Advances in Extended Reach Drilling – An Eye to 10 km Stepout

Abstract

SPE Members Abstract This paper will present recent technological innovations which have been used to surpass previous extended reach records together with other technologies which are viewed as fundamental in overcoming current limitations for extended reach and designer wells. The paper will focus on three specific drilling applications which provide a range of options for operating companies with varying field development philosophies. Introduction With records being continually broken in extended reach drilling (ERD) the obvious question is, how far can we go with existing technology? A recent well in the North Sea extended the step out record by 600. m to 7.8 km. The current limit is presently indeterminate, but as drilling technology continues to improve the final constraint may be economic rather than technical, as the limiting factors are gradually overcome. This paper will address some new technologies that will assist in increasing drilling reach and performance. Directional control and drilling efficiency are two items which have had significant impact on the decisions to attempt ERD and designer wells. The following directly contribute to improving directional control and drilling efficiency:–Tandem motors–Downhole adjustable stabilisers–Performance stabilisers The use of tandem motors offers more power than conventional motors and will increase overall rate of penetration (ROP). New intelligent multi-positional adjustable stabilisers can reduce hole tortuousity, thus extending the reach. It also allows inclination control, when drill string drag prevents further oriented drilling and maximises drill string rotation, which aids hole cleaning. A performance stabiliser, which is run below the motor, increases directional control. These technologies assist in optimising directional drilling performance. Fig. 1 represents a sample well profile that was generated to determine what capabilities were required to drill a 10 km stepout well at a true vertical depth (TVD) of 2900 m. This was an arbitrary two dimensional well profile generated to highlight potential problems in drilling such a well. As this was not based on any specific field, casing points were chosen that were feasible from a design perspective and to ascertain approximately how far out the casing could be run. The profile terminates in 8–1/2 in. hole as this is perceived to be the optimum configuration for most operators. There is obviously no unique 10 km stepout well as the complexity will depend particularly on the TVD of the reservoir which will subsequently determine the final measured depth and hole angle. This will have an impact on all associated activities including wireline logging, completion and workovers. Tandem Motors From the early days of single lobe, high speed-low torque to today's multiple lobe high torque-low speed configurations, the positive displacement motor (PDM) has become the workhorse in directional drilling. The need for improvement was driven by the operator's requirements of driving the latest bit technology and optimising drilling performance. P. 33

Buoyancy Technology Used Effectively in Casing-Running Operations to Extend Lateral Step-Out: Multiple Case Histories Detail Application Risks, Successes, and Improved Operation Procedures

“…Since its inception, flotation technology has allowed operators to extend wells in excess of 12,000 ft, and presently 30,000 ft offsets are being considered (Ryan and Raitt 1995). Other operators have successfully used such techniques in fields around the world.…”

Using a Catenary Trajectory to Reduce Wellbore Friction in Horizontal Extended Reach Drilling

“…This increased in the 1990s, and one targeted 10 km as a likely step out. Ryan et. al (1995) conducted a review of technology in 1995 and concluded that 10 km step out is feasible.…”

An Analytical Model for Axial Force Transfer and the Maximum Compression Point of Work Strings in Extend Reach Drilling

“…Extended Reach Drilling (ERD) is a technique to drill directional/horizontal wells beyond the routine capabilities of drilling rigs and tools. ERD was initiated in 1980's and rapidly evolved during the 1990's [1][2][3][4]. Naegel et al [5] reported an ERD well with a 20,341.2 ft horizontal departure at 5,577 ft true vertical depth (TVD).…”