Application of New Generation Rotary Steerable System for Reservoir Drilling in Remote Areas

Abstract

This paper describes the design criteria and operational experience with a new, second-generation Rotary Closed Loop System (RCLS). Rotary Closed Loop Systems are clearly revolutionizing the way in which oil & gas wells are drilled. During the past 5 years the technology has emerged from prototype status to a standard application in locations with good infrastructures such as the North Sea and the Gulf of Mexico. In remote areas with more challenging logistics such as West Africa, Asia Pacific, and South America, the use of rotary steerable technology has been very limited. Based on the accumulated experience with a leading system, a new generation of Rotary Closed Loop System has been introduced specifically for remote operating areas. These areas have a relatively poor infrastructure, difficult logistics and some experience extreme environments. The paper describes the technological challenges that had to be overcome for the standard application of Rotary Closed Loop Systems in remote areas and illustrates the advantages to the oil & gas industry with some exemplary case histories. Introduction Rotary Closed Loop System (RCLS) drilling technology was first introduced to the North Sea in early 1997. The technology was ground breaking at that time without any significant parallels. It has been as revolutionary to the drilling industry as the introduction of Measurement While Drilling (MWD) or Steerable Motor technology was in the late 1970's and mid 1980's. The complexity of these new systems has been a significant challenge when it came to their wide spread use. In areas with short supply chains and good infrastructure like the North Sea, the new technology has widely replaced conventional directional drilling technology. It has become the standard drilling system for many fields in the 12. 1/4 inch to 8. 1/2 inch hole sections. To continue the expansion of the use of this technology, new system requirements were defined. These new system requirements are aimed at helping the industry explore and develop oil & gas resources more economically throughout the world, including the most remote areas. Design Criteria for the New Generation Rotary Closed Loop System The first generation RCLS has successfully replaced conventional directional drilling methods (such as steerable motor and MWD/LWD systems) in many fields. However, this has primarily been limited to high cost offshore operating areas with high activity and good infrastructure. This is a result of the fact that demand has continued to rapidly grow with new systems being added to the operating areas having an established infrastructure. As operators gained confidence in the technology, the demand spread to all areas of the world where high operating costs drive the need for developing oil & gas reserves more economically. A continuation of the high growth rate for RCLS applications is therefore still expected. Experience in the maintenance of the 1st generation product, in its field application, and in the build up of the supporting infrastructure to maintain and operate the system, led to a requirement for a new RCLS generation. Step change in reliability The first generation system has reached a reliability level comparable to the conventional directional drilling technology with steerable motors in combination with Measurement While Drilling / Logging While Drilling technology. The data shows that the reliability rapidly improved in the first two years of commercial application, Fig. 2. For the years 2000 and 2001, the reliability of the system has stabilized at a level of 75 to 80 % for the probability of successful runs. This trend indicates that no further significant increases are to be expected without major changes to the existing system. This has led to the first major design criteria for a new generation system - to achieve a step change in reliability. Step change in reliability The first generation system has reached a reliability level comparable to the conventional directional drilling technology with steerable motors in combination with Measurement While Drilling / Logging While Drilling technology. The data shows that the reliability rapidly improved in the first two years of commercial application, Fig. 2. For the years 2000 and 2001, the reliability of the system has stabilized at a level of 75 to 80 % for the probability of successful runs. This trend indicates that no further significant increases are to be expected without major changes to the existing system. This has led to the first major design criteria for a new generation system - to achieve a step change in reliability.

Innovative PDC Drill-Bit Cutter Technology Leads to Performance Improvements in Western Desert, Egypt

“…The rotary closed-loop system (Gruenhagen 2002;Johnston 2001) enables continuous steering while rotating and incorporates multiple propagation resistivity and gamma-ray measurements. Combined with an automated directional control, the system reduces hole tortuosity, differential sticking and, generally provides a more in-gauge hole.…”

Lessons Learned From Drilling Horizontal Wells on Didon Field, Offshore Tunisia

“…Rotary steerable drilling systems are described extensively (Edmondson et al 2000;Hahne et al 2004;Weijermans et al 2001;Chen, Gaynor, Comeaux 2002;Stuart et al 2003;Gruenhagen, Hahne, Alvord 2002) and have become the preferred technology for drilling complex or lengthy drainholes, primarily because the tools can negotiate the planned well path without stopping to "steer" as with conventional steerable motor systems. These systems have not only found favour in terms of improving gross drilling efficiency and reducing risk as well complexity increases, they are also frequently favoured by geology and geophysics (G&G) groups in the operator's asset team since they can steer more precisely to and through challenging reservoir targets.…”