Reasonable Diameter Selection of Production String for Puguang Gas Well with High H2S

In the production process of Puguang high-H2S gas well,many problems may occur,such as wellbore sulfur deposition,erosion,liquid loading and hydrate formation.However,reasonable diameter of production string can postpone or avoid these problems.For this purpose,according to the production characteristics of high-H2S gas well and based on the existing string selection method,proper gas production rate range of different tubing diameters was determined by analyzing the critical sulfur particle carrying flow rate,the critical liquid carrying flow rate,the erosion flow rate and wellhead hydrate formation condition.Then according to the production proration and wellbore pressure loss analysis,the reasonable diameter of production string was determined.Using this method,the production condition of high-H2S Puguang Gas Well P was calculated and the results showed that the gas production rate exceeded the erosion rate under current production string diameter,wellbore erosion would occur.In order to protect production string and postpone workover period,the gas production rate of Well P was adjusted to reach gas rate range suitable for current tubing diameter.After the gas production rate adjustment,Well P produced stably,which indicated that this method could not only determine the reasonable diameter of production string,but also adjust gas production rate to suitable production range under current tubing diameter.