Enhancing Well Performance and Economic Value via Better Well Completion Design—A Delaware Basin Case Study


 Operator H’s wells on University Lands acreage in the Delaware Basin were completed with a perforation cluster spacing of around 45 ft and a fracturing fluid volume of about 25 bbl/ft. However, other operators in this area used half or even smaller perforation cluster spacing and a few times more fluid. As a result, the estimated ultimate recovery (EUR) of non-Operator H wells is about 18% higher than that of Operator H’s wells in the Wolfcamp Formation, indicating that Operator H’s completion design can be greatly improved. Therefore, our objective in this work is to locate a better completion design for Operator H’s wells and increase the economic value of the operator and the landowner.
 An integrated fracturing→well performance→economics workflow is implemented to optimize the completion design for Operator H’s wells. First, a 3D geological and geomechanical model is built and calibrated with historic multiwell multistage completion and production data. A decline curve analysis (DCA) is also performed to double-check our history-matching (HM) model. Then, we use an unconventional fracturing model to simulate fracture propagation and proppant transport for multiple wells on the same pad under various completion designs. The resultant complex fracture network is converted into unstructured gridblocks for reservoir-performance simulation. Finally, economic analysis is incorporated to evaluate the net present value (NPV)and internal rate of return (IRR) to identify the optimal completion design.
 Numerical results show that with the same amount of fluid and proppant, halving perforation cluster spacing gives shorter and more nonuniform fractures. Doubling the fluid volume creates 40% more fracture area in our target area and activates more microfractures along the wellbore. Also, a smaller stage spacing significantly improves cluster efficiency and well production. For the Wolfcamp Formation in the Delaware Basin, tighter cluster spacing (10–20 ft) with higher fluid volume (75–90 bbl/ft) plus a smaller stage spacing (~120 ft) greatly improves fracturing efficiency and well performance. Our recommended optimal completion design would increase Operator H’s NPV10 by USD 226 million on its undeveloped Wolfcamp A Formation (WCA).
 With the latest modeling technologies, we model the complex fracture propagation and associated well performance and efficiently identify a better completion design with economic analysis. Compared to multiple field pilot tests needed, the integrated workflow in this work helps operators significantly reduce the time and financial cost to optimize completion design and can be easily adapted to other unconventional wells given their unique data set.