A bug in the temperature equation, which was causing the code to fail during simulation was found and corrected. A new solver, using the partial pivoting method, was developed that reduces numerical rounding error. Also, coordinates were changed from elliptical to rectilinear in order to agree with the coordinate systems of other program modules being developed. A fracturing module is being implemented that allows subcritical fracture nucleation and growth initiation when fluid pressure exceeds the magnitude of the least principal stress. System penneability and porosity correspondingly increase upon fracturing. Testing and calibration of the fracture module should be completed next month. Work continues on the stress solver. A smoothing technique has been ,implemented in order to reduce numerical noise. Excessively fine grid spacing is required for accurate simulation and improvement of the algoritlun to allow this is being investigated. The code is being reworked step by step to determine if errors in code construction are also contributing to numerical inaccuracy. The elastic module of the finite element stress solver is complete. The viscoelastic module is coded and is being tested for various boundary conditions and the addition of pore pressure. Preliminary comparison of the predictions of the finite element code with analytical solutions for simple and/or published results suggests that the second order finite element method being used is ideal for simulating basin stresses and deformation. The next step will involve stress analysis of the Piceance Basin and refinement of the code to reduce computing time. The combined chemistry and pressure solver is being tested for simulations of a hypothetical basin. The sediment input module for the three-dimensional simulator has been further refined to facilitate data input.