DESIGN AND TRAJECTORY CONTROL OF GAO160-8 SIDETRACKING HORIZONTAL WELL IN DAQING QILFIELD

Well Gao160-Ceping 38 was the first short-radius sidetracking horizontal well in Daqing oilfield. It was drilled to develop the remaining oil which has not been touched before at the top of thick oil reservoir. The length of section milled casing was 977~995. 2 m. For the first time, the well was sidetracked from 977. 60m to 1032. 04m. The deviation angle at bottomhole lagged 10° because of the measuring instrument failure. So the well had to be cemented. The cement only returned to the depth of 1011m because the hole enlargement rate was not enough to be estirnated. For the second time, the well was sidetracked from 1007m with 2. 75° bent screw rod. The deviation angle at the bottom hole lagged 11° at the depth of 1028. 53m. The reason for this was that the adapter was not made up, this made angle building change into angle holding or angle dropping. The well had to be cemented again. For the third time, the well was sidetracked from 990. 78m(the cement top 991. 12m).The deviation angle at the target point was 87. 2°, the vertical depth was 1061. 24m. The horizontal displacement was 1182. 88m, the maximum deviation angle was 90. 3°. The wave amplitude of the well trajectory was 0. 61m on the line,0. 26m under the line. This paper introduced preliminary preparation, engineering design and well trajectory cotrol.