Study On Well Completion Control Technology In Halfaya Oilfield

The reservoir has the features of sensitive to press and serious gas kick in Halfaya oilfield.The gas kick affects the bottom hole pressure balance and the pressure drops rapidly after gas kick,the formation is high in sulfur,so killing well opreation is difficult,which brings great difficulty to the well completion.For well completion and downhole operating construction,the well control accident is the worst accident.Therefore,during the operation of Halfaya oilfield,it is very important to do well control work in the completion stage.To this end,First,researching the well control technology and process measures in China and abroad,then do the completion well control technology research based on the actual data of the Halfaya oilfield.This paper mainly carries on the following researches:(1)Discuss the risk and existing problems during the completion well control of the Halfaya oilfield and preliminarily put forward technical countermeasures according to the relevant geological characteristics of the strata in the region,the oil-water system and the completed well conditions.(2)Analyze the leakage characteristics according to the development and distribution of fractures in Yamama formation.Clarify the type of gas kick in this formation and establish the mathematical simulation model of gas kick to study the gas-liquid displacement under the leakage condition.Identify the relevant factors influencing gas kick.Establish the gas-liquid flow model after the gas kick and analyze the change of bottomhole pressure and sensitivity factors after gas kick,Define the change rule of bottom hole pressure.(3)Research the well completion killing method in Halfaya oilfield;clarify the selection principle of well killing method to do the theoretical research on this method.The main parts are the selection reason,the applicable conditions,the establishment of physical and mathematical models.Select an actual well in the Halfaya oilfield as a case to verify the feasibility of this technological method of well control.(4)Study the well control technology in all stages of completion in Halfaya oilfield.This part is based on primary well control and ensure secondary well control,mainly include:the changing trend of mud fluid with temperature and pressure,the analysis of fluctuating pressure and safety velocity of the process of installing casing,the perforation well control technology and the differential pressure control during the testing.In completion of Halfaya oilfield well control technology research,has formed a set of feasible completion well control technology,clear the field gas kick and the overflow within wellbore flow characteristics and the influence factors of wellbore pressure.Discusses the applicable to the field of well completion process well killing method,and simulated calculation,according to a example calculation results show that the feasible,Put forward the technology of well control measures in different stages of the completion,process of Halfaya oilfield overflow,prevention and well control technology measures of each stage is a good reference value.