Deepwater geomechanics improve well design, production plan

Applied geomechanics is more critical in deeper, more complex exploration areas. Pemex E&P, in conjunction with Schlumberger, successfully used geomechanic models to reduce sanding and drilling risks in deepwater drilling on a wildcat well in the southern Gulf of Mexico.

Offshore staff

MONACO -- Applied geomechanics is more critical in deeper, more complex exploration areas. Pemex E&P, in conjunction with Schlumberger, successfully used geomechanic models to reduce sanding and drilling risks in deepwater drilling on a wildcat well in the southern Gulf of Mexico. The field is in 850 to 1,250 m (2,789 to 4,104 ft) water depths.

A mechanical earth model (MEM) was developed to minimize wellbore stability issues and sanding risks. Rock mechanic core tests were used to calibrate the elastic and strength properties of the strata. A pore pressure model was developed using effective stress analysis as well as linear and non-linear pressure estimations, among other techniques. The model took into account the geological and geophysical characteristics of the area, existing drilling, and log data and cores.

The MEM was confirmed by actual drilling and predicted post-drilling behavior of the reservoir. The research provided a base from which to optimize the well trajectory to improve both drilling and production. The rock mechanics model also helped Pemex to understand the rock failure incidents over the producing life of the field.

The drilling was into two gas fields with unconsolidated sands and very weak to weak cementation. Four correlation wells, each in different fields, and one well drilled in the field were used to build the model. A mechanical testing program was done for this field and the results used to calibrate resistivity and deformation parameters.

11/04/2009

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