The Drilling Of A High-Pressure, High-Temperature Well In The North Sea Using 20,000-Psi Well Control Equipment

Summary Data acquisition in extreme environments of high pressure and/or high temperature (HPHT) with pressures up to 30,000 psi and temperatures up to 500°F requires not only specialist technology capable of surviving these conditions but also many months of preparation and planning to ensure a successful operation. The aim of this publication is to provide an overview of what is involved in the planning, preparation, and execution of an extreme HPHT wireline data acquisition—from the customer setting the information objectives through to data delivery. This includes developing an agreed quality plan between the data provider and the customer covering testing and deployment of the latest extreme HPHT logging equipment. One must consider all aspects to minimize risks including detailed tailoring of the logging programs to manage time in hole, to ensure accurate depth control, and, by using a deployment risk-management process, to ensure that what goes in the hole comes out again. The implementation of these procedures is illustrated with a case history of a series of HPHT exploration wells drilled in the Central Graben of the North Sea (the "HPHT Heartland" of the North Sea). Bottomhole conditions were predicted to approach 400°F and 15,000 psi. These extreme conditions negated the use of conventional wireline tools, and so, from initial early planning discussions between client and service provider, new detailed programs were designed and implemented as a specific "Quality Plan" to use the advanced HPHT wireline-logging tools.

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The Application of Slim-Hole Drilling Techniques to High-Pressure and High-Temperature Exploration Programs in the North Sea

10.2118/26340-ms ◽

1993 ◽

Author(s):

Egil Eide ◽

J.I. Hage ◽

P.M. Burge ◽

Rainer Jorgens

Keyword(s):

High Pressure ◽

High Temperature ◽

North Sea ◽

Hole Drilling ◽

The North ◽

The North Sea

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Study on Influx Risk Evaluation of Horizontal Gas Wells With High-Pressure High-Temperature in the South China Sea

Volume 11: Petroleum Technology ◽

10.1115/omae2020-18324 ◽

2020 ◽

Author(s):

Ming Luo ◽

Deli Gao ◽

Xin Zhao ◽

Yuan Chen ◽

Yupeng Yang ◽

...

Keyword(s):

High Pressure ◽

High Temperature ◽

South China Sea ◽

Risk Evaluation ◽

Control Strategies ◽

Control Design ◽

Gas Wells ◽

Well Control ◽

High Pressure High Temperature ◽

Open Hole

Abstract The South China Sea has rich natural gas source with typical high-pressure high-temperature (HPHT) and the extremely narrow drilling window, which leads to frequent influx, even borehole abandonment. However, horizontal gas wells have been placed in the area to develop the gas reservoir, which presents greater well control challenges. Therefore, the influx risk evaluation is quite necessary to guide the well control design. Firstly, the influx mechanism is analyzed based on gas intrusion to provide a theoretical basis for well control design. It is found that influx usually occurs when drilling the high-temperature stratums and target layers. Secondly, the relationship between horizontal open-hole length and influx volume is calculated under different reservoir permeability, reservoir thickness, negative bottom hole pressure and horizontal open-hole section length. Thirdly, the characteristics of gas-liquid two-phase flow are described. Fourthly, the inflow risk evaluation and well control strategies of the target horizontal gas wells are proposed, and the influx risk evaluation envelope was established. The influx risk evaluation and well control strategies have been successfully applied to the DF gas field featuring offshore HPHT. Horizontal gas wells were drilled in the micro pressure window without accidents and the well cost was significantly reduced.

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