Study On Hybrid Lift Oil Production Technologies In Ultra-deep Wells

It is urgent necessary to solve the problem to pump oil from ultra deep wells in many oil fields. Hybrid lift systems which combine two kind of artificial lift methods are effective approach to produce oil from ultra deep wells. Based on integration of research achievements in related fields at home and abroad, the flexibility of each artificial lift method was analyzed and a reasonable hybrid lift system was proposed according to the production features of ultra deep wells. Using some engineering mechanical theories, the tubing pipe string which suit to operate in ultra deep wells was designed. To improve the efficiency and assurance coefficient, some self contained downhole instruments including high efficiency gas liquid sepreator, accumulator unit and compounding wellhead were developed. Based on the common pressure gradient modelof gas liquid flow in the wellbore, a more precise and realistic model to calculate oil gas water three phase flow pressure gradient was improved considering the effect of the slippage between oil/water mixture to pressure gradient. Combining artificial lift theories and optimizing methods of oil production parameters, the theory model and parameters optimizing procedure for rod pump electric submersible pump hybrid lift system producing oil from ultra deep wells was made up, and a complete set of related software to calculate and analyze the characteristics of the hybrid lift technology in ultra deep wells was established. At last 4 hybrid lift systems were tested in ShengLi oilfield and XinJiang oilfield. The success of these tests showed that the model and calculation procedure were accurate, and the hybrid lift system can resolve the probleum to lift oil from Ultra deep Wells.