１前言 本世纪以来，世界范围内钻探的水平井数量日益增多。仅美国和加拿大，１９９０ 年以来钻探的水平共数量已超过 １０，０００ 口。和直井相比，水平井具有许多优点，诸如增加产量、扩大注水效果、减少水、气的锥进及增大泄油面积等。增大泄油面积对裂缝性油层尤其重要， 1 Introduction The number of horizontal wells drilled in the world has been increasing since the beginning of this century. In the United States and Canada alone, the total number of drills since 1990 has exceeded 10,000. Compared with vertical wells, horizontal wells have many advantages such as increasing production, expanding water injection, reducing coning of water and gas, and increasing drainage area. Increasing the drainage area is particularly important for fractured reservoirs,