In an operation in the Venezuelan Faja, well placement and rotary steerable systems (RSS) enabled drilling faster, longer, and shallower ERD wells than those that have been drilled with mud motors in the field over last 20 years. The results demonstrate a performance step change in this area.Standard drilling in the Faja includes dogleg severity (DLS) requirements as high as 8°/100 ft and rates of penetration (ROPs) as fast as 2,000 ft/hr; these were perfect conditions for using mud motors to drill build sections and horizontal wells. As drilling in the Faja moved south, reservoirs at true vertical depth (TVD) from 1,200 to 1,600 ft started to be developed. Shallow reservoirs and even higher DLS made it inefficient to drill the long 4,000-ft extended reach sections planned as this requires multiple pipe swaps to redistribute heavy bottomhole assembly (BHA) components and wiper trips to clean the hole to allow weight-on-bit (WOB) transmission to reach the bit.To reduce tortuosity, torque and drag, and stuck-pipe events; to improve hole cleaning, WOB transmission, and ROP; and to drill longer horizontal sections, a point-the-bit RSS was tried for the first time in Junin division. The first RSS well drilled in a shallow horizontal well exceeded all objectives and expectations set. Seven more horizontal sections drilled with the same RSS proved the system was robust enough to break a different drilling record on each well.The current shallow extended reach well (SERW) record in the Faja was drilled with a mud motor to 1,231 ft TVD with 4,404 ft of horizontal section and a TVD versus horizontal stepout ratio of 1:4.4. Advanced drilling engineering, bed boundary mapping LWD technologies, RSS, and improved drilling practices in six horizontal sections enabled drilling to similar ERD ratios, while breaking records for ROP, horizontal section length, and drilling and completion speed at similar TVDs.The performance step change in the Faja accomplished through the use of RSS and novel drilling practices has enabled increasing heavy oil production through drilling longer horizontal sections and through the reduction of mud filtrate and formation damage. The performance increase along with lesser tortuosity and friction factors have allowed drilling longer horizontal sections, saving valuable rig time, producing wells earlier, and running liners to total depth (TD) trouble-free unless stopped by oil production.

The success of a horizontal drilling campaign depends on the implementation of appropriate technologies and procedures to manage uncertainties and risks that may affect the overall economy of the project. This is the case for most fields in the Orinoco oil belt—the largest reserve of heavy oil in the world—which is mainly developed via horizontal drilling. As with other fields in the area, Junin-6 presents special challenges for horizontal well placement. The friable shallow reservoirs include some of the shallowest currently developed in the Orinoco oil belt. The main target sands range in thickness from 30 ft in the Arenas Basales (Basal sands) to 250 ft in the Oligoceno (Oligocene) reservoir. The lateral sections vary from 3,000 to 4,000 ft. This, combined with a high geological complexity, lack of 3D seismic data, and a limited number of correlation wells, makes the horizontal well placement a real challenge in many cases. Advanced logging-while-drilling (LWD) technologies had to be implemented in the challenging cases, such as in the Basal sands reservoir. A proactive approach based on bed boundary mapping technologies, combined whenever possible with point-the-bit rotary steerable systems, is being used to improve horizontal well placement in this field. The main results include net pay increase and cost reduction compared to wells executed with conventional technologies. The risk of unproductive drilling has been considerably reduced, especially in the thinnest formations drilled in this field. The best results were achieved when LWD bed boundary mapping was combined with point-the-bit rotary steerable systems, since this type of technology enabled better well trajectory control, faster execution, longer horizontal sections, and safer completions. This paper presents the main challenges for horizontal well placement in the giant Junin-6 heavy oil field and how they are being addressed with the use of advanced geosteering technologies.

Drilling for hydrocarbon deposits beneath the salt canopy in the Gulf of Mexico (GOM) has become common in deepwater; however, such drilling is made more difficult because of geological events that can cause difficulties in the drilling process, leading to expensive sidetracks or unwanted extra casing operations. To make operations economically feasible and to accomplish demanding rig utilization schedules, wells are planned to be drilled using one bottomhole assembly (BHA) from casing to casing at optimized rates of penetration (ROP), accurately placing the well while minimizing drilling and geological risks. Sediment inclusions, salt creep, rubble zones, narrow mud-weight windows along with well control events and mud losses, wellbore stability events and thin tar zones are some of those geological events found when drilling through salt and subsalt. Rotary steerable systems (RSS), reamers and synthetic oil-base muds have provided solutions to most of these challenges. This paper presents case histories of two deepwater wells drilled in the GOM. The first case, describes how, after having drilled through a long salt interval, tar was unexpectedly penetrated, requiring sidetracking in two different bypasses at high inclinations. Previous experiences of the operator and the industry indicated that tar cannot be detected in seismic data or accurately correlated from well to well because its short extension, and its presence could prevent reaching programmed total depths. Because of the inability to drill through the few sequences of tar intervals, it was required to sidetrack the well on two different occasions at high inclinations to reach the planned borehole total depth with the planned casing program. The second case presents the history of the deepest sidetrack performed in the GOM. This well was sidetracked for geological resons, subsalt at 28,822 ft measured Depth (MD), off of a cement plug. A push-the-bit RSS (and a reamer in the first case history) was used to sidetrack off cement plugs in both cases. Both cases were planned to sidetrack on the low side; however, this practice commonly used for downhole motors, proved ineffective in both wells. Both cases indicated that good cement was placed in the lower side of the hole, and so a setting to the right of the high side of the toolface was used successfully to deflect the wellbore. The technique, difficulties, and best practices resulting from drilling these high inclination sidetracks are addressed in this paper.

The requirement for a reliable technology to efficiently drill vertical large tophole sections has increased substantially along with the number of deepwater wells. Inefficient salt drilling with mud motors and high rig spread rates were some good reasons for operators to prefer rotary steerable tools (RSS) in large-hole sections since they became available to the Gulf of Mexico (GOM) in October 2004. As the use of RSS in 26-in. and 24-in. sections is becoming more popular and deeper wells require minimum dogleg severities in top holes, the use and requirements for RSS have taken higher importance.Deepwater wells are drilled through ultrasoft formations in the first 800 ft; additionally, surface conductors are normally set with an inclination at the shoe of 0.5° to 2°. The unconsolidated sediments and inclination at the beginning of the 26-in. section present a challenge to either hold vertical or drill directionally with mud motors and RSS. The combination of the issues resulted in difficulty to verticalize a few wells below the surface conductor.While from 2004 to 2009 84% of the runs were successful, a major study was conducted during the drilling moratorium in the GOM to understand the environmental conditions that were the root cause of the issues described above. The investigation of 58 bit runs with 26-in. RSS performed from 2004 to 2010 in deep water were studied using advanced drilling software to understand and solve the issue of inability to drop inclination and, in a few cases, of unwanted inclination buildup. The advanced drilling software included time-and-depth based replay of the drilling operation, bottomhole assembly (BHA) tendency, BHA vibration models, unconfined compressive strength (UCS), and e-Caliper computations.The study helped in understanding that conductor inclination and instantaneous borehole washout, in the first 800 ft below mudline (BML) due to UCS values as low as 350 psi, hinders the RSS push-the-bit pads from contacting the borehole, preventing a drop in inclination and, in some cases, allowing further inclination buildup. As this study was concluded during the moratorium shutdown, the lessons learned and best practices gathered helped to optimize BHAs, drilling parameters, and drilling practices. Implementation of these allowed all 26-in. RSS runs made post-moratorium to deliver vertical well intervals.

Continued growth in worldwide demand for oil and gas has encouraged operators in Latin America to develop reservoirs using wells drilled from congested pads. Without remedial action, this practice would lead to operational or HSE risks, both on land and offshore. An oilfield service company has adopted a comprehensive approach to this issue by incorporating a methodology for planning and preventing the risk of well-to-well collisions while drilling in congested environments. This anticollision methodology has been used to drill thousands of wells in Latin America without the occurrence of collision events. Along with the anticollision methodology, the development and use of advanced surveying techniques allows the placement of complex horizontal and 3D wells in congested land and offshore fields. Multiple case histories support the functionality and effectiveness of the anticollision methodology. These case histories are from operations developed in different countries and include drilling in congested offshore environments. The focus of the methodology is safety of personnel and preventing HSE incidents.