Open-Hole Completion Based Mechanical Diversion of Acid/Chemical Stimulation Operations: Design, Deployment and Field Trial Results

2015 ◽  
Author(s):  
E. I. Carvajal ◽  
Y.. Caline ◽  
M.. Rylance ◽  
K.. Rice ◽  
J.. Waters ◽  
...  
Keyword(s):  
Field Trial ◽  
Low Cost ◽  
Chemical Stimulation ◽  
Lessons Learned ◽  
The North ◽  
Novel Technology ◽  
Austin Chalk ◽  
Open Hole ◽  
The North Sea ◽  
Efficient Distribution

Abstract The ubiquitous challenge that is faced by chemical stimulation techniques, of any kind, has always been achieving an economic and efficient distribution of the stimulation solution across the exposed reservoir interval. Many have approached this problem from a chemical perspective and others from the use of additives for mechanical diversion; however the very nature of stimulation itself means that a changing injection profile will make efficient diversion by such techniques uncertain and unpredictable. Instead, rather than relying on serendipitous deployment techniques, the approach described and reported here places true mechanical diversion as part of the well construction process. This paper will completely describe the process and achievements to date, including successful application in a number of horizontal wells completed in the Austin Chalk, as part of an overall deployment plan. Essentially, this new completion system comprises of multiple pressure actuated assemblies, distributed along the liner/casing. These assemblies, when activated, allow the lateral deployment of forty-foot needles, radially distributed at ninety-degree phasing around the casing, into the unstimulated reservoir. These subs can be precisely located across pre-selected intervals and thereby provide certainty of acid treatment distribution. The acid is pumped through the needles themselves during stimulation; however production takes place through a suite of ports. A bespoke debris basket may be run, after the stimulation treatment, in order to recover a suite of needle deployment indicators. This run, if performed, effectively establishes the success of the deployment. In order to demonstrate the concept and avoid the high-cost environment of the North Sea, a low cost field trial location was sought and identified. An Austin chalk operator was looked for that had an extensive horizontal candidate well set available for re-completion in open-hole. A number of candidate wells were then identified and the wells were recompleted and stimulated with this new system. This paper will present the entire suite of data related to these deployments, stimulation operations, lessons learned, production impact and potential. This novel technology was greatly assisted, supported and delivered via the Joint Chalk Research (JCR) council, comprising of some ten operating companies that encourage, fund and drive the development of carbonate completion and stimulation solutions.

Offshore field trial application of low-frequency passive microseismic technology in the North Sea for exploration, appraisal and development of hydrocarbon deposits

First Break ◽  
2021 ◽  
Vol 39 (4) ◽  
pp. 45-50
Author(s):  
Vasilii Ryzhov ◽  
Dmitrii Ryzhov ◽  
Ilshat Sharapov ◽  
Sergey Feofilov ◽  
Evgeny Smirnov ◽  
...  
Keyword(s):  
North Sea ◽  
Field Trial ◽  
Low Frequency ◽  
The North ◽  
The North Sea ◽  
Offshore Field ◽  
Hydrocarbon Deposits

Significant Performance Improvement with MPD in HPHT Narrow Drilling Window Campaign in the North Sea

2021 ◽  
Author(s):  
Babar Kamal ◽  
Abdul Saboor ◽  
Graeme MacFarlane ◽  
Frank Kernche
Keyword(s):  
Precise Determination ◽  
Lessons Learned ◽  
Overburden Pressure ◽  
The North ◽  
Fracture Pressure ◽  
Open Hole ◽  
Infill Drilling ◽  
Significant Performance ◽  
And Performance ◽  
Formation Pore Pressure

Abstract Significant depletion in reservoir pressure, huge uncertainties in pore and fracture pressure, high overburden pressure on top of reservoir, Narrow Mud Weight Window (NMWW) and Partial/Total losses whilst entering the reservoir made these HPHT (High Pressure High Temperature) wells conventionally un-drillable. Due to these substantial challenges these wells were considered not only costly but also carry a high probability of failure to reach well TD (Total Depth). MPD (Managed Pressure Drilling) is a safer and more effective drilling technique as compared to conventional drilling, especially in wells with NMWW and downhole hazards. The precise determination and dynamic downhole pressure management was imperative to complete these wells without well control incidents. The Constant Bottom Hole Pressure (CBHP) variant in combination of automated MPD system was deployed with a mud weight statically underbalanced while dynamically managed above formation pore pressure to minimize the overbalance across the open hole. MPD enabled the operator to efficiently navigate Equivalent Circulation Density (ECD) through the pore and fracture pressure window, allowed significant improvements throughout the entire campaign. This paper discusses the challenges faced during the last three wells drilled in the campaign which includes equipment issues, commissioning delays, losses whilst drilling, Managed Pressure Cementing (MPC), 7" drill-in-liner and plugged/blocked lines due to weather and mud conditions. The paper describes HPHT infill drilling experience, specific techniques, practices as well as lessons learned from each well during the campaign were implemented to address challenges and to improve performance. The MPD system commissioning was optimized by repositioning the lines which saved significant critical rig time. The blowdown points were added on the lines that were not operational continuously therefore a procedure was developed for flushing to avoid plugging. Optimized drilling strategy was also developed where MW was further reduced to avoid losses as observed in previous wells and CBHP was maintained by manipulating Surface Back Pressure (SBP) from surface. This paper also discusses continuous improvements /upgrades in MPD operating software which assisted the operator in accurate monitoring of flow, SBP and BH-ECD to save significant rig cost in terms of invisible Non-Productive Time (NPT). MPD is a drilling enabler and performance enhancer which saved 80 days of Authorization for Expenditure (AFE) on this challenging HPHT campaign.

Integrated Decommissioning of a Pentagon Shaped Production Semisubmersible in the UK: A Unique Challenge

2018 ◽  
Author(s):  
Luis F. Batalla Toro ◽  
Simon L. Reid ◽  
Alfredo Salcines Tudela ◽  
Duncan Graham
Keyword(s):  
Lessons Learned ◽  
Production Unit ◽  
Original Design ◽  
Successful Operation ◽  
Unique Challenge ◽  
The North ◽  
Sequence Of Events ◽  
The North Sea ◽  
Drilling Rigs ◽  
The Uk

Between 1969 and 1977, eleven semisubmersible drilling platforms were designed and built with an innovative pentagon shaped hull, specifically to work in the harsh environment of the North Sea. One of the drilling rigs, the Alexander L. Kielland, was converted soon after construction into an accommodation platform (flotel) and failed catastrophically in 1980. Another, the Pentagon 83 “Drillmaster” (renamed as Buchan Alpha), was being converted to a Floating Production Unit at the time of the disaster. The structure of Buchan Alpha was significantly modified during the conversion of the platform so that it benefited from the lessons learnt following the Alexander L. Kielland accident to ensure that the same sequence of events could not be repeated. This technical paper objective is to explain the integrated decommissioning process of the Buchan Alpha in the UK after more than 40 years since being built and more than 35 years of successful operation since it was converted to a Floating Production Unit, and how the features of its original design have accompanied the platform through the decommissioning process. The scope covers all phases of Buchan Alpha decommissioning from the detailed planning and preparation, the suspension of production up to the dismantling and recycling process. Significant challenges for the decommissioning team included the requirement to preserve the operational status of the subsea infrastructure for potential future field redevelopment and the diver disconnection of the subsea wells. Buchan Alpha’s deep draught presented limitations on the selection of dismantling and recycling yards due to quayside water depths. Complex ballasting operations and removal of the thruster’s propellers were required to facilitate the platform berthing at the quayside. Key lessons learned applicable for future decommissioning of floating production facilities will be shared.

scholarly journals A Novel Ionic Exchange Membrane Crystallizer to Recover Magnesium Hydroxide from Seawater and Industrial Brines

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 303
Author(s):  
Daniele La Corte ◽  
Fabrizio Vassallo ◽  
Andrea Cipollina ◽  
Marian Turek ◽  
Alessandro Tamburini ◽  
...  
Keyword(s):  
Magnesium Hydroxide ◽  
Saline Solution ◽  
Low Cost ◽  
Feed Solution ◽  
Ionic Exchange ◽  
The North ◽  
Novel Technology ◽  
Co Precipitation ◽  
Exchange Membrane ◽  
By Products

A novel technology, the ion exchange membrane crystallizer (CrIEM), that combines reactive and membrane crystallization, was investigated in order to recover high purity magnesium hydroxide from multi-component artificial and natural solutions. In particular, in a CrIEM reactor, the presence of an anion exchange membrane (AEM), which separates two-compartment containing a saline solution and an alkaline solution, allows the passage of hydroxyl ions from the alkaline to the saline solution compartment, where crystallization of magnesium hydroxide occurs, yet avoiding a direct mixing between the solutions feeding the reactor. This enables the use of low-cost reactants (e.g., Ca(OH)2) without the risk of co-precipitation of by-products and contamination of the final crystals. An experimental campaign was carried out treating two types of feed solution, namely: (1) a waste industrial brine from the Bolesław Śmiały coal mine in Łaziska Górne (Poland) and (2) Mediterranean seawater, collected from the North Sicilian coast (Italy). The CrIEM was tested in a feed and bleed modality in order to operate in a continuous mode. The Mg2+ concentration in the feed solutions ranges from 0.7 to 3.2 g/L. Magnesium recovery efficiencies from 89 up to 100% were reached, while magnesium hydroxide purity between 94% and 98.8% was obtained.

scholarly journals Inaccuracies in routinely collected Atlantic herring (Clupea harengus) maturity data and correction using a gonadosomatic index model

2011 ◽  
Vol 91 (7) ◽  
pp. 1477-1487 ◽  
Author(s):  
Lindsay R. McPherson ◽  
Konstantinos Ganias ◽  
C. Tara Marshall
Keyword(s):  
North Sea ◽  
Low Cost ◽  
Gonadosomatic Index ◽  
Clupea Harengus ◽  
Implicit Assumption ◽  
Multinomial Regression ◽  
Index Model ◽  
The North ◽  
Spawning Stock ◽  
The North Sea

Macroscopic maturity staging data are widely used to distinguish between reproductive and non-reproductive individuals. The implicit assumption is that these data are accurate. The accuracy of macroscopic maturity staging of North Sea herring (Clupea harengus) has not been checked since the macroscopic scale was produced in 1961. The aim of this study was to assess the accuracy of macroscopic maturity staging of female North Sea herring by comparison to histological staging and the gonadosomatic index (GSI). Ovary samples were collected during the North Sea Herring Acoustic Survey in 2006 on-board FRV ‘Scotia’ (Scotland) and in 2007 on-board FRV ‘Scotia’ and RV ‘Johan Hjort’ (Norway). Commercial samples were also collected by Marine Scotland, Aberdeen in both years. The maturity staging error was relatively low in 2006 (21% error) but was much higher on-board FRV ‘Scotia’ (57%) and RV ‘Johan Hjort’ (47%) in 2007. There was estimated to be a 27% under-estimation of the spawning stock biomass (SSB) in 2007 due to the differences in the proportion mature but no change in SSB estimates in 2006. GSI cut-off scores, estimated by means of multinomial regression models were successfully able to separate immature females from both mature-active and recovering females; however, there was some overlap between the mature-active and recovering individuals. We conclude that an effective and low-cost means of reducing error in herring maturity studies is the combined use of a four-point macroscopic maturity scale with routinely collected GSI data, the latter acting to validate and fine tune macroscopic staging.

1300 Tons Grouted Integrity Support Installation Case Study

2020 ◽  
Author(s):  
Beatriz Alonso Castro ◽  
Roland Daly ◽  
Francisco Javier Becerro ◽  
Petter Vabø
Keyword(s):  
North Sea ◽  
Structural Integrity ◽  
High Strength ◽  
Regulatory Compliance ◽  
Lessons Learned ◽  
Oil Field ◽  
The North ◽  
Future Production ◽  
Heavy Lift ◽  
The North Sea

Abstract The North sea Yme oil field was discovered in 1987, production started in 1996 and ceased after 6 years when it was considered no longer profitable to operate. In 2007 a new development was approved, being Yme the first field re-opened in the Norwegian Continental Shelf. The concept selected was a MOPUStor: comprising a jack-up unit grouted to a subsea storage tank. Due to compromised structural integrity and lack of regulatory compliance that came to light shortly after installation, the platform was required to be removed [1]. The remaining riser caisson and the future 1050 t wellhead module required a support to allow the re-use of the facilities and tap the remaining oil reserves. The innovative tubular frame support was designed as a braced unit, secured to the existing MOPUstor leg receptacles and holding a grouted clamp larger than typical offshore clamps for which design guidance in ISO is available. The existing facilities had to be modified to receive the new structure and to guide it in place within the small clearances available. The aim of this paper is to describe the solutions developed to prepare and verify the substructure for installation; to predict the dynamic behavior of a subsea heavy lift operation with small clearances around existing assets (down to 150 mm); and to place large volume high strength grouted connections, exceeding the height and thickness values from any project ever done before. In order to avoid early age degradation of the grout, a 1 mm maximum relative movement requirement was the operation design philosophy. A reliable system to stabilize the caisson, which displacements were up to 150 mm, was developed to meet the criteria during grouting and curing. In the stabilizer system design, as well as the plan for contingencies with divers to restart grouting in the event of a breakdown, the lessons learned from latest wind turbine industry practices and from the first attempt to re-develop the field using grouted connections were incorporated. Currently the substructure is secured to provide the long term integrity of the structure the next 20 years of future production in the North Sea environment.

UKCS exploration: 50 years and counting

2020 ◽  
Vol 52 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Pierrick Rouillard ◽  
Graeme Bagley ◽  
David Moseley ◽  
Keith Myers ◽  
Alyson Harding
Keyword(s):  
Oil And Gas ◽  
Low Cost ◽  
Volume Estimation ◽  
Mature Stage ◽  
Success Rates ◽  
The North ◽  
Cost Development ◽  
The North Sea ◽  
Exploration Drilling ◽  
The Uk

AbstractExploration drilling activity, discovery history and creaming curves in the offshore UK are analysed for each UK Continental Shelf (UKCS) basin and each play in the North Sea from the earliest wells drilled in 1965 until the end of 2017. Around 52 Bboe of commercially recoverable oil and gas has been discovered, with around half of this volume found in the first 10 years of exploration.UKCS exploration plays are generally at a mature or super-mature stage and the exploration challenges reflect this. Although technical success rates have steadily increased since the 1990s, pool sizes are becoming smaller. In the last 10 years the average commercial discovery size has been 27 MMboe recoverable, and since 2010 only 10% of discoveries have been bigger than 43 MMboe recoverable. The UK Oil and Gas Authority's 6 Bboe mid-case yet-to-find estimate, as published in 2018, would take 40 years to unlock at the current rate of discovery.Future exploration in the mature UKCS is intertwined with prolonging the life of production infrastructure and is increasingly dependent on the development of new low-cost development concepts. Increased focus on the search for subtle traps, and more reliable pre-drill risk and volume estimation through improved benchmarking and calibration will be key to future exploration success.

A VSP field trial using distributed acoustic sensing in a producing well in the North Sea

First Break ◽  
2013 ◽  
Vol 31 (1993) ◽  
Author(s):  
K. Nørgaard Madsen ◽  
M. Thompson ◽  
T. Parker ◽  
D. Finfer
Keyword(s):  
North Sea ◽  
Field Trial ◽  
Acoustic Sensing ◽  
The North ◽  
The North Sea ◽  
Distributed Acoustic Sensing
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