Problem of Gas Breakthrough Solved through Installation of Recompletion Assembly with Autonomous Gas Inflow Control Devices AGICD in Oil Producing Wells

During the field tests in oil producing wells at the Verkhnechonskoye field there were autonomous gas inflow control devices (hereinafter referred to as AGICD) applied for the first time as part of a recompletion assembly. The recompletion technology is based on a well completion design solution with AGICD which consists in dividing the liner into intervals, equalizing the total inflow and restriction of the inflow of adverse fluids in producing wells with increasing flowrates of adverse fluids as well as wells shut in due to water/gas breakthroughs. The recompletion assembly is run into the previously lowered liner equipped with sand screens and divided into several zones by swellable packers. The new assembly essentially features the classical completion assembly but comprising original 73-mm-tubing-based equipment such as a shoe, cup packers, a packer hanger, and centralizers. The equipment design allows for its complete retrieval if necessary. Since oil contains a lot of solids and deposits of asphalts, resins, and paraffins, the recompletion assembly has a flush valve enabling acid cleanout of the pay zone of the formation during the operation. In order to prepare for the recompletion assembly to be run in, intense analytical work was done to study the candidate wells and geological conditions and peculiarities of the Verkhnechonskoye field, to analyze the open hole logging data and the oilfield geophysics vs. its hydro-dynamic model data. During the field trials, recompletion assemblies were run in two wells of the Verkhnechonskoye field and monitored to assess their operation with AGICD within a set period of time. Then the equipment was pulled out and the wells were monitored again without AGICD. The findings provided the basis for the assessment of the equipment operation. The analysis of the trials results showed that the equipment is prepared, run in the hole and retrieved in normal mode. The qualitative AGICD performance indicators are based on the stable well operation within the total nonfailure operating time after the recompletion assembly is run in the hole. The quantitative AGICD performance indicators are defined by the achieved gas ratio decrease and oil flowrate rise. The trials also confirmed the convergence of the AGICD expected and field-proven performance indicators which makes it possible to plan precisely well operation modes when using recompletion equipment. The trials findings prove that the recompletion technology is reasonable for wells with high rates of non-targeted fluids as well as idling wells (due to water/gas breakthrough) to make them active again.