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Optimised, Interactive Well Placement and Formation Evaluation Using Advanced Lwd Technology for Extended Reach Wells: A Case Study from the Lakshmi Development Area, Western Offshore India

Manabesh Chowdhury, Satyashis Sanyal, Jaysurya Rath, and Shibatosh Sarkar
Cairn India Ltd, Gurgaon, India

Lakshmi Oil and Gas Field is located in the CB/OS-2 block in Gulf of Cambay, offshore west coast of India. The field was discovered in May 2000 and production commenced from October 2002.

The major challenges in planning development wells in this field are to develop the outer extremities of the reservoirs, which require specialised extended reach wells. The significant challenges in planning and drilling these ERD wells are accurate formation and pressure evaluation for successful completion. Depleted reservoirs encountered in some of the wells require optimal mud weights, which further complicates the well design and drilling.

In this case study, a well was planned to be drilled from a fixed platform and targeted to encounter the reservoirs at approximately 2.6 kilometer horizontal offset. Extensive pre-drill planning was carried out within a multidisciplinary team to optimize the well design and geological requirements. Cairn India has pioneered the deployment of high end drilling technology (rotary closed-loop drilling system) for precise well positioning and state-of-the-art PentaCombo LWD tools for formation evaluation in both virgin and depleted reservoirs. The well was drilled to a total measured depth of 3295m with a maximum inclination of 82 degree. Formation pressure testing while drilling was used to optimally evaluate the pressure regime. Real time Flow Rate Analysis method was successfully implemented for the first time to determine formation pressure and mobility which aided in quick decision making.

Drilling of this well demonstrates the proper integration of accurate geological modelling, precise well planning and advanced LWD technology to fulfill the optimal field development strategy.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery