Optimization Of Sidetracking Development Project For Adjustment Wells In Offshore Oilfield

The special development environment determines that there are significant differences in exploitation strategy between marine oil and land oil field,a platform is designed to develop oil fields quickly within its control as many as possible.Therefore,high production with less wells is the basic principle of offshore oil exploitation,abandoned wells and sidetracking wells are the main methods to improve the reserves in development and exploitation effects.Focusing on 27 reservoir of LX oilfield,through the study of a large number of relevant literature,at the same time,using the previous research results for reference,comprehensively utilizing petroleum geology,reservoir engineering and fluid mechanics,the basic geological reservoir characteristics are summarized.Reservoir geological model is established to study the distribution of remaining oil by the method of numerical simulation.On the basis of results above,production and its influence factors of horizontal well are studied and development project of sidetracking horizontal well in LX oilfield is proposed,considering the technical and economic indexes.The research work has achieved the following results:LX oil field is a complicated anticline which develops a single 27 reservoir.From the plane,the oil saturation is higher in the well-located area,while the remaining oil becomes more in the high structure and non-well area(the south of the reservoir).From the vertical,the remaining oil is more distributed in the K1-K4 formation,which is the concentrated area for tapping the potential of remaining oil.According to the Joshi formula,the absolute productivity of horizontal well tends to increase with the increase of horizontal section length under the premise of certain oil drainage area in a single well.When the horizontal section length is 300-800m,the daily production of horizontal well is linear with the length of horizontal section.By comparing the two ways of oil well extraction and inefficient well sidetracking,it can be seen that the former's effect is decreasing day by day,and the latter can optimize the well pattern and reduce the development cost,which is the most economical and effective way to tap the remaining oil.Considering well pattern,actual oil production trends and project feasibility analysis,based on the well A8H in the South,horizontal well A8H1 is sidetracked,and the optimization of horizontal section location,horizontal section length and initial production has been done.The results show that,when the horizontal section is East-West located,horizontal section length is 600m,the initial production is set as 200m3/d,the cumulative oil production of LX oilfield comes to the largest after 5 years,which is 1162.4×104m3,5.6×104m3 more than that before adjustment.With the optimum scheme of numerical simulation,and reasonably adjusting the amount of diesel oil used during.the period of avoiding typhoons,the economic evaluation of 27 reservoir is carried out.It makes profits when the price of crude oil ranges between 30?100 dollars,so the scheme is feasible.Up to Oct 31th,2017,the cumulative oil production of A8H1 is 1.48×104m3,the water cut slowly increases,the effect of sidetracking is obvious.