1. The Application of Specific Drilling Energy to Identify Overburden Lithological Boundaries and Aid Well Operations - Oman Khazzan Field
- Author
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Nafa Al Jahdhami and Abdullah Al Anboori
- Subjects
Overburden ,Field (physics) ,Mining engineering ,Petroleum engineering ,Drilling ,Energy (signal processing) ,Geology - Abstract
The concept of Specific Drilling Energy (SDE) has been in existence for decades and used in both the mining and oil industries to mainly optimize drilling performance and efficiency. We present a practical application of SDE to pick key lithological boundaries during and post drilling. This in turn is serving as an additional tool used to aid well operations and also characterise the overburden of the Khazzan Field. Developing the giant Khazzan Gas Field requires drilling a large number of wells to the deep target reservoir. Characterizing the overburden in such a field requires a consistent approach in defining the overburden geological formations to aid drilling operations, selecting casing setting points andavoiding future drilling surprises in planned wells. The concept of specific drilling energy is being applied in the Khazzan Field to aid Geologists in three ways:Firstly, picking shallow formation tops for top holes drilled by a rig with no mud logging unit. Secondly, real time picking of shallow formation tops besides potentially removing cuttings lag time factor and consequently to ensure correct casing setting depths in order to avoid wellbore stability issues. Thirdly, it serves as an additional tool to QC formation tops post drilling particularly for tops picked in the absence of petrophysical logs. Various forms of the equation have been developed through time to mainly assist drillers optimize drilling performance. In this case, thevery earliest form proposed by Teale in 1965 was used in which main inputs into the SDE equation include Rate of Penetration (ROP), torque, Weight on Bit (WOB) and Rotations per Minute (RPM) which are readily recorded by drilling sensors at no extra cost. When this data is loaded into petro-technical software, such as Petrel in this case, the powerful display functionality allows comprehensive correlation between wells and eases the process of picking formation tops. A few examples are presented upon which this methodology aided picking the top of a casing setting formation, calling total drilling depths and performing correlations between wells post drilling to aid the provision of tops prognosis in future planned wells. This work proves that the applications of the SDE concept is not just limited to drilling optimization, but also in assisting Geoscientists identify lithological boundaries and aid informed decisions in well operations using solely drilling parameters.
- Published
- 2017
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