bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Application of Heavy Duty Wireline Fishing Techniques Retrieves Wellbore Obstruction and Allows Well to be Plugged and Full Integrity to be Regained
Authors: Flett C. , Macaula R. , Vincent J. M. 
Published: September 2011

Abstract
This case study will examine the removal of an obstruction in Well BC-14 on the Shell operated Brent Charlie platform. Obstructing access to the well was a 3.6″ OD wireline roller bogie cutter, 6600ft of 0.125″ wire, a slickline tool string and a 4-1/2″ PES HE-3 bridge plug complete with setting tool. The fish had been in the well for three and a half years with the condition of the wire lost down hole undetermined, in addition the well had tubing to 'A' annulus communication. The operational objective was to remove all obstructions from the well in order to allow access to set a plug and secure well integrity.
This paper will detail the operation while highlighting the limiting factors and challenges overcome as well as demonstrate how the use of Heavy Duty Wireline Fishing (HDWF) equipment and downhole tools, in conjunction with detailed planning, provided a cost effective solution to alternative options such as Coiled Tubing.
The successful utilization of HDWF techniques were applied with no lost time or safety incidents and resulted in the complete recovery of well obstructions, allowing the well to be plugged and its' integrity to be regained.
Cased-Hole Multistage Fracturing: A New Coiled-Tubing-Enabled Completion
Authors: Ravensbergen J. E. 
Published: September 2011

Abstract
Multi-stage proppant fracturing of horizontal wells has changed the economic landscape of the North American Oil and Gas Industry. Open-hole ball drop completion systems, are an economic solution for many operators, however alternative completions systems are emerging into the marketplace. This paper will describe a novel CT actuated, predominantly cased hole, CT Frac Sleeve completion.
This paper will explain how it works, and how operators are taking advantage of several new capabilities not available in other completion systems. The new capabilities that will be described include better placement control of each treatment and an unlimited number of treatment stages resulting in better drainage of the reservoir.
In addition, this paper will describe how CT and its bottom-hole assembly are not only required to sequentially open each of the CT Frac Sleeves, for each stimulation treatment, but add additional value to the system. How CT enables quick recovery from screen outs, freeing the fracture treatment process engineer to optimize the treatments without the risk of large financial penalties. Further how CT is used to accurately measure the bottom hole pressure during the treatment, also aiding the engineer to optimize the stimulation treatment, ultimately delivering a better stimulation treatment and improving the productivity of the reservoir. Finally, the paper will discuss how the CT BHA has contingent capabilities, as it is equipped with a sand jet perforating device.
Visualization of Natural Convection Flow of (Sub-) and (Super-) Critical CO2 in Aqueous and Oleic Systems by Applying Schlieren Method
Authors: Khosrokhavar R. , Elsinga G. , Mojaddam A. , Farajzadeh R. , Bruining J. 
Published: September 2011

Abstract
Efficient storage of carbon dioxide (CO2) in aquifers requires dissolution in the aqueous phase. Firstly, the volume available for gaseous CO2 is far less than for the CO2 to be dissolved in the water initially present in the aquifer. Secondly, the partial molar volume of CO2 in the gas phase is about twice as large as the partial molar volume of CO2 in water, meaning that storage in the water phase leads to less pressure increase per amount of sequestered CO2. Transfer of CO2 from the gas phase to the aqueous phase would be slow if it were only driven by diffusion. However, dissolution of CO2 in water forms a mixture that is denser than the original water or brine. This causes a local density increase, which induces natural convection currents accelerating the rate of CO2 dissolution.
This study presents a set of high pressure visual experiments, based on the Schlieren technique, in which we observe the effect of gravity-induced fingers when sub- and super-critical CO2 at in situ pressures and temperatures is brought above a liquid, e.g., water, brine or oil. A short but comprehensive description of the Schlieren set-up and the transparent pressure cell is presented. The initial experiments are confined to bulk-phase situations, i.e., in the absence of a porous medium. The experiment is able to demonstrate the initiation and development of the gravity induced fingers. The concentration gradient is high near the gas-liquid interface. The experiments show that natural convection currents are weakest in highly concentrated brine and strongest in oil. The set-up can screen aqueous salt solutions or oil for their relative importance of natural convection flows.
Influence of Downhole Fluid Behavior Changes on Slickline Operations in Burgan and Magwa Oil Fields, Kuwait
Authors: Bouhanna M. 
Published: September 2011

Abstract
Slickline down-hole flow control devices are always subjected to forces created by differential pressure where they are setting in tubing.
The standard practice for retrieving a flow control device (e.g. Plug from landing nipple) is to equalize pressures prior any retrieving attempt.
Slickline operators are always focusing on a mechanical surface wire manipulation of down-hole tools and surface pressure gauge to monitor equalizing pressure, while they overlook the effect of influential down-hole conditions such as: fluid level, fluid gradient, gas segregation and phase changes which based on we can calculate and determine the actual equalizing pressure.
In some cases, the equalizing pressure could not be completed properly due to reservoir fluid behavior change while operating or sometimes equalizing ports might be plugged, therefore any retrieving attempt can lead to an unknown events such as: Slickline tool string blown up due to differential pressure during retrieving plug from a landing nipple.Slickline tool string blown up due to huge differential pressure created by asphaltenes bridge plug formation in the tubing.Slickline toolstring blown up during a flowing gradient survey with a portable well test due to choke changes.Slickline plug stuck in landing nipple, due to the hydrostatic pressure head acting on the plug.Collection of a non representative single phase bottom-hole sample due to downhole phase change.
This paper will discuss the newly developed procedures (best practices) resulting from a meticulous study of downhole fluid behavior changes and their influence on slickline operations. These best practices allow slickline to reduce this risk to a controlled level and provide a high service performance at low cost. Case histories from Burgan & Magwa oilfields will be used to illustrate overlooked slickline job failure root causes and how best practices contribute in providing innovative low cost service options.
Success from Subsea Riserless Well Interventions
Authors: Fjærtoft L. , Sønstabø G. 
Published: September 2011

Abstract
This paper describes how Statoil, over a period of 10 years, have qualified and implemented Subsea Riserless Light Well Intervention (RLWI) applications as their primary means of intervening in subsea wells. The paper will also demonstrate the value of RLWI in relation to the company's Increased Oil Recovery (IOR) goals.
Subsea wells represent the area where least well intervention work has been done, and where the biggest practical and technical challenges also lie. Hence less oil is recovered from subsea completed fields than from those with fixed platforms. RLWI is a cost effective intervention method that allows an operator of subsea wells to increase production and optimize utilization of vessels and rigs.
Statoil is a leading exponent of RLWI services, utilizing two specialized and modern vessels on full year contract. A third vessel is currently being considered. The total RLWI activity for 2010 was 671 days, spanning a total of 32 different jobs. This paper will describe the development of these applications from 2000 until today covering a total of 125 individual operations. Statoil has 34 subsea fields, of which 32 are on the Norwegian continental shelf with a total of around 460 individual wells. Light Well intervention has been performed on 11 of these fields. Experience so far indicates that there are no limitations on equipment regarding interface to subsea templates.
In this paper the contract philosophy for these services will also be discussed. Further on, the agreement between the different production assets for sharing of resources will also be described. The technical achievements and limitations will be listed and described. Then the needs of the future will be described and prioritized.
Finally, the economic benefit and contribution of introducing Riserless Light Well Intervention will also be highlighted. The following three conclusions on RLWI will be elaborated on in this paper: Improves HSE in subsea well interventionsImproves recoveryIntervention cost is cut by more than half compared with anchored rigs and riser systems
Installation of Velocity Strings (VS) Without Loading-Killing the Well
Authors: Chavez Manuel 
Published: September 2011

Abstract
Installation of a small diameter velocity string (VS) is often necessary in tight gas wells to resolve liquid loading problems. Coiled Tubing (CT) is commonly used as a velocity string conduit due to safe live-well installations and speed. A technique is being applied in which wells are cleaned out with coiled tubing which is then hung off as a velocity string in one trip. The wells are left flowing during the entire operation so that the wells are not loaded up completely and off production after the operation. A new coiled tubing hanger was designed and utilized such that two well control barriers are maintained during the operation. This paper will review the equipment package and the installation process.
Hurricane Contingency for Stuck Coiled Tubing: Preparing for Platform Evacuation and Allowing a Safe Recovery Maurice, Louisiana, North Gulf Coast
Authors: Torres Carlos , Creppel Carl , Kelm Charles H. , Moorkamp William , Cottingham Kris 
Published: September 2011

Abstract
Operations in the Gulf of Mexico (GOM) are affected during the months of June through November by the weather, as hurricanes are generated and come into the GOM, creating the need to plan abandonments to avoid harm to any personnel, environment and minimize damage to facilities. During June 2010, while executing a scale clean out operation on a platform with 1.25″ coiled tubing (CT), the pipe got stuck. After 11 days of troubleshooting, it was required to evacuate the platform due to a hurricane that was approaching. A management of change was developed to safely secure the CT string at surface, which would allow for abandonment while maintaining well control (WC). During this process three options were analyzed: the first option was to add additional support to the injector head(IH) jacking frame and leave the pipe stabbed in, this option was rejected because it would not guarantee WC in the event that the storm takes down the IH.
The second option was to secure the CT with the Blow Out Preventers(BOP) then shear it, and rig down the IH. This Approach provided WC, but it created additional risk and limitations when resuming the retrieval operation after the storm. The third option was to secure the CT at the BOP and cut it above the IH. With the removal of the IH, this would leave the section of pipe that was previously across the chains and riser free above the BOP. An appropriate valve would then be connected to the CT stub end, for WC.
Furthermore, by sliding a riser section over the CT stub and making up a gate valve and night cap would minimize the exposure to the storm. Finally, the riser could be secured to the deck. After analyzing available options, the third alternative was recommended and approved by the BOEMRE; as this option addressed WC and allowed safe recovery by re-stabbing the pipe back into the IH, and rigging up the required equipment to proceed with the pipe recovery operation.
Optimization of Operational Time and Workover Resources With the Alternate Use of Coiled Tubing and Pulling Unit for Well Abandonment
Authors: Pando A. , Silva L. , Lopez B. , Cardona G. , Acevedo O. 
Published: September 2011

Abstract
Casabe Field is a mature oil field located in the Mid-Magdalena Valley basin in Colombia, with over 60 than years of production. For the last 25 years it has been waterflooded using a five-spot injection pattern. In 2004 Ecopetrol and Schlumberger initiated a technological alliance aiming to increase the recovery factor and to incorporate new reserves. From an integrated work the project defined an aggressive drilling, completion, workover operations to convert old water injectors into multi-zone selective completion injectors and the abandonment of damaged wells campaign to optimize the waterflooding patterns.
The workover program reached its highest activity peak of from 2008 to 2009. This increment brought the need to perform several well abandonments to avoid interference with the new injector wells. The abandonments also proved to be a main challenge of the campaign because of the well status complexity as severe casing restrictions, fishing, abnormal pressures, and reduced surface location area.
A new methodology to optimize workover resources was developed based on alternating the use of a Coiled Tubing combining a Pulling Unit. This methodology enabled the workover in wells where workover rigs had serious downhole and surface limitations. From 2009, 96 wells were abandoned, 52% of them applying the method that combines both units. The methodology has generated so far 181 days of Workover rig time in savings, therefore allowing the rigs to complete more than 235 wells by the end of 2009, complying with the overall project program contributing with an incremental production of 5000 BOPD. In addition, this methodology to abandon well has generated alone savings of 1.5$MMUSD from the initial CAPEX.
This paper will describe the agile well abandonment methodology combining Coiled Tubing and Pulling Units in a highly efficient, economical way, and complying with HSE standards and regulations allowing its application in any other oilfield.
Ultrasound Logging Techniques for the Inspection of Sand Control Screen Integrity
Authors: Hyde-Barber C. , Weighill G. T. , Tymons T. R. , Solberg M. , Helland A. G. 
Published: September 2011

Abstract
A significant proportion of worldwide production comes from sand prone reservoirs and is increasingly dependent upon the performance of sand control completions. However, sand control screens can fail which may lead to lost production or untimely abandonment of the well. In many cases remedial action may be possible, but the advanced design of sand control devices presents a considerable challenge to many inspection techniques, leading to a gap in understanding the failure mechanism. This paper documents the application of an innovative ultrasound-based technology for the inspection of sand control screen failures, including results and conclusions derived from an extensive testing program.
The objective of the testing was to prove the feasibility of using phased array ultrasound technology to locate sand entry points and assess the integrity of the screen in the down hole environment. Specifically, the aim was to assess the ability to provide integrity information from the internal surface of the base pipe to the outermost surface of the screen. During testing, several types of sand control screens were methodically damaged, simulating the defects observed in screens recovered from sand producing wells. The damaged screens were deployed in a test well and logged with a wireline setup.
The data indicates that damage resulting in enlarged base pipe perforations is detectable and the internal surface of the base pipe imaged in all screen types. Dependent upon the screen type, the ability to detect damage to the external layers of the screen, without any base pipe damage, has been demonstrated. In conclusion, in a test well environment the application of phased array ultrasound has been validated for the investigation of damaged sand control screens.
Revolutionary Matrix Stimulation Process in Offshore Mexico Using Coiled Tubing Equipped With Optical Fibers (CT-EOF) and Distributed Temperature Survey (DTS)
Authors: Garcia S. , Franco E. , Gerardo M. , Davila L. , Ortiz B. , Castillo M. , Miranda R. , Perez J. 
Published: September 2011

Abstract
During the last 30 years, in offshore Mexico, matrix stimulation treatments were designed and executed around pumping large volumes of fluids by a "bullheading technique," which comprised multiple stages of pre-flushes, acids, and solvents without adequate control of placement. The objective of these matrix stimulation treatments in the Ku-Maloob-Zaap carbonate formations fields is to remove drilling-induced damage and achieve maximum well productivity. This is a challenge because this formation is naturally fractured and presents high permeability, around 4-5 Darcies. The "bullheading technique" has been proven to be inefficient because the evaluation logs have shown non-uniform stimulated intervals.
Recently, coiled tubing (CT) operations adapted a new procedure to improve the stimulation treatment's placement technique. However, the biggest concern was to determine if the chemical fluids had correctly stimulated the target zones. The initial solution was achieved by pumping radioactive tracers with the chemicals during the stimulation and an additional CT run performed to take a gamma ray (GR) log. This procedure has proven to be inefficient and time consuming.
For first time in offshore Mexico, the innovative technique of combining coiled tubing equipped with optical fibers (CT-EOF) and distributed temperature survey (DTS) to acquire and record pressure and temperature data—which is compared with petro physical data in real time—to decide selective placement of chemical fluids in target zones, was implemented in a completed oil producer cased hole well in Campeche Bay. This innovative technique reduced operational time and eliminated the additional CT run while optimizing the placement of the stimulation fluids for improved well productivity. The information obtained from the DTS allowed informed decisions to be made on alternative lifting methods to improve the well productivity performance for this well.
The job design, execution, and post-treatment evaluation of a matrix stimulation treatment in well M-432—where CT-EFO and DTS were combined—will show how the operation was optimized. In addition, the comprehensive analysis from DTS data was used to optimize placement of the stimulation treatment, the evaluation of effectiveness of the matrix stimulation treatment, the analysis used to identify the well productivity problem, and the benefits this new technique offers in the Ku-Maloob-Zaap carbonate formation.
3D Borehole Model for Evaluation of Wellbore Instabilities in Underbalanced Drilling
Authors: Roshan H.. , Rahman S. S. 
Published: September 2011

Abstract
Underbalanced drilling (UBD) has been used in the oil industry to avoid formation damage, reduce lost circulation and increase the rate of penetration. Underbalanced drilling in incompetent rocks, however, poses severe borehole stability problems. Numerous models have been developed to predict the time dependent wellbore collapse during drilling, in particular underbalanced drilling. Experience shows that these models require data that are hard to obtain and without these data results become unreliable. A three dimensional wellbore model has been developed at university of New South Wales to help drilling engineers determine the optimal mud composition and a range of bottom hole pressure for underbalanced drilling. The concept of thermodynamics of irreversible processes, consolidation and elastoplastic constitutive law are employed to predict the temperature and ion distribution, pore pressure and effective stresses around a borehole. These data sets can be used as input to borehole stability analysis. From the results of this study it was revealed that the effect of plasticity on stress relaxation around the wellbore is a major concern during underbalanced drilling. This relaxation especially in hoop stresses can lead the wellbore to collapse. The results also showed that the size of plastic zone depends not only on the horizontal in-situ stresses but also on the vertical in-situ stress.
Innovative Coiled Tubing Equipment for Successful Temporary or Permanent Zonal Isolation
Authors: Al-Harbi Mesaad S. , Said Rifat , Haldar Surajit , Burov Anton , Kharrat Wassim , Ahmed Danish 
Published: September 2011

Abstract
The well stimulation and water shut off (WSO) job in the carbonate reservoir of Ghawar field in Saudi Arabia is becoming increasingly challenging, considering the complex well completion. Many challenges are therefore encountered during coiled tubing (CT) interventions when trying either to permanently shutdown water production or to temporarily isolate the water zone to stimulate the oil intervals. In fact, the lack of real-time bottom-hole control of mechanical or chemical diverters caused these jobs to fail with conventional CT strings, which eventually called for costly solutions using workover rigs.
This paper describes multiple shortfalls of previous WSO and matrix stimulation jobs, and how this trend is reversed after the emergence of the fiber optic enabled CT (FOECT) string with real-time downhole measurement sensors.
The permanent zonal isolation utilizing an inflatable packer with cement plug is now possible with greater accuracy and enhanced success ratio even in wells with complex completions. The availability of a real-time casing collar locator (CCL), bottom-hole temperature (BHT) and differential pressure readings enables adequate control of packer setting depth and inflation, and optimization of the cement design and its injection.
The temporarily zonal isolation using chemical diverters can now be assessed real-time with the Distributed Temperature Survey (DTS). The stimulation fluids will not be pumped unless the isolation of the water zone is confirmed. The CT acid job can be now optimized by eliminating the risk of losing acid into the water intervals and by ensuring a uniform acid coverage across the oil zones with DTS.
This method was validated with the wireline log run just before the CT job. Challenges, design, execution and results of zonal isolation interventions with both conventional CT and FOECT are detailed in this paper to demonstrate that this type of CT job becomes more successful with the FOECT.
Survey of More than 1,000 Fracture Stage Database with Net Pressure in the Barnett Shale, Part 2
Authors: Shelley Robert F. , Lehman Lyle V. , Shah Koras 
Published: September 2011

Abstract
This paper is a continuation of SPE 138277, which studied a database of microseismic data and compared the information with net pressure. This second phase focuses on creating a completion tool that provides completion and stimulation designers a better guideline to generate quality or effective design.
The data was clustered using Self-Organizing Mapping (SOM) techniques to associate treatments with similar characteristics. These techniques included proppant type, injection rate, volume of frac fluid and proppants, perforation interval spacing and other key factors that shape a completion design to effectively stimulate a targeted volume of shale reservoir rock.
The completion workflow was developed through several data-mining techniques while using sound engineering observations. SPE 138277 unveiled the theory of "Managed Fracture Complexity" by illustrating the impact of perforation spacing on stimulated reservoir volume in principally isotropic shale such as Barnett. This paper will extend that concept toward creating an optimized design.