scholarly journals A Low-Cost and Low-Density Cement Slurry System Suitable for a Shallow Unconsolidated Stratum

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Jiaping Yue ◽  
Zhaonian Liu ◽  
Jie Wang ◽  
Ting Sun ◽  
Zhiqiang Wu ◽  
...  

The shallow unconsolidated stratum in the offshore oilfield is characterized by large porosity, low temperature, and weak formation and often faces problems such as low density and poor compressive strength of a cement slurry, among others, which pose serious challenges to construction. A high-performance low-density cement slurry system must be used for cementing to ensure the safety of subsequent drilling and mining on-site and to reduce the cost of cement slurry for the efficient development of oil and gas fields. Based on these problems, according to the principle of particle gradation, a mixture with a high accumulation rate and low density composed of five types of mineral materials, i.e., artificial microbeads, floating beads, microsilicon, fly ash, and slag, has been developed through a large number of indoor experiments, and a set of low-cost and low-density cement slurry systems has been developed; these systems are suitable for the shallow loose formations of offshore oil fields. The cement slurry system meets the requirements of the cementing operation conducted under different temperatures and pressures. The density range is 1.4–1.7 g/cm3, which can be adjusted. The cement slurry is stable and exhibits good fluidity. The thickening time meets the requirements of cementing construction. Moreover, the compressive strength of the cement paste is high, and the compressive strength of cement paste is greater than 12 MPa for 24 h and 14 MPa for 48 h of curing at 50°C, which maximizes the economic benefits. The research results provide technical support for the safe and efficient development of offshore oil and gas fields.

2021 ◽  
Vol 775 ◽  
pp. 145485
Author(s):  
Yiqian Liu ◽  
Hao Lu ◽  
Yudong Li ◽  
Hong Xu ◽  
Zhicheng Pan ◽  
...  

2021 ◽  
Vol 881 ◽  
pp. 33-37
Author(s):  
Wei Na Di

The application of nanomaterials in oil and gas fields development has solved many problems and pushed forward the development of petroleum engineering technology. Nanomaterials have also been used in wellbore fluids. Nanomaterials with special properties can play an important role in improving the strength and flexibility of mud cake, reducing friction between the drill string and wellbore and maintaining wellbore stability. Adding nanomaterials into the cement slurry can eliminate gas channeling through excellent zonal isolation and improve the cementing strength of cement stone, thereby facilitating the protection and discovery of reservoirs and enhancing the oil and gas recovery. This paper tracks the application progress of nanomaterials in wellbore fluids in oil and gas fields in recent years, including drilling fluids, cement slurries. Through the tracking and analysis of this paper, it is concluded that the applications of nanomaterials in wellbore fluids in oil and gas fields show a huge potential and can improve the performance of wellbore fluids.


Author(s):  
Xiaozhi Wang ◽  
Booki Kim ◽  
Yanming Zhang ◽  
Ping Liao

Floating production, storage and offloading systems (FPSOs) have been widely used in the development of offshore oil and gas fields because of their many attractive features. These features include a large work area and storage capacity, mobility (if desired), relatively low construction cost and good stability. They are mostly ship shaped, either converted from existing tankers or purpose built. The hull structural scantling design for tankers may be applicable to FPSOs; however, FPSOs have their own unique characteristics. FPSOs are located at specific locations with a dynamic loading that is quite different from that arising from unrestricted ocean service conditions for tankers. It is also noted that the wave conditions in recent FPSO applications may be very complicated when operating in areas such as those offshore West Africa and offshore Brazil where both seas and swells exist and propagate in different directions. In this paper, the unique FPSO operational aspects, especially the load assessment due to on-site environments will be described. The methodology of handling complicated wave conditions in fatigue assessment will be addressed. Special considerations for converted FPSOs, which need to take into account their operational history as a trading tanker and low cycle fatigue due to FPSO operations, will also be introduced. Case studies will be presented and appropriate analysis methodology will be summarized. The methodology has also been adopted by ABS Guide, see ABS [1].


1987 ◽  
Vol 27 (1) ◽  
pp. 357
Author(s):  
M. Thatcher ◽  
D.B. Marietta

Subsea production systems have been an accepted method of developing offshore oil and gas fields since the installation of the first subsea trees in the early 1960s offshore California. Generally subsea completions have been done from floating drilling vessels on wells with subsea wellhead equipment. A number of wells have been completed subsea by bottom supported jackup rigs on wells drilled using mudline suspension equipment. The subsea completion equipment and methods utilised to adapt mudline suspension wells for a subsea production tree are described. This method of completion offers important benefits as it allows completion of wildcat or delineation wells, it can be used in areas of small, scattered reservoirs, and it can be used in conjunction with floating production systems. The cost associated with these subsea completions is roughly equivalent to those of standard subsea completions from floating vessels. An overview of a typical completion system is presented and compared.


1999 ◽  
Vol 121 (2) ◽  
pp. 71-76 ◽  
Author(s):  
K. P. Thiagarajan ◽  
S. Finch

Turret-moored floating production storage and offloading (FPSO) vessels have found application in several offshore oil and gas fields in Australia’s North West Shelf (NWS). These vessels are either custom-built or converted tankers, with an internal or external turret. The position of an internal turret is decided based on a number of design considerations, primarily, available deck and interior space, and weathervaning capabilities. It is known that turret position can influence vertical motions and accelerations of a vessel, but this factor has not been given much importance, in comparison with the effects on the horizontal plane motions, primarily surge. This paper presents the results of a pilot study conducted at the Australian Maritime College, Tasmania, to study the vertical motions of a single-point moored FPSO model in waves, while systematically varying the mooring position across the length of the model. The displacement of the vessel was held constant at 50-percent-loaded condition. A single-point mooring system was designed and implemented on the model to simulate the prototype turret mooring system. Results show that the mooring location significantly affects the vertical motions and accelerations of the vessel. Astern turrets were found to produce higher heave and pitch than other locations tested. Although turrets positioned close to the longitudinal center of gravity produced the lowest overall motions, it is suggested that turret position forward of midships be preferred, as it provides a balance between lowering vertical motions and improving weathervaning characteristics.


Author(s):  
Chingiz Saibovich Guseinov ◽  
Dmitry Leonidovich Kulpin ◽  
Galie Hamzaevna Efimova

The article dwells upon the problem of developing offshore oil and gas fields around the world accompanied by producing not only stationary and semi-submersible rigs and drilling vessels, but also a large number of auxiliary vessels for various functional purposes. It would be impossible to extract offshore hydrocarbons under the sea bed without them. Special fleet was formed during the years of development of offshore oil and gas fields in the Russian Federation, the part of it being imported. In the upcoming years, our country will face some challenges related to the development of Arctic reservoirs which are mainly located in the long-frozen deep seas. Their development in deep water will only be possible with auxiliary fleet, as it will be necessary to build deep water drilling vessels and other facilities/vessels. The types of vessels of the modern oil and gas fleet are presented, depending on the area of navigation, the depth of use and the specifics of the work performed. It is noted that currently in world practice there are no examples of using proven drilling and production technologies in severe ice conditions, when ice thickness exceeds 2-3 m, because the modern ice-resistant stationary platforms can not withstand the load at a depth of more than 80-100 m. The auxiliary fleet will both service offshore rigs and ensure their long-term productivity and functionality. For the development of oil and gas fields in the long-frozen Arctic deep-sea areas it is necessary to create a full-fledged underwater oil and gas fleet.


2010 ◽  
Vol 50 (1) ◽  
pp. 241
Author(s):  
Tony Slate ◽  
Ralf Napalowski ◽  
Steve Pastor ◽  
Kevin Black ◽  
Robert Stomp

The Pyrenees development comprises the concurrent development of three oil and gas fields: Ravensworth, Crosby and Stickle. The fields are located in production licenses WA-42-L and WA-43-L, offshore Western Australia, in the Exmouth Sub-basin. The development will be one of the largest offshore oil developments in Australia for some time. It is a complex subsea development consisting of a series of manifolds, control umbilicals and flexible flowlines tied back to a disconnectable floating production, storage and offloading (FPSO) vessel. The development involves the construction of 17 subsea wells, including 13 horizontal producers, three vertical water disposal wells and one gas injection well. The project is presently on production with first oil achieved during February 2010. This paper gives an overview of the field development and describes the engineering and technologies that have been selected to enable the economic development of these fields. The Pyrenees fields are low relief, with oil columns of about 40 metres in excellent quality reservoirs of the Barrow Group. Two of the fields have small gas caps and a strong bottom water drive common to all fields is expected to assist recovery. The oil is a moderate viscosity, low gas-to-oil ratio (GOR), 19°API crude. Due to the geometry of the reservoirs, the expected drive mechanism and the nature of the crude, effective oil recovery requires maximum reservoir contact and hence the drilling of long near horizontal wells. Besides the challenging nature of well construction, other technologies adopted to improve recovery efficiency and operability includes subsea multiphase flow meters and sand control with inflow control devices.


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