Jairo Leal

A New Analytical Model to Predict Gas Rate Volume Measurement through Well Head Chokes

Historically, choke gas equations have been extensively used for gross estimation about gas volumes. These analytical models give a quick evaluation on gas volume but also face some serious limitations on specific topics like water presence, excessive gas velocity and pressure drop, limited differential pressure and high condensate to gas ratios. Many different efforts have being completed using several analytical models which can be applicable under certain conditions. This paper details a new predictive model for estimating the gas rate measurement through wellhead chokes and also covers all efforts for Saudi Aramco to get a single digit error on estimating gas rates for Ghawar gas condensate producers by implementing this new analytical model.

An Overview of the Completion Challenges in a Tight-Gas Formation in Saudi Arabia

Tight gas refers to natural gas reservoirs that have very low porosities and permeabilities. Most of the tight-gas reservoirs presently being developed are sandstone formations, although carbonate rocks can also be tight-gas producers. The standard industry definition for a tight-gas reservoir is a rock with matrix porosity of 10% or less and permeability of 0.1 millidarcy or less, exclusive of natural fracture permeability. Unconventional gas resources, including tight sands, constitute some of the largest components of remaining natural gas resources in the Middle East and North Africa. Developing unconventional and tight-gas reservoirs will allow Saudi Arabia to better meet rising domestic energy needs. During the past decade, conventional formations were stimulated successfully in Saudi Arabia using conventional completion techniques. However, as the development of existing fields continues into deeper formations and the exploration of new reservoirs is mainly toward unconventional reservoirs, new challenges are now faced, especially considering that lower permeabilities, higher stresses, and higher temperatures are experienced. An evaluation of the current techniques is necessarily in order to overcome the challenges in these extreme conditions. This paper reviews the successful application of specific completion techniques and technologies being implemented in the development of tight-gas reservoirs currently being exploited in Saudi Arabia.