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Copyright 2014, SPE/IADC Managed Pressure Drilling and Underbalanced Operations Conference and Exhibition This paper was prepared for presentation at the SPE/IADC Managed Pressure Drilling and Underbalanced Operations Conference and Exhibition held in Madrid, Spain, 8-9 April 2014. This paper was selected for presentation by an SPE/IADC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers or the International Association of Drilling Contractors and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers or the International Association of Drilling Contractors, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers or the International Association of Drilling Contractors is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE/IADC copyright. Abstract Conventional drilling methods initially utilized to drill an east Texas HPHT well, presented in this case history, ultimately failed after six attempts were made by an independent operator to drill a "straightforward" horizontal wellbore. The subject HPHT well proved extremely challenging with reservoir BHT of 334 F and approximate 13,900 - 14,500 psi reservoir pressure. The well was plagued by several drilling problems including multiple well-control incidents, a casing failure, surgeswab issues, stuck pipe incidents, trip problems, directional control issues, and finally a blowout.
Rodriguez, Freddy Rojas (M-I SWACO, Schlumberger Company) | Prasetia, Andi Eka (M-I SWACO, Schlumberger Company) | Mettai, Adel (M-I SWACO, Schlumberger Company) | Umar, Lawrence (Petronas) | Thiam, Yap Yun (Petronas) | Murad, M. Syazwan (Petronas)
TTD-1 has been identified as the deepest HPHT well ever drilled by PCSB in Malaysia. Managed Pressure Drilling (MPD) enabled the Operator to drill and explore new sands and confirm new hydrocarbon reservoirs at 325 degree F with an undisturbed bottomhole pore pressure of over 14,000 psi.The MPD technique in conjunction with the best HPHT practices were able to overcome the most difficult planned and unplanned challenges while drilling this exploration well. Challenges included:
1. Abnormal pressure ramp-up (greater than 17 psi/ft).
2. high pore pressure steps in new sands
3. identifying and controlling wellbore breathing
4. controlling losses on the HPHT tight window zone
Technology and expertise, including well control, HPHT drilling practices,
pore pressure prediction and MPD, were integrated and wisely implemented by the Operator during the planning and execution stages. The focus was to integrate MPD and HPHT procedures as well as optimize the available tools to maximize daily drilling footage and maintain the integrity of the well at all times. Annular friction losses (greater than 800 psi) were offset by annular backpressure to maintain constant bottomhole pressure (BHP) at all times, except for instances when the annular backpressure was reduced for short periods to perform dynamic flow checks. Dynamic flow checks were performed every half stand to map the pore pressure without interrupting the drilling progress. One of the dynamic flow checks identified one pressure step increase (greater than 1.0 ppg) and a 0.5 bbls gain on the trip tank at the same time. The dynamic formation integrity test (FIT) was successfully implemented to identify the upper limit of the operating window. These two MPD procedures identified the minimum operating window as 1.0 ppg and guided the Operator to call for TD of the well. The well was drilled to a depth of 15,847 ft (4,830 m), and thus penetrated vast gas bearing reservoirs. This technical paper aims to share a case study of HPHT drilling practices combined with Automated MPD that have been successfully adopted to explore new sands with minimal offset geological and petrophysics information.
Epps, Steve (Lavaca River Operating Company) | Pellegrini, Thomas (Lavaca River Operating Company) | Valecillos, Juan C. (Weatherford International Ltd.) | Craig, Hunter (Weatherford International Ltd.) | Arnone, Maurizio (Weatherford International Ltd.)
Multiple operators had attempted to conventionally drill wells in an area of south Texas targeting an over pressurized sand. A majority of them were unsuccessful showing a history of lost time events and poor well results related to kicks and losses. Information suggests little was known about the pore and fracture pressure gradients, and that uncertainties regarding real stratigraphic distribution were present, resulting in improper casing points and mud trends not in accordance with actual wells requirements. For these reasons, one operator decided to implement Managed Pressure Drilling (MPD) technology in order to safely and efficiently drill a well to the pay zone.
The scope of the operation was a re-entry sidetrack on a vertical well that originally encountered well control and multiple mud losses events. The first interval was an 8-1/2 inch intermediate section to be cased with a 7 inch liner. The liner shoe was to be set approximately 80 feet above the over pressurized target sand. The second interval was a 6-1/8 inch production section targeting the well pay zone, to be cased with a 4-1/2 inch production casing. Both intervals were considered critical, the first one having depleted zones interbedded with gas bearing formations with a final depth immediate to abnormal gas pressures, and the second demanding accurate ECD management to avoid well control events, losses and formation damage, this of cardinal interest for the operator.
The implementation of MPD enabled both intervals to be drilled to the planned target in a constant bottom hole pressure (CBHP) state safely and efficiently. The well was drilled near balanced to improve drilling efficiency and increase the ability to identify pore pressures. The annular pressure profile was adjusted instantly as the well dictated by means of MPD surface equipment avoiding kicks and losses. Continuous evaluation and monitoring of well behavior in real time allowed for pore pressure predictions, which were later used to plan proper kill mud weights, tripping/stripping procedures, and managed pressure cementing operations. Implementing MPD techniques and technology proved successful in enhancing safety and drilling efficiency on a well with many uncertainties and potential hazards.
This paper will describe the planning and execution of a successful drilling operation on a high potential oil/gas producer well using MPD techniques in an area where others were unsuccessful.
This paper describes some successful applications of Managed Pressure Drilling on exploration wells drilled in deep waters. Building upon successful experience utilizing MPD from HPHT jack-up wells, the Operators transferred the experience across to deepwater exploration projects.
Extensive engineering, training and development of procedures were carried out prior to spud for each project. Specific techniques were developed to handle floating drilling operations. The resulting benefits associated with MPD led to improvements in drilling performance, and eliminated many of the traditional problems faced on other HPHT wells in the area. MPD has now become an integral part of the well operating philosophy and has established new standards for drilling wells of this type in the area.
Some critical wells were classified as wildcats with considerable pore pressure unknowns, coupled with narrow pore-fracture drilling window characteristic of HPHT conditions. MPD was able to minimize the problems faced on the wells by enabling various techniques to be utilized. These techniques included the use of pressure build up analysis to quantify formation pressures, the application of dynamic flow checks, dynamic formation strength limits, and the application of constant bottom hole pressure during dynamic and static drilling fluid circulation conditions. The planning, development and execution phases of the MPD projects are detailed in this technical paper.
Managed Pressure Drilling (MPD) usually employs a closed and pressurizable circulating drilling fluids (mud) system which facilitates drilling with precise management of the wellbore pressure profile. The primary objective of MPD is to optimize drilling processes by decreasing nonproductive time (NPT), mitigating drilling hazards and to enable the drilling of otherwise technically or economically un-drillable high-complexity prospects.
Because MPD addresses NPT, the technology is of greatest potential benefit to offshore drilling programs where cost of dealing with drilling trouble zones is much higher than onshore. Although MPD was been safely and efficiently practiced from all types of offshore rigs and producing the desired results in the process, it is still considered a relatively "new?? technology to the majority of offshore drillers.
This impressive uptake in offshore MPD applications is due in part to a requirement to drill in greater water depths, through depleted zones or reservoirs and into narrow or relatively unknown equivalent mud weight (EMW) drilling windows.
As evidenced by the greatly increased cost of drilling today's prospects, pre-salt drilling in deep water and HT/HP wells being good examples, it is easy to understand why many are concluding that most of the "easy?? prospects have already been drilled. Those remaining are more likely to be "hydraulically challenged,?? requiring more precisely controlled management of the wellbore pressure profile to be drilled safely and efficiently.
This paper describes the successful application of Managed Pressure Drilling on a HPHT well drilled offshore.
Wells in located in the field where this particular paper was focused and other offset wells in the area had faced many problems including inadequate mud management due to depleted or over pressured zones, influxes, mud losses and differential sticking. This well was a High Pressure and High Temperature (HPHT) well drilled in the area using the MFCS MPD system, closed loop method of accurately monitoring and controlling flow and pressure which can significantly reduce NPT.
Extensive engineering, training and development of procedures were carried out prior to spud. MPD was utilized to drill two hole sections. Specific MPD techniques were developed to handle the drilling operations. The resulting benefits associated with MPD led to improvements in drilling performance, and eliminated many of the traditional problems faced on other HPHT wells in the area. MPD has now become an integral part of the well operating philosophy and has established new standards for drilling wells of this type.
The MPD system was used from the start drilling of the 12 ¼?? section to end of drilling 8 ½?? section. One of the main benefits of using the MPD system was the ability to control the pressure dynamically when drilling through abnormally pressure layers by manipulation of surface back pressure instead of mud weight changes to maintain drilling progress. This facilitates rapid and safe rising of bottomhole pressure to control influxes and their subsequent bleed down. The utilization of this system on this well helped drilling to target depth while effectively handling influxes with significant time saving. The system was used for the first time to facilitate fishing operation by using a lighter mud weigh and manipulate the proper surface back pressure. The planning, development and execution phases of the MPD project are detailed in this technical paper.