Ingenuity Water Shut Off Solution in Turkmenistan

Abstract Water cut has been one of the major challenges causing decline in hydrocarbon production for operators for years. Several methods of water shut off were used to isolate the unwanted water zone such as mechanical patches, micro cement and various forms of resin and polymer based chemical injection. The key to successfully shutting off the water zone requires understanding of the reservoir in the context of when and how the water influx occurs, the wellbore condition, completion architecture installed and effective placement methodology. The Dzheitune (LAM) Field, situated within the Cheleken Contract area on the eastern coast of the Caspian Sea, offshore Turkmenistan, has witnessed water cut on a few producer wells. All these wells concentrated within the A-sand formation spanning a 100-meter gross interval. As A-Sand is prone to sanding issues, the primary well completion has downhole sand control mechanism which makes the water shut off intervention more challenging than common well completion such as cased and perforated wells. The implementation of water shut off involves a two-stage process, identifying zone of the water flux and then effective shut off technique and placement methodology. This paper describes the well, which was competed with a dual string configuration sand control mechanism in A-Sand layer. Through initial PLT logging, the water zone was identified. The influx of water came from the upper zone and flooded the productive lower zone. The completion sand control accessories were installed with seal units sealing across the lower zone seal bore packer and thereby provide isolation between the long and the short string. Through multiple wellbore pressure tests the water zone influx from the upper zone was identified and it is to be from the leaking seal units. The problem was identified, however the zone of interest for water shut off is about 47 meters of perforation. The top to bottom perforation length is 407 meters (upper zone). This is an extremely challenging well with a long interval to effectively inject and isolate through chemical injections. This paper offers insights on the problem diagnostic, chemical selection, placement methodology to effectively seal off the water influx. It describes the innovative approach of the combination of polymer-based gel with particulate material making it a single stage chemical treatment with higher yield strength. Chemical injections are known for their effectiveness inside the matrix and deep into the formation. This paper also outlines the extension of the chemical isolation application inside the wellbore effectively sealing off from water influx (i.e. the leak point in the completion sting). The novelty of the combination of chemicals and effectively sealing off the leakage revived the water flooded well back to production. It also provides the solution foundation of future water shut off wells in this field. This ingenuity approach creates fresh opportunities in chemical shut off application in challenging wellbore and complex completion architecture.