Sidetrack and recompletion risk evaluation — Waterflooded reservoir

Ajibola

Int. J. Petrol. Technol.

2015

Sidetrack during field development and ongoing production arises to exploit bypassed reserves, unexploited zones and to tackle unforeseen conditions that are likely to occur due to uncertainties and heterogeneity in initially characterizing a reservoir. Whereas recompletion is due to sequential production of stacked reservoirs or multiple pay zones that is caused by regulation on commingling. The purpose of this paper is to investigate the application of experimental design (ED) in optimizing sidetrack/recompletion time of multiple pay zones in view of maximizing returns on investment by net present value (NPV) and expected monetary value (EMV). A hypothetical reservoir of two pay zones with uncertainties associated with pay thickness, porosity, permeability and time to perform the sidetrack was considered. The ED method of Box-Behnken response surface design was used to reduce the number of runs made by generating the most effective combination of variables for the experiment. Experimental runs were conducted with a Black Oil reservoir simulator to give production profile and the computed NPV was used afterwards to produce the Proxy model in ED. NPV computed from the Proxy Model was reasonable compared to that of the production profile from the simulator. However, a higher level D-Optimal or factorial design may be required for a reasonable match of EMV with respect to obtaining a realistic sidetrack/recompletion time.

Section: Resultsmentioning

confidence: 99%

Section: Sidetrack Optimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sidetrack/Recompletion Time Evaluation by Proxy Model

Ajibola

Int. J. Petrol. Technol.

2015

Advances in Mechanical Engineering

Research on cutting mechanics of window bit cutting teeth

Kong

Zheng

Zhang

et al. 2016

According to structural characteristics of dual-effect strong side-cut window bit (hereinafter referred to as window bit) and the theory of metal cutting and the rule of teeth arrangement of window bit, a cutting mechanical model of window bit cutting teeth is established, window bit geometric equations deduced and the solution of the cutter cutting mechanical model completed; finally, the casing window experiment is conducted with the dual-effect strong side-cut window bit developed to verify the accuracy of the cutting mechanical calculation model and the simulation results. The results show that the variation tendency of the main cutting force of the bit and the experimental data are similar in the windowing process, the simulation results can accurately reflect the change rule of the main cutting force and the requirements of engineering applications are basically met. The research results of this article provide theoretical basis for the analysis and calculation of the cutting force of the window bit and can serve as a reference for the design of deep/ultra-deep well casing window bits and cutting mechanics research.

Sidetrack/Recompletion Time Evaluation by Proxy Model

2013

Sidetrack during field development and ongoing production arises to exploit bypassed reserves (unswept areas under secondary and/or tertiary recovery), unexploited zones and unforeseen conditions likely to build due to uncertainties and heterogeneity in initially characterizing a reservoir. Whereas recompletion is prone due to sequential production of stacked reservoirs or multiple pay zones that is necessitated by regulation on comingling. The purpose of this paper is to optimize the time for sidetrack/recompletion job in multiple pay zones in view of maximizing returns on investment. A simple case to elicit the workflow is based on two pay zones and applies Experimental Design (ED), and economic analysis in the form of Net Present Value (NPV). The procedure followed for this study started with the identification of the reservoir uncertainties and their ranges; focusing basically on net pay thickness, porosity, permeability, and time to perform the sidetrack; the reservoirs are assumed to be undersaturated. The Box-Behnken response surface design in ED was used to reduce the number runs to make by generating the most effective combination of variables for the experiment. Experimental runs were conducted with a Black Oil reservoir simulator to give production profile. NPV values using stipulated Oil price, CAPEX, OPEX, tax rate, royalty and production rates were estimated, which was used afterwards to produce the Proxy model in ED and this developed correlation was used to analyse the effect of time changes. NPV computed from the Proxy Model was reasonable; however, a higher level D-Optimal design as against the 2-level design used in this study may be required for a reasonable match of NPV with respect to sidetrack (recompletion) time. In conclusion, the incorporation of time was successful and gives way to studying the impact of not only reservoir uncertainties but the uncertainty that arises from a success or failure of the sidetrack that further gives way to the application of decision analysis and the evaluation of NPV by Proxy Models for each possible outcome.