degree of damage around the wellbore. For this reason, it is important to focus fluids injected during the completion directly to the fracture and increase the number of perforations communicating with the fracture. This paper will discuss the justification and theoretical background for a newly proposed design that develops this concept. The paper also discusses the tools and procedures necessary to achieve the stated goals.A case history will be presented that will discuss the methods employed by an operating company in offshore Louisiana in perforating unconsolidated formations with the new system to obtain highly conductive gravel-pack fractures in deviated vertical wells. Significant to the success of the completions was the use of a high shot density perforating gun, oriented at 180-degree phasing. To facilitate the new approach, an innovative perforating gun system was also developed, and a wide perforation was designed to minimize friction.

Coal breaking characteristics of high pressure water jet and the law of coordinated pressure relief of slits

“…The mechanism of coal and gas outbursts has been extensively studied in the academic community, leading to a comprehensive and widely accepted explanation known as the integrated action hypothesis (Taylor, 1852;Halbaum, 1899;Jou, 2000;Li and Lin, 2010). Conducting research and applications on the intensified unloading and permeability enhancement of low-permeability coal seams contributes to finding solutions and preventive measures for coal and gas outburst accidents (Liu et al, 2014;Zarrouk and Moore, 2009;Liu et al, 2011;Soliman, 1999).…”

“…Tang et al (2012) conducted theoretical and numerical simulation studies on the effectiveness of hydraulic fracturing. Song et al (2011) analyzed the stress changes induced by hydraulic fracturing in terms of stress variation angles. They employed theoretical analysis and numerical simulation methods, based on the permeation mechanics theory of planar radial flow, to conduct in-depth analysis and exploration of the permeability enhancement principles of hydraulic fracturing.…”