| The development of Longwangmiao Fm gas reservoir in Moxi block has achieved great success.high output per gas well, Production test is produced with 80% load, The average daily output is 60.0×104m~3/d. At the same time with high yield, MX8 well, MX10 well and MX13 well appeared wellhead uplift phenomenon. The MX8 wellhead uplift 46mm within 7 days. The uplift of the casing pressure relief pipeline on the right-wing makes the concrete floor above pipeline cracked 3 point about 1-2mm and the high pressure production pipeline appeared different degrees of deformation.The gas contains high concentration of hydrogen sulfide gas in the Longwangmiao Fm gas reservoir. If the wellhead uplift phenomenon can not be controlled, there will be a serious security accident. the wellhead uplift and deviation ofthe Christmas Tree will affect the ground equipment layout and cause the production pipeline to bend, bring difficulties to various wellhead operation and construction, and even cause well overhaul, Serious situation may cause production pipeline broken. It’s a hidden trouble for efficient production in the gas field.Based on the above problems, this paper carries out the following researches:(1) Based on the analysis of the cause of the uplift of the wellhead, the main factors influencing the uplift of the wellhead are identified by engineering factors and production factors.(2) The wellbore temperature field distribution and wellhead lifting height prediction model are established. The finite element method is used to analyze the stress and displacement changes of the casing pipe from the cementing stage to the production. The wellhead uplift process and related parameters are obtained. And verifies the accuracy of the wellhead uplift model.(3) Carrying out the evaluation method of wellhead uplift, forming a wellhead uplift evaluation method and carrying out the wellhead uplift evaluation of 1 to 2 wells.(4) To carry out the risk identification and prevention and control measures of wellhead uplift in high temperature and high pressure and large production gas wells, and to form the prevention and control method of the wellhead uplift.(5) Carry out the analysis of high temperature and high pressure and large production single gas well, predict the uplift height and casing pipe bearing capacity of the wellhead, and guide the wellhead uplift management in the site.Wellhead uplift height prediction and analysis evaluation technology can accurate predict the height of the well uplift, and judge the casing bearing capacity, which can effectively guide the high yield of the production system, to ensure the safe and efficient production of gas well. The results of this paper have been applied in 38 production wells of Longwangmiao Fm gas reservoir, which effectively know the efficient production of gas wells, and have wide application prospect. |
