CHALLENGE:
Most coiled tubing sidetrack wells within the up structure area of Greater Prudhoe Bay (GPB) field are competed with relatively small production liners (2-3/8” OD and 2-7/8” OD). These wells usually begin producing at very high Gas Oil Ratios (GOR) within a couple of years of being brought on line. The lateral length within the reservoir can be as long as 2000ft MD. One of the ways to lower the GOR is to set a plug within the lateral section. However, without a valid production profile (PLT) it’s almost impossible to tell which section of the lateral is producing the most gas. Logging can be accomplished by running a PLT with 1.5” coiled tubing. However, the ID of a 2-3/8” liner is only 1.92”. With 1.5” coiled tubing in the well, the flow area is reduced to only 0.42”. This small of an area results in the well being severely choked back during the PLT run (with flow being either stopped or very sluggish / intermittent). This often results in an uninterpretable production log / profile and consequently no viable gas shut-off options.
SOLUTION:
Our engineer introduced logging with Distributed Temperature Sensors (DTS), which eliminated the need for a conventional PLT run. DTS was used to identify the gaseous zones – after flowing the wells and then performing a hard shut-in to create the Joule Thompson effect. This resulted in a more effective intervention and/or gas shut-off operations.
TECHNOLOGIES IMPLEMENTED:
• DTS
• I-Coil
• Prosper / GAP
