Study On Restoring Productivity Assessment And Workover Program For Old Wells In Samandepe Acidic Gas Field

In the face of the urgent situation that China's consumption of oil and gas resources grows rapidly, making full use of foreign and domestic markets and resources, developing various forms of international cooperation actively, and establishing security, stability and economic oil and gas supply channels are important to maintain national energy security guarantee. Judging from the long-term interests, the natural gas in Turkmen is one of the ideal choices for China's energy diversification, and it can make up for the shortage of oil and gas and decentralize energy security risks in our country, and it also can provide long-term stability for the gas supply security from Turkmen to China, which has strategic importance. Repairing the old wells in Samandepe gas field is important to the productivity recovery, which can greatly reduce the number of new drilling wells, save huge amounts of investment, restore the gas production, and gain valuable time for the gas transmission as soon as possible.In this paper, the situation gas field development and the old wells in Samandepe are analyzed and studied. As for the characteristics of old wells with high gas H2S and CO2 in Samandepe gas field, the corrosion mechanism of acid gas reservoir, the production technology, especially the anti-corrosion technology, are studied. At the same time, the products in specialized technology companies (FMC, the U.S. Drilling, Lake, Cameroon, Halliburton, Baker, BHGC) are studied. Based on the principle of security, economics and suitability, the re-completion equipments for the productivity restoration of old wells, such as downhole tools, testing pipe, gas wellhead, christmas tree , tubing material and button-type, are determined, which lay a solid material foundation for the productivity restoration of old wells as soon as possible.The status of 25 old wells that can be repaired in Samandepe gas field in Turkmenistan are studied. Based on the principles of safety first, the easier, overall arrangements, implements with batches, the workover operations can be divided into 4 steps. The technical difficulties, workover and well repairing construction and other technical measures conducted serious research program for each well are studied. Meanwhile, the security problems and issues in the process of repairing work for old wells are analyzed and evaluated scientifically and effectively, and the corresponding technical measures are established.Based on the arrangement and evaluation of original materials of 33 old wells, the current status of old wells are grasped. The restore of old wells are completed, and it has passed the assessment of project companies and experts, and has been implemented. The 34 old well have been repaired with excellent results, and it has a daily output with 62.3×104m3/d gas flow successfully. The study in this paper shows excellent prospects for the repair of old wells and capacity-building, and provides a valuable experience for the repair of old wells in Samandepe gas field.