Horizontal drilling was under consideration for the development of the poorer reservoir quality northern area of a large onshore oil field in Abu Dhabi. This paper presents the case history of two horizontal holes drilled in a pilot well to help evaluate horizontal well performance for development planning purposes. Geological and petrophysical data are described. The reservoir consists of layered limestone with porous layers alternating with continuous, thin, dense, stylolitic intervals. An existing vertical well, with production test history from two completion intervals, was re-entered. The short radius technique was used to drill two horizontal holes into two porous layers, separated by several intervening dense and porous intervals. Production test results, before and after horizontal drilling, are presented. For both horizontal holes, productivity was higher than the previous vertical completions. Vertical interference testing was also carried out, by monitoring the pressure in the lower hole while producing from the upper hole. Well test interpretation is discussed. Results of analysis, assuming a single homogenous layer, are described. The layered nature of the reservoir appears to affect transient pressure behavior. Numerical simulation, with local grid refinement around the horizontal holes, was also used to match the test results, including the vertical interference test observed pressures.

The principal objective of this study is to determine the accuracy of calculating stresses in concrete pavements and unbonded overlays under different loading conditions. The computed stresses for the