OPTIMAL SIDETRACK TIME EVALUATION BY SEGMENTED PROXY MODEL

Sidetrack operations which involves accessing a new zone and commingling production gives rise to uncertainties and proxy models have shown to be able to incorporate uncertainties and mimic real-life scenarios to an acceptable degree of accuracy. In this paper, a time-based proxy model which inte-grates the uncertainties that emerge as a result of several reservoir parameters was developed using NPV as the objective function. A black oil simulator was used to generate the production profile and NPV computed using certain economic parameters. The Box-Behnken response surface design was used to generate a combination of variables with which the experiment was carried out. Non-linearity of the NPV which was caused by the impact of time was corrected using segmented regression and the split design was based on visual observation of the main effect plot. The segmented proxy models obtained were reasonable to an acceptable degree of accuracy in mimicking the simulation model

Dataset on the beneficiation of a Nigerian bentoniteclay mineral for drilling mud formulation

This paperpresentsdatasetonthebeneficiation ofaNigerianclay mineral fordrillingmudapplication.Theexperimentaldesign applied usedaResponseSurfaceDesign(RSM),whichinvolved24 (2-Level, 4-Factors)togeneratestatisticalmodels,andanalyzethe dataset. Theindependentvariableswere(Bentonite; X1), (Polymer; X2), (SodiumCarbonate, X3) and(AgingTime; X4). Therheological properties ofinterest,whichformstheresponsevariables,were selected basedontheAPIspecification 13-Afordrillinggrade bentonite.Theoutcomesshowthatthesecond-orderstatistical models derivedfromresponses fitted wellwiththeexperimental results. Predictivemodelsobtainedfromthestatisticalcharacter- ization ofthebeneficiation processwouldallowforthedesignand cost-effectiveplanningoftheprocedure.Thebeneficiation ofthe clay usingsodiumcarbonateandKelzans XCDpolymerensuedin an improvementintherheologicalpropertiesoftheformulated drilling mud.ThesepropertieswerecomparablewiththeAPI specification 13-Afordrilling fluid material

Effect of foam and WAG (water alternating gas) injection on performance of thin oil rim reservoirs

A design of experiment was used to create oil rim models from a wider range of reservoir, operational and reservoir architecture parameters. A response surface model was generated based on a concurrent oil and gas production and a Pareto analysis was conducted to ascertain the significance of the parameters. The models were classified based on the Pareto analysis and due to the low oil recoveries arising from the complexity of oil rims, a series of secondary injection schemes were instigated. The results from the models indicated an optimum 2 cycle WAG up dip injection and WAG down dip injection for thin oil rims. Also the results estimated an incremental oil recovery of 9.2% and 30.1% with respect to base case (no injection) for WAG up dip injection and 10.66% and 6.11% for WAG down dip injection while an incremental recovery of 14.2% and 52.74% for up dip foam injection and 18.19% and 29.73% incremental oil recovery for foam down dip injection for oil rim model ‘3’ with large gas cap and large aquifer and model ‘7’ with small gas cap small aquifer respectively. A case study reservoir from the Niger delta region of Nigeria showed an 8.57% and 8.56% incremental oil recovery for foam up dip and foam down dip injection and incremental oil recovery of 8.35% and 7.94% for WAG up dip and WAG down dip injection. This paper will provide useful information as to the extent of oil recovery in different oil rim models under different foam and WAG injection

PREDICTING POST BREAKTHROUGH PERFORMANCE OF WATER AND GAS CONING

Water coning is a serious issue for the oil and gas industry. This poses a big concern regarding the costs that to be incurred for separation and equipment capacity. Coning is the production of an unwanted phase with a desired phase. Over the years, many techniques and control methods has been birthed, however, the issue of coning can only be mitigated and not completely discharged. Reservoir and production engineers need to understand the basic framework; the parameters that greatly influence coning and how effective manipulation of it can deal with it. With the introduction of horizontal wells, the production rate is two to four times that of vertical wells, and coning is reduced and the breakthrough time is increased. Numerous papers has been written regarding to coning and vertical wells, only a few emphasize on horizontal wells and simultaneous water coning and gas coning. The objective of this research is to study the post breakthrough performance in simultaneous coning and a black oil simulator was use for the research. Sensitivity analysis was carried out on: the production rate of oil (qt), horizontal permeability, vertical permeability, perforation length, the height above perforation, extent of reservoir area and the formation porosity. A generalized correlation was developed for predicting coning behavior using non-linear analysis

Dataset on modelling a synthetic oil rim reservoirs for optimizing oil production during gas cap blow down strategy

Oil rim reservoirs with very large gas caps, strong aquifers, and pay thickness below 30 ft. pose oil production challenges to operators. With best operational practices, very high gas oil ratios are recorded at the initial onset of oil production, thus such reservoirs are subjected to a gas cap blow down leading to an ultimate loss in oil reserves. This loss is at- tributed to a rapid and drastic drop in pressure over the productive life of the reservoir. To maximize oil production, a simulation study is focused on initiating oil wells at dif- ferent time intervals and estimating oil recoveries at these points. It is believed that the gas cap would have been blown down in time to accommodate for substantial oil produc- tion. This study presents the reservoir data (from the Niger- Delta) that can be incorporated in a black oil reservoir simu- lator (Eclipse) coupled with best production and optimization strategies (water and gas injection) for maximum oil pro- duction during gas cap blow down. The data presented will provide a detailed process developing an oil rim synthetic model, support and enhance further studies in optimizing oil production in oil rims subjected to gas cap blow down, create a template for secondary and enhanced oil recovery processes