Vertical, or deviated, oil wells cross a production formation for only short distances. Horizontal wells, however, are capable of remaining within a reservoir for distances up to several hundred metres in an effort to enhance production possibilities.
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special flexible equipment is used to drill lateral completions with rapid build rates;
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modified conventional hardware is used to drill medium-radius horizontal wellbores; and
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conventional directional drilling equipment is utilized to drill horizontais with long radii of curvature.
A state-of-the-art discussion covers configurations and drilling procedures for each method. Applications are discussed. with information on why and when horizontal completions should be considered. A table comparing the limitations of each is also included.
Horizontal drainholes can be placed in reservoirs using one of three methods:
Un puits vertical, ou dévié ne traverse un gisement que dans sa dimension la plus faible. Un puits horizontal peut se maintenir pendant plusieurs centaines de mètres dans le gisement, ce qui permet d'augmenter fortement sa capacité de drainage. - par une complétion latérale, forée avec un équipement spécial flexible, permettant un rayon de courbure faible, - par forage latéral à rayon de courbure moyen, utilisant un train de forage légèrement modifié, - en forant avec un matériel standard, ce qui entraîne un plus grand rayon de courbure.
I1 existe trois façons d'obtenir un drain horizontal: Chaque méthode est décrite et elles sont comparées, dans l'état actuel de leurs capacités respectives.
Les différents cas d'application possibles sont envisagés du point de vue amélioration de la production, les puits horizontaux pouvant être considérés comme une nouvelle méthode de récupération améliorée, la récupération géométrique.
Vertical or deviated oil wells cross a production formation for only short distances. Horizontal wells, however, are capable of remaining within a reservoir for distances up to several hundred metres in an effort to enhance production possibilities.
The idea is not new. The concept of drilling horizontally into a reservoir to enhance production has intrigued innovators since the late 1920's.
In the mid-to-late 1950s numerous short-radius horizontal boreholes were drilled in the US to promote additional drainage in tar sands and other lowpressure, easy-to-drill, formations. Most of these drainholes were less than 1OOft (30m) in total length273. There also is documented evidence of horizontal boreholes being drilled in the USSR during this same period435.
It has only been since 1979 that conventionally drilled long drainholes have had favourable economic results, thus renewing the interest of the
