Research for Horizontal Well Reasonable Drawdown Pressure of Heavy Oil Reservoir with Bottom Water

Abstract

Abstract In this paper we detail the work done in rearch for horizontal well reasonable drawdown pressure of heavy oil reservoir with bottom water based on detailed analysis of the geological, reservoir, production history, horizontal well data and production conditions with the intent to enhance rate and recovery efficiency in a heavy oil reservoir with bottom water. We study the geological, reservoir, production history and horizontal well data relate to optimizing horizontal well reasonable pressure drawdown in a heavy oil reservoir with bottom water, like reservoir thickness, horizontal well standoff over oil water contact, honrizontal section length, barriers distribution and viscosity in-place oil. This paper breaks up the past development idea of controlling horizontal well drawdown pressure to delay bottom water conning, and a new theory to high efficiency develop bottom water reservoir is present. This new development theory comes from geology & reservoir and takes production conditions on sea into account, has strong base of theory and practicability. A combination of geological, reservoir and production history is considered to optimize horizontal well pressure drawdown. Through the work done we are able to identify the reasonable pressure drawdown with every horizontal well including on production and planning. And we are able to identify how much these factors affect optimizing horizontal well pressure drawdown. There are 27 horizontal wells to develop heavy oil reservoir with bottom water at QHD32-6 Oilfield, and next step more horizontal wells will drilled. Some horizontal wells produce poorly because bottom water coning quickly, these wells obtain successful production after enlarging drawdown pressure and accumulative oil production exceed those wells with small drawdown pressure to delay bottom water conning.The rate and recovery efficiency in QHD32-6 Oilfield have been increased largely after this pressure drawdown optimization. The paper details techniques for pressure drawdown optimization in heavy oil reservoir with bottom water, and indicates high efficiency recovery by horizontal wells in heavy oil reservoir with bottom water is obtainable. This development idea has been applied to several fields at Bohai bay including QHD32-6, CFD11-1, SZ36-1 and CB. Producing practice have testified that high recovery rate for horizontal well of heavy oil reservoir with bottom water is very successful.