The Innovative Integration of Wellbore Strengthening and Managed-Pressure Drilling Redraw the Line Between Undrillable and Drillable - Case Study from Offshore Mediterranean Deepwater

Mapping Intimacies ◽

10.2118/206230-ms ◽

2021 ◽

Author(s):

Mahmoud El-Husseiny ◽

Taher El-Fakharany ◽

Samir Khaled

Keyword(s):

Total Concentration ◽

Pressure Control ◽

Control Mode ◽

Integrity Test ◽

Gas Field ◽

Drilling Performance ◽

Managed Pressure Drilling ◽

Weight Window ◽

Minor Losses ◽

Wellbore Strengthening

Abstract Managed pressure drilling (MPD) has a reputation for enhancing drilling performance. However, in this study, we use it as a technology for making undrillable wells drillable. In the deepwater of the Mediterranean of Egypt, a gas field has been producing for few years. Water broke through in one well, thus, we must drill a new well to compensate for the reduction in production. Years of production led to pressure depletion, which makes it difficult to drill this well conventionally. In this study, we will discuss the combination of MPD and wellbore strengthening (WS). In addition, we will discuss the challenges we met while drilling and how we tackled them, and the best practices and recommendations for similar applications. The 12¼" × 13½" hole section passed depleted sands, followed by a pressure ramp. First, we drilled the depleted sands and confirmed the pressure ramp top. To strengthen the sand, we spotted a stress-cage pill of 645 bbls with a total concentration of 29 ppb. In addition, we conducted a formation integrity test (FIT), but its value was lower than the required value to drill to the section target depth (TD). Then, we switched to MPD and increased the mud weight. MPD in annular pressure control mode (AP) enabled us to walk the edge as near as possible to the impossible. Drilling this section was challenging due to the narrow mud weight window (MWW). We faced kick-loss cycles, where we had high-gas levels (from 20% to 55%) while drilling with a loss rate from 60 to 255 bph, at the same time. The 8½″ × 9½″ hole section will cover a depleted reservoir. Therefore, we decided to use the MPD to drill this section. To widen the MWW, we decided to stress-caging the hole, as we drill. We loaded the active-mud system with stress-cage materials totaling 39 ppb. We drilled the hole section while keeping the bottom hole pressure (BHP) at 14.6 ppg. We drilled using MPD by maintaining 525-psi surface back pressure (SBP). We used the SBP mode (semi-auto mode) to add connections, resulting in minor background gases and minor losses. This study discusses the application of a novel combination of MPD and WS. It emphasizes how MPD can integrate with other technologies to offer a practical solution to future drilling challenges in deepwater-drilling environments.

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Comparative Study of Managed Pressure Drilling Application in Deepwater Gas Wells - Case Study from Offshore Eastern Mediterranean of Egypt

10.2118/202192-ms ◽

2021 ◽

Author(s):

Mahmoud Ahmed El-Husseiny ◽

Samir Mohamed Khaled ◽

Taher El-Sebaay El-Fakharany ◽

Yehia Mohamed Al-Nadi

Keyword(s):

Comparative Study ◽

Detection System ◽

Eastern Mediterranean ◽

Gas Wells ◽

Gas Field ◽

Well Control ◽

Rate Of Penetration ◽

Drilling Performance ◽

Managed Pressure Drilling ◽

Conventional Drilling

Abstract Although devised in 2003, managed pressure drilling (MPD) has gained widespread popularity in recent years to precisely control the annular pressure profile throughout the wellbore. Due to the relatively high cost and complexity of implementing MPD, some operators still face a challenge deciding whether or not to MPD the well. In the offshore Mediterranean of Egypt, severe to catastrophic mud losses are encountered while conventionally drilling deepwater wells through cavernous fractured carbonate gas reservoirs with a narrow pore pressure-fracture gradient (PP-FG) window, leading to the risk of not reaching the planned target depth (TD). Furthermore, treating such losses was associated with long non-productive time (NPT), massive volume consumption of cement, and lost-circulation materials (LCM), in addition to well control situations encountered several times due to loss of hydrostatic head during severe losses. Accordingly, the operator decided to abandon the conventional drilling method and implement MPD technology to drill these problematic formations. In this paper, the application of MPD is to be examined versus the conventional drilling in terms of well control events, NPT, rate of penetration (ROP), mud losses per drilled meter, LCM volume pumped, and drilling operations optimization. According to the comparative study, MPD application showed a drastic improvement in all drilling performance aspects over the conventional drilling where the mud losses per drilled meter reduced from 19.6 m3/m to 3.7m3/m (123.2 bbl/m to 23.4 bbl/m). In addition to that, a 35% reduction of NPT and also a 35% reduction of LCM pumped, and 67.2 % reduction by volume of cement pumped to cure the mud losses. Moreover, the average mechanical rate of penetration increased by 37.4%. MPD was also credited with eliminating the need for an additional contingent 7" liner which was conventionally used to isolate the thief zone. The MPD ability to precisely control bottom hole pressure during drilling with the integration of MPD early kick detection system enables the rapid response in case of mud loss or kick, eliminating kick-loss cycles, well control events, and drilling flat time to change mud density. This paper provides an advanced and in-depth study for deep-water drilling problems of a natural gas field in the East Mediterranean and presents a comprehensive analysis of the MPD application with a drilling performance assessment (average ROP, mud losses, LCM and cement volumes, well control events) emphasizing how MPD can offer a practical solution for future drilling of challenging deepwater gas wells.

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Multivariate Control for Managed-Pressure-Drilling Systems by Use of High-Speed Telemetry

SPE Journal ◽

10.2118/170962-pa ◽

2016 ◽

Vol 21 (02) ◽

pp. 459-470 ◽

Cited By ~ 12

Author(s):

Reza Asgharzadeh Shishavan ◽

Casey Hubbell ◽

Hector D. Perez ◽

John D. Hedengren ◽

David S. Pixton ◽

...

Keyword(s):

Rotational Speed ◽

High Speed ◽

Data Communication ◽

Pressure Control ◽

Feedback Controllers ◽

Loop Control ◽

Performance Improvements ◽

Drilling Performance ◽

Managed Pressure Drilling ◽

Weight On Bit

Summary With the recent advance in high-speed data communication offered by wired-drillpipe (WDP) telemetry, it is now possible to design automated control systems that directly use downhole data (e.g., pressure) to optimize drilling procedures. This research couples drilling hydraulics, rate of penetration (ROP), and rotational-speed (rev/min) control into a single controller for managed-pressure-drilling (MPD) systems. This novel multivariate controller improves drilling performance during normal drilling operations and enhances safety during abnormal drilling conditions such as unwanted gas-influx situations. New advances in drilling automation have made the closed-loop control of downhole weight on bit (WOB) and drillstring rotational speed (rev/min) possible. This study uses two feedback controllers that control the downhole WOB and rev/min by use of surface data. A multivariate nonlinear model-predictive controller (NMPC) uses downhole and surface measurements to simultaneously regulate the bottomhole-assembly (BHA) pressure and maximize the ROP. For this purpose, NMPC provides the necessary set points for the WOB and rev/min feedback controllers and manipulates the choke-valve opening and pump-flow rates. Controller performance is enhanced by means of a nonlinear estimator that works continuously online with the NMPC and provides the necessary estimated parameter values (such as annulus density, friction factor, and gas influx) for precise and efficient drilling control. The designed NMPC controller has a multipriority approach that is described in the following three scenarios: during unexpected gas influx, the NMPC gives priority to BHA pressure control and attenuates the influx effectively by means of a novel kick-attenuation method that switches the control objective from BHA pressure to choke-valve pressure; during connection procedures when adding a new stand, ROP is stopped and the NMPC focuses on maintaining the BHA pressure constant; and during normal drilling operation, which involves changes in the rock formation and differential pressures, NMPC gives priority to ROP maximization while maintaining rev/min, WOB, and BHA pressure within specified bounds. Preliminary results suggest that this multivariate controller for ROP and BHA-pressure control decreases drilling costs, reduces operator workload, and minimizes risk significantly. Specific improvements in drilling performance include higher ROP, effective kick attenuation, and more-uniform cuttings. The use of a multivariate NMPC allows for better ROP optimization and BHA-pressure control than is possible with the use of two independent controllers. These benefits are demonstrated across the three scenarios mentioned previously. In simulation, this technology delivers significant performance improvements during MPD and furthers the development of automated-driller systems.

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Successful Implementation of Managed Pressure Drilling and Managed Pressure Cementing Techniques in Fractured Carbonate Formation Prone to Total Lost Circulation in Far North Region

10.2118/208508-ms ◽

2021 ◽

Author(s):

Zhanna Kazakbayeva ◽

Almas Kaidarov ◽

Andrey Magda ◽

Fuad Aliyev ◽

Harshad Patil ◽

...

Keyword(s):

Real Time ◽

Successful Implementation ◽

Integrity Test ◽

Lost Circulation ◽

Far North ◽

Carbonate Formation ◽

Managed Pressure Drilling ◽

Geological Conditions ◽

Minor Losses ◽

Bottomhole Pressure

Abstract Drilling reservoir section in the oilfield located in Far North region is challenged with high risks of mud losses ranging from relatively minor losses to severe lost circulation. Numerous attempts to cure losses with traditional methods have been inefficient and unsuccessful. This paper describes implementation of Managed Pressure Drilling (MPD) and Managed Pressure Cementing (MPC) techniques to drill 6-1/8″ hole section, run and cement 5″ liner managing bottomhole pressure and overcoming wellbore construction challenges. Application of MPD technique enabled drilling 6-1/8″ hole section with statically underbalanced mud holding constant bottom hole pressure both in static and dynamic conditions. The drilling window uncertainty made it difficult to plan for the correct mud weight (MW) to drill the section. The MW and MPD design were chosen after risk assessment and based on the decisions from drilling operator. Coriolis flowmeter proved to be essential in deciphering minor losses and allowed quick response to changing conditions. Upon reaching target depth, the well was displaced to heavier mud in MPD mode prior to open hole logging and MPC. MPD techniques allowed the client to drill thru fractured formation without losses or gains in just a couple of days as compared to the months of drilling time the wells usually took to mitigate wellbore problems, such as total losses, kicks, differential sticking, etc. This job helped the client to save time and reduce well construction costs while optimizing drilling performance. Conventional cementing was not feasible in previous wells because of risks of losses, which were eliminated with MPC technique: bottomhole pressure (BHP) was kept below expected loss zones that provided necessary height of cement and a good barrier required to complete and produce the well. Successful zonal isolation applying MPC technique was confirmed by cement bond log and casing integrity test. Throughout the project, real-time data transmission was available to the client and engineering support team in town. This provided pro-active monitoring and real-time process optimization in response to wellbore changes. MPD techniques helped the client to drill the well in record time with the lowest possible mud weight consequently reducing mud requirements. The MPD system allowed obtaining pertinent reservoir data, such as pore pressure and fracture pressure gradients in uncertain geological conditions.

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Wellbore instability management using geomechanical modeling and wellbore stability analysis for Zubair shale formation in Southern Iraq

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-021-01279-y ◽

2021 ◽

Vol 11 (11) ◽

pp. 4047-4062

Author(s):

Raed H. Allawi ◽

Mohammed S. Al-Jawad

Keyword(s):

Shear Failure ◽

Gamma Ray ◽

Failure Criteria ◽

Wellbore Stability ◽

Integrity Test ◽

Direction Parallel ◽

Wellbore Instability ◽

Drilling Performance ◽

Weight Window ◽

Shale Formation

AbstractWellbore instability problems cause nonproductive time, especially during drilling operations in the shale formations. These problems include stuck pipe, caving, lost circulation, and the tight hole, requiring more time to treat and therefore additional costs. The extensive hole collapse problem is considered one of the main challenges experienced when drilling in the Zubair shale formation. In turn, it is caused by nonproductive time and increasing well drilling expenditure. In this study, geomechanical modeling was used to determine a suitable mud weight window to overpass these problems and improve drilling performance for well development. Three failure criteria, including Mohr–Coulomb, modified Lade, and Mogi–Coulomb, were used to predict a safe mud weight window. The geomechanical model was constructed using offset well log data, including formation micro-imager (FMI) logs, acoustic compressional wave, shear wave, gamma ray, bulk density, sonic porosity, and drilling events. The model was calibrated using image data interpretation, modular formation dynamics tester (MDT), leak-off test (LOT), and formation integrity test (FIT). Furthermore, a comparison between the predicted wellbore instability and the actual wellbore failure was performed to examine the model's accuracy. The results showed that the Mogi–Coulomb failure and modified Lade criterion were the most suitable for the Zubair formation. These criteria were given a good match with field observations. In contrast, the Mohr–Coulomb criterion was improper because it does not match shear failure from the caliper log. In addition, the obtained results showed that the inappropriate mud weight (10.6 ppg) was the main cause behind wellbore instability problems in this formation. The optimum mud weight window should apply in Zubair shale formation ranges from 11.5 to 14 ppg. Moreover, the inclination angle should be less than 25 degrees, and azimuth ranges from 115 to 120 degrees northwest-southeast (NE–SW) can be presented a less risk. The well azimuth of NE–SW direction, parallel to minimum horizontal stress (Shmin), will provide the best stability for drilling the Zubair shale formation. This study's findings can help understand the root causes of wellbore instability in the Zubair shale formation. Thus, the results of this research can be applied as expenditure effectiveness tools when designing for future neighboring directional wells to get high drilling performance by reducing the nonproductive time and well expenses.

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Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

Journal of Applied Physiology ◽

10.1152/japplphysiol.00002.2006 ◽

2007 ◽

Vol 102 (1) ◽

pp. 331-339 ◽

Cited By ~ 27

Author(s):

Rebecca S. Syring ◽

Cynthia M. Otto ◽

Rebecca E. Spivack ◽

Klaus Markstaller ◽

James E. Baumgardner

Keyword(s):

Cardiac Output ◽

Lung Injury ◽

Respiratory Rate ◽

Pressure Control ◽

Plateau Pressure ◽

Control Mode ◽

Intrinsic Peep ◽

Mixed Venous Saturation ◽

Mixed Venous ◽

Saline Lavage

Cyclical recruitment of atelectasis with each breath is thought to contribute to ventilator-associated lung injury. Extrinsic positive end-expiratory pressure (PEEPe) can maintain alveolar recruitment at end exhalation, but PEEPe depresses cardiac output and increases overdistension. Short exhalation times can also maintain end-expiratory recruitment, but if the mechanism of this recruitment is generation of intrinsic PEEP (PEEPi), there would be little advantage compared with PEEPe. In seven New Zealand White rabbits, we compared recruitment from increased respiratory rate (RR) to recruitment from increased PEEPe after saline lavage. Rabbits were ventilated in pressure control mode with a fraction of inspired O2 (FiO2) of 1.0, inspiratory-to-expiratory ratio of 2:1, and plateau pressure of 28 cmH2O, and either 1) high RR ( 24 ) and low PEEPe (3.5) or 2) low RR ( 7 ) and high PEEPe ( 14 ). We assessed cyclical lung recruitment with a fast arterial Po2 probe, and we assessed average recruitment with blood gas data. We measured PEEPi, cardiac output, and mixed venous saturation at each ventilator setting. Recruitment achieved by increased RR and short exhalation time was nearly equivalent to recruitment achieved by increased PEEPe. The short exhalation time at increased RR, however, did not generate PEEPi. Cardiac output was increased on average 13% in the high RR group compared with the high PEEPe group ( P < 0.001), and mixed venous saturation was consistently greater in the high RR group ( P < 0.001). Prevention of end-expiratory derecruitment without increased end-expiratory pressure suggests that another mechanism, distinct from intrinsic PEEP, plays a role in the dynamic behavior of atelectasis.

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Adult respiratory distress syndrome: outcome in a community hospital

American Journal of Critical Care ◽

10.4037/ajcc1994.3.5.337 ◽

1994 ◽

Vol 3 (5) ◽

pp. 337-341 ◽

Cited By ~ 6

Author(s):

D Willms ◽

M Nield ◽

I Gocka

Keyword(s):

Survival Rate ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Adult Respiratory Distress Syndrome ◽

Distress Syndrome ◽

Community Hospital ◽

Survival Rates ◽

Pressure Control ◽

Control Mode ◽

Significant Difference

BACKGROUND: Published reports indicate that survival rates of patients with adult respiratory distress syndrome have not improved dramatically since the first report of the condition in 1967. However, changes in ventilator strategies and improved critical care management may result in better survival rates in patients with well-defined, severe adult respiratory distress syndrome. OBJECTIVES: To report the outcomes of patients with adult respiratory distress syndrome treated in a community hospital and compare these findings with those in previously published reports. METHODS: A retrospective study design was used. All patients diagnosed with adult respiratory distress syndrome (N = 47) over a 2-year period were studied. RESULTS: For the study patients, the survival rate was 64%; 29% died from respiratory failure alone. Analysis demonstrated that advanced age was not associated with mortality. Pressure-control ventilation was used for 31 patients and there was no significant difference in the presence of barotrauma in the pressure-control mode vs volume ventilation. CONCLUSION: This survival rate exceeds most recently reported rates and thus supports the idea that improvement in treatment of adult respiratory distress syndrome is occurring.

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