Multirate Welltest Design - Niger Delta Field Experience

Abstract

Multirate welltests are conducted to determine well deliverability, skin and distance to major fault boundary; as well as reservoir data like permeability and pressure. A reservoir was planned for development with four wells to supply about 500 MMscf/d of gas to a primary treatment facility. The proposed wells were designed for multirate welltests to boost confidence on meeting the gas supply obligation. The multirate welltest program includes (1) Initial Build Up, (2) Flowing, (3) Final Build Up and (4) Static Survey periods. The test design determines optimal duration for each activity in the program; to ensure the test objectives are achieved. This paper shares results of the test designs for the wells and insights gained from the exercise. The results show that wells close to boundary fault (less than 250 m gap) were not good candidates for final build up survey as the fault signal appears early (within 0.1 hr survey time) as boundary effect; thereby overlapping with wellbore storage effect phase and masking infinite acting radial flow period (used for estimating well and reservoir parameters). Hence, final build up was not proposed in such wells. Those parameters can be estimated from other wells in the same reservoir. Sensitivities were done by varying the reservoir structure, permeability, well skin and wellbore storage effect. Test design results also show that infinite acting radial flow period signal was observed within 0.1 to 2 hrs of final build up; followed by fault boundary response visible from 2 to 24 hrs. It can be concluded that final build up survey period of 10 hours is optimal to meet the test objectives.

Socioeconomic Analysis of the Relationship between the Socioeconomic Characteristics and the Leverage Ratio of Rice Farmers in Anambra State, Nigeria

“…Forthecountrytobridgethisgapbetweendemandandsupply,recoursehasbeenmadetothe importationofricethusmakingNigeriathesecondlargestriceimporterintheworld.Nigeriaimported approximately17milliontonnesofriceinthepastfiveyearswiththecropaccountingfor1.26%of theentire2017budgetandaddedthatNigeriaspends$5m(£4m)adayforriceshipments (Ndukwe, 2017).Importationofricemakesforeignricefarmerswealthierattheexpenseoflocalricefarmers whofacehighcostofproduction (Abbas,Agada,&Kolade,2018).Riceimportbillconstitutesa heavyburdenonthefinancesofthecountryandalsotendstostiflelocalproduction.…”