The Maximum-Allowable Well Depth While Performing Ultra-Extended-Reach Drilling From Shallow Water to Deepwater Target

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 224-236 ◽  
Author(s):  
Xuyue Chen ◽  
Deli Gao

Summary Ultra-extended-reach wells can be drilled from one platform to develop the remote surrounding satellite oil and gas reservoirs in deepwater. Although the platform is in shallow water, some ultra-extended-reach wells can target the reservoirs in deep water. In ultra-extended-reach drilling from shallow water to deepwater target, some challenges that may be faced are the presence of low temperature, typically weak overburden sediments, unconsolidated formations, and a small sedimentary coverage above the reservoir. This results in a narrow safe-mud-weight window and a limited well depth for ultra-extended-reach drilling operation. In this work, considering the pressure balance of bottom hole including the specific thermal and seepage effects, a method for predicting the well's maximum-allowable measured depth (MD) (MAMD) while performing ultra-extended-reach drilling from shallow water to deepwater target is presented. Meanwhile the factors affecting the MAMD are also investigated. The study shows that seepage significantly affects the MAMD while performing ultra-extended-reach drilling from shallow water to deepwater target: seepage turns out to significantly decrease the MAMD whereas heating the formation is found to be helpful in extending the MAMD. It also shows that the predicted MAMD turns out to be obvious anisotropy; for a normal regime depositional environment, drilling in the direction of minimum horizontal in-situ stress in the formation is prone to attain a wider safe-mud-weight window and a longer MAMD than other directions. Moreover, for a given target zone, the ultra-extended-reach drilling with a horizontal bottom hole has a much longer MAMD than that of ultra-extended-reach drilling with an inclined bottom hole, and the MAMD can also be effectively increased by reducing the annular friction-pressure loss. This work provides a practical tool for enhancing the design of ultra-extended-reach wells to develop the remote satellite oil and gas reservoirs in deep water.

2013 ◽  
Vol 734-737 ◽  
pp. 1381-1390
Author(s):  
Heng Song ◽  
Zi Fei Fan ◽  
Lun Zhao ◽  
An Gang Zhang

Zhanazhol oilfield is a large-scale complicated carbonated oil and gas field , Гnorth is the main oil and gas reservoirs of the oil field, The gas cap index is 0.38, the gas cap on a high condensate content. Reservoir development for nearly 25 years, exploitation in the past only to oil ring. Due to insufficient water injection in early age, the oil ring pressure dropped substantially, and the formation pressure to maintain the level of only 58%. For oil and gas reservoirs with a condensate gas cap, gas cap and oil ring at the same pressure system, with the decline in the pressure of the oil ring, the gas cap continue to spread to the oil region, while there are a large number of condensate oil anti-condensate from the gas cap, which loss into the formation. In this paper, the authors consider the characteristics of the oil and gas reservoirs and research the technique policy of collaborative development, These are all in order to solve technical problems, which is keep the pressure balance between the gas cap and oil ring during collaborative development. Not only provide technical to support the rational and efficient development of the Г North oil and gas reservoirs, but also provide a stable source for natural gas pipeline from Kazakhstan to China.


Author(s):  
Elton J. B. Ribeiro ◽  
Zhimin Tan ◽  
Yucheng Hou ◽  
Yanqiu Zhang ◽  
Andre Iwane

Currently the oil and gas industry is focusing on challenging deep water projects, particularly in Campos Basin located coast off Brazil. However, there are a lot of prolific reservoirs located in shallow water, which need to be developed and they are located in area very far from the coast, where there aren’t pipelines facilities to export oil production, in this case is necessary to use a floating production unit able to storage produced oil, such as a FPSO. So, the riser system configuration should be able to absorb FPSO’s dynamic response due to wave load and avoid damage at touch down zone, in this case is recommended to use compliant riser configuration, such as Lazy Wave, Tethered Wave or Lazy S. In addition to, the proposed FPSO for Tubarão Martelo development is a type VLCC (Very Large Crude Carrier) using external turret moored system, which cause large vertical motion at riser connection and it presents large static offset. Also are expected to install 26 risers and umbilicals hanging off on the turret, this large number of risers and umbilicals has driven the main concerns to clashing and clearance requirement since Lazy-S configuration was adopted. In this paper, some numerical model details and recommendations will be presented, which became a feasible challenging risers system in shallow water. For instance, to solve clashing problem it is strictly recommended for modeling MWA (Mid Water Arch) gutter and bend stiffener at top I-tube interface, this recommendation doesn’t matter in deep water, but for shallow water problem is very important. Also is important to use ballast modules in order to solve clashing problems.


2015 ◽  
Vol 75 (11) ◽  
Author(s):  
Mostafa Alizadeh ◽  
Zohreh Movahed ◽  
Radzuan Junin ◽  
Rahmat Mohsin ◽  
Mehdi Alizadeh ◽  
...  

The purpose of modelling the fractures is to create simulation properties with the power to predict the reservoir behaviour. Petrel software is one of the best softwares in the market that can do this task very well, but there is no available educational paper for every researcher. Therefore, in this work, a fracture modelling job was done in one of the most important Iranian fields using Petrel software and image log data. The purpose of this work was  to determine the new information of the fractures in Gachsaran field and also to prepare a valuable educational paper for other researchers who are interested to learn about the fracture modelling. This work revealed that in this field, the longitudinal fractures had been parallel to minimum stress (Zagros trend), fracture intensity was the nearest to the major fault and northern flank, fracture porosity was 0-7%, fracture permeability was 0-6000 MD, and more valuable information is provided in this paper.


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