This paper was prepared for presentation at the 1999 SPE International Thermal Operations and Heavy Oil Symposium held in Bakersfield, California, 17–19 March 1999.

As conventional oil and gas are now in a scarcer condition than they have ever been, attentions have shifted into unconventional resources. These unconventional resources, although abundant in nature, cannot be produced by conventional means economically. Therefore, efforts must be done to calculate reserves in such a fashion that uncertainties can be acknowledged, reducing errors and inaccuracies in the process. Researchers in the past have argued that uncertainties in reserve estimation cannot be measured by a single number and as the scale of reserve grows bigger, so will the uncertainties be. Two novel methods are developed from the basis of operation-based reserves' calculation, where development strategies namely hydraulic fracturing plans will be a deciding factor in determining reserves. These two methods are adapted from Monte Carlo-based approach, in which the first method will be using random numbers that are generated for listed properties to calculate ranged probability of reserves. The second approach is based on simple well-testing procedures that can also be referred to fracture design. The procedures are then compared to define practicality and situational capability of each method prepared. The models presented are dynamically flexible, due to the fact that they are integrated into development scenarios of the reserves.

No abstract

One of the challenges in producing a well is formation damage. Stimulation treatment is known can improve production by removing the formation damage. Matrix acidizing is the most known and proven effective for stimulation treatment. Three matrix acidizing models for sandstone are commonly used, i.e., Dowell, McLeod, and Kalfayan. Matrix acidizing study is conducted in geothermal sandstone formation well with quartz and silica dominated. Five acid fluid models will be injected to compare and evaluate the result of skin factor and productivity index during acidizing. Five types of acid will be used 12% HCl - 3% HF (Dowell model), 6% HCl – 1.5% HF (McLeod model), 10% HCl – 5% HF (Kalfayan model), 5% HF main acid, and using 9% HF main acid. This study uses well performance calculation and analysis to determine whether this well is a good candidate for acidizing. This study presents the sensitivity of the acid fluid model, volume and concentration injected to determine the optimum result of matrix acidizing design in this well. The result consists of the skin factor value after acidizing and the productivity index ratio before acidizing and after acidizing (FOI).