Managed Pressure Drilling Techniques Research Articles

Combined Mud-Cooling, MPD Techniques Enable HP/HT Drilling in Egypt

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 210252, “Drilling the Deepest HP/HT Onshore Exploration Well Using a Combination of Mud-Cooling and MPD Techniques: A Field Case Study From the Nile Delta of Egypt Targeting a Mesozoic Carbonate Platform,” by Mahmoud El-Husseiny, Egyptian Natural Gas Holding Company, and Taher Elfakharany, Al-Azhar University. The paper has not been peer reviewed. _ The complete paper reviews the successful application of a mud-cooling and managed-pressure-drilling (MPD) system in a high-pressure/high-temperature (HP/HT) well to explore the potential of the Mesozoic carbonate platform with a pressure ramp and narrow mud-weight window (NMWW) in the Nile Delta. The constant bottomhole pressure (CBHP) variation of MPD in combination with mud cooling was used to drill from the middle of the pressure ramp to the target depth, maintaining the mud-inlet temperature at approximately 50°C. Geological Targets and Geohazards The primary objective of Well T-1 is the edge of a Mesozoic carbonate platform. These carbonates are expected to be high-energy shallow marine deposits with fair reservoir properties (20–50% net-to-gross, 5–10% porosity). The secondary objectives are turbiditic sandstone channels of the Oligocene. These sandstones are expected to have 9–20% porosity and 50–300 md permeability. Potential Middle and Late Miocene geohazards include pressure rampup associated with losses, kicks, and borehole degradation, including tight holes, overpull, and caves; and reported sticking and hangup events. The HP domain begins below approximately 4000 m. Potential Oligocene to Paleocene geohazards include NMWWs associated with losses, kicks, and simultaneous gains and losses (ballooning); borehole degradation, including tight holes, overpull, and caves; and sticking and hangup events. The HP and HT domains begin below approximately 4500 m. Potential Mesozoic carbonate geohazards include possible losses of fractured and pressure-regressed carbonates. Mud-Cooling Technique Concept and Equipment The mud cooler consists of two circuits. In the first, hot mud is circulated through a dual mud cooler using a centrifugal pump. Because of heat exchange through the plate heat exchanger, the mud is cooled and transferred back into the active mud system. The discharge of cold mud takes place upstream of the point where the suction of hot mud occurs. In the second circuit, a fluid mixed with water and glycol is circulated between a dual air cooler and the dual mud cooler using a dedicated pump. When passing through the plate heat exchanger, this mixture of water and glycol is evacuated. When this mixture returns to the dual air cooler, it is cooled using high-performance ventilators. The mud-cooling system features 16 ventilators. The efficiency of the mud-cooling system is adjusted with a number of operated ventilators. The mud-cooling units used in this well consist of two dry air coolers and two sets of air fans (Fig. 1), with each set containing 24 fans. A mixture of 10% glycol and water was used as a cooling fluid.

Case Study: Not Just for Drilling: A Survey of the Application of Managed-Pressure Techniques

Every activity within a well alters the pressure being exerted on the open hole, and every mitigation technique attempts to maintain the desired pressure within acceptable limits. If the pressure becomes too low, kicks, borehole breakouts, and hole collapse are the primary consequences (Fig. 1). Pressure that is too high can damage the reservoir, induce fluid losses, and slow down operations. When these unfortunate events occur, remedial actions are usually necessary, increasing safety exposure, nonproductive time, and the overall costs of the project. To mitigate these concerns, operators have used the techniques of managed-pressure drilling (MPD) to maintain annular pressure and create a pressure-tight barrier against drilling hazards and manage inflow from the formation during drilling. While conventional drilling uses the hydrostatic pressure of the drilling mud to manage the pressure of the wellbore, MPD uses a combination of surface pressure, hydrostatic pressure, and annular friction to balance the exposed formation. Over the decades, MPD has been associated as a technology that is used only on problematic wells and only as a last resort. However, recent developments have highlighted that managing pressure is not just for drilling operations or just the most challenging wells. When integrated at the beginning of operations as part of a comprehensive well plan, managing pressure becomes a performance-enhancing solution for any type of well classification, including development, directional, multilaterals, and horizontals. Wellbore stability is maintained throughout the entire operation and pressure is dynamically altered in the annulus, enabling any operation to become faster with fewer challenges while delivering a more productive well and reducing overall costs and exposure to hazardous risks. The managed-pressure approach has even been leveraged to fully optimize a field/reservoir development program. An example of how MPD techniques can be incorporated into an overall well plan occurred on an ultradeepwater exploration well drilled by TotalEnergies in the Mexican waters of the Gulf of Mexico (SPE 200503). The operator and the service providers wanted to manage the pressure during the entire well program—including drilling, tripping, running casing, and cementing—to address pore pressure uncertainty, pressure ramp increase, and a narrow pore pressure/fracture gradient (PP/FG) window. The seafloor rested under 10,748 ft (3276 m) of water, and with the exploratory nature of the well, the conventional solution involved an excessive number of casing strings and an overbalanced mud weight (MW). Integrating MPD techniques enabled the operator to adjust the bottomhole pressure instantaneously, the result being a recognition that conventionally cementing a string of 13⅜ -in. casing to isolate the critical formation and safely continue drilling further stages of the well was impractical. To make the situation even more challenging, the engineers did not precisely know the size of the hole. A collaboration between the engineering teams of the operator, the cementing service provider, and MPD professionals resulted in a generated plan. A tail slurry of 15.86 ppg (1.90 SG) followed a 12.52 ppg (1.50 SG) lead gas-tight slurry. At a total depth of 13,622 ft (4152 m), the combination kept the equivalent circulating density (ECD) at 9.18 ppg (1.10 SG) without exceeding 9.51 ppg (1.14 SG). At the casing shoe, located at 12,801 ft (3902 m), the plan called for a 9.01 ppg (1.08 SG) without exceeding 9.35 ppg (1.12 SG), as shown in Fig. 2.

Utilizing Managed Pressure Drilling Technique to Prevent Rock Failure and Maintain Wellbore Stability

Rock failure is one of the major concerns of drilling operation, especially in the formation with narrow drilling window, which may lead to several technical issues and even endanger the operation safety, such as wellbore collapse, stuck pipe, formation breakdown, lost circulation, etc. A new technology is proposed in this paper to prevent rock failure and maintain wellbore stability through controlling the annular pressure profile.A new managed pressure drilling equipment named pressure control drilling system (PCDS) is developed which combines the constant bottom hole pressure technique and micro-flux control technique to quickly create overbalanced, near-balanced and underbalanced wellbore condition in the whole process of drilling operation. Based on the proposed MPD equipment, a novel technology is developed to maintain the annular pressure within the range of formation fracture pressure and formation collapse pressure, ensuring the formation rock to be neither shear failure nor tensile failure. Hydraulic calculation is performed before and during the drilling operation to predict the pressure profiles inside and outside the drill pipe, frictional pressure and equivalent circulating density, providing reference to the maintenance of wellbore stability. Real-time monitoring of multiple parameters such as properties of drilling fluid, bottom hole pressure and circulating flow rate as well as logging data is conducted to detect any minor change of down hole circulating system, minimizing the potential of wellbore collapse and formation breakdown.The proposed technology has been applied in several onshore and offshore wells with a great success. Generally, a relatively low density of drilling fluid is used to cooperate the application of this new technology, due to its advantage of fast response to down hole conditions, minimizing the possibility of formation breakdown and formation damage as well as enhancing the rate of penetration. The easily collapsed formation is successfully drilled through with the assistance of the proposed technology by maintaining the annular pressure profile to be constant as pre-designed and eliminating the pressure fluctuations. Several incidences of early phase lost circulation are detected in time, and the annular pressure would be modified, avoiding the failure of the borehole wall rock, therefore prevent the serious losses.On the basis of specific MPD equipment, this new technology gives drilling engineers a fast and effective way to ensure the borehole wall stability, thus eliminate the potential of multiple technical issues due to shear and tensile failure of borehole wall rock. Application of this technology could significantly improve the operation efficiency and enhance the economic benefits of drilling operation.

Using of surface back pressure with water based mud in managed pressure drilling technique to solve lost circulation problem in Southern Iraqi Oil Fields

Many drilling problems are encountered continuously while drilling oil wells in the southern Iraqi oil fields. Many of these problems are ineffectively handled resulting in a longer non-productive time. This study aims to identify the formations such as Dammam, and Hartha formations،diagnose potential problems and provide the solution for lost circulation problem. After conducting a comprehensive study on the subject and based on available data, previous studies and some information, the managed pressure drilling (MPD) method was the best technique to solve this problem. This process may use various techniques including control of back pressures .Thus, reducing the risk and control the costs of drilled wells, which have narrow pressure window by managing the wellbore pressure profile. The well plan software program provided by Halliburton Company was used, this software is based on a database and data structure common to many of Landmark’s drilling applications. Mud used with various injection rates to choose the rate that provides the conditions to achieve the best drilling process, as it using mud weights of (8.8 -8.7 ) ppg and applied a surface back pressure (50 psi). Depending on specifications of second hole the optimal injection rate was chosen using the (hydraulics) program. As a results, rate of water injection (850) gpm, is the best which it provides a good efficient cutting transport ratio (CTR), which means high stability and preventing formation damage in addition to controlling in mud losses

Design and application of well cementing technology based on the precise managed pressure balancing method in narrow pressure window hole sections

In the Sichuan Basin, the drilling of complex deep and ultradeep wells is restricted by the casing sequence. Multiple pressure systems are usually encountered in the same open hole section, and narrow safety density window is observed in vertical strata. The application of managed pressure drilling (MPD) technique which is often used in well drilling ensures the safe and efficient drilling, but it also brings about great challenges to the small-gap liner cementing at the lower part. Therefore, it is of great practical significance to research a cementing technology that can not only satisfy the quality requirement of small gap liner cementing, but also ensure the safe cementing in the strata with narrow safety density window. In this paper, a cementing technology based on precise managed pressure balancing method was proposed by referring to the successful application of MPD technique. According to the cementing design, the hydrostatic column pressure of annulus fluid is under-balanced (slightly lower than the formation pore pressure), and then a precise managed pressure drilling device is adopted to produce back pressure through wellhead restriction or apply wellhead compensation pressure, so that the balanced pore pressure can be reached in the process of cementing via the wellhead pressure and the flow friction of fluid in the annulus. After the cementing is completed, a certain compensation pressure is applied to the annulus continuously to prevent annulus channeling during waiting on cement caused by insufficient static pressure and slurry weight loss. After this technology was applied to an ultradeep exploration well in the Sichuan Basin, the qualification rate of borehole cementing quality reached 97%, and the well sections with good cementing quality accounted for 76%. In conclusion, this technology needs no additional equipment, and only by virtue of the MPD equipment, it can achieve safe cementing construction and cementing quality improvement under high displacement efficiency.

Integrating Managed-Pressure Drilling Into HP/HT-Well Planning

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 188335, “Integrating Managed-Pressure Drilling Into HP/HT-Well Planning,” by Michael Cadd, Lewis Steven, and Robert Graham, Shell; Fedderik van der Bos, Nederlandse Aardolie Maatschappij; Craig Leggett, Blade Energy Partners; and Emil Stoian, Weatherford, prepared for the 2017 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 13–16 November. The paper has not been peer reviewed. Managed-pressure drilling (MPD) is an increasingly common technique in narrow-margin high-pressure/high-temperature (HP/HT) wells. However, MPD is sometimes viewed as a bolt-on technology, only added after much of the planning work has been carried out and all other alternatives have been exhausted. The decision to use MPD should be made at the earliest stage of well planning. An early commitment to integrate MPD into an HP/HT drilling operation can make MPD more than just an enabling tool and turn it into a performance tool that offers significant operational benefits. Overview Project 1. For an HP/HT field redevelopment in the UK North Sea, seven side-track wells were drilled from a jack-up over an existing platform. MPD was used from the beginning, but the full benefits of MPD were not realized until later in the project. MPD was initially included to hold surface backpressure (SBP) across two connections to mitigate borehole-stability risk in an un stable shale. However, once the system was operational, further benefits continued to be identified and the scope of MPD operations grew significantly. At the same time, more knowledge of the subsurface was being gained, and it became clear that some of the planned wells would not be drillable without MPD because of a significantly reduced drilling window in the overburden. MPD became a key part of the design philosophy for later wells, where managed-pressure techniques were used to set and cement casings significantly deeper than would have been possible conventionally. MPD successfully mitigated classical HP/HT issues so that problems with losses and gains, handling of elevated gas levels, and mud-weight-selection issues were all virtually eliminated. Project 2. For a standalone HP/HT exploration well drilled from a jack-up offshore the Netherlands, MPD was initially selected because of the extremely narrow margins between the pore and fracture pressures in the 8½- and 6-in. sections. Conventional drilling would not have been possible without inducing losses and spending significant time circulating to adjust mud weights, as seen in a key offset well. Taking advantage of the learnings from Project 1, MPD was selected at an early stage of the planning process and was fully integrated into the well design and operations. Mud weight, drilling parameters, and bottomhole-assembly design were all tailored to suit MPD operations. Integrated HP/HT and MPD procedures were developed on the basis of traditional HP/HT techniques but were modified to make full use of the additional functionality provided by MPD. A combined HP/HT and MPD training course was developed, and key personnel were trained in HP/HT and MPD techniques. Rig modifications were made well in advance, and MPD was implemented one hole section earlier than required to familiarize all crews with the new equipment and procedures. The result was a potentially extremely challenging well that was drilled without any of the conventional HP/HT problems observed in the offset wells.

Use of Managed-Pressure Drilling Requires Adjustments To Bridge Gap to Well Control

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper IADC/SPE 178810, “Bridging the Gap Between MPD and Well Control,” by Thiago Pinheiro da Silva, Landon Hollman, SPE, Gustavo Puerto Corredor, and Patrick Brand, SPE, Blade Energy Partners, prepared for the 2016 IADC/SPE Drilling Conference and Exhibition, Fort Worth, Texas, USA, 1–3 March. The paper has not been peer reviewed. Managed-pressure drilling (MPD) challenges the conventional drilling paradigm, along with drilling-contractor and operator policies and standards. Conventional drilling practices for connections, flow checks, tripping, and well control have been long understood and standardized both onshore and offshore. The addition of an MPD system to a drilling operation, inclusive of the recommended practices, requires bridging the gap between conventional policies and standards and those of MPD. Introduction Often, an MPD bridging document that supplements the standard drilling-contractor and operator bridging document is seen as an operational requirement. The drilling contractor remains responsible for well control and well monitoring. The driller will continue to monitor the well at all times, using standard operating procedures while observing key drilling parameters. The MPD system provides enhanced well-control-event-detection methods in addition to standard downhole-event-detection methods. In addition, it allows rapid and accurate control of bottomhole pressure (BHP), but it does not replace standard drilling-contractor or operator procedures during well-control events. Depending on the MPD-system avail-ability and capabilities and the actual well conditions, most operators use several MPD techniques on the same well. The techniques may include conventional drilling with riser-gas-handling capabilities, dual-gradient dynamic-mud-cap drilling, pressurized-mud-cap drilling, floating-mud-cap drilling, or applied-surface-backpressure MPD. All of these fall into the group of techniques now referred to in the industry as MPD. Depending on the technique used, the mud density might be statically overbalanced, meaning that the hydrostatic pressure alone exceeds the highest formation pore pressure exposed, or it might be statically underbalanced, meaning that hydrostatic pressure alone may be less than the highest formation pore pressure exposed and the well is kept overbalanced by applying backpressure at surface. Well-established corporate policies have guided conventional drilling practices with respect to operational issues such as kick-indicator response, frequency of equipment testing, fingerprinting, and proactive kick-minimization techniques. Although MPD serves the same purpose as conventional drilling—to drill a section safely overbalanced—its use requires procedures that deviate from established policies. Barriers Conventional Drilling. For conventional drilling techniques, a minimum of two independent and tested barriers must be in place at all times. Upon failure of a barrier, normal operations must cease and not resume until a two-barrier position has been restored.

Application of fine managed pressure drilling technique in complex wells with both blowout and lost circulation risks

Fractured carbonate reservoirs are susceptible to blowout and lost circulation during drilling, which not only restricts drilling speed, but also poses big threat to well control. Moreover, there are few technical means available to reconstruct pressure balance in the borehole. Accordingly, the fine managed pressure drilling was used in the drilling of Well GS19 in the Qixia Formation with super-high pressure and narrow density window, which is a success: ① back pressure in the annular spaces will be adjusted to maintain a slightly over-balanced bottom-hole hydraulic pressure, and fluid level in the circulation tank will be kept in a slight dropping state to ensure that natural gas in the formation would not invade into the borehole in a massive volume; ② inlet drilling fluid density will be controlled at around 2.35 g/cm3, back pressures in the annular be maintained at 2–5 MPa, and bottom-hole pressure equivalent circulation density be controlled at 2.46–2.52 g/cm3; ③ during managed pressure drilling operations, if wellhead pressure exceeds or expects to exceed 7 MPa, semi-blind rams will be closed. Fluids will pass through the choke manifold of the rig to the choke manifold specifically for pressure control before entering gas/liquid separators to discharge gas; ④ during tripping back pressure will be kept at less than 5 MPa, volume of injected drilling fluid will be higher than the theoretical volume during tripping out, whereas the volume of returned drilling fluid will be higher than the theoretical volume during the out-tripping. This technique has been applied successfully in the drilling of the Qixia Formation, Liangshan Formation and Longmaxi Formation with a total footage of 216.60 m, as a good attempt in complicated wells with both blowout and lost circulation risks, which can provide valuable experiences and guidance for handling similar complexities in the future.

Automated Managed-Pressure Drilling Protects Caprock Integrity

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 170152, ’The Successful Application of Automated Managed-Pressure Drilling To Protect Caprock Integrity by Narrow-Margin Drilling in SAGD Wells,’ by Nadine Osayande, Elvin Mammadov, and Sheldon Sephton, Weatherford Canada, and Vincent Boucher, Suncor Energy, prepared for the 2014 SPE Heavy Oil Conference—Canada, Calgary, 10-12 June. The paper has not been peer reviewed. This paper presents a drilling solution through application of an automated managed-pressure-drilling (MPD) technique proved to identify and react to actual wellbore pressures and detect and control gains and losses while still having the ability to maintain a constant bottomhole pressure (BHP) while drilling through tight windows. The paper demonstrates the successful application of advanced automated MPD technologies on the Dover well close to Fort McMurray, Alberta, Canada. Introduction A well in the Dover field had multiple failures in the liner that resulted in excessive sand production, causing the well to be shut in. After reviewing the options of well repair or redrilling the horizontal section to install a new slotted liner, it was determined that redrilling was the best option. After the well-schematic analysis and in collaboration with the operator, the combination of a proprietary control system and MPD techniques was recommended along with a water-based mud (WBM) weight to drill the well and still be able to maintain the BHP required to overbalance the formation. The capability to detect microinfluxes/-losses while drilling, combined with an automated control system covering the drilling parameters [including the surface backpressure (SBP) and constant BHP], allowed the well to be drilled while maintaining the downhole pressure values as required. This approach additionally mitigated the challenges with weighted-WBM systems. For this particular well, reservoir temperature had cooled down to 145°C. If the well was not circulated for a period of time during drilling operation, mud temperature would increase, which would lead to the breakdown of the polymers and the loss of suspension of weighting material, effectively reducing the density to values near water density, thus creating an underbalanced situation. Redrilling a producer well in a shallow, overpressured, hot reservoir was a first for the operator in this area. Typically, during any completion workover, full fluid/mud losses occur, so the potential of these to occur during drilling operations was considered high.

Managed-Pressure Drilling - A Solution for Challenging Wells in Vietnam

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 165775, ’Managed-Pressure Drilling - A Solution for Drilling the Challenging and Undrillable Wells in Vietnam and Southeast Asia,’ by Ben Gedge, SPE, Harpreet Kaur Dalgit Singh, Elsofron Refugio, and Bao Ta Quoc, Weatherford Asia Pacific, and Nguyen Viet Bot, PVD Well Services, prepared for the 2013 SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, 22-24 October. The paper has not been peer reviewed. Managed-pressure drilling (MPD) has been used in Vietnam since 2007 to address a number of drilling and reservoir challenges. The main application of MPD has been to overcome the challenges of granite-basement, fractured and vugular carbonate, high-pressure/ high-temperature (HP/HT), and overpressured clastic reservoirs. This paper examines the procedural approaches of MPD, including constant bottomhole pressure (CBHP), equivalent-circulating-density (ECD) management, early kick detection, and pressurized-mud-cap drilling (PMCD). MPD Techniques and Applications The International Association of Drilling Contractors (IADC) defines MPD as “an adaptive drilling process used to precisely control the annular pressure profile throughout the wellbore. The objectives are to ascertain the downhole pressure environment limits and to manage the annular hydraulic pressure profile accordingly. MPD is intended to avoid continuous influx of formation fluids to the surface. Any influx incidental to the operation will be safely contained using an appropriate process.” MPD Variants The definition of MPD covers a wide range of variations and applications, but the most commonly used among them are the PMCD and CBHP variations (Fig. 1). PMCD as defined by the IADC as “a variation of MPD that involves drilling with no returns to surface and where an annulus fluid column, assisted by surface pressure [made possible with the use of a rotating control device (RCD)], is maintained above a formation that is capable of accepting fluid and cuttings. A sacrificial fluid with cuttings is accepted by the [lost] circulation zone. This technique is applicable for cases of severe [lost] circulation that preclude the use of conventional wellbore construction techniques.” The PMCD variant of MPD allows conventional drilling operations until losses are experienced and has been used successfully to drill through fractured and vugular carbonate formations where circulation losses can be simultaneously sudden and severe. This allows drilling to target depth despite massive losses being encountered. The CBHP variant of MPD involves the ability to maintain a constant bottomhole pressure (BHP), especially when drillpipe connections are made and the rig mud pumps are turned off. In this instance, the MPD system exerts a backpressure value that corresponds to the frictional pressure loss. This backpressure is slowly relieved once the connection has been completed and the rig mud pumps resume operation. However, given the sophistication of current MPD-control systems, BHP not only can be kept constant but also can vary to ascertain the downhole-pressure-environment limits and allow drilling personnel to manage the annular- hydraulic-pressure profile accordingly, thereby making the drilling operation more effective and more efficient.

Technology Focus: Multilateral/Extended Reach (May 2012)

Technology Focus Mitigating Risks in Development Projects Our industry has been involved in incidents that demonstrated the need of a new approach for evaluating and mitigating the risks in well construction. The “what’s worked well in the past” conservative approach is not possible anymore, in face of the damaged trust of the public about upstream activity. Though the criticism soars against exploration and production activities, the industry has allocated substantial investments in research for new technologies aimed to preclude risk events of recent years. New procedures and technologies, in addition to existing ones, will be deployed in the near future to eliminate blowouts or underground contamination from upstream operations. The initial results can be seen in field operations such as the application of managed-pressure drilling (MPD) for offshore and onshore, the use of long horizontals or extended reach in the shale plays, and new fluids and techniques for fracture treatments that minimize the amount of water required in such operations. The effects of drilling operations in the shale plays of the USA are clear, but recent research will result in a consistent reduction of environmental damage. Research is minimizing fluid losses into reservoirs and helping with mitigation of well-control situations when applying the MPD technique. The use of nanotechnology will provide fluids that improve fracture treatments through the control of fluid losses, with a subsequent reduction in the amount of fresh water required. Today, an average fracture treatment in the Barnett shale requires 235,000 bbl of water. These treatments are essential to reduce the number of wells and to improve the performance of the fracture treatments for environmental-impact reduction. The use of extended-reach drilling or long horizontal wells, combined with multilaterals, will reduce the number of wells without impairing expected production. This will mitigate the effect on aquifers or shallow formations with a reduction in surface infrastructure. Some of the papers featured or listed for reading show advances in the technology of extended-reach and multilateral wells that will help achieve such objectives. Finally, the combined use of extended-reach and multilateral wells, nanotechnology fluids, and MPD will result in a more environmentally-friendly operation with a cost-effective development plan, which is essential for improving the industry’s image. Recommended additional reading at OnePetro: www.onepetro.org. SPE 145400 Achieving Brazilian Extended-Reach-Drilling Records on the Polvo Project With Ultrahigh-Torque Connection by Nathan Biddle, Devon Energy do Brasil, et al. IPTC 14258 Burgan Multilateral Campaign: A Success Story in Development of a Complex Siliciclastic Reservoir in Kuwait by Javed Ahsan, Kuwait Oil Company, et al. IPTC 14823 Review of Ultrashort-Radius Radial System by S.K. Putra, Pertamina Upstream Technology Centre, et al.

Design and calculation of a MPD model with constant bottom hole pressure

Abstract Bottom hole pressure can be maintained in a reasonable range by using the managed pressure drilling (MPD) technique with special equipment. A calculation model is established for the back pressure and drilling fluid density of constant bottom hole pressure MPD, which are calculated by iterative method. The calculation model is applied to the Well Kela 201. In the comparison of the annulus pressures at 3 314 m in the well, the conventional drilling method cannot provide the appropriate drilling fluid density, but the constant bottom hole pressure MPD technique can make the annulus pressure within the pressure window. The design result of back pressure and mud weight of the narrow pressure window illustrated that the well can drill the target zone at 2 800 m directly by using the MPD technique. It can simplify casing program and save drilling cost. The calculation example demonstrates that this technique not only reduces mud density, but also meets the demand of annulus pressure control. Narrow pressure window can be drilled safely. It provides a technical basis for optimizing well profile.

Developing a Managed Pressure Drilling Strategy for Casing Drilling Operations

Casing drilling can be an effective method of reducing drilling costs and minimising drilling problems but its uptake around the world has been slow with only a few wells drilled so far with casing. Complex geological features like the high overburden on top of shallow unconsolidated reservoirs characteristic of offshore West Africa can benefit from casing drilling when effectively combined with Managed Pressure Drilling technique. For the industry to develop a managed pressure drilling capability that will allow today’s generation of complex wells to be drilled safely with casing, it is necessary to develop models that include the effect of eccentricity , rotation and fluid rheology at bottom hole conditions on flow and pressure regimes, and to embed these models within an easy to use, intuitive well design package for pre planning and as a real time tool to monitor and provide forward simulations based on real time rig and downhole data. The paper presents new results of the theoretical predictions of the wellbore pressure regimes incurred when different types of drilling fluid flows in concentric and eccentric horizontal annuli. The concentric and eccentric casing drilling results are compared with parallel predictions from conventional drillstring results from developed analytical solutions integrated into the VisWELL(DeskTop Simulator) , which is used in simulating well operations.

Improved Riser Design for Managed-Pressure Drilling in the Norwegian Sea

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 113672, "Managed-Pressure Drilling Resolves Pressure-Depletion-Related Problems in the Development of the High-Pressure/ High-Temperature Kristin Field," by S.A. Solvang, SPE, StatoilHydro; C. Leuchtenberg, SPE, Consultant; and I.C. Gil, SPE, and H. Pinkstone, SPE, Halliburton, originally prepared for the 2008 SPE/IADC Managed Pressure Drilling and Underbalanced Operations Conference and Exhibition, Abu Dhabi, UAE, 28-29 January. The paper has not been peer reviewed. Depletion of the Kristin high-pressure/high-temperature (HP/HT) field (13,213 psi, 342ºF) is occurring, which challenges the drilling of future increased-recovery wells. The full-length paper describes the need to implement managed-pressure-drilling (MPD) techniques in the Kristin field to overcome the problems related to a narrow drilling window. The Kristin development wells may be the first wells globally to use MPD techniques in a harsh-weather offshore environment on a floating drilling installation. Introduction The initial drilling program for Kristin is complete, with 11 wells drilled and completed. Because of the high initial reservoir pressure, the pore pressure declines rapidly with production. Looking ahead at the possible need to drill increased-recovery wells, several challenges to drilling were identified as a result of depletion, particularly with respect to the conventional requirement of keeping the bottomhole pressure (BHP) during drilling above the original pore pressure. MPD allows the safe use of lower mud weights much closer to the conventional drilling-window limits, but to implement such drilling techniques on a floating drilling installation in the harsh-weather environment of the Norwegian Sea, several issues had to be addressed. The equipment used to date for MPD from floaters is not suitable for use on a HP/HT well with Norwegian Sea weather conditions. Depletion affects both the lower and upper boundary of the drilling-fluid density. This implies that the drilling window changes with depletion. Drilling in a depleted zone is not necessarily a problem; provided that the depleted zone is evenly depleted, that the depletion is known, and that only the depleted zone is open for drilling, the operating window actually may increase with depletion. For the Kristin case, this would imply having the overlying Lange shale behind casing and knowing the pore pressure to be relatively constant in the Garn reservoir. High overbalance in depleted zones also may be a problem with respect to potential differential sticking, formation damage, poor rate of penetration, and drilling-fluid losses. MPD Implementation The main technical challenge for enabling MPD on the Kristin project is the closure of the standard marine riser using a rotating control device (RCD), with rig-independent solutions that allow the full retention of the conventional weather operating window, even in the harsh weather conditions seen in the Norwegian Sea.

Techbits: Assessing Managed-Pressure Drilling

The SPE Applied Technology Workshop (ATW) "Managed-Pressure Drilling (MPD)" held during 11−14 June in Phuket, Thailand, drew 82 participants from 47 different organizations and 14 countries. The focus of the ATW was the use of MPD, precisely controlling the annular pressure in a closed system while drilling, to drill reservoirs that have been deemed economically undrillable by conventional means or to avoid drilling-related issues in others. Wee Si Boon, Head of Wells Delivery (Malaysia), Shell Malaysia E&P, delivered the keynote address, titled "Developing Mud Cap Drilling and Completion Technology." His upbeat opening speech on the impact MPD has had on the Shell Malaysia operations emphasized its continued use to alleviate drilling problems in carbonate reservoirs often associated with severe lost circulation. These points were followed by comments on the wider application of MPD in the Asia Pacific region and its expanding use as a drilling enabler. Ben Gedge, Brunei Country Manager and Shell E&P-Asia focal point for Weatherford, and Ian Davidson, Middle East Regional Manager, UBD Global Implementation Team, Shell E&P Intl. Ltd., gave the past, present, and future prospects for MPD and explained how this technology evolved out of underbalanced drilling (UBD) over the past 10 years, especially for the challenging drilling applications where full UBD is not appropriate. The workshop reviewed the many applications for MPD, including, land, offshore, deepwater, high-pressure/high-temperature, and tight-gas air drilling. David Castillo, Director-Asia-Pacific, GeoMechanics, set the scene by reviewing and analyzing the many geological challenges that are encountered during the well-construction process and how these can be addressed with MPD techniques. Particular attention was paid in the workshop to the cur-rent projects employing MPD techniques in Asia Pacific, particularly in carbonate reservoirs. Leo Maekiaho, Well Engineer-Operations, Shell Malaysia E&P, gave an overview of Shell Malaysia groundbreaking operations from jackups and semisubmersible rigs in the South China Sea. Andy Timms, Drilling Manager, Amerada Hess, reviewed a recent successful project in Thailand where high-pressure gas wells were successfully drilled with MPD technology, so much so that the number of development wells in the field was cut dramatically as a result of much-improved flow rates achieved with MPD technology (especially as a result of novel completion techniques). Don Reitsma, Vice President-Engineering, At Balance, gave a description of a new dynamic-annular-pressure-control drilling technique that has only recently been commercialized. Planning of MPD wells is one of the most critical parts of an operation. A group consisting of Oliver Coker, Principal Engineer, Conoco/Phillips; John Ramalho, UBD Regional Implementation Manager, Shell; Don Reitsma; Phil Frink, President, Blade Energy Partners; and Ben Gedge led the presentations and subsequent panel discussion.