A number of companies are pushing for alternative approaches to offshore development that seek to access marginal reservoirs. Their differing and unique ideas call for a departure from the usual playbook, but share a common goal of slashing capital costs. Eight of the world’s 10 longest wells have been drilled by ExxonMobil as operator of the Sakhalin-1 project in Russia.
This paper describes a new approach to evaluating the effectiveness of the rotary-steerable-system (RSS) steering mechanism on wellbore tortuosity in horizontal wells. This paper demonstrates a work flow to determine optimal lateral lengths and trajectories in the Midland Basin by studying the effect of the lateral length and trajectory on well production. With the arrival and development of rotary steerable systems in the late 1990s, the industry thought that drilling a perfectly smooth and controlled trajectory would not be an issue. Range Resources' drilling head talks about how the company went from drilling the shortest laterals in the Marcellus to the longest and why. The Apollonia tight-gas chalk play is located in the Abu Gharadig Basin in the Western Desert of Egypt.
The drilling records of Extreme Reservoir Contacts (ERC) like Extended Reached Drilling (ERD) and Multi-Lateral wells(ML) continue to be broken. From the initial limit of MD 10,000ft to now almost 50,000 ft with extended reach depths and from dual-lateral to quad-laterals’ with 40,000-50,000ft reservoir contact. Completions rule of engaging with this type of wells continues to play ‘catch-up'. As a result, getting the full potential out of these extreme wells with limited completions options had always been a challenge. Recent innovation in "wireless electric connect/disconnect" technology combined with all electric integrated intelligent completions architecture has addressed these challenges. The well completion design is an all electrical system that provides a multi trip connect/disconnect system enabling seamless communication between upper and lower completions enabling permanent downhole monitoring and control, at the sand face. The highlight of this digital edge solution and deployment architecture enables completions to deploy in ERC wells meeting targeted drilled depths and achieving reservoir goals. The digital enablement provides real time downhole data for permanent production logging and zonal well testing capability while producing. Production and reservoir management is at finger tips of the end user.
A new innovative down hole electric telemetry enabled data transmission and power to be distributed across multiple sensors like pressure, temperature, water cut and electric flow control valve. Run on a single electrical cable, this digital completion technology with its induction coupling capability continue to complete record-drilling wells and makes today's completions limitations a history. It is now a reality for fully-digitalized Intelligent Completions solution, which can support any well type scenarios; multi-zones, horizontals, multi-laterals and extended reached drilling (ERD), including subsea completions. Each zone can be equipped with a permanent downhole infinite position valve-control, flowmeter, water-cut sensor and/or pressure/temperature gauges. This allows real-time reservoir measurement and supports ‘Dial A Rate’ flow control. Conventional flow control valves depend on hydraulic actuation system, although the technology has worked for decades, it has some inherent limitations such as need for multiple control lines limiting the number of zones, maximum depth of deployment as well the response time of hydraulic systems for very long completions. Electric valves are free from these limitations by design and provides lot more flexibility in the hands of the completion engineer. The multiple sensors measurement and data integration is achieved with a single surveillance, monitoring, diagnostics and valve-optimization production software to ensure real time data streaming, management and bringing insights to production and reservoir engineers for production optimization through remote valve control.
This digital solution of Intelligent Completions technology can finally claim that completions is no longer the limiting factor, effective reservoir management with intelligent completions can follow wherever the drill bit can go. It has been deployed worldwide from the Middle East to the open Sea in Pacific to enable zonal production-control and reservoir management. Its borderless completions architectures and standardization of modular system is the answer for Digital Oilfield and Data driven continual production optimization and reservoir management without intervention.
For the first time in Completions history, extended drilling records are matched with completing the entire well to Measured Depth (MD) with fully digitized solution of multi-zone measurements, infinite-control valves and real time data enabled production optimization system.
Drilling ultra-extended-reach (ultra-ERD) wellbores has redefined industry standards. Operators and service companies must fully assess the accompanying risks to maximize the overall productivity of an asset. New drilling technologies, such as improved drilling fluid design and geomechanics analyses, allow wellbores to be drilled to the lateral displacement of greater than 13 km. This requires improved absolute wellbore positioning, in conjunction with reduced uncertainties. When developing these drilling technologies, the economics must be considered so as not to exponentially increase the cost per barrel of oil. The increase in infill drilling of nearby offset wellbores requires developing improved methods that reduce wellbore position uncertainty when placing the wellbore in the reservoir, in addition to avoiding collisions.
The proposed geomagnetic referencing technique is suitable for the application to the Sakhalin-1 project in eastern Russia. Here there is a predominance of ultra-ERD wellbores coupled with considerable knowledge of the varying depth of the basement rock structure. This paper presents a process used for creating a geomagnetic crustal field model that can be updated to the actual survey location with the date and time for real-time application. This process can also be used in the reprocessing of legacy measurement-while-drilling (MWD) data. The application of this process significantly improves wellbore position accuracy. The ability to have a greater understanding of the overall geomagnetic field, along with enhanced techniques in multistation algorithm processing, removes the effects of drillstring and the cross-axial interference due to mud shielding effects. Additional benefits of this application include reduced wellbore tortuosity for planned wells, improved anticollision separation factors, and improved torque and drag profiles.
This new geomagnetic model, updated to the actual survey location, date, and time and incorporating realistic uncertainty determinations based on basement rock depth analysis, has resulted in a 50% improvement in the overall ellipse of uncertainty (EOU) when compared with previous definitive surveys, in addition to an accurate bottomhole location. Incorporating these advanced techniques reduces position uncertainty that improves overall 3D wellbore positioning. Other studies, such as a disturbance field study, evaluate the effects of the magnetospheric ring current, auroral electrojets, and secondary induced fields, and was conducted by analyzing the magnetic observatory data from the same magnetic latitude to quantify the maximum and minimum declination variations during a magnetic storm.
Before his Vice-Minister position at the Ministry of Oil and Gas, Magzum Mirzagaliyev has been Vice-Chairman of the Board for Innovative Development and Service Projects at KazMunaiGas national oil and gas company of Kazakhstan. In the period of 2011-2012 he was Managing Director of KazMunaiGas. Previously, he was Director General of TenizService. He started his career as a drilling fluid engineer in MI Drilling Fluids International Company (Schlumberger) at the oil fi elds of Tengiz and West Siberia. Mr Mirzagaliyev was educated at Turan University (1999), Diplomatic Academy (2003), Caspian State University of Technologies and Engineering named after Sh.Yessenov (2010), in 2002-2004 he carried out a traineeship in MI Drilling Fluids based in the USA and Malaysia.
Eight of the world's 10 longest wells have been drilled by ExxonMobil as operator of the Sakhalin-1 project in Russia. Components and drilling tools involved in the well design are evaluated and redesigned throughout the program to maximize penetration rate and reduce flat time. Drillstring-torque capacity was recognized as a limiter for increasing penetration rate and for reaching total measured depth capability. The operator consequently sought an alternative drillpipe connection with higher torque capacity. The Sakhalin-1 project comprises the Chayvo, Odoptu, and Arkutun Dagi fields off the east coast of Sakhalin Island, Russian Federation.
The development of multilateral wells and long-reach wells has become important to maximizing recovery for many fields. These technologies are often applied in offshore environments, where large reservoir areas are drained from one or more platforms. In the late 1980s, long-reach wells started to use existing infrastructure better by drilling beyond the design limits of that time. Several major operators were extending their limits, and, in the late 1990s, BP Wytch Farm showed that a horizontal departure exceeding 10 km was feasible. This had a significant effect on the industry because offshore platforms now could be designed for up to 10-km reach, as opposed to the early 1980s when 3-km reach was common.
In the book A Journey to Sakhalin, the great Russian writer Anton Chekhov described the island, then a "katorga"--a penal colony--as a hellish place. Two centuries later, Sakhalin has changed in numerous ways and has become famous for its enormous hydrocarbon resources that lie underneath the island's shelf. Even with the considerable infrastructure investments related to oil and gas activity, Sakhalin remains a place of large contrasts: some may find it a sparsely populated island whose few cities are dominated by gloomy concrete apartment blocks and scarce roads, while others will enjoy its spectacular scenery and will keep in their memory the charming bubble of the Okhotskoye Sea. Sakhalin is the largest island in Russia. This fact alone makes locals proud, as they are the residents of the biggest island in the largest country in the world.
The Sakhalin-1 consortium has drilled a 15,000-m horizontal well from the Orlan platform at Chayvo field in the Sea of Okhotsk, topping four previous wells drilled between 2013 and 2015 that reached between 12,450 ft and 13,500 ft. Partner Rosneft described the well as "super complex" with a 14,129-m stepout drilled about 5 km offshore. Sakhalin-1 has been a proving ground for extended-reach drilling (ERD) technology since the first well was drilled there more than a decade ago. More recently, development well О-14 in 2015 was drilled to 13,500 m, well Z-40 in 2014 reached 13,000 m, and in 2013 wells Z-43 and Z-42 extended to 12,450 and 12,700, respectively. The longer horizontal wells eliminate the need for additional offshore facilities and pipelines, utilizing existing infrastructure to cut costs.
An operator was drilling complex big-bore gas extended-reach drilling (ERD) wells from an offshore Sakhalin Island platform. Because of the shallow gas anomaly presence beneath the platform, there was a requirement to set an intermediate casing or liner at ~375-m true vertical depth (TVD), which was between the 30-in. driven conductor at 170 to 175-m TVD and the next casing setting depth of 950 to 1065-m TVD. Due to the well complexity and completion requirements, conventional casing design with no underreaming operations was not an option.
Well reach and complexity significantly increased since the project started in 2007, which called for improvements in wellbore geometry. The wellbore geometry underwent few changes, concluding with the latest most favorable required for a 27 to 28-in. directional tophole out of a 30-in. conductor with the maximum bit size pass-through diameter of 25-in., and setting 24-in. liner at ~375-m TVD. Originally, these types of topholes were delivered in two separate trips. On the first trip, the 24-in. borehole was drilled with a mud motor bottomhole assembly (BHA), and on the second trip, underreaming-only operations were performed to obtain final borehole diameter. This operation required additional rig time and caused excessive vibrations during underreaming. A different type of underreamer was implemented successfully to eliminate vibrations, but it did not reduce the number of trips. The ultimate solution was to run the underreamer below a bent mud motor, enabling simultaneous drilling and underreaming of the directional top hole while steering the trajectory in a crowded subsurface environment. The presence of deviated conductors with 6 to 8° inclination at the shoe in all outer slots played a substantial role in overall success of the operation. It is very unlikely that the same results could be achieved if the outer slot conductors were straight.
Installing the underreamer below the mud motor worked successfully in five recent wells, saving a trip in each well. The tophole trajectory was effectively steered away from the offset wells, creating a no-collision-risk situation. A 24-in. liner was run to the planned depth and cemented. This technique was accepted by the operator for the major offshore project and used as the way forward for the remaining five outer slots.
The successful implementation of the simultaneous drilling and underreaming technique demonstrated the benefits and qualitative acceptance of using an underreamer below the mud motor for the directional tophole in this major Sakhalin offshore project. The knowledge and lessons learned from the project can be applied to other worldwide projects with identical or similar casing design requirements.