Study On Production Prediction For Horizontal Wells

The development technology about horizontal wells is the revolutionary technology in the field of the petroleum industry, with more and more obvious economic benefits of oilfield developed by using this technology, the application is more and more widely. Not only it is used in the reservoirs that are difficult to exploit, such as low permeability reservoirs, heavy oil reservoirs, and also is used in reservoirs with good properties reservoirs.With more and more obvious economic benefits of oilfield developed by using this technology, the application is more and more widely, in the early period, the horizontal well is mainly used in oilfields that are difficult to exploit and the production rate is relatively small and the horizontal section is short. In this case, the flow performance in the horizontal section has not significant influence on the production of the oil well. While the current drilling technology is able to drill the length of horizontal well from thousands of meters to even tens of thousands of meters, such as the Middle East oilfield with high production rate.in which the horizontal well technology is also widely used. For horizontal wells with high production rate and long horizontal section, the flow performance of the horizontal section will affect the inflow performance of the horizontal well obviously. The variable mass flow law in horizontal wellbore is studied in depth and so the productivity prediction of oil well can be better, which will lay a solid foundation for the design and production schedule optimization of oil well, and have important theory and practical significance to enhance oil recovery and the efficiency of overall development.On the basis of full investigating and researching the related literatures about the horizontal wells at home and abroad, the paper established wells of both the offshore oilfields of the South Sea in China and oilfields in the Middle-East affiliated to the CNPC with the high production rate, high gas oil ratio and complex wellbore structure as the research object, and studied the reservoir seepage law of horizontal wells, the variable mass flow law in wellbore, the coupling rules of the two laws, and the sensitivity parameters of the productivity prediction of horizontal wells by the method of the combination of physical model experiment, numerical simulation, theoretical modeling analysis and the measured data validation.1. The method of using skin factor and additional pressure drop for the productivity prediction. This paper discusses the method of using skin factor on the basis of its definition. For single phase steady state productivity prediction analytical method, the skin factor or additional pressure drop can be used for productivity prediction. But it is more convenient to use additional.2. A new productivity prediction analytical model with single-phase steady flow for horizontal well. On the basis of the equivalent permeability calculation model, two new productivity prediction analytical models with single-phase steady flow for horizontal well are established respectively by using the equivalent seepage resistance method and conformal transformation method.3. The numerical simulation method, analyses the horizontal well, the flow law of variable mass flow in Iraq oil field measured data validation.4. Both the offshore oilfields of the South Sea in China and oilfields in the Middle-East affiliated to the CNPC are regarded as the research object. The parameters sensitivity analysis for the productivity of the horizontal wells are done by using the 3D well trajectory semi analytical method of single-phase steady variable mass flow and they are evaluated.