Research Of Gravity-assisted Steam Flooding Optimization In H127-we Reservoir

Liaohe oilfield is the largest heavy oil production zone in China.At present,the recoverable reserves of the main heavy oil block have exceeded 80% and have entered the later stage of development.Most oil Wells had a large decline range and entered the stage of lowproduction and low-efficiency development.It is urgent to study new development conversion methods.H127-we block has entered the late development stage with high water cut and high return rate.Based on the geological conditions and exploitation status of the study area,conduct research of transformation of exploitation of the study area.Drawing on the development experience of similar reservoirs,the study area is to be transformed into gravity drainage assisted steam drive.This paper analogy depression 59 block reservoir conditions for the feasibility analysis,use numerical simulation for optimization of injection-production parameters and best time for transformation,combining with field production conditions for steam injection process,the lifting process and form a complete set of technical methods to improve,to carry out the production of gravity drainage auxiliary steam flooding pilot test area effect analysis,in order to lay a foundation in the scheme of transformation.The results show that,compared with Wa59 block,the geological conditions and exploitation status of the study area accord with the conditions of gravity drainage assisted steam flooding.The historical fitting effect of numerical simulation is good.The vertical distance between vertical Wells is 100 m,and that between horizontal Wells and vertical Wells is 50 m.In the longitudinal gravity drainage auxiliary steam flooding,the vertical distance between steam injection Wells and drainage horizontal Wells is 15-20 m.H127 bottom-hole steam dryness exceeds 0.5,steam injection rate per unit volume is controled between 1.6-1.8t/(d?ha?m),and the injection-production ratio is set as 1.2 to ensure the effective control of the thickness of the wellbore group in the vertical well shooting out at 1/3.The technology of dual pipe steam injection,multi-point steam injection in horizontal well and the technology of high temperature and large displacement lift are used to improve the operation degree of horizontal well and control water cut effectively.The actual production in the field has been significantly improved.Reservoir physical properties,recovery degree before tansformation,formation void and formation water storage are the four main influencing factors for the field effect.