Near-Wellbore Formation Damage Effects On Well Performance - A Comparison Between Underbalanced And Overbalanced Drilling

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractPrediction of formation damage that occurs while drilling horizontal wells is a critical point for optimising an oil field development. The economic impact of near wellbore drillinginduced damage and clean up efficiency has led to make significant progress in both experimental and numerical studies in order to assess wellbore flow properties during oil production. As a result, a numerical model has been developed to study the impact of various parameters related to the properties of drilling fluids on the well inflow performance. This paper describes a numerical approach developed in this model to simulate near wellbore formation damage due to underbalanced (UBD). It is generally expected that UBD will be of benefit from preventing formation damage. However, this benefit can be lost for various reasons. For instance, an overbalanced pressure can be applied on the formation during short periods of time for various operational reasons and it can cause a severe formation damage due to the absence of external cake protection and huge filtrate invasion. Another possible cause of formation damage in UBD is related to spontaneous imbibition which induces water blocking, experienced while drilling tight gas reservoirs.A methodology for the modelling of possible formation damage during UBD is presented. Cross flow phenomena due to spontaneous imbibition is taken into account to model the filtrate invasion from the well to the porous media as the well is producing.

Rheological behavior of oil-based drilling foams

“…This results in formation damage and creates various drilling problems. Another possible cause of formation damage during foam drilling is related to spontaneous imbibition that occurs while drilling tight gas reservoirs (Ding et al, 2006). Recently, new types of drilling foams have been introduced to drill water sensitive formations.…”

A Simple Analytical Approach to Simulate Underbalanced- drilling in Naturally Fractured Reservoirs—The Effect of Short Overbalanced Conditions and Time Effect

“…The model can be used to evaluate formation damage in heterogeneous media. In their next work, Ding et al [3] presented a model of near wellbore formation damage in anisotropic media, which is particularly important for horizontal wells.…”

“…Ding et al [3] presented a numerical approach to modelling possible formation damage during UBD in a homogenous reservoir. In their work, they used a two-phase flow model to describe invasive formation damage during UBD.…”

Equivalent Skin Factors for Nonuniformly Damaged Horizontal and Multilateral Wells

“…[21][22][23][24][25][26][27][28] Most recently, a numerical model to characterize the formation damage due to use of water-based-mud and natural cleanup during production has been proposed. [26][27][28] The numerical model presented by Ding and co-workers [26][27][28] is capable of predicting the horizontal well performance under the influence of unevenly distributed formation damage.…”