n one well (multiple well test). During interference tests, pressure changes due to production or injection or shut-in at an active well is monitored at an observation well. Interference tests investigate the reservoir properties and establish pressure connectivity between wells.
Interference tests are primarily used to establish sand continuity between the active and observation wells. In situation where more than one observation well is used, interference test can be used to find maximum and minimum permeability and their directions.
Figure 1.6: Interference test
1.1.3 Uses of Bottom-hole pressure test Derived Information
Results obtained from BHP tests are used for the following purposes:
- Reservoir Surveillance.
- Determination of Stimulation Candidates.
- Gaslift Optimization.
- Input for Reservoir Simulation.
- Material Balance Calculation.
1.2 Statement Of The Problem
During the process of drilling a well, foreign particle may invade into the porous space and plug it, there may be formation of clay dispersion and migration etc. which have great effect on the flow of the reservoir fluid. When this occurred in the wellbore and reservoir, it cannot be known without the help of well testing. Furthermore, for every test conducted, there is an objective to be arrived at but there are challenges of improper design of the test and accurate analysis and interpretation to meet objective.Hence, the need for an effective and accurate tool “Saphir” to determine if there is a damage to the wellbore and impairment to flow.
1.3 Aim And Objectives Of The Study
The importance of well testing in the oil and gas industry cannot be overemphasized just as a doctor trying to treat a patient without carrying out a test to actually diagnose the problem to know the right prescription for the situation. This is also the case of an oil and gas well. Thus, the main aim of this study is to determine well and reservoir properties from a well test data. In order to achieve this aim, the following objectives need to be carried out:
- Test a producing well and obtain relevant data from the test.
- Characterize reservoir such as permeability, skin and formation capacity.
- Estimate average reservoir pressure and define reservoir limit.
1.4 Relevance Of Study
- Prevent wrong decision making as a result of accurate estimation of well and reservoir properties.
- Help monitor reservoir and well performance.
- Detect possible causes of performance deviation.
- Data obtained will help in reservoir surveillance, input into reservoir simulation study and for production optimization.
1.5 Scope of study
This study is basically carried out to characterized reservoirs in terms of permeability, skin estimate to know if the wells are damaged or ascertain the success of stimulation jobs. Also determine the average pressure and drainage volume with the use of well test analysis software “Saphir”. Because of the difficulty of getting data from the industry, only build up will be analyzed.
1.6 Project outline
The outline of this thesis is in five chapters. Chapter 1 gives an introduction to the whole work which includes the aim and objectives, the scope and the relevance of the project. Presented in Chapter 2 is an extensive literature survey on the process route involved in pressure transient analysis. It looks at well testing, operation of Saphir software and interpretation of results. Chapter 3 presents the collected data and the sequential procedure by which these data were implemented in SAPHIR as well as figures for clarity of such processes. The results obtained from pressure transient analysis using SAPHIR and the discussion on how it monitors reservoir performance and well deliverability makes up Chapter 4. The conclusions made after analyzing the final results and future work recommended for further investigations are stated in chapter 5.
Conclusion And Recommendation
Two dual string oil wells were tested and the resulting data run in a tool (Saphir) to obtain reservoir characteristics such as permeability, skin and formation capacity as well as reservoir