Memory-Based Depth Control Technique -- Practical Application for Precise Deployment of Explosives on Slickline, Coiled Tubing And Drillpipe

摘要

With the advent of intelligent memory based controllers for initiation of pyrotechnic passenger loads, there has been an expansion of the range of services available to operators via non-traditional conveyance. The primary concerns for non-real time initiation of pyrotechnics are safety and depth control. Modern memory based trigger devices include multiple fail safe routines within the fire command sequence and these are well documented in technical and commercial literature. This paper deals with the concepts and challenges of achieving reliable depth control. The technique employed here applies to all non-conductive deployment systems, (slickline, conventional coiled tubing, and jointed pipe) and does not require specialized surface equipment other than standard depth encoders and memory correlation logging tools (typically Gamma Ray and or CCL). The technique relies on understanding the limitations and observing a few simple conventions. A reasonable analogy of the technique would be aviation under IFR (Instrument Flight Rules) versus VFR (Visual Flight Rules). Both methods are valid when the accepted methodology is respected. This is an important development in the industry because it affords flexibility to operators where there are fiscal or logistical barriers to conventional, real time correlation. Some benefits: Reduce critical path rig operations by multi-tasking standard completion steps Minimize rig up / rig down time by concentrating more tasks into a single deployment medium. Permit access to previously unrecoverable shut in reserves. Many platforms will accept no more than a small slickline unit. Wells that previously would require prohibitively expensive rig intervention can be re-completed using slickline. Taking advantage of these options, offshore facility designers can realize significant savings in fabrication. The paper demonstrates that, when proper conventions are observed, the technique reliably deploys payloads with precision compatible to the full range of pyrotechnic completion and intervention services in the modern energy services market. The technique fundamentally consists of two steps: a correlation logging run, with establishment of the control flag, followed by deployment, space out, and initiation of the payload. The following subjects are central to success of the memory based depth control operations: The role of the depth measurement system vs. the role of the Control Flag; Accurate on-going tally of toolstrings and deployment medium (slickline, etc.); Data handling; Stretch.