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Collaborating Authors
Well Integrity
Abstract In recent times the topic of well barrier integrity has become increasingly salient. Within the well completion arena, there have traditionally been two main alternatives for barrier plugs used for packer setting or temporary well abandonment; these are the metallic flapper or ball type isolation plugs. This paper describes the evolution of an innovative glass type barrier plug from its first appearance in the oilfield in 2004, to the deployment of third generation prototype systems into wells in the North Sea today. Traditional ball or flapper type plug systems need to operate in two states: open and closed. This functionality typically necessitates the use of dynamic seals, which also have to compensate for the pressure differential applied across the plug. Plugs built in this manner can be prone to malfunctions in the dynamic seals and have limitations as to the pressure differentials that can be applied to them when opening. Additionally as the balls or flappers themselves are traditionally manufactured using metallic alloys, in the event that a plug fails to open the only alternative is milling, which if successful, will still leave a restriction in the well limiting options for future well interventions. Glass barrier plugs have to operate in two slightly different states, solid or shattered. When the plug is run in hole the glass is in a solid state with pressure integrity maintained using static elastomeric seals. Once well operations have progressed to the stage when the plug needs to be opened, a preinstalled trip saver can be activated which would shatter the glass and open well communication. Operating in this manner avoids the use of dynamic seals thereby increasing plug reliability. Other major advantages are that the differential pressure applied across the plug when opening has no effect on the plugs functionality and since the plug is made out of glass, in the event of a trip saver malfunction the plug can be opened using a shoot down tool, a spear, or milled within approximately 10 minutes using a wireline tractor (Welltec, 2011) leaving a full bore ID for future well interventions. This paper describes how BP Norway and TCO used the lessons learned from two generations of Glass Barrier Plugs (GBPs) to develop a system with increased debris tolerance, improved redundancy and a larger inner diameter.
- Europe > United Kingdom > North Sea (0.24)
- Europe > Norway > North Sea (0.24)
- Europe > Netherlands > North Sea (0.24)
- (2 more...)
- Production and Well Operations > Well Intervention (1.00)
- Well Completion > Completion Installation and Operations (0.84)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (0.56)
- Well Completion > Well Integrity > Zonal isolation (0.34)
Innovative Solution Successfully Recompletes Problematic Well in Malaysia
Elliott, Chris (Petronas Carigali Sdn, Bhd (PCSB)) | Mahzan, Mohammad (Petronas Carigali Sdn, Bhd (PCSB)) | Feroze, Mohd Imran (Petronas Carigali Sdn, Bhd (PCSB)) | Mahadi, Khairul Azmi (Petronas Carigali Sdn, Bhd (PCSB)) | Mahdzan, Abdil Adzeem (Petronas Carigali Sdn, Bhd (PCSB)) | Aziz, Khairil Faiz (Halliburton) | Forbes, Murray (Halliburton) | Dzul-Fikar, Nasri (Welltec)
Abstract An offshore operator in Malaysia had run a completion string in a highly deviated 7-in. gas well. When continuous pressure build-up in the production casing annulus was observed during well clean-up, leakage in the completion system was suspected. After several attempts to mitigate the pressure build-up failed, the operator initiated further investigation, which confirmed the suspicion. Small tubing leaks that were allowing produced gas inside the tubing to seep through to the annulus were found. These leaks could have allowed the pressure to increase, and possibly, could have caused the casing to collapse. In order to produce through the annulus, the pressure would have to be vented. With the high demand of gas in Malaysia and since the rig was still at the location, the project team decided to initiate immediate recompletion of the project instead of waiting for a later intervention. This well is one of three wells completed to develop the FN field within KCL area, located approximately 200 km offshore from Bintulu. The field was expected to deliver up to 100mmscf/day per well to help relieve an anticipated gas shortage. This paper discusses the history of the wells, the diagnostic methods used to analyze the well problems, the pros and cons of each solution considered, details regarding the recompletion chosen, and the challenges encountered during the recompletion activities. The discussion also highlights the successful solution used for closing and reopening the fluid loss isolation barrier valve (FLIBV) with a wireline tractor rather than with other options considered after conducting a successful system integration test (SIT) prior to the project execution. The unique solution chosen was a first for Malaysia, and probably, for the world. The success of the recompletion results provided improvements for future applications and will be a benchmark solution for future operations.
- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Drilling Operations (1.00)
- Well Completion > Well Integrity (1.00)
- (8 more...)
Abstract Delineation of oil and water in heterogeneous carbonate formations can be challenging, especially in the presence of low resistivity formations and low mobility zones. Advanced wireline formation testers (WFTs) have traditionally been used in openhole logging for pressure profiles, coupled with downhole fluid analysis (DFA) and sampling for an integrated approach. It is often difficult to obtain well defined oil and water gradients with pressure measurements in tight formations, especially with probe-type tools. Straddle-packer modules are often used to enable flow from low mobility formations. However, the straddle-packer module has operational and differential pressure limitations, as well as a relatively large storage volume in the isolated interval. A field example of oil-water delineation is presented for a low resistivity, heterogeneous carbonate formation. Low formation fluid mobilities required the utilization of a new wireline tester module over the standard probe type tool. A newly designed fluid inlet module with multiple openings was utilized across the low mobility zones for the first time in the industry. This new module avoids issues associated with the interval volume of a dual-element straddle-packer-type tool and provides significantly faster clean up from the formation. In addition, minimized storage results in better Interval Pressure Transient Test data. Faster set/retract operation of this tool and a much higher pressure differential limit are additional advantages over existing dual packer tools. Several station measurements with mobilities of less than 0.1 md/cp were conducted. This allowed oil to be identified across a low resistivity zone, leading to an increased oil column height in the field. Results showed that more accurate oil-water delineation was provided using the new module along with high resolution optical fluid analyzers, identifying mobile oil from low resistivity carbonate zones. In addition, more accurate permeabilities for the tested zones were obtained through pressure transient data analysis.
- Asia (0.46)
- North America > United States > Texas (0.28)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Pressure transient analysis (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Formation test analysis (e.g., wireline, LWD) (1.00)
Abstract A subsea production well in the North Sea was being serviced with a riserless intervention which inadvertently resulted in fill atop a temporary bridge plug. Riserless slickline and traditional e-line attempts to remove the debris and pull the plug were unsuccessful. A rig or intervention vessel with riser for coiled tubing cleanout was unavailable for approximately a year. The operator requested innovative solutions and selected a unique riserless light well intervention consisting of an e-line cleaning tool with a reverse circulating bit and bailer sections to break through the hard-packed debris, vacuum it into the bailers, and retrieve it to surface. The remaining debris in the internal fishing neck of the plug was sucked up by a high-powered e-line cleaning tool and the plug was pulled in the same run. The job was executed without incident from a small, dynamically positioned, vessel with a moon pool and a subsea lubricator, saving the operator about one year's deferred production versus waiting for the coiled tubing solution. This paper discusses the operation of the downhole tools and procedure for riserless deployment to achieve the objectives and create this value.
- North America > United States (0.28)
- Europe > United Kingdom > North Sea (0.25)
- Europe > Norway > North Sea (0.25)
- (3 more...)
Abstract The last well on the Morvin subsea High Pressure High Temperature (HPHT) field, located offshore Norway, was a combined production and exploration well. This well had as objective to drill through two known producing reservoirs and then continue drilling whilst dropping into two deeper and unexplored reservoirs. Drilling conditions on Morvin are very tough due to extremely hard and abrasive sandstone formations combined with long horizontal reservoir sections with temperatures of up to 167° C. Neighbouring wells had been on production for several months causing depletion in the upper formations. This depletion had to be carefully monitored and managed to prevent any losses/well control scenarios. In order to prove the reservoir fluid system in the exploration part of the well several operations were conducted. These consisted of, amongst others: extensive logging, coring, pressure points and a newly developed formation sampling tool. The results were used to adjust the well path and to decide whether the new formations would be completed, or cemented back. An HPHT oil and water tracer system was developed to be installed in the completion. The specially developed tracer technology enables the localisation of any possible water or oil producing formations. In addition, blank pipe combined with openhole swell packers were installed between the different formations for zonal isolation. Wireline conveyed bridge plugs give the possibility to plug water produsing zones back. This paper describes the strategy which was followed, together with the technology that was used, to prove the reservoir fluid system in the exploration part of the well. After assessing all data it was decided to complete both exploration formations. The well was successfully put in production 5 weeks after the exploration part was finished making this an extreme fast track project.
- South America > Brazil > Rio de Janeiro (0.29)
- Europe > Norway > Norwegian Sea (0.29)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Block BM-C-7 > Peregrino Heavy Field (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Block BM-C-47 > Peregrino Heavy Field (0.99)
- North America > United States > Oklahoma > Morvin Field (0.99)
- Europe > Norway > Norwegian Sea > Halten Bank Area (0.98)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > HP/HT reservoirs (1.00)
- (3 more...)
Abstract Several offshore gas fields are present in Adriatic Sea (Italy), producing since the 60s from multilayer metric sand reservoirs. The declining production in these mature fields is normally offset by drilling new deviated wells. Recent technology evolution shifted the focus from metric reservoirs to thinly laminated intervals (thin beds), until now not produced due to difficulties in identifying gas bearing zones. While gas identification in metric reservoirs can be normally achieved with standard petrophysical measurements, thin beds are challenging since lamination thickness is half inch or less and even advanced petrophysical logs struggle in discriminating gas from water in this environment. Conventional pressure gradient approach also does not work, since thin beds are often overpressurized and pressures are supercharged due to low mobility. A new wireline formation testing approach for thin beds to discriminate gas from water zones was introduced, using a dual packer string with downhole fluid analysis capabilities, including fluid density measurement. This provided the possibility of testing very low permeability zones with high uncertainties in saturations. Dual packer tests were also successfully carried out in the underlying shale formation never considered before a real reservoir, revealing potential for gas production. The possibility to verify gas presence in zones with high uncertainties saved the cost of multiple well tests, optimized the completion strategy of the different reservoirs and allowed to increase the field production and reserves, reducing at the same time uncertainties in reservoir model. Four jobs with dual packer and downhole fluid analysis to test thin beds were performed so far in Barbara NW, Barbara and Clara Fields, resulting in added gas reserves estimated in 2 Billions Sm3 and gas production higher than the one at fields startup several years ago. This is a remarkable result for development wells in a mature environment (balanced exploration), maximizing asset value. Based on these results, several gas fields producing today from metric reservoirs will be revisited in the very near future in order to start production from thin beds, untouched until now, with the advanced wireline formation testing approach described in this paper playing a key role.
- Europe > Italy (0.52)
- North America > United States > Texas > Wichita County (0.24)
- North America > United States > Texas > Archer County (0.16)
- Europe > United Kingdom > North Sea > Central North Sea (0.16)
- North America > United States > Texas > Fort Worth Basin > Barbara Field (0.99)
- North America > United States > Texas > Fort Worth Basin > Clara Field (0.98)
A Unified Approach to Well Integrity Evaluation Led to Better Decision Making for Workovers in Mature Wells in the Waddell Ranch, West Texas
Babaniyazov, A.. (ConocoPhillips) | Clayton, R.. (Schlumberger) | Sykes-Bookhammer, D.. (Schlumberger) | Walker, R.. (Schlumberger) | Amezcua, J.. (Schlumberger)
Abstract The often referenced Norwegian standard D-0101 describes well integrity as the "application of technical, operational and organizational solutions to reduce the risk of uncontrolled release of formation fluids throughout the life cycle of a well". Well integrity can therefore be considered in terms of the structural soundness of the well, its casing, cement and wellhead; and how it reduces the risk of the uncontrolled flow of formation fluids to other formations or surface. Well integrity is a critical issue when working over and recompleting mature wells. This paper describes common integrity issues and develops a workflow for managing well integrity information during the design, execution, and evaluation of workover operations. It was found that no one measurement can give a complete well integrity analysis; instead a unified systematic approach considering a variety of measurements will lead to successful, economical, and well executed workovers. There is a great deal of value in obtaining certainty about the status of a wellbore from a clear logging and testing regime. The type of logging package will depend on the economics of the recompletion campaign, but the cost of logging operations pales in comparison to a lost hydraulic fracture or series of expensive squeezes. The evaluation and quantification of workover rates, reserves and economics in this field are not within the scope of this paper, and will not be addressed here.
An Integrated Case Study of Improve Oil Pay Evaluation in Shaly, Laminated, Low Mobility Reservoirs Using Wireline Cased Hole Dual Packer and Production Test
Mas, C.. (Schlumberger) | Yaxley, L.. (Tately NV) | Ardila, M.. (Schlumberger) | Ayan, C.. (Schlumberger) | Tanuwidjaja, V. Indrayanti (Schlumberger)
Abstract The subject of the case study is a recently discovered oil and gas accumulation characterized by laminated, shaly sandstones with high apparent water saturation. Conventional openhole log data was inconclusive in identifying hydrocarbon type and net hydrocarbon pay zones. Moreover, reservoir complexity, low mobility, and inadequate differentiation of oil versus gas pay made it unlikely that a conventional production testing program would be successful and cost effective. However, reservoir fluid identification and pressure measurements were critical for resolving key uncertainties and guiding decision making for future appraisal and development. Cased-hole wireline formation testing was used to better determine reservoir fluid type and productivity in selected intervals so as to differentiate oil pay from gas pay and net pay limits. A total of 30 dual packer stations were conducted in cased hole. The test results were used to choose the intervals, methodology, and equipment for subsequent production tests, which successfully proved the existence of three separate oil reservoirs and demonstrated commercial production rates.
- North America > Mexico (0.28)
- North America > United States (0.28)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Well Completion > Completion Installation and Operations (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- (2 more...)
Abstract The wells in the southern area of Saudi Arabia are mostly horizontal wells in highly fractured carbonate reservoirs. Due to high water cut caused by water influxes through the fractures, some of these wells were dead or on intermittent production between 2005 and 2010. To increase oil production, we performed several water shutoff jobs using inflatable packers with mixed results. The water shutoff candidate selection process starts with a reservoir and production data evaluation, followed by a coiled tubing (CT) logging run to identify the water source and adjust the required isolating fluids formulation and volume. Successful execution of the water shutoff treatment requires controlling the placement, inflation, injection, and disconnect of the inflatable packers. Fiber-optic enabled coiled tubing (FOECT) systems, which enable real-time downhole data measurement, can optimize water shutoff treatment design, execution, and evaluation—increasing the success ratio. For the job design, we ran production logging tools on the FOECT string to detect the water source, measure the bottomhole temperature required for the formulation of water shutoff fluids, obtain a gamma ray and/or casing collar locator (CCL) log, and get an X-Y open hole (OH) caliper critical. This helped us determine the best setting depth for the inflatable packer in the openhole section, and confirm the required water shutoff fluids volume. The depth correlation for the packer setting was performed with a fiber-optic bottomhole assembly (BHA) gamma ray conveyed on CT. This enabled us to monitor and adjust the inflation of the packer, and the injection through it, in real time Then, the packer setting and release was confirmed with the world's first application of a fiber-optic, CT-conveyed tension and compression tool. Recent production results showed significantly higher production with no more than 10% water cut. The integrated CT solution proved to be an effective water shutoff technique in these horizontal wells, and has potential to bring many wells around the world back to economic production.
- Asia > Middle East > Saudi Arabia (0.89)
- North America (0.68)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Well Completion > Completion Installation and Operations > Coiled tubing operations (1.00)
- (3 more...)
ABSTRACT A recent LWD density log in an exploration well showed excessive abrasive metal loss on the density measurement stabilizer. Towards the end of the drilling run it was noticed that the bottom quadrant density correction (delta rho) was slowly moving from values normalized on zero to a more positive number of about 0.15 g/cm. Measurements of the density stabilizer diameters performed after the logging run showed the diameter had been reduced by abrasion by approximately 0.2 inch along the entire length of the stabilizer. Therefore, the compensated density measurement was logically questioned. A post-job calibration showed a significant difference from the pre-job calibration, as expected. What was unexpected was that the compensated density computed from the pre- and post-job calibrations compared favorably at the end of the well, but not at the beginning of the well. This implies that the density correction algorithms derived during characterization will compensate for metal loss but not for metal gain. Monte Carlo N-Particle (MCNP) modeling is used to review this finding and investigate a method to define the amount of metal loss that can be tolerated before compensated density measurement inaccuracies exceed specifications. In order to compute an accurate photoelectric effect (PEF) and caliper that are derived from the individual short and long detector densities, the pre- and post-job calibrations need to be utilized for processing the data. A new methodology of blending the pre- and post-job calibrations as a function of metal loss was developed to accurately reprocess the density count rate data over the entire drilled interval. The final compensated density measurement from this reprocessing compared favorably to the original compensated density measurement (with only the pre drilling calibration in effect). This blending process resulted in valid single detector and compensated density data over the entire interval confirmed by independent measurements.
- Asia (0.68)
- North America > United States > Texas (0.48)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)