New Applications of Multidetector Pulsed Neutron Technologies in Gravel Pack Completions
Gravel Pack (GP) and Frac Pack (FP) are common sand control completion designs. There are various well known methods to evaluate effectiveness of gravel placement in the screen - casing annulus, allowing top of pack detection, void location and gross pack quality assurance. The increasing trend in using Non Radiation Traceable (NRT) proppant in both open and cased hole completions assists the evaluation of pack quality when using pulsed neutron logging technologies. Unlike traditional GP and FP evaluation techniques, Multi-detector Pulsed Neutron (MDPN) instrumentation provides a broader suite of nuclear attributes that can be used both qualitatively and quantitatively. Moreover, MDPN data can provide a baseline fluid saturation as has been widely documented.
Multiple datasets obtained from yard tests and two observation wells have been used to benchmark theoretical models based on multiple tool response equations. MDPN time lapse data and other static and dynamic log data will be discussed to emphasize the value of NRT proppant and MDPN surveillance during well life. The complexity of the logging environment means that a huge amount of rigor is required in the areas of job planning and execution in order to ensure the resultant dataset is optimized for use quantitatively. It is possible to generate a GP Quality Index scaled from 0% (no pack) to 100% (perfect pack) using one or more nuclear attributes depending upon the environmental conditions.
This paper will describe the advantages and disadvantages of each of the conventional GP evaluation techniques based on datasets from both yard test and live wells.
For NRT / MDPN applications, the processed nuclear attributes resulting from the NRT/MDPN GP evaluation show reduced uncertainty when compared with the conventional logging techniques. Using MDPN for GP evaluation also means this data can be used for other reservoir and well surveillance applications.
Authors: Xiaogang Han (BP) | Manasi Scott (BP) | Virginie Schoepf (BP) | Maryam Mousavi (BP) | Carlos Stewart (BP) | Adrian Zett (BP)