Investigation of Well Plan Parameters for Directional Drilling in Gulf of Thailand

Abstract

Directional drilling is commonly practiced in complex structure reservoir in Gulf of Thailand. Directional well path is planned by different well planner experiences. Torque and drag analysis are performed to examine drillability of well path. This process may take time and effort. This study provides optimum sets of well plan parameters i.e. kick off point (KOP), inclination (INC), build rate (BUR) based on torque and drag as criterion, to improve well planning process. This study is based on 4 well profiles; 2 dimensional (2D) build and hold, 2D build hold and drop, 3D build and hold and 3D build hold and drop. Each well profile requires different well plan parameters. To allow efficiency of well plan parameters varying process, a set of fundamental well construction and reservoir data are assumed. Constrain values are based on Gulf of Thailand field data. Derivative torque and drag from each well profile are observed, analyzed and evaluated. The effect of mud weight also investigates in this study. The study found that KOP and INC are the most important well plan parameters on torque and drag generated in deviated wells. Other well plan parameters show minor effect. 2 deg./100ft. BUR generates significantly low torque and drag in build section. However, there is a limit to apply. Varied mud weight afftects torque and drag as increase 1 pound per gallon of mud weight yields lower torque and drag as 1.5 percent approximatly. The parameters set and limit of well plan parameters for each well profiles are presented in this paper.