Innovative Design Rotary Steerable Technologies Overcome Challenges of Complex Well Profiles in a Fast Growing Unconventional Resource— Woodford Shale

Abstract

Woodford Shale of Oklahoma is emerging as one of the fastest growing natural gas fields in North America because it has all the characteristics required for a profitable shale-gas play. More than $2 billion were spent in 2008 on some of the major productive intervals in this field. Although the upside potential is tremendous, efficient extraction of natural gas from the Woodford Shale poses several drilling and completion challenges. Low porosity and permeability limits well productivity. Complex well profiles and extended length laterals are required to maximize productivity. Long laterals posed several drilling challenges such as excessive slide drilling time, difficulty controlling well trajectory, unacceptably low penetration rates, high torque, and high drag. Engineers determined that wellbore tortuosity and high friction factors caused inefficient transfer of weight on bit and reduced rate of penetration (ROP). Existing rotary steerable systems available are typically cost prohibitive for this application/environment. To overcome these challenges, research, field testing and several years of experience gained with other automated rotating and non-rotating rib steering systems has culminated in the development of a new state-of-the-art rotary steerable closed-loop system (RCLS). This system, specifically designed for 3D wellbores for rotary steerable directional drilling in low spread cost land-drilling applications uses an automated rib-steering closed-loop system. Since the introduction of this innovative system, many wells have been drilled in North America with build/drop of 8°/100 ft. Bottomhole assembly (BHA) modeling software with finite element analysis was used to optimize BHA design. This strategy has been implemented to drill several wells in the Woodford Shale with excellent results. The new design of RCLS coupled with advanced BHA modeling software has significantly improved the drilling performance. The results achieved are excellent control over the well trajectory in the curve and lateral, improved transfer of weight to the bit, minimum torque and drag. Drilling complex well profiles have increased the length of laterals by several hundred feet. This has enabled additional recovery of gas, and the days required to drill the lateral interval have been reduced by more than five days. Introduction Oklahoma's geology presents numerous challenges for the oil and gas industry. In the past, the operator had faced several problems while drilling in Kiowa and Washita Counties of southwestern Oklahoma. Extreme geological complexities had posed several drilling challenges. The operator in conjunction with the service provider had implemented advanced drilling technologies and drilling optimization to significantly improve drilling performance in southwestern Oklahoma (Simonton et al. 2005). Additionally the service provider had completed several drilling optimization projects in Oklahoma and north Texas (Bone et al. 2005; Poulain et al. 2004; Janwadkar et al. 2006; Janwadkar et al. 2007). Building on this success and to meet the operator's drilling schedule, the operator and the service provider once again teamed up with the objective to improve drilling performance in their current drilling project in Canadian County. The current drilling project comprises drilling horizontal wells in the Woodford Shale of the Anadarko basin (Fig. 1) located in the Canadian County of Oklahoma. Fig. 2 shows the geological provinces of Oklahoma in addition to the major fault systems.

A critical evaluation of unconventional gas recovery from the marcellus shale, northeastern United States

“…Since the primary joint set (J 1 ) trends east-northeast, horizontal wells should be drilled to the northnorthwest. At the surface, the borehole may be as wide as 20 inches to accommodate casings, but the lower sections of the well are typically drilled with a 9-inch diameter and filled with a 5.5-inch production casing (Ottaviani, 2009;Janwadkar, 2009).…”

“…5. The RCLS system improves ROP over traditional systems from roughly 16 ft/hr to over 20 ft/hr (Janwadkar, 2009 …”

Application, Prospect, and Challenge of Small-Spacing Stereo-Staggered Well Pattern Deployment Technology in the Shale Oil Reservoir

“…In the field exploitation practice of shale oil, the area with high abundance of movable reserves in the sweet spot should be preferred for well location deployment. • Engineering factors: The application of rotary steering technology (Janwadkar et al, 2009;Yan et al, 2021;Al Amri et al, 2021) and element logging technology (Zhu et al, 2018;Zhang et al, 2021) has greatly improved the drilling rate of horizontal wells. Research shows that the foundation of high shale oil production is to make the horizontal section as much as possible in the reservoir, especially in the area with high reserves.…”