Research On Temperature And Pressure Distribution Of Deep Water Gas Well Testing

With the deep exploration of oil and gas in deep water,the development of deep-water gas well is gradually increasing.Accurately predicting the wellbore temperature and pressure distribution of the test string is to ensure the safety of deep-water well testing,which is the key to obtain accurate test parameters.Because of the special deep-water environment,the heat transfer mechanism of water segment is more complex than stratigraphic section.In this paper,the deep-water wells in NW tested as research subjects,having special conditions of its testing process:in the testing,open the booster pumps,circulating fluid through the riser pipe from the outside of the pressurized test string loop injection valve,and flow in the annulus between marine riser and test string.while the existing wellbore temperature calculation models don't meet the above testing conditions.In this paper,for the special conditions of deep-water gas well test in NW,we carried out extensive literature research,field data collection.For the gas wells' test string in NW,according to the principle of conservation of energy and heat transfer theory,establishing a model to predict wellbore temperature and pressure in NW.The model can predict the testing string and annulus during temperature cycling,pressure distribution.Combined with easy deep-water gas hydrate formation characteristics in the testing,through models of predicting hydrate generating can predict gas hydrate formation temperature and pressure,prevent hydrate blocking the testing string.In this paper,I prepared wellbore temperature and pressure calculation program and hydrates prediction calculation program using VB.The program has four modules,including column temperature and pressure calculation module and hydrates prediction module,seawater temperature field calculation module,pressurized pipe circulating fluid temperature calculation module.In this paper,the measured data of gas wells in XW and NW validated the reliability of temperature and pressure calculation model,and did the sensitivity analysis to the parameters affecting wellbore temperature distribution.The NW block similar deep-water gas well by temperature and pressure testing will have a good reference value.This study showed when the depth of more than 200 meters,similar to the testing of deep-water gas well in NW,pressurized circulating cycle of heat loss is greater than non-pressurized testing,it should not open pressurized circulation.