Gaining an understanding of the well to well interference during hydraulic fracturing and subsequently production interference is paramount in optimizing the costs associated with field development. Much work has been done in the industry to better understand the interference during hydraulic fracturing and production among adjacent wells. This paper presents an analysis that employed both a pressure interference analysis and chemical tracer analysis to gain a better understanding of the fracture interference in a well pad in the Jafurah field. The subject pad consists of 4 wells. Two of which run parallel in a north direction and the other two run parallel in the southern direction. All four wells were hydraulically fractured with slickwater design. Adjacent to the subject pad is another pad that had been previously stimulated with crosslink design and was used for pressure monitoring. The distance between the laterals was relatively similar (X ft) with one exception (2 × ft). Initially, one well from both directions was stimulated with 33 stages each of slickwater design and the plugs were subsequently milled out. Afterwards, the other two wells were stimulated with 33 stages of slickwater each. In 7 of the 33 stages of the later wells, 20 oil and 20 water tracers were injected in sequence in an attempt to study the physical extent of the fractures generated. While the latter two wells were being stimulated, the wellhead pressure on the parallel wells was being monitored and recorded along with the wellhead pressures on the adjacent pad. During flowback, the southern wells were flowed back simultaneously and flowback samples were collected to be analyzed for tracers. Subsequently, the northern wells were opened up to flowback in the same manner and flowback samples were also collected for tracer analysis. Wellhead pressure was monitored on the adjacent pad during flowback of all the wells. The pressure data during the fracturing operation indicated for distance × ft and the size of stimulation stages pumped, a level of communication which was further verified by the production interference analysis as well as the tracer data.

The Edwards Limestone in South Texas often requires stimulation to be commercially productive. The relatively low permeability, high Young's Modulus, presence of natural fractures, minimal stress barriers to control height growth, and formation temperatures up to 375°F provide a challenging environment for a successful stimulation. Conventional stimulation approaches using acid fracturing and proppant fracturing techniques often have resulted in less than optimal effective etched or propped fracture half lengths, respectively.Horizontal openhole completions have increased the potential reservoir contact to the wellbore, but are not effective without stimulation. Achieving the diversion along the horizontal wellbore that is required to effectively treat the entire interval proved difficult using conventional diversion techniques with particulate and chemical diversion. Furthermore, the difficulty in achieving sufficient fracture width limits the proppant concentration that can be pumped into the formation. Acid fracturing was a desirable stimulation technique, but because of the high reservoir temperature and associated high acid spending rate, it was difficult to achieve a long effective etched half length with acid fracturing.A unique approach was developed by combining a novel diversion technique with a new stimulation treatment. The diversion technique enables mechanical isolation of the openhole completion during the stimulation treatments. The mechanical diversion system also facilitates efficient pumping of multiple stimulation treatments, resulting in increased reservoir contact to the wellbore. The new stimulation treatment uses a unique lightweight (1.25 SG) proppant-like material that is pumped into the well as an inert substance. The product hydrolyzes only after the solid particles are in the reservoir for an amount of time at temperature. This enables the fracture etching process to occur during shut-in and flowback of the well thus solving the problem of creating long effective etched fracture half lengths with acid. The combination of these two techniques has enabled a much larger stimulated reservoir contact to the wellbore in the Edwards Limestone in South Texas, which leads to improved production.

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